Fruits & vegetables Technology

FRUITS AND VEGETABLES TECHNOLOGY NotesPreparedBy: - Mohit Jindal Page 1 of 101
FRUITS AND VEGETABLES TECHNOLOGY
1. Introduction (03 hrs)
Status and scope of fruits and vegetables industry in India, classification, composition and nutritive value of
fruits and vegetables
2. Preparatory Operations and Related Equipments (05 hrs)
Cleaning, sorting, grading, peeling and blanching methods
3. a) Ingredients and processes for the manufacture of: (08 hrs)
i) jam, jellies, marmalade, preserves, (ii) pickles and chutneys
b) Defects and factors affecting the quality of above
4. Tomato Products (04 hrs)
Ingredients and their role, process for the manufacture of tomato ketchup, sauce, puree and paste.
5. Juices (04 hrs)
Raw materials, extraction, classification, processing and aseptic packaging
6. Thermal Processing of Fruits and Vegetables (08 hrs)
History, definition, various techniques of thermal processing and their effects on the quality of fruits
and vegetable products, types of containers and their selection, spoilage of canned foods
7. a) Dehydration of fruits; equipment and process for dehydration of plums, apricot, apple, fig,
grapes peach etc (04 hrs)
b) Dehydration of Vegetables: equipment and process for dehydration of peas, cauliflower,
potato, methi, mushroom, tomato etc
c) Osmo-dehydration – basic concept and applications
8. Freezing (04 hrs)
Freezing process of selected fruits and vegetables: peas, beans, cauliflower, apricot, mushroom –
changes during freezing and spoilage of frozen foods
9. Food Laws and FPO standards for fruits and vegetable products (04 hrs)
10. By-products utilization (04 hrs)
LIST OF PRACTICALS
1. Orientation to different processing equipments, their functions and uses
2. Preparation of Jam, jelly and preserve
3. Preparation of pickle by various methods

4. Preparation of chutney
5. Extraction of tomato juice by hot and cold break methods
6. Preparation of tomato sauce/ketchup
7. Preparation of tomato puree/paste
8. Extraction of juice by various methods
9. Bottling and processing of fruit juice
10. Preparation of syrup and brine solutions
11. Dehydration of peas, potatos
12. Dehydration of grapes and apples
13. Freezing of peas
14. Preparation of tomato powder
15. Visits to different fruit and vegetable processing industries
Status and scope of fruits and vegetables industry in India, classification, composition and nutritive
value of fruits and vegetables

India is the second-largest producer, next to China, of fruit and vegetables in the world, contributing
a total of 150 million tonnes of the produce to the global production annually. But only 2.2% of the fruit and
vegetable are processed here as compared to countries like USA (65%), Philippines (78%) and China (23%).
That’s why there is a huge opportunity for companies looking at investing in this sector in the country.
Although India is a very large producer of fruits, but yield levels of most of the fruits are relatively low as
compared to those in other major fruit producing countries. India is a front runner in many fruits and
vegetables with share in world production (Indian Horticulture Database 2013) as follows:
 44.1% of mango
 42.6% Papaya
 25.6% of banana
 20.2% of onion
 35.6% of cauliflower
About 25 to 30 per cent of the total production is lost due to spoilage at various post-harvest stages. In
value terms, the post harvest wastage and losses per year are estimated at over Rs. 3000 crores. Because of
these losses, the per capita availability of fruits is only of the order of 75 gm per person per day, which is
just half of the requirements of a balanced diet. This happens due to:
1. Lack of Transport
2. Lack of Storage facilities
3. Poor availability of package materials
4. Poor road conditions
5. Lack of local cold storage to store the surplus
43.0 45.2 45.9 50.9 55.4 59.6
65.6 68.5 71.5 74.9 76.4
88.6 84.8 88.3
101.2
111.4
115.0
128.4 129.1
133.7
146.6 156.3
0
50
100
150
200
250
VEGETABLES
FRUITS
(Production in Million Tonnes)
Trends in Fruits and Vegetables Production
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This results in the inadequate pricing of produce during off season and spoilage. This provides the
farmer to gain a higher price on his product, due to palatability of the product.
The major fruits grown are banana, mango, citrus, guava, grapes, apple and pineapple which
constituted nearly 80 per cent of the total fruit production in the country. Banana has the largest share of

31.7 per cent in total fruit production, followed by mango with 28 per cent. Production of mango has
remained almost stagnant during the decade 1983-93. The annual growth in production during 1983-93 was
9.6 per cent in the case of banana, 10.3 per cent for papaya, 9.4 per cent for grapes and 4.7 per cent in
respect of citrus fruits. The major fruit producing states are Andhra Pradesh, Maharashtra, Karnataka, Bihar,
Uttar Pradesh, Tamil Nadu, Kerala and Gujarat. These eight states contribute 78 per cent of the total fruit
production.
The Indian gourmet food market is currently valued at US$ 1.3 billion and is growing at of 20 per
cent. It is expected to cross US$ 2.8 billion by 2015 and is expected to reach US$ 78 billion by 2018. Share
of online food ordering would be in single digits of the overall food ordering business which in 2014 was
estimated to be around Rs 5,000-6,000 crore (US$ 800.19-960.12 million). We are growing at 20-30 per
cent month-on-month.
The total food production in India is likely to double in the next 10 years with the country’s domestic
food market estimated to reach US$ 258 billion by 2015.
Consumption pattern
Out of the total production of fruits and vegetables, nearly 76 per cent is consumed in fresh form,
while wastage is around 20 to 22 per cent. Only 2 per cent of vegetable production and 4 per cent of fruit
production are being processed.
Processing facilities
It is significant to note that the current installed capacity can process only 3 to 4 per cent of their total
production of fruits and vegetables in the country. There were around 4100 to 4200 processing units licensed
with an installed capacity of 12 lakhs tonnes. The actual production in 1993 was only 5.6 lakhs tones
implying a capacity utilization of less than 50per cent. Being seasonal in nature, the units operate for less
than 150 days in a year.
Exports
The government has initiated several policy measures for encouraging exports of processed fruits
and vegetables. As a result, exports of these products have increased from Rs. 122.5 crores in 1990/91 to Rs.
332.4 crores in 1993/94.
India’s share in word exports of fresh and processed fruits and vegetables was quite insignificant
being just 1 per cent. India’s major exports are in fruit pulp, pickles, chutneys, canned fruits and vegetables,
concentrated pulps and juices, dehydrated vegetables and frozen fruits and vegetables.
India has the potential to achieve a 3% share in the world trade of agricultural and food products by
2015. The vast production base offers India tremendous opportunities for export. During 2013-14, India
exported fruits and vegetables worth Rs. 8760.96 crores which comprised of fruits worth Rs. 3298.03 crores
and vegetables worth Rs. 5462.93 crores.
Demand
The demand for processed fruits and vegetables comes from both the domestic and export markets.
In the domestic market, a substantial share is contributed by defence, hotels and restaurants. Household
consumption accounts for less than 50 per cent of the production. India’s exported are constrained by several
factors such as poor quality, lack of standardization and unattractive packaging.

Government
It is evident that there is considerable scope for expansion of processing of fruits and vegetables. Indian
government is striving hard to build a strong fruit and vegetable processing industry to sustain its market
share in the global market. Indian Government to promote food-processing industry and also its sub-sector
like fruit and vegetable processing industry in India. Indian government has considered for investing US $
22.97 million in establishing around 10 mega food parks and offered the tax benefits to the concerned sub-
sector of the food processing industry. The present fruits and vegetables processing scenario compared to the
developed countries is not satisfactory. The factors responsible for this are many and complex in nature.
 The basic problem associated with the industry is the sustained availability of suitable raw material
for processing. Moreover, the productivity is also very low as compared to many other countries. The
cost of raw material used for processing is 3 to 4 times more as compared to costs in the world
market.
 With the increasing competition from the international trade, quality of imported products will
become more available in the developing countries. Therefore, to compete, the developing countries
require proper post harvest management, distribution and processing chains. Hence, it is necessary to
have better human resource capabilities in technology, management and marketing.
 Policies like participation of private sectors through contract farming and land leasing arrangement
can assure supply of good quality raw material to the fruit and vegetable processing industry.
 Clustering of small and medium units can reduce cost of production.
 It is very vital to educate consumer about the processed fruit and vegetable based products and their
nutritional quality.
 It is imperative to have better linkages between fruit and vegetable processing industry, Government
and other institutions.
 Should have control over taxation with other nations during export and import of the processed fruit
and vegetable products.
 It is necessary to integrate food laws, which is expected to meet the requirements in the International
trade and make the Indian food industry competitive in the global market.
Scope
There is tremendous production of fruits and vegetables in a shorter period. Availability of cheap labour,
Government Subsidy for cold storage and processing units, convenience of roads in case for marketing and
transport. Availability of cans, bottles, and other equipments at cheap rate, there is tremendous for export of
processed products like Jam, jelly, marmalade, pickles, etc. dehydrated and dried vegetables in addition to
domestic demand in India. Five-year tax holiday for new food processing units in fruits and vegetables
processing along with other benefits in the budget has bolstered the government’s resolution of encouraging
growth in this sector.
A vegetable is an herbaceous plant cultivated for an edible part, such as the root of the beet, the leaf
of spinach, or the flower buds of broccoli or cauliflower. The botanical term vegetable refers to any plant,
edible or not, including trees, bushes, vines and vascular plants, and distinguishes plant material from
animal material and from inorganic matter.

There are two slightly different botanical definitions for the term vegetable as it relates to food.
According to one, a vegetable is a plant cultivated for its edible part(s); according to the other, a vegetable is
the edible part(s) of a plant, such as the stems and stalk (celery), root (carrot), tuber (potato), bulb
(onion), leaves (spinach, lettuce), flower (globe artichoke), fruit (apple, cucumber, pumpkin, strawberries,
tomato) or seeds (beans, peas).
Edible plant parts including stems and stalks, roots, tubers, bulbs, leaves, flowers and fruits; usually
includes seaweed and sweet corn; may or may not include pulses or mushrooms; generally consumed raw
or cooked with a main dish, in a mixed dish, as an appetizer or in a salad There are many numbers of
Vegetables. Different parts are used for consumption. They are botanically different and their climatic and
cultural requirements are different.
There are four Main Methods of Classification Based on:
1. Education Botanical relation
2. Based on Hardiness (Tolerance to low temp)
3. Parts Used for consumption
4. Methods of Culture
1. Botanical Classification:
This method of classification is based on botanical relationships. Classification based on the
plants botany is the favored method for plant botanists, taxonomists and breeders. It gives information on
class, family, genus, species, variety etc. Some plants do however have similar cultural requirements the
most notable of these is the Solanaceae and Cucurbitaceae families. This is useful to crop improvement and
seed producer for deciding isolation distance. Solanaceous family includes potato, chili. There are same
cultural requirements. At the same time cucurbitaceous have similar cultural requirements and common
pests and diseases. Botanical name avoids infusion in name as common names are different but scientific
names are common all over would.
2. Classification Basedon Hardiness:
Vegetables are grouped as hardy or tender on the basis of tolerance to frost, tolerance to lower temperature.
This gives information of season of growing i.e. summer or winter. Not useful to grower, since soil and
climatic requirements are
Hardy
Semi Hardy Tender
Asparagus Beet Root Okra
Cabbage Carrot Brinjal
Garlic Cauliflower Tomato / Chili
Onion Palak Beans
Peas Potato Cucurbit
Radish Sweet Potato
Spinach Sweet Potato
Spinach Amaranthus
Turmp
3) Basedon Parts Usedfor Consumption:
From roots to fruits different parts of vegetables are consumed. On that basis vegetables are classified.
Leafy Vegetable Palak, Amaranthus Methi (leaves)

Root Carrot, Radish, Turnip', beet root
Fruit Tomato, Biinjal; Cucurbit,
cucumber, olives
Bulb Onion, Garlic
Tuber Potato, Sweet Potato
Podded Green bean, Moth Bean, Mung
Bean,
Steam Asparagus, Cardoon,
Celery(Ajvayan), Fennel(Sonf)
Flower cauliflower, Broccoli
Leaf Vegetables Also known by the name, ‘potherbs’, leafy vegetables are plant leaves that are eaten as a
vegetable. Leafy vegetables have high nutritional value though it is the presence of Vitamin K.
Fruit vegetables are so called because botanically they fulfill the definition of fruits, but are used as
vegetables by human beings. They are considered to be fruits because in the scientific sense of the term,
fruits are those that carry the seeds of the plant. Legally, the confusion between whether these vegetables
should be called fruits or vegetables was solved in the United States by the Supreme Court in the year 1883
where tomato was declared as a vegetable.
Bulb vegetables are those varieties of vegetables that are not eaten directly on their own, rather, they are
used in food dishes to enhance the flavor of the food. Most of the bulb vegetables are structured in the shape
of a bulb, wherein all its nutrients are stored. The best known bulb vegetables are onion, chive, spring onion
and garlic. These bulb vegetables are said to be medicinal, especially onion and garlic.
Podded vegetables, popularly known as legumes, are seeds that are found inside two-sided pods. Podded
vegetables are a rich source of proteins which help in providing the energy and strength required to carry out
daily activities. They also contain potassium, folic acid, complex carbohydrates, magnesium, iron, fibre and
zinc
Root vegetables are those that are grown under the soil and possess nutrients that they gain from the soil.
They are actually, storage organs that are enlarged to store energy in the form of carbohydrates.
Stem vegetables are those that have shoots or stalks which can be consumed. Some of the most popular
stem vegetables include asparagus, celery, fennel, etc. These vegetables can be used to make a variety of
dishes and are usually served with pasta, sandwiches, soups, etc.
Flowering vegetables are so called because they have the shape of flowers. They are usually small in size
and appear like many flower buds clustered together.
Tubers grows underground, it is a type of specialized stem tissue that stores nutrients for the plant. A potato
is actually an enlarged stem. Root crops derive from root tissue. Carrots are an enlarged tap root. Tubers
differ from root crops in three ways. Tubers are enlarged stems rather than enlarged roots. Cut up a tuber,
and each section will grow a plant; root crops cannot do this. Tubers contain more starch than root crops.
4) Basedon Method of Culture:
In this method all those crops having similar cultural requirements are grouped together. They" are
botanically different. System has practical utility for vegetable grower. In this method one can generalise

cultivation practices for one group and thus avoid repetition individually for all crops. There are 11 classes.
In some cases they are botanically also similar Ex. cucurbits. On excises for convenience they are grouped
as under.
I. Perennial Vegetable Asparagus, cocinia (Tondali), Parwal, Drumstick
2 Greens Spinach
3 Salad Crops Lettuce, celery
4 Cole Crops Cabbage, Cauliflower
5 Bulb Crops Onion, Garlic
6 Root Crops Carrot / radish, turnip
7 Tuber a) Potato, b) Sweet Potato
8. Peas & Beans Cluster bean, cowpea, Dolichas
9 Solanaceous Tomato, Brinjal, Chili,
10 Cucurbits Watermelon, pumpkin, gourds, Cucumber etc.
11 Okra Okra
Composition and nutritive value of vegetables
Vegetables have a low energy value. They generally provide between 10 Kcal and 50 Kcal per 1 g;
to obtain about 1000 Kcal, it would be necessary to eat about kg. Their nutritional advantage is that they
offer a high concentration of micronutrients for low contents of calories and fat. All vegetables have a high
water content, which ranges from 9% in potato to 96% in cucumber. They vary in chemical composition
even within one variety, depending on the species, conditions of growth, and method of cooking.
Vegetables are generally rich in carbohydrates but not in proteins and lipids. Vegetables are
composed chiefly of carbohydrates, mainly simple sugars and complex carbohydrates (starch and dietary
fiber). The content ranges from 1-2% in the leaf and stem vegetables to 27% in sweet potato. Root
vegetables have the highest carbohydrate content. Dietary fiber content ranges from 0.8% in cucumber to
8.0% in artichoke.

Most vegetables contain substantial amounts of minerals, particularly calcium, iron, and potassium. All
vegetables contain small amounts of the B-complex vitamins, but their nutritive value is mainly derived
from the supply of ß-carotene, vitamin C, and folic acid. Although most vegetables contribute to the
formation of vitamin A, their ß-carotene content varies and is generally linked to color. All vegetables
contain substantial amounts of vitamin C, but the quantity varies and much of it is lost during cooking and
preparation. The exact nutrient content of fresh vegetables off the shelf cannot be determined because of a
high degree of variation. Sources of variation include genetic potential, crop growth and cultural conditions,
maturity at harvest, postharvest handling and storage conditions, and type as well as degree of processing.
Fruit
Broadly, the botanical term fruit refers to that a fruit is
defined as the developed ovary of a seed plant with its contents
and accessory parts, as the pea pod, nut, tomato, or pineapple. It
is the edible part of a plant developed from a flower, with any
accessory tissues, as the peach, mulberry, or banana.
But As related to food, the botanical term fruit refers to
the edible part of a plant that consists of the seeds and
surrounding tissues. This includes fleshy fruits (such as blue-
berries, cantaloupe, poach, pumpkin, tomato) and dry fruits,
where the ripened ovary wall becomes papery, leathery, or woody as with cereal grains, pulses (mature
beans and peas) and nuts.
As the ovary develops into a fruit, its wall often thickens and becomes differentiated into three, more
or less, distinct layers. The three layers together form the pericarp, which surrounds the developing seed or
seeds.
The three fruit layers are:
 Exocarp—the outermost layer often consisting of only the epidermis
 Mesocarp—or middle layer, which varies in thickness
 Endocarp—which shows considerable variation from one species to another, is the inner-most layer
of the fruit

FRUITS AND VEGETABLES TECHNOLOGY NotesPreparedBy: - Mohit Jindal Page 10 of
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Fruit Classification
All fruits may be classified into three major groups on the basis of the number of ovaries and the number of
flowers involved in their formation. The following outline includes most of the common types of fruits.
A. Simple Fruits—simple fruits develop from a single matured ovary in a single flower. Accessory
fruits have some other flower part united with the ovary. There are two basic kinds of simple fruits:
fleshy fruits and dry fruits.
1. Fleshy Fruits—defined as having a fleshy pericarp at maturity. There are five basic kinds of fleshy
fruits.
 Berry—consisting of one or more carpels with one or
more seeds, the
ovary wall is
fleshy.
Examples of
berries include:
grape, tomato
 Pepo—an accessory fruit is defined as a berry with a hard rind, the receptacle partially or completely
encloses the ovary. Examples include: Watermelon, honeydew melon, cucumber, Pumpkin
 Hesperidium—a specialized berry with a leathery rind. Examples include: Orange, lemon, grapefruit
 Drupe—sometimes called a “stone” fruit. It is derived from a single carpel and usually containing
one seed (pit). The exocarp of a drupe consists of a very thin skin. Examples of the drupe include:
Peach, Apricot, Plum, Coconut (fibrous walls instead of fleshy walls), Cherry

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 Pome—(an accessory fruit) is derived from several carpels, receptacle and outer portions of the
flower. The pericarp is fleshy with an inner portion of the pericarp papery or cartilaginous forming a
core where the seeds are located. Examples of a pome are: apple, pear
2. Dry Fruits—are defined as having a dry pericarp upon maturity. The Dry Fruits are classified into
two groups: the dehiscent fruits and the indehiscent fruits.
(a) Dehiscent Fruits—these fruits will split open when mature. The splitting process is
known as “dehisce”…hence the name for this group of fruits. There are four basic types
of dry dehiscent fruits:
 Follicles—composed of one carpel and splitting along one suture line. Examples of follicle
fruits are: Columbine, Milkweeds
 Legumes—composed of a single carpel and splitting along two suture lines. Examples of
legumes are: Peas, Peanuts
 Capsule—composed of several carpels. Examples of the capsule type fruits: Lily, Sweet Gum
 Silique—composed of two carpels. Examples of the silique fruit: Members of the Mustard
Family

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(b) Dry Indehiscent Fruits—are defined as fruits that do not split open at maturity. There are
several categories of dry indehiscent fruits.
 Achene (or sometimes called an akene)— Examples of achenes are: Dandelion parachutes,
Sunflowers
 Caryopsis or Grain—is defined as a one-seeded fruit in which the seed is firmly attached to
the fruit at all possible points. Examples of grain include: Corn, Rice, Wheat, All grasses
 Samara—We sometimes refer to this type of fruit as “helicopter” seeds. Examples include:
Elms, Maples, Ashes
 Schizocarp—Examples of schizocarp fruits are: apiaceaes
 Nut—a hard one-seeded fruit, generally formed from a compound ovary, with the pericarp
hard throughout. Examples of true nuts are: acorns, chestnuts, walnuts, pecans brazil nut
B. Aggregate Fruits—consist of a number of matured ovaries formed in a single flower and arranged
over the surface of a single receptacle. The individual ovaries of the aggregate fruit are known as
fruitlets. Each individual fruitlet will contain a stony pit…so in reality an aggregate fruit is
composed of many tiny drupes. Examples of aggregate fruits are:
1. Raspberries
2. mulberries
3. strawberries
C. Multiple Fruits—consist of the matured ovaries of several to many flowers more or less united into a
mass. Multiple fruits are almost invariably accessory fruits. Examples of multiple fruits are:
1. Pineapples
2. Jackfruit

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3. Breadfruit
Composition and nutritive value of fruit
The carbohydrates in fruit have a moderate energy value. Fruit contain protective vitamins and
minerals, and dietary fiber but very little protein. They are practically fat-free except for avocado and olive,
both of which contain up to 15% of fat. Fruit vary widely in their carbohydrate content (between 1.5% and
26 %).
Ripe fruit contain no starch; the main sugars are fructose and glucose which are often present in
equal proportions. Apple and pear contain more fructose, while apricot and peach also contain sucrose. Like
vegetables, fruit also contain dietary fiber. Various organic acids in unripe fruit produce the typical sour
taste. During ripening concentration of these acids falls and that of sugars rises.
Vitamin C is present in all fresh fruit, but strawberry, citrus fruit and particularly kiwifruit are
outstanding sources of this vitamin. For example, one kiwifruit or medium-size orange supplies the normal
daily requirement of adults. Apple and peach provide moderate amounts of vitamin C and can contribute
substantially to the diet when consumed in sufficient quantity.
Most fruit also supply varying amounts of ß-carotene and the B-complex vitamins. Yellow fruit, such
as cantaloupe and apricot, are good sources of vitamin A, whereas plum and dried fruit (those not treated
with sulphur dioxide) are the best sources of thiamin.
Fruit contribute appreciable amounts of iron and calcium. Calcium is found in small amounts in
citrus fruit; the whole fruit contains double the amount contained in an equal quantity of juice. Strawberry
and dried fig also contains calcium. As in the case of vegetables, careful preparation and storage are
essential to retain the maximum nutritive value of fruit. Some of the nutritive value is lost during cooking,
drying, and canning, but the losses are not as high as they were once supposed. Frozen fruit compare
favorably in vitamin content with fresh ones. Bruising and cutting of fruit, and exposing fruit and fruit juices
to air cause considerable loss of vitamin C.

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Preparatory Operations andRelatedEquipments-Cleaning, sorting, grading, peeling and
blanching methods
The preliminary preparative operations in food processing include cleaning, sorting and grading of
food raw material. These may be considered as separation operation. Cleaning involves the separation of
contaminants from the desired raw materials. Sorting involves the separation of the raw materials
into different categories based on their physical characteristics such as size, shape and colour.
Grading involves the separation of the raw materials into categories based on the differences in their
overall quality.
CLEANING OF FOOD RAW MATERIALS
Cleaning is an essential preliminary operation in any food industry. The ultimate quality of the finished
product, storage stability, organoleptic properties, safety from health hazards, and consumer acceptance
depend on cleaning process. The methods adopted depend on the type of raw material, type and extent of
contamination, the degree of cleaning to be achieved and the type of finished product. Different food raw
materials are associated with different types of contaminants. These include
 Mineral contaminants- soil, sand, stone metallic particles, grease and oil.
 plant part- stalks, pits, husks and rope,
 Animal parts and contaminants—excreta, hair, insects eggs and body part
 Chemical contamination- sprayed residues of pesticides, insecticides and fertilizers
 Microbial contaminants—microorganisms and their metabolites.
The two main objectives of cleaning food raw materials are
1. Removal of contaminants which constitute a health hazard or which are aesthetically unacceptable
2. Control of microbiological loads and biochemical reactions which impair subsequent process
effectiveness and product quality.
The chosen cleaning process must satisfy the following requirements in order to achieve the aforesaid
objective:-
1. The separation efficiency of the process must be high and consistent and should produce minimum
wastage of good material
2. Damage of cleaned raw material must be avoided.
3. Recontamination of the cleaned food should be avoided by complete removal of the contaminants.
4. The design of the process equipment should be such that recontamination of the cleaned food due to
flying dust or wash water is prevented.
5. The cleaning process must leave the cleaned surface in acceptable condition,
6. The volume and concentration of liquid effluents must be kept be minimum and the effluents should
be disposed off effectively Complete cleaning of a raw material is not possible and in practice, a
balanced approach, considering the economic aspects of cleaning and the need to produce good
quality food, is usually adopted,
Cleaning Methods
The cleaning methods can be classified into two groups, namely

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 Dry cleaning methods which include screening, brushing, aspiration, abrasion and magnetic
separation
 Wet cleaning methods which include soaking, spraying, flotation, ultrasonic cleaning, filtration and
settling.
Dry cleaning methods
These methods are relatively cheap and convenient as the cleaned surface is dry However, a major drawback
is the spread of dust.
Screening-Screens are primarily size separators or sorting machines but may be used as cleaning
equipment for removing contaminants of different size from that of the raw material. These machines are
useful in cleaning fine materials such as flour and ground
spices but must be frequently cleaned to remove oversized
contaminants which may otherwise get pulverized due to
abrasion and spread contamination of the raw material.
Abrasion cleaning- Abrasion between food
particles or between the food and moving parts of cleaning
machinery is used to loosen and remove adhering
contaminants. Tumblers, vibrators, abrasive discs and
rotating brushes are used for this purpose.
Aspiration cleaning- Aspiration (or
winnowing) is based on the differences in the
aerodynamic properties of materials. The raw
material to be cleaned is fed into a stream of air
flowing at controlled velocity to separate the raw
materials into two or more streams (e.g. light and
heavy streams). The cleaned products are usually
discharged as the middle stream leaving the heavy
debris (stones, pieces of metal or wood) behind
while floating off the light debris such as stalks,
husks and hairs. This method is used in cleaning
cereals, nuts, beans, onions, melon, eggs and other
foods which are not amenable to wetting.
The method cannot be used with
oxidation-sensitive materials.
Magnetic cleaning- This type of
cleaning involves where the food
contaminated with high amount of
metallic material. Magnetic separators
used for this type of cleaning include

101
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rotating or stationary magnetic drums, magnetized belts, magnets located over belts carrying the food or
staggered magnetized grids through which the food is passed.
Miscellaneous dry cleaning methods- Such cleaning methods include:
1. Electrostatic cleaning
2. radio isotope separation
3. X-ray separation.
Electrostatic cleaning- Electrostatic cleaning can be used in a limited number of cases where the
surface charge on raw materials differs from contaminating particles. The principle can be used to
distinguish grains from other seeds of similar geometry but differences in electrostatic charging of materials
under controlled humidity conditions, charged particles being removed by oppositely charged or earthed
rollers, grids, etc. and it has also been described for cleaning tea. The feed is conveyed on a charged belt and
charged particles are attracted to an oppositely charged electrode according to their surface charge.
Radio isotope separation- Clods of earths and stones may be separated from the potatoes.
X-ray separation- Stones, gloss and metal fragments in foods such as confectionery can be
separated by this method.
Wet cleaning methods-
Wet cleaning has the advantage of removing firmly adherent soils and owing the use of detergents
and sanitizers. However, wet methods have a number of disadvantages such as the use of large amounts of
high quality water and generation of large volume of effluent (about 15,000 liters per ton of canned food).
Wet cleaning methods include soaking, spray washing, flotation washing and ultrasonic cleaning methods.
Soaking- This is the simplest method and is often used as preliminary stage in the cleaning of heavily
contaminated root vegetables and other foods. Soaking softens adhering soil and also facilitates the removal
of sand, stone, and ether abrasive material. The use of warm water and detergents increase the efficiency but the
use of chemicals may affect the texture of the food, e.g, sodium hexametaphosphate softens peas while some metal ions
toughen peas and peaches destined for canning, Chlorination is used to decrease bacterial load of water in the soak
tank.

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Spray washing. This is the most widely used method for wet cleaning of fruits and vegetables.
The surface of the food is subjected to water sprays, The efficiency of spray washing depends on
several parameters such as water pressure, volume of water, temperature, the distance of the food from
jets, the time of spraying and number of spray jets used. A small volume of water at high pressure is the
most effective combination. High pressure sprays may be used to cut out parts of peaches and tomatoes
and to remove adherent soil and black moulds on citrus fruits. It may damage ripe fruits and vegetables
such as straw berries and tomatoes and delicate vegetables such as asparagus.
The washer is equipped with a central spray rod which is fitted with jets for spraying water.
A rubber disc cleaner requires less amount of water for cleaning. It uses soft rubber discs
spinning axially at about 500 rpm. The soil is collected into the base of the channel. The disc cleaner
uses only about 20 liters of water per ton of fruit while other washers use 1500-5000 litres.
Flotation washing- The method depends on the differences in buoyancy of the desired and
undesired parts of the food raw material to be cleaned. For example, bruised or rotten apples sink in
water and can be removed at the base of tank and the good fruit can be collected as overflow. The
flotation washer effectively removes stones, dirt and plant debris from peas, beans, dried fruits and
similar materials. Water requirement is about 4,000-10,000 liters per ton of raw material to be
cleaned.
Froth flotation has been used to separate peas from weed seeds by immersing the peas in dilute
mineral oil-detergent emulsion through which air is blown, the contaminants float on foam and are
removed. The cleaned peas are given a final wash to remove the emulsion.

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Dewatering- Wet cleaning results in a cleaned product that may have some excess water adhering
to it. Dewatering may be effected by passing the food over vibratory screens or specially designed
rotary screens. In the case of cleaned peas for freezing, or washed wheat for milling, centrifuges may
be used. Occasionally it may be necessary to resort to drying procedures, as in the case of cereals or
fruits, which arc to be stored or sold as fresh.
SORTING OF FOODS
Sorting and grading are terms which are frequently used interchangeably in the food
processing industry, but strictly speaking they are distinct operations.
Sorting is a separation based cm a single measurable property of raw material units,
while grading is the assessment of the overall quality of a food using a number of attributes".
Sorting may be regarded as a separation operation based on the differences in physical properties of
the food raw materials or products such as colour, size, shape or weights of the food raw material.
Sorting is an important operation in controlling the effectiveness of many processes in food
industry. For example, sorted vegetables and fruits are better suited for mechanized operations of
peeling, pitting and coring or blanching. Similarly, food materials of uniform size or shape are better
suited for efficient heat transfer during sterilization, pasteurization, dehydration or freezing.
Sorting and grading can both damage the food raw material or product because of improper
handling by human operators (operator damage), dumping (dumping damage) or dropping of material
(drop damage). Such damages can be eliminated or minimized by choosing effective food process.
Sorting Methods
Sorting methods include weight sorting, shape sorting, size sorting and photometric or colour sorting.
Weight sorting- Weight is usually the most precise method of sorting. The weight of a food
unit is proportional to the cube of its characteristic dimension and hence weight sorting is more
precise compared to dimensional sorting. Meat cuts, fish fillets, fruits such as apples, pears and citrus
fruits, vegetables such as potatoes, carrots and onions and eggs are sorted by weight using spring-
loaded, strain gauge, or electronic weighing devices incorporated into conveying systems.. An
alternative system is to use the "catapult' principle where units are thrown into different collecting
section, depending on their weight. A disadvantage of weight sorting is the relatively long time
required per unit and other methods are more appropriate with smaller items such as legumes or
cereals, or if faster throughput is required.
.

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Size sorting- Different types of screens are used for size separation of foods, The screen
designs commonly used in food industry may be grouped into two types: (i) variable aperture screens
using cable, belt, roller or screw sorters and (ii) fixed aperture screens using stationary, vibratory,
rotary, gyratory or reciprocating screens. Fixed
aperture screens of flat-bed type are used in
preliminary sorting of potatoes, carrots and
turnips. Multi-deck screens are used in size
sorting of cereals, nuts and also partly
processed and finished foods such as flour,
sugar, salt, ground spices and herbs. Drum
screens are used for sorting peas, beans and
other similar foods capable of withstanding
tumbling action in a rotating drum screen.
Variable aperture screens with continuously
variable apertures of roller, belt or screw type find use in size sorting of fruits and vegetables.

101
Shape sorting- Shape sorting is adopted when food raw materials contain undesirable material even
after size or weight sorting and cleaning. For example, cleaned and size or weight sorted wheat may
still contain weed seeds of similar size and weight compared to wheat. Shape sorting on the basis of a
combination of length and diameter is useful under such circumstances. A disc sorter is used for
shape sorting wheat, rice, oats and barley. The principle is that disks or cylinders with accurately
shaped indentations will pick up seeds of the correct shape when rotated through the stock, while
other shapes will remain in the feed.
Photometric/Color sorting- Photometric sorting uses optical properties of foods to effect
separation of desired material from contaminants. The goal is the separation of items that are
discolored, toxic, not as ripe as required, or still with hull. The color separator separates the fruits,
vegetables or grains due to difference in color or brightness. The color separators are generally used
for larger crop seeds like peas and beans. These seeds differ in color because of varietal differences
and also due to immaturity or disease. Color sorters are also used for color sorting harvested
foodstuffs, such as coffee, nuts, rice, and other cereals such as wheat or rye and pulses.
Two photocells are fixed at a particular angle, which direct both beams to one point of the
parabolic trajectory of the grains. A needle is placed on the other side, which is connected to a high
voltage source. When a beam falls on a dark object through photoelectric cells, current is generated
on the needle. The needle end receives a charge and imparts it to the dark seeds. The grains are then
passed between two electrodes with a high potential difference between them. The seed is compared
with a selected background or color range, and is separated into two fractions according to difference
in color. Since this machine views each produce individually, the capacity is low.
Reflectance properties are used to indicate:
1. Raw material maturity (e.g. color of fruit, vegetables and meat indicates ripeness and
freshness characterize ;)
2. the presence of surface defects (e.g. worm holed cereals or nuts and bruised fruits)

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3. The extent of heat processing (e.g. in manufacture of bread and potato chips or crisps).
Other sorting methods- Sorting on the basis of surface roughness or stickiness may be used for
separating seeds. In Surface Texture/Roughness Separator the mixture to be separated is fed over the centre
of an inclined draper belt moving in upward direction. The round and smooth grains roll or slide down the
draper at faster rate than the upward motion of the belt, and these are discharged in a hopper. The flat shape
or rough surfaced particles are carried to the top of the inclined draper and dropped off into another hopper.
GRADING OF FOODS
Grading is quality separation on the basis of an overall assessment of those properties, which affect the
acceptance of the food raw material for processing, and finished food product for consumer acceptance and
safety. The grading factors which determine the quality of the food include:
1. Process suitability
2. consumer safety
3. Consumer acceptance.
The grading parameters commonly used in food industry include the following:
 size and shape as functional and acceptability factors,
 maturity to describe the freshness of eggs, ripeness of fruits and aging of meat,
 texture to grade the crumb structure in bread and cakes, crispness in apples and viscosity of
creams
 flavour and aroma as indicators of ripeness of fruits as well as effectiveness of processing
conditions,
 colour as indicator for consumer acceptability and effectiveness of process,

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 Blemishes such as cloudy yolk, blood spot and shell cracks in eggs, bruises in fruits and insect
holes in coffee beans and cereals to indicate their defect and impurity.
Contaminants and undesired parts such as rodent hair and insect parts in flour, soil and spray residues on
fruits and vegetables, microorganisms and their metabolites on meat, toxic metals in shell fish, hone
fragments in meat products, pod residues in peas and beans and stalks and stones in fruits all these are the
adverse qualities of the raw food materials.
Grading Methods
Grading methods may be classified into two types:
 Quality control procedures in which the quality of the food is determined by laboratory tests on
samples drawn statistically from a batch of food.
 Procedures in which the total quantity of food is subjected to physical separation in quality
categories. This grading may be carried out manually or by specialized machines.
For proper grading, the food unit must be presented singly before the human grader or machine for
assessment. These devices may be roller or vibratory tables or rotating wheels equipped peripherally with
pneumatic devices which pick up food pieces, rotate them for viewing and then release them at a given
signal.
Manual grading is done by trained operators who are able to assess a number of grading parameters
simultaneously. For example, eggs are graded manually by candling.
. Machine grading is only feasible where quality of a food is linked to a single physical property, and
hence a sorting operation leads to different grades of material. But can be carried out by combining a group
of sorting operations so as to separate the food units on quill it basis. Thus wheat of a particular variety may
be graded by a combination of cleaning and sorting operations. Sometimes a single property may be helpful
in grading the food. Thus peas of small size are recognized to be most tender and of highest quality so that
size sorting of cleaned peas results in quality grading. Peas may also be graded on the basis of their density
using flotation in brines of varying densities. Similarly, potatoes or high density, desirable for manufacturing
French fries, potato crisps and dehydrated mashed potato, may be graded using Rotation in brines.
Mechanical grading is cost effective and efficient.
Peeling
Peeling is used in the processing of many fruits and vegetables to remove unwanted or inedible material, and
to improve the appearance of the final product. The main consideration is to minimise costs by removing as
little of the underlying food as possible and reducing energy, labour and material costs to a minimum. The
peeled surface should be clean and undamaged. There are five main methods of peeling:
1. flash steam peeling
2. knife peeling
3. abrasion peeling
4. caustic peeling
5. flame peeling.
Flash steam peeling

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Foods (for example root crops) are fed in batches into a pressure vessel which is rotated at 4–6 rpm.
High-pressure steam is introduced and all food surfaces are exposed to the steam by the rotation of the
vessel for a predetermined time, which differs according to the type of food. The high temperatures cause
rapid heating of the surface layer (within 15–30 s) but the low thermal conductivity of the product prevents
further heat penetration, and the product is not cooked. Texture and colour are therefore preserved. The
pressure is then instantly released which causes steam to form under the skin, and the surface of the food
‘flashes off’. Most of the peeled material is discharged with the steam, and water sprays are needed only to
remove any remaining traces. This type of peeler is gaining in popularity owing to the lower water
consumption, minimum product loss, good appearance of the peeled surfaces, a high throughput (up to 4500
kg h_1) with automatic control of the peeling cycle, and the production of a more easily disposable
concentrated waste.
Knife peeling
Stationary blades are pressed against the surface of rotating fruits or vegetables to remove the skin.
Alternatively the blades may rotate against stationary foods. This method is particularly suitable for citrus
fruits where the skin is easily removed and there is little damage or loss of fruit.
Abrasion peeling
Food is fed onto carborundum rollers or placed into a rotating bowl which is lined with
carborundum. The abrasive surface removes the skin and it is washed away by a copious supply of water.
The advantages of the method include low energy costs as the process operates at room temperature, low
capital costs, no heat damage and a good surface appearance of the food. Irregular product surfaces (for
example ‘eyes’ on potatoes) may mar the appearance of the peeled product and require hand finishing. The
limitations of the method are:
• a higher product loss than flash peeling (25% compared with 8–18% losses, for vegetables)
• the production of large volumes of dilute waste which are difficult and expensive to dispose of
• relatively low throughputs as all pieces of food need to contact the abrasive surfaces.
An exception is the peeling of onions where the skin is easily removed by abrasive rollers at production rates
of up to 2500 kg h_1.

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Caustic peeling
A dilute solution of sodium hydroxide (named lye) is heated to 100–120ºC. In the older method of
lye peeling, food is passed through a bath of 1–2% lye which softens the skin and the skin is then removed
by high-pressure water sprays. Product losses are of the order of 17%. Although once popular for root crops,
this method causes changes in the colour of some products and incurs higher costs. It is now largely replaced
by steam or flash peeling. A development of lye peeling is named dry caustic peeling. Food is dipped in
10% sodium hydroxide and the softened skin is removed with rubber discs or rollers. This both reduces
water consumption and product losses and gives a concentrated skin ‘paste’ which is more easily disposed
of.
Flame peeling
Developed for onions, this peeler consists of a conveyor belt which carries and rotates the food through a
furnace heated to 1000ºC. The outer ‘paper shell’ and root hairs are burned off, and the charred skin is
removed by high-pressure water sprays. Average product losses are 9%.
Blanching
Partial pre-treatment in which fruits or vegetables are heated in water or in steam to
inactivate enzyme before processing.
Blanching is done by immersing fruits and vegetables in hot water or by exposing to steam
followed by cooling.
Blanching is a partial pre-cooking treatment in which vegetables/ fruits are usually
heated in water or in live steam to inactivate the enzymes before processing.
Blanching is a unit operation applied to fruits and vegetables prior to canning, drying or
freezing. Blanching is a mild type of heat processing. It involves heating food to preset temperature
for preset time. It is usually done in water or steam at a temperature less than 100°C. Prepared fruits
and vegetables is kept in hot water or exposed to steam and then cool rapidly to ambient temperature.
Blanching is used to destroy microorganism and enzymatic activity in fruits and vegetables.
Blanching caused inactivation of enzymes in canning, freezing and dehydration, because freezing and
dehydration are insufficient to inactivate enzymes. Sometimes canning process may allow sufficient
time for enzymatic activity. And under blanching may increase the enzymatic activity.
There are four types of enzymes such as lipoxygenase, polyphenololase, polygalacturonase and
chlorophyllase, which causes loss of quality in fruits and vegetables, must be inactivated. Because at
lower temperature time the enzyme chlorophyllase remains active for little time and convert
chlorophyll to a phyllin, which retain green colour. The enzymes such as catalase and peroxidase are
heat resistant, which need appropriate time and temperature to inactivate them.
Blanching also reduces the number of microorganisms..
Purpose of blanching
• Reduces drying time

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• Removes intercellular air from the tissues
• Causes softening of texture
• Retards the development of objectionable odour and flavour during storage by enzyme inactivation
• Retain carotene and ascorbic acid during storage
• Removes pungency (onion)
• Impart desired translucent appearance to the product.
Different blanching methods:
Blanching can significantly reduce the nutrient content of foods. The extent of losses of nutrient is
dependent on the blanching method and the product.
1. Immersion
2. Steaming
Immersion
Immersion blanching refers to blanching by directly immersing the food particles in boiling
water. This treatment has number of advantages and disadvantages. In water blanching the loss of
water –soluble vitamins increases with contact time, and fat – soluble vitamins are relatively
unaffected and also risk of contamination and higher cost of water and disposal of effluent than
steam blanchers. Sometimes certain additives may be used in blanching water to complement
blanching. For instances, addition of citric acid (0.5%) to immersion bath decreases pH. Addition of
bisulfite (0.5%) prevents mushroom browning and yellowing of cauliflower. Blanching is quickly
followed by a cooling stage. This is done by cooling the product under cool water to bring down its
temperature. Rapid cooling avoids microbial growth on the exposed surfaces..
Steaming
Blanching by steaming has the advantage of minimizing the leaching out of soluble materials,
less volume of waste, easy to clean and sterilize. Steam Blanching results in greater retention of
water – soluble nutrients than water blanching. But it has some disadvantages i.e. higher capital
costs, uneven blanching, and low efficiency However, at the same operating temperature, steam
blanching takes 20-40% longer than immersion blanching because of poor thermal exchange.

101
(d) it has adverse environmental impacts, such as large water and energy use and problems of
effluent disposal.
Process Equipment
Rotary hot water and steam blanchers are common process equipment and are respectively. They are
available with variable speed drive.
The rotary hot water blancher receives the product through a valve just above the drive end.
The product is conducted into a spiral unit which conveys it to the opposite end.
In the case of the hooded live steam blancher which has a perforated wire belt, the blancher
serves as a conveyor making it very adoptable to the system. The steam blancher consists of a metal
frame with galvanized sheet metal forming the steam chamber. The unit is frequently equipped with
both water and steam sprays to increase its versatility as a scolder/blancher. The lower belt of the
hooded chamber is pitched to a separate drain outlet for removal of condensate.
A typical commercial steam blancher is approximately 20 ft. long, 4 ft. wide and 4 ft. high. A
typical water blancher would be around 6 ft. in height with an overall length of 21 ft. In general
Disadvantages of Blanching
The disadvantages of blanching are that
(a) it may change texture, color, and flavor because of the heating process,
(b) it increases the loss of soluble solids, especially in the case of water blanching,
(c) it may change the chemical and physical state of nutrients and vitamins,

101
steam blanching results in greater retention of water-soluble nutrients due to less leaching loss.
The advantages of steam blanchers are: smaller loss of water soluble components, smaller
volume of waste, lower disposal charges and easy to clean and sterilize.
The disadvantages associated with a steam blanchers are: limited cleaning of food, higher
capital cost, uneven blanching, some mass loss in food and poor energy efficiency.
At the same time, the advantages of hot water blanchers are lower capital cost and better
energy efficiency. The disadvantages are loss of water soluble components, higher cost of water
and disposal of effluent and risk of contamination. A thermal screw may also be used to steam blanch
products. Here, the product is conveyed in a trough by a closely fitting helical screw. Steam injected
at regular interval is used to heat the product. Similar designs use hot water as the transfer medium,
and this reduces abrasion and damage to sensitive products such as mushroom.
We should select a size of blancher which will handle the line capacity without being over crowded.
As an operator, we have to ensure maintenance of the unit on a regular basis and check that
automatic controls are performing well. The use of a check thermometer to ascertain the accuracy of
the one installed on the unit is a good practice..

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Ingredients and processesfor the manufacture of: i) jam, jellies, marmalade, preserves,
(ii) pickles and chutneys b) Defects and factors affecting the quality of above
FRUIT JAM
Jam: Jam is prepared by boiling whole fruit pulp with cane sugar (sucrose) to a moderately thick
consistency with out retaining the shape of the fruit. As per FPO specification 45 parts of fruit to each 55
parts of sugar and contain 0.5-0.6% acid and invert sugar should not be more than 40%. is used for
preparation of jam.
Or
Jam is a product with reasonably thick consistency, firm enough to hold the fruit tissues in position,
and is made by boiling fruit pulp with sufficient sugar.
Preparation of Jam
Jam can be prepared from one kind of fruit or from two or more kinds. It may be made from
practically all varieties of fruit. Apple, papaya, carrot, strawberry, mango, grapes, pineapple, etc. are used
for the preparation of jams. Various combinations of different varieties of fruit can be often made to
advantage, pineapple being one of the best for blending purposes because of its pronounced flavour and
acidity.
1. Selection of fruit: Fruit should be in right proportion which gives good quantity of pectin and also
natural flavour. For this fully ripped and ripped fruit are used in right proportion.
2. Preparation of fruit pulp: Sound fruit is sorted, washed in running water or, preferably, brush-
washed and prepared. The mode of preparation varies with the nature of the fruit. For example,
mangoes are peeled, steamed and pulped; apples are peeled, cored, sliced, heated with water and
pulped; plums are scalded and pulped; peaches are peeled and pulped; apricots are halved, steamed
and pulped; berries are heated with water and pulped or cooked as such.
3. Addition of sugar: To make jams and jellies, up to a maximum of 25% of corn syrup for sweetness
can be utilized. Generally, cane sugar of good quality is used in the preparation of jams. The
proportion of sugar to fruit varies with type and variety of fruit, its stage of ripeness and acidity. A
fruit pulp to sugar ratio of 1:1 is generally followed. This ratio is usually suited to fruits viz., berries,
currants, plums, apricots, pineapple and other tart fruits.
4. Addition of acid: Citric, malic or tartaric acids are present naturally in different fruits. These acids
are also added to supplement the acidity of the fruits deficient in natural acids during jam making.
Addition of acid becomes necessary as adequate proportion of sugar- pectin- acid is required to give
good set to the jam. The recommended pH for the mixture of fruit juice and pectin is 3.1. The acidity
of finished jam varies between 0.5 to 0.7 % depending on the type of the jam. It is often advisable to
add acid at the end of cooking which leads to more inversion of sugar. When acid is added in the
beginning, it will result in poor set.

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5. Processing/boiling: Fruit pulp is cooked with the requisite quantities of sugar and pectin, and
finished to 69% Total Soluble Solids (TSS). Permitted food colours, requisite amount of citric acid
and flavourings are added at this stage. The boiling process, in addition to excess water removal, also
partially inverts the sugar, develops the flavour and texture. During jam boiling, all microorganisms
are destroyed within the product. When this is filled hot into clean receptacles which are
subsequently sealed, and then inverted the hot jam contacts the lid surface, thus prevents the spoilage
by micro-organisms during storage.
6. Judging of End Point
Concentration of jam is finished at an optimum point avoiding over cooking which leads to
economic losses due to less yield. But under cooking will result in the spoilage of jam during storage
due to fermentation. The finishing or end point of jam can be determined by the following methods.
 Drop test: This method is the simplest way and commonly
used by housewives where no other facilities are available. In this method, a
little quantity of jam is taken from the boiling pan in a tea spoon and allowed
to air cool before putting a drop of it in a glass filled with water. Settling
down of the drop without disintegration
denotes the end point
 By sheet test: In this test, a
small portion of jam is taken with a large
spoon or wooden ladle, cooled slightly and then allow to
drop off keeping the spoon or ladle in horizontally inclined
position. If the jam drops like syrup, further concentration
is needed. If it is in the form of flake or forms a sheet, the
finishing point is attained
 Refractometer method: This is the most common
method used by small and large scale fruit
processing industries for jam making. The cooking
is stopped when the refractometer shows 69 oBrix.
 Boiling point method: Jam containing 69% TSS
boils at 106 oC at sea level. This method is simplest and best to determine the finishing point
of jam.
 By weighing method: Weighing method is more laborious and time consuming. Here the
boiling pan is weighed before and again after transferring the extract and sugar in to it. The
end point is attained when the net jam weight is one and a half times of the quantity of sugar
added.
 Packaging The product is packed in cans or glass jars, and cooled, followed by labeling and
packaging. Containers including can or jar gets sterilized when hot jam (not less than 85oC)
is poured in them. Boiling the containers in hot water can also effect sterilization.
Special Care/ Problems in Jam Production
1. Crystallization: The final product should contain 30–40% invert sugar. If the
percentage is less than 30, cane sugar may crystallize out on storage and if it is more
than 50 the jam will become a honey-like mass due to high inversion of 40 % sugar
into glucose. Corn syrup or glucose may be added along with cane sugar to avoid
crystallization.

101
2. Sticky or gummy jam: Because of high percentage of total soluble solids, jams tend
to become gummy or sticky. This problem can be solved by addition of pectin or
citric acid, or both.
3. Premature setting: This is due to low total soluble solids and high pectin content in
the jam and can be prevented by adding more sugar. If this cannot be done a small
quantity of sodium bicarbonate is added to reduce the acidity and thus prevent pre-
coagulation.
4. Surface graining and shrinkage: This is caused by evaporation of moisture during
storage of jam. Storing in a cool place can reduce it.
5. Microbial spoilage: The mould attack on jam can be eliminated by storing them at
less than 90% RH (Preferably at 80% RH). It is also advisable to add 40 ppm
sulphur dioxide in the form of KMS. In the case of cans, sulphur dioxide should not
be added to the jam as it causes blackening of the internal surface of the can.
FRUIT JELLY
Jelly: Jellies are gellified products obtained by boiling fruit juices with sugar, with or without the addition of
pectin and food acids.
OR
Jelly is a semi solid product prepared by boiling a clear, strained solution of pectin containing fruit extract,
free from pulp, after addition of sugar and acid.

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A jelly is a semisolid product prepared by boiling fruit with water, expressing as water (pectin) extract),
adding sugar, and concentrating to such consistency that gelatinization takes place on cooling. A perfect
jelly should be transparent, well set, but not too stiff, and should have the original flavour of the fruit. It
should be of attractive colour and keep its shape when removed from the mould. It should not be gummy,
sticky, or syrupy or have crystallized sugar.
Preparation of Jelly
Selection of fruits: Guava, sour apple, plum, papaya, certain varieties of banana and gooseberry are
generally used for preparation of jelly. Other fruits can also be used but only after addition of pectin powder,
since these fruits are low in pectin content. Fruits can be divided into four groups according to their pectin
contents. This classification is highly useful in preparation of jelly, because pectin is the important
component, which is responsible for the texture of the jelly. The classification is as follows.
1. Rich in pectin and acid: sour apple, grape, lemon, sour oranges, jamun, sour plum.
2. Rich in pectin but low in acid: apple, unripe banana, pear, ripe guava, etc.
3. Low in pectin but rich in acid: sour apricot, sweet cherry, sour peach, pineapple and strawberry.
4. Low in pectin and acid: ripe apricot, peach, pomegranate, strawberry and other over ripe fruits.
Extraction of pectin/boiling: After selection, the fruits are washed thoroughly. Most of the fruits are boiled
for extraction of the juice in order to obtain maximum yield of juice and pectin. Boiling converts protopectin
into pectin and softens fruit tissues. Very juicy fruits do not require the addition of water and are crushed
and heated to boiling only for 5 min. Firm fruits are cut or crushed and boiled with water for 5 min. The
length of boiling will vary according to the type and texture of fruit. The amount of water added to the fruit
must be sufficient to give a high yield of pectin e.g. apples require one half to an equal volume of water,
where as citrus fruits require 2-3 volumes of water for each volume of sliced fruits.
Straining and clarification: Pectin extract is obtained by straining the boiled fruit mass through bags made
of linen, flannel, or cheese cloth folded several times. For large scale production, the fruit extract is made to
pass through filter presses for clarity.
Analysis of extract: Clarified extract is analysed for pH, acidity, soluble solids and pectin content by
common laboratory methods.
 For determining pectin content the easiest way adopted is precipitating the pectin with alcohol. A
rapid test for evaluation of juice pectin content is by mixing a small sample of juice with an equal
volume of 96% alcohol in a tube. The mixture from the tube is then emptied on a plate. The
appearance of a compact gelatinous precipitate indicates sufficient pectin content for jellification
(Figure J-1). Insufficient pectin will remain in numerous small granular lumps

101
.
Figure J-1 .4: Pectin test for jelly extract. a) Low pectin extract; b) High pectin extract
Addition of sugar and pectin: Based on the pectin test of the fruit extract, quantity of sugar to be added is
worked out. For the extract rich in pectin, sugar equal to the quantity of the extract is added. To the extract
with moderate pectin 650 – 750 g of sugar should be added to each kg of extract. For juices rich in pectin,
jellification will occur without pectin addition. If pectin content is less, 1-2% powder pectin will be added to
the juice.
Addition of acid: Jelly strength increases with increasing hydrogen ion concentration until an optimum pH
is reached which is generally 3.2 at 65%sugar concentration. Jellying strength depends on the quantity of
pectin and the acid present in the original fruit extract.
Processing/boiling: The juice is boiled up to remove about half of the water that has to be evaporated. Then
the calculated sugar quantity is added gradually. The remainder of the water is evaporated until a TSS
(refractometric extract) of 65% is reached. During boiling it is necessary to remove foam / scum formed.
Product acidity must be brought to about 1% (malic acid) corresponding to pH > 3. Any acid addition is
performed always at the end of boiling. Boiling of jellies is performed in small batches (25-75 kg) in order
to avoid excessively long boiling time which brings about pectin degradation.
Judging of End Point
Boiling of jelly should not be prolonged, because excessive boiling results in greater inversion of sugar and
destruction of pectin. The end point can be judged by sheet test, drop test, refractometry, thermometer, and
by weighing the boiling mass. Methods like sheet test, drop test, and weighing of the boiling mass can be
done in the similar way as in the case of jam preparation.
 Refractometer method: This is the most common method used in fruit processing industries for jelly
making. The cooking is stopped when the refractometer shows 65o Brix.
 Temperature test: A solution containing 65% TSS boils at 105oC. Heating of the jelly to this
temperature would automatically bring the concentration of solids to 65%. Endpoint of finishing
jelly should be 4.5-5oC higher than that of the boiling point of water at that place.
Packaging
After jelly is ready, it is skimmed to remove foam. It is cooled slightly before pouring into dry and hot glass
jars. Cooling is optional and is carried out up to 85oC, in double wall baths with water circulation. Filling is
performed at a temperature not below 85oC in receptacles (glass jars, etc.), which must be maintained still
for about 24 hours to allow cooling and product jellification.

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Problems in Jelly Making
The most important difficulties that are
experienced are as follows:
• Failure to set: This may be due to the addition
of too much sugar, lack of acid or pectin,
cooking below/ beyond the end-point.
• Colour changes: Darkening at the top of the
jars can be caused by storing them in too warm
place or by an imperfect jar seal.
• Gummy jelly: It is the result of prolonged or
over cooking in which more than desired
inversion of sugar occurs
• Stiff jelly: Over cooking or using too much
pectin makes too tough jelly which fails to
spread when applied on bread.
• Cloudy or foggy jellies: It is due to the use of
non-clarified juice or extract, use of immature
fruits, over-cooking, over-cooling, non-removal
of scum, faulty pouring, and premature gelation.
• Formation of crystals: It is due to addition of
excess sugar and also due to the over-
concentration of jelly. This excess sugar comes
from over cooking, too little acid or from under
cooking.
• Syneresis or weeping of jelly: The
phenomenon of exudation of fluid from a gel is
called syneresis or weeping and is caused by several factors. The factors include; excess of acid, too low
concentration of sugar, insufficient pectin, premature gelation, and fermentation
• Presence of mold: Due to imperfect sealing and insufficient sugar.
• Colour fading: This is due to high temperature and bright light in storage room. Another possible cause
could be the insufficient processing to destroy the enzymes affecting colour or the elevated processing
temperature, which might cause colour fading. Trapped air bubbles can also contribute to the chemical
changes by oxidation.

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MARMALADE
Marmalade is a fruit jelly in which slices of the fruit or its peel are suspended.
OR
Marmalade is a clear jelly in which shreds of peel are suspended. It is generally prepared from citrus fruits
Marmalade preparation is similar to jelly with the difference that it contains citrus fruits like oranges and
lemons in which shredded peel is used as the suspended material. In the preparation of marmalade bitterness
is regarded as desirable characteristic of product. The principles of jelly making, apply also to the
preparation of marmalade Marmalades are classified into two:
1. jelly marmalade
2. jam marmalade
Jelly Marmalade
Good quality jelly marmalade can be prepared from a combination of Sweet orange/ Mandarin
orange and sour orange in a 2:1 proportion. Shreds of sweet orange (Malta) peel are used in the
preparation.
1. Selection of fruit-Sound, ripened fruit is sorted, washed, and prepared. The mode of preparation
varies with the nature of the fruit. The fruits are then cut in to slices and are boiled for the
preparation of extract.
2. Extraction of pectin/boiling: After selection, the fruits are washed thoroughly. Most of the fruits are
boiled for extraction of the juice in order to obtain maximum yield of juice and pectin. Boiling
converts protopectin into pectin and softens fruit tissues. The amount of water added to the fruit must
be sufficient to give a high yield of pectin e.g. apples require one half to an equal volume of water,
where as citrus fruits require 2-3 volumes of water for each volume of sliced fruits.
3. Straining and clarification: Pectin extract is obtained by straining the boiled fruit mass through bags
made of linen, flannel, or cheese cloth folded several times. For large scale production, the fruit
extract is made to pass through filter presses for clarity
4. Analysis of extract: As like Jelly.
5. Preparation of peel shreds: The outer layer of yellow portion of citrus fruits is peeled off carefully.
The stripped-off peel is cut into slices of about 2-2.5 cm long and 1-1.2 mm thick. Boiling in water
with 0.25% sodium bicarbonate or 0.1% ammonia solution can soften the shreds. Before addition to
the jelly, the shreds may be kept in heavy syrup for some time to increase their bulk density to avoid
floating on the surface when it is mixed with jelly.
6. Addition of sugar and pectin: Based on the pectin test of the fruit extract, quantity of sugar to be
added is worked out. For the extract rich in pectin, sugar equal to the quantity of the extract is added.
To the extract with moderate pectin 650 – 750 g of sugar should be added to each kg of extract. For
juices rich in pectin, jellification will occur without pectin addition. If pectin content is less, 1-2%
powder pectin will be added to the juice.
7. Addition of acid: Jelly strength increases with increasing hydrogen ion concentration until an
optimum pH is reached which is generally 3.2 at 65%sugar concentration. Jellying strength depends
on the quantity of pectin and the acid present in the original fruit extract.
8. Processing: During boiling, the impurities in the form of scum are occasionally removed. When the
temperature of the mixture reaches 103oC, the prepared shreds of peel are mixed in it at the rate of 5-
7% of the original extract. Boiling is continued till the end point is reached. The end point is judged

101
in the same way as in the case of jelly. Like jelly, marmalade also contains 65% TSS at 105oC.
Boiling should not prolong for more than 20 min, after the addition of sugar to get bright and
sparkling marmalade.
9. Cooling: The marmalade is cooled to permit the absorption of sugar by the shreds from the
surrounding syrup. If the marmalade is filled in hot, the shreds may come to the surface instead of
remaining in suspension. During cooling, the product is gently stirred occasionally for uniform
distribution of shreds. When marmalade temperature reaches around 85oC, viscosity of syrup
increases and a thin film begins to form on surface, which prevents shreds from coming to surface.
10. Flavouring: This is done by adding some flavour or orange oil to the product near the end of boiling
to supplement the flavour lost during boiling. Generally, a few drops of orange oil are mixed in
marmalade before filling into containers.
11. Packaging and Storage: Like jams and jellies, marmalade is also filled into jars and cans at a
temperature around 850C. Storage of marmalade must be done in dry rooms (relative humidity at
about 75%), well ventilated, medium cool places (temperature 10-20oC), disinfected and away from
direct sunlight and heat. These measures are necessary because marmalade is a hydroscopic product
and, by water absorption, favorable conditions for mould development are created.
Jam Marmalade
Jam marmalade is practically made by the method used for preparation of jelly marmalade except that the
pectin extract is not clarified. The orange peel after removing albedo portion is sliced into 0.3 cm thick
pieces and treated in the same way as recommended for jelly marmalade. The sliced fruit of orange, lemon,
or grape fruit after removing peel is mixed with little quantity of water and boiled to soften. The boiled
mixture is pressed through coarse pulper to remove seed and to get thick pulp. The pulp is mixed with equal
quantity of sugar and cooked to a consistency of 65o Brix or consistency of jam. The treated shreds are
mixed in the jam when it is slightly cool. Some orange oil is also mixed in the marmalade before filling into
containers. Filling and packaging is done in the similar way as adopted for packaging of jelly and jelly
marmalade.
Problems in Marmalade Making
Browning during storage is very common which can be prevented by the addition of 0.09g of potassium
metabi-sulphite (KMS) per kg of marmalade and not using tin containers. KMS dissolved in a small quantity
of water is added to the marmalade while it is cooling. KMS also eliminates the possibility of spoilage due
to moulds.

101
PICKLES
Pickle is an edible product preserved in a solution of common salt and vinegar. It is one of the
most ancient method of preserving fruits and vegetables. Pickles are good appetizers and add to the
palatability of meal. They stimulate the flow of gastric juice and thus help in digestion. Several kinds
of pickles are sold in Indian market. Mango pickle ranks first. Pickles can also be prepared from
fruits and vegetables like lemon, amla, onion, cauliflower, cabbage, beans, cucumber, bitter gourd,
jackfruit, turnip etc. Fruits are generally preserved in sweetened and spiced vinegar, while vegetables
in salt.
Pickling Process
The preservation of food in common salt or in vinegar is called pickling. Pickling may also be
the result of fermentation by lactic acid forming bacteria, which are naturally present in large
numbers on the surface of fresh vegetables and fruits. These bacteria can grow in acid medium and in
the presence of 8- 10% salt solution, whereas the growth of majority of undesirable organisms is
inhibited. Lactic acid bacteria are most active at 30oC, so this temperature should be maintained, as
far as possible, in the process of pickling. Pickling is done in two stages.
Stage I can be done by any of the three following methods :
i) Fermentation with dry salting,
ii) Fermentation in brine, or
iii) Salting without fermentation.
Stage II is finishing and packing.
Fermentation with Dry Salting
In this method, the vegetable is treated with dry salt. The salt extracts the juice from the vegetables
and forms the brine, which is fermented by lactic acid bacteria. The method of dry salting in general
is as follows:
1. The vegetable is washed, drained, weighed for preparing pickles.
2. Several alternate layers of the prepared vegetable and salt (20-30 g of dry salt/ kg vegetables)
are kept in a vessel which is covered with a cloth and a wooden board and allowed to stand for
24 hrs. During this period brine is formed by osmosis. As soon as the brine is formed, the
fermentation process starts and the CO2 begins to evolve.
3. When fermentation is over, gas formation stops. Under favorable conditions fermentation is
completed in 8-10 days, however in cold weather it may take 2 to 4 weeks. When sufficient
lactic acid has been formed, lactic acid bacteria stop to grow and no further change takes
place in vegetables.

101
4. Precaution should be taken against spoilage by aerobic microbes, because in the presence of
air “pickles scum”, a kind of wild yeast, is formed which brings about putrefaction and
destroys the lactic acid.
5. The product may be preserved and kept by excluding air.
Fermentation in Brine
In this method steeping of the vegetables in brine, it penetrates in the tissues of the vegetables
and soluble material present in vegetable diffuses into the brine by osmosis. The soluble material
includes fermentable sugars and minerals. The sugars serve as food for lactic acid bacteria, which
convert them into lactic and other acids. The acid brine thus formed acts upon vegetable tissues to
produce characteristic taste and aroma of pickle. The amount of brine required is usually half the
volume of vegetables. Brining is the most important step in pickling. The growth of the majority of
spoilage organisms is inhibited by brine containing 15% salt. Lactic acid bacteria are salt-tolerant
and can grow in brine of 8-10% strength. In a brine containing 10
% salt, fermentation precedes somewhat slowly so 5 % brine used for fair fermentation. Fermentation
takes place to some extent up to 15 % but stops at 20% brine strength. After fermentation process,
the salt content is now increased gradually, so that by the time pickle is ready, salt concentration
reaches 15%.
Salting Without Fermentation
In this type of process vegetables are washed, prepared and is mixed with salt (250 g/kg of prepared
material). This high salt concentration will inhibit the fermentation. After curing of Vegetables with
large amount of salt they are drained and excess of salt is removed by soaking them in cold or warm
water. Thereafter, the vegetables are stored in plain vinegar of 10% strength for several weeks.
Vegetables can also be stored in sweetened and spiced vinegar. The spices can be added in the
ground form or essential oil of spices may be added to impart the spice flavour.
VARIOUS PICKLES
At present, pickles are prepared with salt, vinegar, oil or with a combination of above ingredients
with spices. These methods are discussed below:
Preservation with Salt

101
Salt improves the taste and flavour and hardens the tissue of vegetables and controls fermentation.
Salt content of 15% or above prevents microbial spoilage. This method of preservation is generally
used only for vegetables, which contains very little sugar. Since the sugar content is less, sufficient
lactic acid cannot be formed by fermentation to act as preservative. However, some fruits viz.,
mango, lemon, etc. are also preserved with salt. An example for pickle preparation with salt is shown
Mangoes (Matured green)
↓
Washing
↓
Peeling
↓
Slicing
↓
Putting slices in jar
↓
Sprinkling salt
↓
Putting in sun for one week
(shaking jar at least twice a day to mix the salt)
↓
Mixing spices
↓
Storage at ambient temperature
(In cool dry place)
Flow chart of mango pickle
Preservation with Vinegar

101
This technology is based on the addition of food grade vinegar which has a bacteriostatic
action in concentrations up to 4% acetic acid and bactericidal action in higher concentrations.
Vegetables preserved in vinegar need to reach a final concentration of 2-3% acetic acid in order to
assure their preservation.
To achieve this final concentration, 6-9% acetic acid vinegar is used, as related to the specific ratio
of vinegar: vegetable. This higher concentration treatment helps to expel the gases present in the
intercellular spaces of vegetable tissue.
In vinegar pickles, salt (2-3%) and sometimes sugar (2-5%) are also added. If the vinegar
concentration is lower than 2%, vinegar pickles need to be submitted to pasteurization in order to
assure their preservation. Mango, garlic, chilies, etc. are preserved as such in vinegar. Vinegar
pickles are the most important pickles consumed in other countries.
Onion (small)
↓
Peeling
↓
Blanching for 5 minutes
↓
Filling blanched onions in jar
↓
Addition of salt
↓
Keeping for 1-2 days
↓
Draining off water
↓
Addition of vinegar and Spices
↓
Storage
Flow chart of onion pickle

101
Preservation with Oil
Oil pickles are highly popular in India. They are highly spiced. In India, mustard oil, rapeseed oil,
sesame oil are generally used. The fruits or vegetables should be completely immersed in the edible
oil. Cauliflower, lime, mango and turnip pickles are the most important oil pickles. The pickle
remains in good condition for one to two years if handled properly. A schematic flow chart of lemon
pickle by using oil as preservative is shown in
Lemon
↓
Washing
↓
Cutting into 4 pieces
↓
Squeezing out juice from 1/4th amount of fruit
↓
Mixing spices and salt with juice
↓
Mixing with pieces
↓
Filling in jar
↓
Keeping in sun for 4-6 days
↓
Addition of oil after heating
↓
Cooling it
↓
Storage
Flow chart of lemon pickle

101
Preservation with Salt, Vinegar, Oil and Spices
This method combines the advantages of fermentation action of salt and the preservation action of
both vinegar and oil. The flavouring property of spices is also made use of. The spices are usually
fried in oil and mixed to the prepared fruit/ vegetable before the addition of vinegar. The spices can
be added separately or in the form of spice vinegar. A schematic flow chart of tomato pickle by using
salt, vinegar, oil and spices as preservative is shown
Tomatoes
↓
Washing
↓
Blanching for 5 minutes
↓
Cooling immediately in water
↓
Peeling & Cutting into 4-6pieces
↓
Frying all ingredients in a little oil (except vinegar)
↓
Mixing with pieces
↓
Heating for 2 minutes & Cooling
↓
Addition of vinegar & remaining oil
↓
Filling in jars & storage
Flow chart of tomato pickle

101
Problems in pickle making
 Bitter taste: Use of strong vinegar or excess spice or prolonged cooking of spices imparts a
bitter taste to the pickle.
 Dull and faded product: This is due to use of inferior quality materials or insufficient curing.
 Shriveling: It occurs when vegetables (e.g., cucumber) are placed directly in a very strong
solution of salt or sugar or vinegar. Hence, a dilute solution should be used initially and its
strength gradually increased.
 Scum formation: When vegetables are cured in brine, a white scum always forms on the
surface due to the growth of wild yeast. This delays the formation of lactic acid and also helps
the growth of putrefactive bacteria which cause softness and slipperiness. Hence, it is
advisable to remove scum as soon as it is formed. Addition of one per cent acetic acid helps to
prevent the growth of wild yeast in brine, without affecting lactic acid formation.
 Softness and slipperiness: This very common problem is due to inadequate covering with
brine or the use of weak brine: The problem can be solved by using a brine of proper strength
and keeping the pickles well below the surface of the brine.
 Cloudiness: When the structure of the vegetable used in pickling, e.g., onion, is such that the
acetic acid (vinegar) cannot penetrate deep enough into its tissues to inhibit the activity of
bacteria and other microorganisms present in them, fermentation starts from inside the tissues;
rendering the vinegar cloudy. This microbial activity can only be checked by proper brining.
Cloudiness may also be caused by use of inferior quality vinegar or chemical reaction between
vinegar and minerals.
 Blackening: It is due to the iron in the brine or in the process equipment reacting with the
ingredients used in pickling. Certain microorganisms also cause blackening.
Chutneys-
Good quality chutney should be palatable and appetizing. Mango chutney is an important food
product exported from India to many countries. Apple and apricot chutneys are also very popular in
the country. The method of preparation of chutney is similar to that for jam except that spices,
vinegar and salt are added.
Preparation of Chutney
Ripe fruit or vegetable is selected, cut into slices or pieces of suitable size and are softened by
boiling in water. These are then, slowly cooked at a temperature below boiling point. Onion and
garlic are added at the start to mellow their strong flavours. Spices are coarsely powdered before they
are added to the product. Whole spices, if used, are bruised and tide loosely in muslin cloth before
adding to the mixture and removed before bottling. Vinegar, sugar, and spices are added just a little
before the final stage of boiling. This prevents the loss of some essential oils of spices and vinegar

101
due to volatilization. Long cooking of sugar darkens the colour of the chutney. For the preparation of
dark colour chutney brown sugar is usually preferred, where as, white sugar is preferred for white
colour chutneys. Spiced vinegar gives high quality product. Chutneys usually get thickened on
cooling. The chutneys are bottled, while hot, in clean and warm jars which are then, adequately
sealed and sterilized.
Fruit/Vegetable
↓
Grading for Ripeness & Freshness
↓
Washing
↓
Peeling, Slicing/Crown Removing/Coring
↓
Boiling
↓
Cooking with Onion and Garlic and/or Ginger
↓
Adding Coarsely Powdered Spices/ Spiced Vinegar & vinegar
↓
Coking till required consistency obtained
↓
Boiling hot and sealing
↓
Sterilizing
↓
Cooling
↓
Labeling & Storage
Flow chart of chutney production

101
Chutney and its Method of Preparation
 The method of preparation of chutney is similar to that for jam except that spices, vinegar and
salt are added.
 The fruits/vegetables are peeled, sliced or grated, or cut into small pieces and cooked in water
until they become sufficiently soft.
 The quality of chutney depends to a large extent on its cooking which should be done for a
long time at a temperature below the boiling point.
 To ensure proper thickening, cooking is done without a lid even though this results in some
loss of volatile oils from the spices.
 Chopped onion and garlic are added at the start to mellow their strong flavours. Spices are
coarsely powdered before adding.
 Vinegar extract of spices may be used instead of whole spices. Spice and vinegar are added
just before the final stage of cooking, because prolonged boiling causes loss of some of the
essential oils of spices and of vinegar by volatilization. In mango and apricot sweet chutneys,
where vinegar is used in large quantity, the amount of sugar added may be reduced because
vinegar itself acts as a preservative.
 The chutneys are cooked to the consistency of jam to avoid fermentation.
Some of the common recipes for preparation of chutney are given below
Sweet mango chutney
Mango slices or shreds 1 kg, sugar 1 kg, salt to taste, onions (chopped) 50g, garlic (chopped) 15g,
ginger (chopped) 15g, red chilli powder 10g, black pepper, cardamom (large), cinnamon, cumin,
aniseed (powdered) 10g each, clove (headless) 5 numbers and vinegar 170 ml.

101
Apple chutney
Apple slices 1 kg, sugar 750 g, dried dates (chopped) 100g, salt to taste, raisins 50g, ginger
(chopped) 15g, red chilli powder 10g, black pepper, cardamom (large), cinnamon, cumin, aniseed
(powdered) 10g each, clove (headless) 5 numbers, onions (chopped) 250g, garlic (chopped) 15g, and
vinegar 200 ml.

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Tomato Chutney
Tomato chutney is produced from tomato pulp, and other ingredients like sugar, salt, vinegar, spices,
onion, ginger, garlic, etc. The preparation of tomato chutney is similar to that of the chutney
produced from other fruits and vegetables.
QUALITY STANDARDS
FPO specifications for the
products discussed in the
present unit. FPO
specifications for tomato
products, pickles, chutneys
and sauces are as follows:

101
Some important considerations:
 In case of oil pickles the name of the fruit or vegetable used shall be declared on the label.
 When more than one vegetable is used in vinegar pickle the product shall be labeled as ‘mixed
pickles’.
 In case of sauces other than tomato and soybean, the names of fruits, vegetables or dried fruits
used shall be declared on the label.
 In case of fruit chutney, the names of fruits may not be declared on the label, However, in
case of mango chutney or other chutneys the content shall be declared on the label.
 Permissible limit of Copper (a toxic element) in tomato ketchup is 50 ppm, whereas the same
can be up to 100 ppm in tomato puree, paste, juice powder and cocktails.
KEY WORDS
Brine: Solution of common salt.
Brining: Steeping of the vegetables in a salt solution of pre determined concentration for a certain
length of time.
Vinegar: It is a liquid obtained by alcoholic and acetic fermentation of material containing sugar. It
contains about 4% acetic acid.
Chutney: It is an unstrained, concentrated product, which contains a mixture of fruit or vegetable,
spices, salt and/ or sugar, vinegar.
Sauce: It is a strained, concentrated product, which contains a mixture of fruit or vegetable, spices,
salt and/ or sugar, vinegar. These are thinner and smoother in consistency than chutneys.
Tomato paste: It is a concentrated and strained tomato product and contains not less than 25%
tomato solids.

101
Tomato puree: It is a concentrated and strained tomato product but thinner than the paste and
containing not less than 9.0 % of salt free tomato solids.
Spice bag: Bruised spices tide loosely in muslin cloth
Ketchup: Thick sauces made from tomato

101
Tomato Products -Ingredients and their role, process for the manufacture of tomato
ketchup, sauce, puree and paste
Tomato is grown in our country in abundance, in all seasons. The farmer will get a very low profit
during the peak-harvesting season and nearly 25% of the produce is spoiled due to improper post
harvest practices. Such losses can be avoided by converting tomatoes into delicious products. Tomato
can be processed to a variety of products like; canned tomato, paste, puree, juice, ketchup and sauce.
In India tomato sauce and ketchup are very popular and are being manufactured on an increasingly
large scale.
Tomato ketchup: – Tomato ketchup (catsup, catchup) can be defined that it is a clean, sound product
made from strained tomato juice, with spices, sugar, salt, vinegar, onion and garlic etc.
Ketchup is a condiment, usually made from tomatoes. It should contain not less than 12 percent
tomato solids and 28 percent total solids. Ketchup with a 28-30% TSS has a better flavour. Tomato
ketchup is similar to tomato sauce except that it is thick in consistency.
Raw Materials
The main ingredients of ketchup are tomatoes, sweeteners, vinegar, salt, spices, flavorings, onion,
and/or garlic.
 The types of sweetener used are usually granulated cane sugar or beet sugar. Other
sweeteners include dextrose or liquid sugar in the form of corn or glucose syrup. About one
third of the sugar required is added at the time of commencement of boiling to intensify and
fix the red tomato colour. If the whole quantity of sugar is added initially, the cooking time
will be longer and the quality of pulp will be adversely affected. Generally the sugar content
in sauces/ ketchups varies from 10- 26 %.
 Good quality vinegar is essential for the preparation of high quality sauce/ketchup. Vinegar
helps to preserve the ketchup. It should contain 5.0-5.5% acetic acid and should be added
when the product has thickened sufficiently, so that the acid is not lost by volatilization.
Tomato sauce/ ketchup generally contain 1.25-1.5% acetic acid. Sometimes glacial acetic acid
(100% acetic acid) is used which is colorless and cheaper than vinegar.
 Salt is used as a main flavouring ingredient in ketchup but slat also bleaches the colour of the
tomato product. It is therefore desirable to add towards the end of cooking process.
 The spices commonly used to enhance the flavor of the tomatoes are all spice, cassia,
cinnamon, cayenne, cloves, pepper, ginger, mustard, and paprika. Pepper is widely used as a
condiment, preferred for its characteristic aroma, pungency and biting taste. It is used to
garnish culinary preparations, ketchups, sauces
Thicker consistencies require a greater ratio of sugar and spices relative to the tomato juice.

101
The Manufacturing Process
1. Selection of Tomatoes: - Tomato which are superior in color, flavor, texture, and yield.
Consistency is an important factor, as slight variations in tomato characteristics could alter the
flavor and color of the finished product.
2. Pre-washing and washing: Pre-washing is carried out by immersion in water, cold or heated
up to 50°C (possibly with detergents to eliminate traces of pesticides). Then washing is
performed with water sprays.
3. Sorting: Only sound ripe red coloured tomatoes are used for the juice preparation. This is
done on rolling sorting tables. This enables the removal of non-standard tomatoes − with
green parts, yellow coloured, etc.
4. The tomatoes are cut and chopped.
5. Now chopped tomatoes are precooked at 70 to 900 C in stainless steel vats to preserves the
tomatoes and destroy bacteria.
6. Crushing and pulping: Crushing is carried out in special equipment. Fluted wooden roller
crushers are utilized for this purpose. The crushed tomatoes can be pulped by the hot process
or by the cold process.
a) In hot pulping, crushed tomatoes are boiled in their own juice in steam jacketed stainless
steel pans or in aluminum pans for 3 to 5 minutes. Heat treatment yield higher juice
recovery than cold method. Because heat treatment inactivates/destroy the pectate enzymes
due to this pectin present in the skin and seeds separate into liquid and pulp easily. This
process also contributes to the maintaining of vitamins and natural pigments.
b) In cold pulping, the tomatoes are crushed in cold and as such passed through a pulper.
Here the extraction of juice is difficult and yield will be less compared to hot process.
7. Extraction: Extraction of juice and part of pulp (maximum 80%) is performed in special
equipment / tomato extractors with the care to avoid excessive air incorporation. In some
installations, as an additional special care, a part of pulp is removed with continuous
centrifugal separators.
8. Adding ingredients and cooking: - The pulp is pumped into cooking tanks or kettles and
heated to boiling. Foaming may occur if fresh tomato pulp is used, but can be corrected with
anti-foaming compounds or compressed air.
Precise amounts of sweeteners, vinegar, salt, spices, and flavorings are added to the
tomato pulp. Most spices are added early in the cooking process. To avoid excessive
evaporation, volatile spice oils and vinegar must be mixed in later. Onions and garlic can be
mixed in with the spices, placed in a separate bag, or chopped and added to the pulp.

101
Salt and sugar may be added at any stage of cooking though it is better to add sugar
later to prevent burning. The mixture cooks for 30-45 minutes upto one third of the original
volume and is circulated by rotating blades installed in the cookers.
Open Pan cooking – the tomato juice is cooked or boiled in aluminium vessel (Patila),
at smaller scale. In large scale, the juice is heated mostly in stainless steel steam jacket
kettle to the desired consistency. The open cooking is generally employed, but it has some
disadvantages. During cooking the product is exposed to the oxygen in the air, which may
destroy vitamin C and makes the juice brown.
In vacuum cooking – All the above defects are removed in vacuum cooking. In this
method the juice is placed in vacuum pan and heated. Under vacuum, boiling takes at reduced
temperature of 71°C. This method gives better retention of vitamin C and superior quality of
finished product. In the end vacuum is broken and the juice is sterilized by heating to 100°C
for about 10 minutes.
9. Finishing: Once the cooking is complete, the ketchup mixture passes through a finishing
machine. Finishers remove excess fiber and particles through screens, creating a smoother
consistency.
10. Deaeration (Removing air): The air from the extracted juice is removed by using a deaerator
under high vacuum. De-aeration prevents discoloration and growth of bacteria. Excess air
might also create unattractive air pockets and impede the closure process.
11. Addition of Vinegar & Preservative: - Add 0.025% sodium benzoate to the product before
bottling. Good quality vinegar is essential for the preparation of high quality sauce/ketchup. It
should contain 5.0-5.5% acetic acid Tomato sauce/ ketchup generally contains 1.25-1.5%
acetic acid.
12. Filling: To prevent contamination, the ketchup passes from the receiving tanks to the filling
machines at a temperature not lower than 88°C. The containers are filled with the ketchup and
immediately sealed to retain the freshness of the product. Ketchup containers come in various
sizes and shapes.
13. Pasteurization: - Pasteurize the bottles at 85 to 90°C for 30 minutes as a precaution against
spoilage during the 3 to 4 weeks that the ketchup remains in the opened bottle before it is used
up.
14. Cooling: The containers must be cooled to prevent flavor loss through stack burning, which
occurs when ketchup stays at high temperatures after cooking is complete. Containers of
ketchup may be cooled in cold air or cold water.
15. Labeling and packing: Finally, the ketchup containers are labeled and coded with product
information, including ingredients, date and location of manufacture, and shelf-life.

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SAUCES
Sauce: It can be defined that the sauce is a clean, sound product made from properly prepared fruits/
tomatoes / peppers with spices, salt, sugar, ginger, onion, garlic etc. It should contain total solids
from 12 to 25 per cent.
Sauces and chutneys are usually made from the same raw materials, spices and flavours,
however, difference is that, all sauces are sieved and as a result, are thinner and of smoother
consistency than chutneys. The sieving is done to remove the skin, seeds and stalks of fruits,
vegetables, and spices and to give a smooth consistency. Here the cooking process is longer
compared to the chutney due the use of fine pulp or juice.

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Sauces are generally of two kinds, and they are the thin sauces and the thick sauces. A good
sauce whether thin or thick, have a continuous flow with no skin, seeds and stalks of the fruit and/ or
vegetables and spices used for its preparation, and possesses pleasant taste and aroma.
 Thin Sauces
Thin sauces are those where the flavour of spices, grains fruits, vegetables are extracted in
Vinegar. Their quality depends mostly on the raw material used. Some sauces are matured by storing
them in wooden barrel or casks. During storage they develop flavour and aroma. Freshly prepared
products have often a raw and strong taste and they should, therefore, be matured by storage. The
final concentrated product contains not less than 12% tomato solids and 25% TSS. The most popular
in this category are a) Worestershire Sauce, b) Soya Sauce, c) Walnut Ketchup.
Preparation: For the preparation of thin sauces of high quality, the spices, herbs, fruits, and
vegetables are macerated in cold vinegar. Some times, they are also prepared by boiling them in
vinegar. The sauce is filtered through a fine or coarse mesh sieve of non corrodible metal, according
to the quality desired. The skin, seeds and stalks of fruits, vegetables and spices used, should not be
allowed to pass through the sieve as they spoil the appearance of the sauce. Commercial vinegar
extracts is prepared with each kind of spice and fruit separately by boiling in vinegar and then
blending these extracts suitably before filling the sauce into barrels for subsequent maturation.
Soya sauce made from soybeans and Worcestershire sauce made from tamarind are examples of
thin sauces.
Preparation of Thin Sauce
Fruit/Vegetable
↓
Grading for Ripeness & Freshness
↓
Washing
↓
Macerated in cold vinegar with spices & herbs
↓
Extraction of pulp
↓
Cooking with spices/spiced vinegar and Vinegar
↓
Filtering

101
↓
Bottling
↓
Sealing
↓
Sterilizing
↓
Cooling
↓
Labeling & Storage
Flow chart of thin sauce production
 Thick Sauces
Thick sauces are those where spices, vinegar, sugar and starch are mixed with fruit and
vegetable pulps. They are concentrated to desired consistency. Thick sauces are generally prepared
from tomatoes or from vegetables. Thick sauce does not flow freely and is highly viscous. Thick
sauces also contain more of sugar and less of acid.
Generally spices and colouring added are practically similar to those in the case of thick
ketchups and sauces. It should contain at least 3% acetic acid to ensure its keeping quality. The
acidity should not however, exceed 3.4% as otherwise the sauce would taste sharp. The sugar content
may usually vary from 15-30% according to the kind of sauce made. Usually malt vinegar is used.
The colour of the sauces varies with the raw material use. Some times a little caramel is added.
Preparation: The manufacturing process is the same as for chutneys. Thickening agents are also
added to prevent or retard sedimentation of solid particle in suspension in the sauce. The starch
obtained from maize, potato, arrow root, sago and rye are also used as thickening agents. Indian gum,
gelatin, Irish moss, pectin and other similar substances can also be used subject to the food laws of
our country. Tomato sauce and apple sauce are some of the examples for thick sauce.
Tomato Sauce
Tomato sauce is the concentrated product prepared from the liquid extract from mature,
sound, whole tomatoes to which is added salt, spices, sugar, vinegar, with or without onion, garlic, or
other vegetable flavouring ingredients. The final concentrated product contains not less than 12%
tomato solids and 25% TSS. The salt content of the product should be 1.3-3.4%.Good quality vinegar
is essential for the preparation of high quality sauce/ketchup. It should contain 5.0-5.5% acetic acid

101
Tomato sauce/ ketchup generally contain 1.25-1.5% acetic acid. Sauces can be obtained from fresh
tomatoes or from concentrated products (tomato paste or concentrated tomato juice), those from fresh
tomatoes being of superior quality. Technological processing covers the following steps:
 concentrated juice processing,
 Addition of flavour/taste ingredients (salt, sugar, vinegar, spices, etc.). : About one third
of the sugar required is added at the time of commencement of boiling to intensify and fix the
red tomato colour. If the whole quantity of sugar is added initially, the cooking time will be
longer and the quality of pulp will be adversely affected. Generally the sugar content in
sauces/ ketchups varies from 10- 26 %. On the other hand, salt bleaches the colour of the
tomato product. It is therefore desirable to add towards the end of cooking process. Spices are
generally added in powdered form to the product by spice bag method
 Boiling
 fine sieving
 filling
 closing and
 Pasteurization (45 min at 85°C).
Chilly Sauce
It is highly spiced product made from ripe, peeled and crushed tomatoes and salt, sugar,
spices, vinegar, with or without onion and garlic. The method of preparation is similar to that for
tomato sauce except that the total unstrained pulp is used and the seeds are not removed. Hot product
is filled in bottles or cans and processed in water at 85-90oC for 30 minutes. Tomato Sauces Surface
of the product turns black at the contact zone with air; this is due to the action of iron on the tannins
from spices, tomato seeds, etc. Prevention is by avoiding iron equipments, avoiding crushing of
tomato seeds and by sealing the bottles under vacuum.
Tomato Puree
Tomato pulp without skin or seeds, with or without added salt, and containing not less than 9.0% of
salt free tomato solids is known as “Medium tomato puree”. It can be concentrated further to ‘heavy
tomato puree’, which contains not less than 12% solids. If this is further concentrated so that it
contains not less than 25% tomato solids, it is known as tomato paste. On further concentration to
33% or more of solids, it is called concentrated tomato paste.
Preparation of tomato puree: Manufacturing steps fall into three successive categories:
 obtaining tomato juice from the raw materials
 juice concentration
 tomato puree pasteurization

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Tomato pulp and juice extraction is done from ripe tomatoes in the same manner as tomato juice
preparation. Concentration of the pulp is carried out either in an open cooker or in a vacuum pan.
In open cooking, most of the vitamins are destroyed and the product becomes brown. On the other
hand, use of vacuum pans, nutritive value is preserved and browning is also reduced. In vacuum pans
the juice is boiled at about 71°C only. Normally tomato juice can be concentrated to 14-15% solids
in an open cooker, but for obtaining higher concentrations a vacuum pan is required and sterilization
of the product is also possible in a vacuum pan. However this method is quite expensive.
In an open cooker, a little butter or edible oil is added to prevent foaming, burning and sticking. The
end-point of cooking puree and paste can be determined either with a hand refractometer or by
measuring the volume (a known volume of juice is concentrated to a known volume of final product)
with the help of a measuring stick.
Tomato puree pasteurization assures the microbiological stability of the product. For this purpose,
the puree coming out from concentration equipment is passed continuously and in a “forced” mode
through a tubular pasteurizer from which it emerge, at a temperature of 90-92° C. The pasteurized
puree is then filled hot in to cans or in glass receptacles.
Tomato Paste
The product with highest production volumes among concentrated products is tomato paste, which is
manufactured in a various range of concentrations, with a minimum of 25% and up to 44%
refractometric extract. The product is very similar to tomato puree except that the solid concentration
is more. Tomato paste is the product obtained by removal of peel and seeds from tomatoes, followed
by concentration of juice by evaporation under vacuum. Good quality tomato paste is a homogenous
mass, with a high density, without foreign bodies (seeds peel, etc.), with a red colour, and an
agreeable taste and smell, close to those of fresh tomatoes.
Preparation procedure is also similar to that of tomato puree. Here the tomato juice obtained is
further concentrated so that it contains not less than 25% tomato solids. This is known as tomato
paste. On further concentration to 33% or more of solids, it is called concentrated tomato paste. Paste
of good quality must have a volatile acidity of maximum 0.15% as lactic acid. An 8% salt addition is
accepted. The end point is judged by using a refractometer. The product with required TSS is then
pasteurized and filled into receptacles in the same way as explained under tomato puree.
Tomato Puree and Paste
Concentrated tomato pulp without skin or seeds, with or without added salt, and containing not less
than 9.0 % of salt-free tomato solids, is known as ‘medium tomato puree’. It can be concentrated
further to ‘heavy tomato puree’, which contains not less than 12% solids.
In the former most of the vitamins are destroyed. On the other hand, use of vacuum pans, which are
expensive, help to preserve the nutrients and also reduce the browning to a great extent. Moreover,
While cooking. If, after cooking, the total solids content of the juice is higher than required, more
juice is added to lower it, if it is lower, cooking is continued till the desired concentration is reached

101

101
Definition of some terms used above
 Brine: Solution of common salt.
 Brining: Steeping of the vegetables in a salt solution of pre determined concentration for a
certain length of time.
 Vinegar: It is a liquid obtained by alcoholic and acetic fermentation of material containing
sugar. It contains about 4% acetic acid.
 Chutney: It is an unstrained, concentrated product, which contains a mixture of fruit or
vegetable, spices, salt and/ or sugar, vinegar.
 Sauce: It is a strained, concentrated product, which contains a mixture of fruit or vegetable,
spices, salt and/ or sugar, vinegar. These are thinner and smoother in consistency than
chutneys.
Or
It can be defined that the sauce is a clean, sound product made from properly prepared fruits/
tomatoes / peppers with spices, salt, sugar, ginger, onion, garlic etc. It should contain total solids
from 12 to 25 per cent.
 Tomato paste: It is a concentrated and strained tomato product and contains not less than
25% tomato solids.
 Tomato puree: It is a concentrated and strained tomato product but thinner than the paste and
containing not less than 9.0 % of salt free tomato solids.
 Spice bag : Bruised spices tide loosely in muslin cloth
 Tomato Ketchup: Tomato ketchup (catsup, catchup) can be defined that it is a clean, sound
product made from strained tomato juice, with spices, sugar, salt, vinegar, onion and garlic
etc. It should contain not less than 12 percent tomato solids and 28 percent total solids.

101
Juices -Raw materials, extraction, classification, processing and aseptic packaging
FRUIT JUICE
In India, a little over 60 per cent of fruit produced is used in fruit based beverages. Fruit juice means the
unfermented and un-concentrated liquid expressed from sound, ripe fresh fruit and with or without:
 sugar, dextrose, invert sugar, or liquid glucose, either singly or in combination;
 water, peel-oil, fruit essences and flavour, common salt, ascorbic acid, citric acid, and preservatives.
The acidity of the finished product calculated as citric acid shall not be less than 4% in the case of pure
lemon juice or pulp and not less than 5% in the case of pure lime juice but shall not exceed 3.5%t in the case
of other juices. The total soluble solids for sweetened fruit juice (except tomato juice) shall not be less than
10%. There are different types of fruit beverages:
Fruit juice: This is a natural juice pressed out of a fresh fruit. This is unaltered in its composition during
preparation and preservation, e.g., fresh juice and canned natural fruit juice.
Fruit drink: This is made by liquefying the whole fruit. At least 10 per cent of the volume of undiluted
drink must be whole fruit about and about 0.3 per cent acid. e.g. grape juice, apple juice and mango juice.
Fruit squash: This is made from strained fruit juice, sugar and preservative. This contains 25 per cent fruit
juice, 45 per cent sugar, e.g., mango squash.
Crush-This type of fruit beverage contains at least 25 per cent fruit juice or pulp and 55 per cent total
soluble solids. It is more or less similar to squash, contains about 1.0 per cent acid and is diluted before
serving.
Fruit cordial: It is a sparkling, clear, sweetened fruit juice from which pulp and other insoluble. Substances
have been completely removed. It contains at least 25 per cent juice and 30 per cent TSS. It also contains
about 1.5 per cent acid and 350 ppm of sulphur dioxide. This is very suitable for blending with wines. Lime
and lemon are suitable for making cordial.
Nectar: This type of fruit beverage contains at least 20 per cent fruit juice/pulp and 15 per cent total soluble
solids and also about 0.3 per cent acid. It is not diluted before serving.
Fruit punch: Fruit punches are made by mixing the desired fruit juices. This contains 25 per cent of total
fruit juice and 65 per cent of sugar.
Fruit syrups: In fruit syrup only one type of fruit is used. This type of fruit beverage contains at least 25 per
cent fruit juice or pulp and 65 per cent total soluble solids. It also contains 1.3-1.5 per cent acid and is
diluted before serving.
Fruit juice concentrates: This is the fruit juice which has been concentrated by the removal of water either
by heat or freezing or by reverse osmosis.
There are no guidelines or specification that particular equipment is dedicated to extraction of juice
or pulp of a particular fruit. It entirely depends on the equipment that gives the best juice or pulp of high
quality. Generally, crushing and pressing extract juice from fresh fruits. There are various types of
equipment used in extraction of fruit juices and pulp. Freshly extracted juices and pulps are highly attractive
in colour and excellent in flavor, but deteriorate very rapidly if they are not preserved immediately, various
factors influence and/or accelerate the loss of quality both internally and externally. Preservation of pulp and
juices by chemical preservatives, heat processing and freezing are very popular.
Preparation of Fruit Juice

101
Fruit juices must be prepared from sound, mature fruits only. Soft fruit varieties such as grapes, tomatoes
and peaches should only be transported in clean boxes, which are free from mould and bits of rotten fruit.
Fruits
↓
Receiving the material
↓
Washing
↓
Sorting
↓
Crushing/Grinding/Disintegration
↓
Enzyme treatment
↓
Extraction/ Expression
↓
Straining/Filtration
↓
Clarification (Optional)
↓
De-tartarisation (Optional)
↓
Preservation of fruit juice
↓
Filling in sterilized bottles
↓
Corking
↓
Pasteurization
↓
Labeling and Storage
Flow chart for fruit juice production
Washing: Fruit must be thoroughly washed. Generally, fruits are submitted to pre-washing before sorting
and a washing step just after sorting. Washing can be done either by water or by dilute hydrochloric acid (1
part acid: 20 part water).
Sorting: Removal of partially or completely decayed fruit is the most important operation in the preparation
of fruit for production of first quality fruit juices; sorting is carried out on moving inspection belts or sorting
tables.
Extraction of juice-The method of extraction of pulp and juices depends upon the structure of fruit, location
and character of the tissues in which the juice is located. In fruits like aonla, apple, grapes etc the juice is
located throughout the fruit and is readily recovered by crushing and pressing. While in case fruits like
apricot, peaches, plum, mango, tomato etc. the raw or cooked fruits are passed through a pulper or similar
machine. In case of citrus fruits the juice is embedded in a sac and it requires entirely different machine such
as halving and burring machine halving and burring machine. Requirements for extraction and preservation
of pulps and juices are as follows:
Extraction
• Pulper

101
• Screw type juice extractor
• Citrus juice extractor
• Citrus halving machines
• Fruit mill/fruit grater
• Basket press/hydraulic press/rack and cloth press,
• Crown corking/pp cap sealing machine
Crushing/Grinding/Disintegration: This is applied in different ways and depends on fruit types:
Crushing for grapes and berries; Grinding for apples, pears; Disintegration for tomatoes, peaches,
mangoes, apricots etc. This processing step will need specific equipments, which differs from one
type of operation to another.
Enzyme treatment: The enzyme treatment of crushed fruit mass is applied to some fruits by adding
0.2-0.8% pectolitic enzymes at about 50° C for 30 minutes. This optional step has the following
advantages:
 Extraction yield will be improved
 The juice colour is better fixed
 Taste of finished product is improved.
Expression/extraction: Generally juice is expressed from the crushed/disintegrated fruit pulp.
During expression, juices should not be unnecessarily exposed to air as it will spoil the colour, taste
and aroma and also reduce the vitamin content. The equipments used for the juice extraction are
screw type juice extractors, basket presses or fruit pulper. All equipments used in the preparation of
fruit juices and squashes should be rust and acid proof. Copper and iron vessels should be strictly
avoided as these metals react with fruit acids and cause blackening of the product. Machines and
equipments made of aluminium, stainless steel, etc can be used.
Straining/Filtration: The extracted juice contains some amount of suspended matter. The suspended matter
consists of broken fruit tissue, seed, skin, gums, pectic substances and protein in colloidal suspension. These
materials can be removed by straining through a thick cloth or sieve. Removal of all suspended matter
improves the appearance but often results in disappearance of fruity character and flavour. The present
practice is to let fruit juices and beverages retain a cloudy or pulpy appearance to some extent.
Clarification: It is the process of complete removal of all suspended material from the juice. This can be
performed by many methods viz. centrifugation, enzyme treatment, settling, filtration, freezing (-18oC), use
of high temperature (nearly 82oC) and low temperature (-2 to –3oC). The chemical treatments like addition
of gelatin, albumin, casein, or a mixture of tannin and gelatin are also used for the removal of suspended
particles. Centrifugation is carried out in centrifugal separators with a speed of 6000 to 6500 rpm. Enzyme
clarifying is based on pectic substance hydrolysis; this will decrease the viscosity of juice and facilitate their
filtration. The treatment is the addition of pecolitic enzyme preparations in a quantity of 0.5 to 2 g/l. This
will last for 2 to 6 hours at room temperature, or less than 2 hours at 50° C, a temperature that must not be
exceeded.
De-tartarisation is applied only to raisin juice and is aimed to eliminate potassium bi-tartrate from solution.
This step can be performed by the addition of 1% calcium lactate or 0.4% calcium carbonate.
Preservation of Fruit Juices
Fruit juice is preserved to prevent the decay/spoilage and to extend the shelf life of the juice in a good
condition for future use. This is generally done by the use of high temperature (pasteurization and flash
pasteurization), use of low temperature (refrigeration and freezing), preservation with chemicals (sulphur
dioxide and benzoic acid), drying, filtration, carbonation, and by using sugar. The methods used for the
preservation are follows:
Pasteurization

101
Preservation by heat is the most common method. The juice is hermetically sealed in containers
before being pasteurized. Usually the fruit juices are pasteurized at about 85°C for 25 to 30 minutes
according to the nature of the juice and size of the container.
Flash Pasteurization
In this method, fruit juice is heated for a short time at a temperature higher than the pasteurization
temperature and held at that temperature for about a minute and then filled into containers which are
sealed air tight under cover of steam to sterilize the seal and then, cooled. This method has many
advantages viz., minimum loss of flavour, preservation of vitamins, economy of time and space,
uniformity in body of juice, and minimum cooked flavour.
Preservation by Chemicals
Pasteurized fruit beverages undergo spoilage once opened. To avoid this it is necessary to use
chemical preservatives. Chemically preserved beverages can be kept for a fairly long time even after
opening the seal of the bottle. The two important chemical preservatives permitted in our country by
FPO are sulphur dioxide (including sulphites) and benzoic acid (include benzoates).
Sulfur dioxide: It is widely used throughout the world in the preservation of fruit juice and
other beverages. It has good preserving action against bacteria, moulds and inhibits enzymes.
In addition, it acts as an antioxidant and bleaching agent. It is generally used in the form of
it’s salts such as sulphite, bisulphite and metabisulphite.
The limitations of sulphur dioxide are:
 It can’t be used in some coloured juices like those of jamun, strawberry etc on account
of its bleaching action.
 It corrodes the tin containers.
 Some consumers may be sensitive to sulphur dioxide.
Benzoic acid: It is only partially soluble in water and hence its salt, namely sodium benzoate
is used as preservative. Pure sodium benzoate is tasteless and odorless. The antibacterial
action of benzoic acid is increased in the presence of CO2 and acid. Benzoic acid is more
effective against yeast than against moulds. The quantity of benzoic acid depends on the
acidity of the products. In case of fruit juices with pH of 3.5-4, addition of 0.06% of sodium
benzoate is recommended.
By Addition of Sugar- Syrups containing 66 % or more of sugar do not ferment. Sugar
absorbs most of the available water with the result that there is very little water for the growth
of microorganisms. This reduction in water will inhibit the multiplication of microorganisms
and gradually they die out from the product.
By Freezing- Microbial growth and enzymatic reactions are retarded in juice stored at low
temperatures. This method is particularly useful in case of juices whose flavour is adversely affected
by heating. Preservation by freezing is carried out at about −30° C, after a preliminary de-aeration.
Then storage is done at −15 to −20° C.
By Drying
By Carbonation- It is the process of dissolving sufficient carbon dioxide
in fruit juice so that the product when served gives off the gas as fine
bubbles and has characteristic taste. Carbonation is done at a
concentration of 1.5% CO2 under a pressure of 7 kg/cm².
By Filtration- In this method, the juice is first clarified through ordinary
filters and then passed through special filters. These special filters retain
yeast and bacteria.
By Irradiation- The irradiation process involves passing of fruit juice
through a radiation field allowing the juice to absorb desired amount of
radiation energy. The juice itself never comes in contact with radioactive
material. The gamma radiations from the radioactive material will
disinfest, sterilize and preserve the fruit juice. The dose required to
provide stability is partly determined by the solid content of the juice. A
dose of 3 kilo Grey is adequate to secure stability at ambient temperature

101
for more than a year.
Bottling
Bottles are thoroughly washed with hot water and drained before filling. A 1.5 to 2.5 cm head space is left
during filling. They are then sealed either with crown corks (by crown corking machine) or with caps (by
capping machine).A typical corking machine is shown in Figure
EQUIPMENTS FOR THE PRODUCTION OF JUICE AND PULPS
Different types of equipments are used in the juice processing plant, starting from equipments for
washing, sorting, extracting to pasteurizers. While selecting equipment the material of construction is very
important. A unit of machinery made of different metals should also be avoided because are similar metals
in the system or unit will lead to the setting up of small electrical couples and consequently corrosion will
take place. Use of rubber in the equipments should be avoided as far as possible.
Washing Equipments- Different types of equipments are available for washing of fruits and vegetables.
Tender fruits are usually washed with a fine overhead spray of water, while the fruits travel on a continuous
woven wire belt. On small scale processing plants washing is carried out in cement or galvanized iron tanks.
Sorting Equipments- In large factories, a continuous broad belt, made of woven metal, is generally
employed for sorting the fruits. In smaller factories, however, batch sorting will be sufficient
Pulping/Grinding Equipments- There are two types of extractions. In the first case, the fruits are crushed
and pressed continuously in one operation. In the second case, the
fruits are crushed or cut into small pieces or comminuted in a mill,
and these are subsequently pressed in a suitable press. Some of the
crushing/ extraction equipments are discussed here.
Hammer mills: These are devices to pulp/crush the whole
fruit in preparation for extraction. Hammer mills consist of
heavy stainless steel bars spinning from a common axis
under a high speed of rotation. The fruit is disintegrated
until it will pass out through a screen of specific size
mounted in the bottom of the mill. The mash will be of
finer particle size and the smaller particle size will allow
greater yields in case of firm fruits. Softer fruit presses

101
with more difficulty, and a larger particle size in the mash will enhance ease of pressing.
Grating mills: These offer an alternative method for disintegrating fruits. In grating mill, the fruit is
drawn past fixed knifes mounted on a cylinder. Control of the grind is accomplished by adjusting the
depth of the knifes and thus the size of cut from the fruit
Crusher: In grape juice processing, a stemmer/crusher removes residual stems, leaves, and petioles
from the grapes and does the initial crush of the fruit after arrival at the plant. This unit is designed
around a rotating drum perforated with holes of approximately 2.5 cm diameter. In the process of
traversing the rotating drum, grapes are caught by the perforated drum and knocked from the stems.
The individual grapes are broken open or crushed in the process and drop through the drum.
Screw Press
A typical screw press consists of a reinforced stainless steel cylindrical screen enclosing a large bore screw
with narrow clearance between the screw and the screen. Breaker bars are located between the screw
intervals in order to disrupt the
compressing mash. Back pressure
is provided at the end of the
chamber and is usually adjustable.
The segments of the fruit are fed
through a hopper at one end of a
feeding screw, revolving inside
the perforated screen. The juice
flows out through the perforations
and the pomace comes
out through the other end.
Capacities for screw press with a
30.5 cm and 41 cm diameter are
5,080 kg and 15,240 kg per hour.

101
Basket Press
These are of various designs and capacities and are
worked manually by hydraulic pressure. The
manually operated press consists of a strong
cylindrical basket which is made of wooden slates. It
rests on a wooden or metallic base. There is strong
screw at the top of this frame. The mash is folded in a
strong cloth and placed inside the basket. By turning
the screw by hand or with a hydraulic pump, the juice
is pressed out.
Rack and Frame Hydraulic Press
The hydraulic rack and frame press is a very
common press system found in small juice
operations. It was the primary method of fruit juice
pressing operations for many years. Heavy cotton or
nylon cloths are filled with a set amount of mash
and then folded to produce what is called a cheese.
The individual cheese is stacked and separated by a
wooden, stainless steel, or plastic spacer platen. The
combined stack is then compressed using a
hydraulic ram, during which the juice is expressed.
Decanter
A high solid stream can be partially clarified using decanters and finishers. Both pieces of equipment
operate on the principle of a spinning central cone, drum, or set of paddles pushing the juice through a
screen of some type. The unit is typically mounted horizontally, and throughput is relatively high. Total
Suspended solids may be reduced to 1% or less during operation, depending upon characteristics of the feed
stream and operating conditions of the separator.
Filtration Equipment
Finely suspended particles in the juice are removed with special equipment known as filter press. Filter
presses are available with various designs and capacities. The filtering media may be finely woven cloth,

101
canvas, fibre, asbestos pads, cotton or wood pulp discs, porous porcelain wares etc. The frame and filter
press is highly effective for clarification of lime juice required for the preparation of lime juice cordial.
Deaerator
Freshly extracted and screened juice contain large amount of oxygen, which should be removed before
packing. Most of the air is present on the surface of the juice and some is dissolved in it. The airs as well as
other gases are removed by subjecting the fresh juice to a high vacuum. This method is highly expensive due
to the vacuum creation. The equipment used for the removal of oxygen from the fruit juice is called
deaerator. The deaerated juice is heated in flash pasteurization equipment.
Flash pasteurizer/Rapid Pasteurizer
In this equipment, the juice is heated rapidly to a temperature of about 5.5°C higher than the pasteurization
temperature and kept at this temperature for about 10-60 second. By this technique, the loss of flavour and
vitamin destruction is minimum and the juice keeps a uniformly cloudy appearance.
ASEPTIC PACKAGING
Aseptic packaging: It is a process by which micro-organisms are prevented from entering into the package
during and after packaging. An aseptic process is achieved by filling a sterilized package with a sterile food
product within the confines of a hygienic environment.

101
Or
Aseptic packaging: It is packaging of the food material in a sterile environment.
Aseptic packaging can be defined as a procedure consisting of sterilization of the packaging
materials or container, filling of a commercially sterile product in a sterile environment and producing
containers which are hermetically sealed so that recontamination or reinfection is prevented. This results in a
product which is shelf stable under ambient conditions. The term ‘aseptic’ is derived from the Greek word
‘Septices’ and implies the absence or exclusion of any unwanted organisms from the product, package or
other specific areas. The term ‘hermetic’ is used to indicate suitable mechanical properties to prevent the
passage of microorganisms and gas or vapour into or from the container.
Aseptic packaging refers to a technique in which the product and the containers are sterilized
separately and packed in a completely aseptic environment till it comes out of the system. Aseptically
packaged juices and puree can be distributed in parts where refrigeration is not common. In aseptically
processed ‘bag-in-box’ packed guava and papaya puree, no loss of vitamin C and flavour was observed but
loss in colour took place. In order to destroy any Cl. botulinum spores and extend the shelf life of lowacid
foods, aseptic packaging may be utilized.
I. Steps followed in aseptic system
Aseptic processing comprises the following:
a) Sterilization of the product before filling
b) Sterilization of the packaging material or container before filling operation
c) Filling the product into the sterile package by maintaining the aseptic condition
a) Sterilization of product-The product sterilization is carried out by in-process or on-line
sterilization which is popularly known as the ultra high temperature (UHT) or high temperature short
time (HTST) depending upon the product treatment. Normally, the sterilization temperature is
maintained at 133–135°C for 3 to 5 seconds under HTST/UHT method to make the product sterile.
However, there may be slight variation in temperature and duration depending on the type of
product.
b) Sterilization of packaging materials and equipment- Different kind of sterilizing agents like
heat, chemicals and radiation are used alone or in combination for sterilization of aseptic equipment
and packaging materials.
i) Heat
ii) Hydrogen peroxide
iii) Radiation
c) Filling of the product under aseptic condition-Once the product has been brought to the
sterilization temperature, it flows into holding tube. The tube provides the required residence time at
the sterilization temperature. No external heating of holding tube should take place.
Aseptic packaging system has been introduced in India by Tetrapack Company and marketing the
different process food in tetra packs. The most commonly system is followed by Tetra pack, called as Tetra
classic aseptic (TCA) system. A number of processed food products which are liquid or semi solid in nature,
are available in the aseptic packages. The common products aseptic all packed are fresh milk and flavored
milk, fruit juices, yogurt, vegetable oil, chocolate milk, Milk curd, cream.

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PRECAUTIONS
• Avoid overripe and microbiologically spoiled fruits for making juice and pulp.
• Wash the extractors and other equipment with hot water to reduce the chance of infection.
• Preserve the juice and pulp immediately after extraction in order to avoid quality deterioration and
incidence spoilage.
• Dry the pomace immediately in order to avoid spoilage and use it for the production of value added
products.

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The use of chemical preservatives in fruit juices and fruit drinks
As the name suggests, pure fruit juice is solely the extracted juice of fruit and should not have any
preservative, or any other ingredients (such as sugar) added.
Fruit drinks that are not consumed in one go can have preservatives added to help prolong the shelf life once
they have been opened.
There are several chemical preservatives that can be added to fruit juices. Processors need to check with
local authorities or standards agencies to find the maximum permitted levels.
Compound Comments Commonly used
levels
Sulphites and
sulphur
dioxide
Sulphur dioxide gas and the sodium or potassium salts of
sulphite, bisulphite or metabisulphite are the most commonly
used forms. Sulphurous acid inhibits yeasts, moulds and bacteria.
Sulphur dioxide is mainly used to preserve the colour of fruits
during drying.
0.005-0.2%
Sorbic acid Sorbic acid and sodium and potassium sorbate are widely used to
inhibit the growth of moulds and yeasts. The activity of sorbic
acid increases as the pH decreases. Sorbic acid and its salts are
practically tasteless and odourless in foods when used at levels
less than 0.3%.
0.05-0.2
Benzoic acid Benzoic acid, in the form of sodium benzoate is a widely used
preservative. It occurs naturally in cranberries, cinnamon and
cloves and is well suited for used in acid foods. It is often used in
combination with sorbic acid at levels from 0.05-0.1% b y
weight.
0.03-0.2%
Citric acid Citric acid is the main acid found naturally in citrus fruits. It is
widely used in carbonated beverages and as an acidifier of foods.
It is a less effective anti-microbial agent than other acids.
No limit
Permitted preservatives used in fruit juices and beverages

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Thermal Processing ofFruits and Vegetables-History, definition, various techniques of
thermal processing andtheir effects on the quality of fruits and vegetable products,
types of containers and their selection, spoilageofcanned foods
There are several methods of preservation of fruits and vegetables and canning is one of them. It is
an important method of food preservation by heat. In this process, the foodstuff (fruits & vegetables) are
placed in containers, and sterilized by placing them in hot water or steam. Canning is also known as
appertizing in honour of its inventor.
Canning : is defined as preservation of foods in sealed containers and usually implies heat treatment as the
principal factor in the prevention of spoilage.
Or
the process of preserving food by sterilization at >1000 C and cooking in a sealed metal can, which destroys
bacteria and protects from contamination.
History of Canning
The canning process dates back to the late 18th century in France when the Emperor Napoleon
Bonaparte, concerned about keeping his armies fed, offered a cash prize to whoever could develop a reliable
method of food preservation. Nicholas Appert conceived the idea of preserving food in bottles, like wine.
After 15 years of experimentation, he realized if food is sufficiently heated and sealed in an airtight
container, it will not spoil. Peter Durand, took the process one step farther and developed a method of
sealing food into unbreakable tin containers, which was perfected by Bryan Dorkin and John Hall, who set
up the first commercial canning factory in England in 1813. As more and more of the world was explored,
and as provisioning armies took on greater importance, the demand for canned foods grew. Thomas Kensett,
who emigrated to the United States, established the first U.S. canning facility for oysters, meats, fruits and
vegetables in New York in 1812. More than 50 years later, Louis Pasteur provided the explanation for
canning’s effectiveness when he was able to demonstrate that the growth of microorganisms is the cause of
food spoilage.
CANNING PROCESS FOR FRUITS AND VEGETABLES
Canning is defined as the preservation of foods in the sealed containers and usually implies heat
treatment as the principal factor in prevention of spoilage. Mostly the canning is done in tin cans but other
containers like glass, plastics, etc. The fruits and vegetables used for canning should be as fresh as possible
so that their quality could be retained. Fruits should be mature, firm ripe and free from all defects, while
vegetables should be usually tender.
Principles
1. Destruction of spoilage organisms within the sealed containers by application of heat,
2. To improve the texture, flavour and appearance by cooking, and
3. To stop recontamination of food during storage.
Selection of fruits & vegetables
Sorting & Grading
Washing
Peeling
Cutting

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Blanching
Filling
Syruping/Brining
Lidding /Clinching
Exhausting
Seaming
Processing
Cooling
Storage
Selection of Fruits and Vegetables
We should select the fresh good quality fruits and vegetables for canning because quality of canned
product is dependent on the quality of raw material. Fruits should be firm, mature and uniformly ripe.
Over-ripe, insect infected and diseased fruits and vegetables should be rejected. Unripe and immature
fruits should be rejected because they generally shrivel and toughened on canning. Vegetables should be
tender. Fruits and vegetables should be free of dirt.
Sorting and Grading
We should see that any spoiled, blemished, injured fruit or vegetable be discarded. Raw material should
be sorted based on maturity and ripeness. Fruit and vegetables should be graded according to size and
colour to obtain uniform quality of canned product. Grading can be done by hand or by machines. Screw
type and roller type grader are generally used. Fruits like berries, cherries, grape and plum are graded
whole, while peach, pear, apricot, mango, pineapple, etc., are generally graded after cutting into pieces.
Washing
Fruits and vegetables should be washed with water thoroughly. Washing will remove dust, dirt and any
sprayed chemical residue. Any microorganism over the surface of the fruits or vegetables are also
washed out. Water used for washing may be cold or hot. We may employ chlorine (150ppm) or
potassium permanganate (dilute solution) in water to disinfect fruits and vegetables. Fruits and
vegetables are generally soaked in water tank before washing by hand. They can be washed by spraying
water, which is the most effective method.
Peeling
Washed fruits and vegetables are prepared for canning. The fruits and vegetables are peeled by hand
with knife or machine, heat treatment or lye solution. Lye is a solution of caustic soda. For example,
peaches and potatoes are scaled in steam or boiling water and put in cold water to soften and loosen or
cracking of skin. Later the skin can easily be removed by hand or pressure spray of water. In case of lye
peeling of fruits and vegetables, e.g., peaches, apricots, orange and sweet potatoes are dipped in boiling
lye (1-2% caustic soda) for ½ to 2 minutes. Any trace of alkali is removed by washing fruits and
vegetables in running cold water; sometimes they are also washed in water containing 0.5 per cent citric
acid or hydrochloric acid.
Cutting

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We should cut the fruits and vegetables depending upon the requirement like slice, dice, finger etc either
by knife or by machine. At the same time seed, stone and core are also removed by special coring knife.
Blanching
In blanching operations the prepared fruits and vegetables are kept in boiling water or exposed to steam
for 2 to 5 minutes followed by cooling in running cold water. The time and temperature of blanching
vary depending on the type of raw material. Inactivation of peroxidase enzyme is used as an index
adequacy of blanching.
The purposes of blanching are:
(1) to inactivate the enzymes, which cause discoloration and off-flavour
(2) to reduce the volume by shrinkage, making their packing easier
(3) to reduce the microbial load on raw materials
(4) to enhance the green colour of vegetables like peas and spinach,
(5) to remove undesirable acids and astringent taste of the peel resulting improved flavour, and (6) to
remove occluded gases for reducing strain on the seam of can during processing.
Filling
Tin cans are used as containers for canning. The cans can be opened from any end as they are called
open top sanitary can. Cans are washed with hot water. Prepared fruits and vegetables are filled into cans
either by hand or by machine. Plain cans are used generally, although in case of coloured fruits like
black grapes, red plum, strawberries, etc., lacquered cans are employed. In case of canned fruits the
drained weight should not be less than 50% and for berry fruits not less than 40%. Similarly for canned
vegetables the drained weight should not be less than 55% but in case of tomatoes limit is the 50%.
Therefore, fruits and vegetables are filled about 60 percent of the filling capacity of a can.
Syrup
A solution of sugar in water is called syrup. Generally the fruits are covered with sugar syrup. Cans are
filled with hot (79°–82°C) sugar syrup, leaving a headspace of 0.3 to 0.5cm. Syrup of 10° to 55° Brix
(per cent sucrose) is generally used. We can prepare sugar syrup of 20° Brix by dissolving 250 g sugar in
one-liter water and of 50oBrix by dissolving one kg of sugar in one litre water. Sometimes citric acid
and ascorbic acid are also mixed with the syrup to improve flavour and nutritional value, respectively.
The purpose of adding syrup to fruits is
(1) to improve taste
(2) to fill up the interspaces in can
(3) to facilitate further processing.
Brining
Brine is a solution of common salt in water. Brine is used in canning of vegetables. A brine of 1 to
3% salt is used at 79°-82°C, leaving a headspace of 0.3 to 0.5 cm in the can. The objectives of brining are to
improve the taste of vegetables and to facilitate further processing by filling the interspaces of vegetables in
the can.
Lidding or Clinching
Now the filled cans are covered loosely with the lid before exhausting. It has some disadvantages
such as spilling of the contents and toppling of the lids. In modern canning, lidding has been replaced by
clinching operation. In this case, lid is partially seamed. The lid remains sufficiently loose to permit the
escape of gases, air and vapour formed during exhausting operation.
Exhausting
There are respiratory gases and air remains in the cans, which are to be removed before processing. The
method of removing these gases is known as exhausting. Containers are exhausted by heating or
mechanically. In heat exhausting, the cans are passed through a tank of hot water or exhaust box under

101
steam. The fruit cans are exhausted at 82 to 100°C for 7-10 minutes or until temperature at the centre of the
can reaches 74°C. The vegetable cans are exhausted at 90 to 100°C for 7-10 minutes or until temperature at
the centre of the can reaches 77°C. The proper exhausting reduces the strain on the seam of the can. The
time and temperature of exhausting vary with the size and contents of can, but it should be sufficient to
ensure a vacuum of 12 to 15 inch Hg in processed and cooled can.
Sealing or Seaming
After exhausting, the cans are sealed by double seaming machine and the method is called seaming. In
sealing lids on cans, a double seam is created, and the method of sealing or closing is also known as
seaming.
Processing
Process of heating and cooling of canned food to inactivate bacteria and to preserve food is also called as
commercial sterilization. Many bacterial spores are heat resistant, which can only be killed either by very
high or by very low temperature treatment or prolonged cooking. Such drastic treatment, however, affects
the quality of food. Thus processing time and temperature should be adequate to eliminate all bacterial
growth. We must not over-cook the canned foods otherwise it will spoil the flavour, appearance and texture
of the product. All fruits and acid vegetables can be processed satisfactorily at a temperature of 100°C, i.e.,
in boiling water. The acid present in fruits and acid vegetables retards the growth of bacteria and spores.
These bacteria and spores do not thrive in heavy sugar syrups, which are normally used in canning fruits.
Vegetables, generally non acidic (except tomato and rhubarb), are processed at a higher temperatures of
about 115 to 121°C. Bacterial spores usually do not grow below pH 4.5 as you have read in previous
chapters. We, generally process the canned products having pH less than 4.5 in boiling water but products
with pH higher than 4.5 require processing at 115 to 121°C. The higher temperature can be obtained by
processing in a retort under a pressure of 0.70 to 1.05 kg/cm2 (10 to 15 lb/sq. inch). The centre of can should
attain these high temperatures. The temperature and time of processing vary with the size of the can, the
larger the can, the greater is the processing time. Fruits and acid vegetables are generally processed in open
type cookers, continuous non-agitating cookers and continuous agitating cookers. The open cookers are
galvanized iron tank of desired capacity. Sealed cans are placed in iron crates and immersed in the tank
containing boiling water. In continuous cookers, the cans travel in boiling water in crates carried by
overhead conveyors. In continuous agitated cookers, the cans are rotated by special mechanical devices to
agitate the contents of the cans. Agitation reduces the processing time considerably. The non-acid vegetables
are processed under steam pressure in closed retorts. The sealed cans are placed in the retort, keeping the
level of water 2.5 to 5.0 cm above the top of the cans. The cover of the cooker is then screwed down tightly
and the cooker is heated by steam to the desired temperature. The period of processing (sterilization) should
be counted from the time the water starts boiling or steaming. After heating for the required period, heating
is stopped and the petcock or vent is opened. When the pressure comes down to zero the cover is removed
and the cans are taken out.
Cooling
After processing, the cans are cooled rapidly to about 39°C to stop the cooking process. Cooling can be done
by several methods such as
(1) immersing the hot cans in tank containing cold water
(2) spraying cold water
(3) turning in cold water into the pressure cooker,
(4) exposing the cans to air. Generally the first method is practiced.
Cooling water may be kept sterile with 1 or 2 per cent chlorine. If canned products are not cool immediately
after processing, the quality is deteriorated, e.g., peaches and pears become dark in colour, tomatoes turn
brownish and become bitter in taste, while peas become mashy with a cooked taste.
Testing for Defects

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Before the canned products are marketed, we should test them for any defect. The finished cans are tested
for leak or imperfect seals. We should tap the top of the can with a short steel rod. A clear ringing sound
indicates a perfect seal, while a dull and hollow sound shows a leaky or imperfect seal. Leaky cans should
be removed from the lot.
Storage, labelling and packing
Before storage, the cans should be completely dry, small traces of moisture are likely to induce rusting. They
should be stored in a cool and dry place. Storage of cans at high temperature should be avoided, as it
shortens the shelf life of the product. The high temperature may lead to hydrogen swell and perforation
during extended storage. The basement stores are useful, especially during summer months. The temperature
in these stores is lower by about 6° to 8°C, compared to outside temperature. Before dispatch, the cans are
labelled and packed either in wooden or cardboard boxes, and are ready for marketing. The cans may be
stored for 1 to 2 years depending upon the type of raw materials used and the shelf life of the product.
Spoilage in Canned Fruits and Vegetables
Canned products are liable to spoilage for various reasons. Spoilage in canned food may be caused due to
two reasons. Heated canned foods may undergo spoilage either due to chemical or biological reasons.
A) Spoilage due to physical and chemical changes:
1. Swell – Swell or bulge in cans caused due to the positive internal pressure of gases formed by microbial
or chemical action. Hydrogen Swell – This type of swelling is due to the hydrogen gas produced by the
action of food acids on the metal of the can. The swelling ranges from flipper – springer, soft swell or hard
swell.
2. Overfilling – Overfilling should be avoided.
3. Faulty retort operation – It gives cans look like swells.
4. Under exhausting – It causes severe strain during heat processing.
5. Paneling – It is seen in large sized cans that the body is pushed inward due to high vacuum inside.
6. Rust – Rust is mostly seen under the label and subsequently affects the label. Cans lacquered externally
do not rust.
7. Leakage – Cans generally leak due to defective seaming and nail holes.
8. Bursting – Cans may burst due to excess pressure of gases produced by decomposition of the food.
9. Discolouration – This may be due to enzymatic and non – enzymatic browning. Enzymatic discolouration
can be avoided by placing the peeled and cut pieces of fruits and vegetables in 2% salt solution.
10. Stack burning – The contents in the can if remain hot for a long time during storage result in stack
burning. It may cause discolouration. To avoid stack burning cans should be cooled quickly to about 39oC
before storage.
B) Spoilage by microorganisms
The time gap between filling and heat processing may cause microbial spoilage. If cans are not processed
properly they may result in spoilage by bacteria and the spoilage is termed as “Under processed” spoilage.
Clostridium botulinum a Major Threat in Canned Products
Various spoilages caused due to different microorganisms are:
1. Flat sour – The non-acid vegetables spoiled by Bacillus coagulens and Bacillus sterothermophilus.
2. Thermophilic acid spoilage – Cans swell due to production of carbon dioxide and hydrogen by
Clostridium thermo-saccharolyticum.
3. Sulphide spoilage – Caused by Clostridium significance in low acid foods.
Tin Containers for canning

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The cans are made of thin steel plate of low carbon content, lightly coated on both sides with tin metal.
Sometimes discolouration of the product or corrosion of the tin plate takes place. In order to avoid
corrosion, these cans are coated inside and or outside with lacquer, the process is known as “lacquering”.
There are two types of lacquers used.
1. Acid-resistant-Acid-resistant lacquer is a golden colour enamel, cans coated with it are called R enamel
or A.R. cans. The lacquered cans are used for packing fruits having water soluble colour (anthocyanins) for
example raspberry, strawberry, red plum, coloured grapes, pomegranate, etc. Fruits having water insoluble
colour, for example pineapple, mango, grapefruit, etc., are packed in plain cans only.
2. Sulphur-resistant – This lacquer is also of a golden colour, cans coated with it are called C. enamel or
S.R. cans. These cans are used for packing pea, corn, lima beans, etc. The tin cans are supplied to the
canning factory in flattened form, where they are reformed using a machine, reformer, into cylindrical
shape. After that, they are flanged by using flanger, which curls the rings outwards at each end. The one end
of the cylindrical can is then fixed, before filling it, using a machine known as double seamer. After filling,
processing and exhausting the can, the lid is fixed using the same machine.
Sterilization
Sterilization: A process to heat food product to a specific temperature for a specific time to kill the most
heat resistant spore-forming organism.
Sterilization is a process of heat application above 100°C, by sterilization we mean complete
destruction of micro-organisms. Because of the resistance of certain bacterial spores to heat, this frequently
means a treatment of at least 121° C (250° F) of wet heat for 15 minutes or its equivalent by using steam
under pressure. It also means that every particle of the food must receive this heat treatment. If a can of food
is to be sterilized, then keeping it at 121° C or retort for the 15 minutes will not be sufficient because of
relatively slow rate of heat transfer through the food in the can to the most distant point. In such cases time
needs to be increased.
At 121° C temperatures the spores of the heat resistant bacteria are quickly killed. The longer is the
heat treatment time at lethal temperatures, the larger is the number of killed microorganisms. At higher
temperature, the shorter is the time required to kill microorganisms and lower is heat-included damage to
food products. But in the case of canned food keeping it at 121° C or retort for the 15 minutes will not be
sufficient because of relatively slow rate of heat transfer through the food in the can to the most distant
point. In such cases time needs to be increased.
Theoretically, absolute sterility does not exist. In commercial practice not all cans of food are sterile.
However, they usually do not spoil because conditions in the container are not favorable for the growth of
concerned microorganisms. The pH may be too low or absence of oxygen. Therefore, the term processing is
highly suitable than the term ‘sterilization’ applied to canned foods.
The foods products low in acid and often high in protein and contain spore forming bacteria are
difficult to sterilize. The acidity of fruits and tomatoes greatly lower the death or sterilizing temperature,
which usually explains why acid fruits are easily sterilized.
This process wills make the treated product safely preserved at room temperature.
Effectof commercialsterilization
The destruction of nutrients the thermal process is dependent on
i) time temperature treatment used as the basis of the process
ii) rate of heat transfer into the product.

101
The commercial developments have focused primarily on increasing the rate of heat transfer into the
product. Hence, agitated retorts such as the orbitort, steritort, flame sterilizer and hydrostatic cooker have
been developed.
It has been observed (Ammerman 1957) that retention of vitamin C in tomato juice is improved
when processing is conducted at a HTST condition.
Under HTST conditions nutrient retention may be greatly enhanced. HTST aseptic canning also results in a
significant improvement in organoleptic qualities i.e. colour, taste and aroma. In an evaluation of HTST
aseptic processing, it was found that thiamin retention was significantly greater in HTST products than in
conventionally canned and retorted products.
It is a misconception to think that commercially sterile products remain unchanged during storage.
This is not the truth. Organoleptic and nutrient changes do occur during storage, the extent of the changes
being dependent on the time and temperature of storage. It has been observed that low temperature storage
results in an improvement in nutrient retention.
Dehydration of fruits; equipment and process for dehydration of plums, apricot, apple,
fig, grapes peach etc
b) Dehydration of Vegetables: equipment and process for dehydration of peas,
cauliflower, potato, methi, mushroom, tomato etc
c) Osmo-dehydration – basic concept and applications

101
Drying or dehydration is accomplished by the removal of water from the fruits and vegetables below a
certain level at which enzyme activity and growth of microorganisms is affected adversely. Both term drying
and dehydration mean the removal of water.
The term drying is generally used for drying of the produce under the influence of non-conventional energy
sources like sun and wind.
Dehydration on the other hand refers to the process of removal of moisture by the application of artificial
heat under controlled conditions of temperature, relative humidity and air flow. The sun drying is dependent
upon the elements which are beyond the strict control. It is a slow process and thus, not suitable for many
high quality products. Generally, it will not lower the moisture contents below about 15% which is too high
for storage stability of numerous products. Removal of water from foods provides microbiological stability
and assists in reducing transportation and storage costs.
Drying is one of the oldest methods of preserving food. Today the drying of foods is still foods can be stored
for long periods without any deterioration in quality. The principal reasons for this are that the
microorganisms, which cause food spoilage and decay, are unable to grow and multiply in the absence of
sufficient water and many of the enzymes which promote undesired changes in the food cannot function
without water. Two important process-controlling factors that enter into the unit operation of drying:
a) Transfer of heat to provide the necessary latent heat of vaporization, Movement of water or water
vapour through the food material and then away from it to effect separation of water from foodstuff.
PROCEDURES FOR DRYING
Drying of fruit/ vegetable involves three stages; pre-drying treatments, drying of the commodity and post
drying treatments.
Raw Material Preparation (washing, Peeling, Preparation)
This includes selection of fruits, sorting, washing, peeling (for some fruits and vegetables), cutting
into the appropriate form, and blanching (for some fruits and most vegetables). Fruits and vegetables are
selected and sorted according to size, maturity and soundness. It is then washed to remove dust, dirt, insect

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matter, mould spores, plant parts and other material that might contaminate or affect the colour, aroma, or
flavour of the fruit or vegetable. Peeling or removal of any undesirable parts is followed by washing. The
raw product can be peeled by hand, with lye or alkali solution, with dry caustic and mild abrasion, with
steam pressure, with high-pressure washers, or with flame peelers.
Blanching
Blanching is a partial pre-cooking treatment in which vegetables/ fruits are usually heated in water or in live
steam to inactivate the enzymes before processing.
Purpose of blanching
• Reduces drying time
• Removes intercellular air from the tissues
• Causes softening of texture
• Retards the development of objectionable odour and flavour during storage by enzyme inactivation
• Retain carotene and ascorbic acid during storage
• Removes pungency (onion)
• Impart desired translucent appearance to the product.
Sulphuring
The whole fruits, slices or pieces are exposed to the fumes of burning sulphur inside a closed chamber
known as sulphur box for 30-60 minutes.
Purpose of sulphuring
• Prevent oxidation and darkening
• Act as preservative/ antimicrobial agents
• Check the growth of moulds
• Prevent cut fruits from fermentation
• Prevent the vitamin losses
Drying/Dehydration
Dehydrated fruits and vegetables can be produced by a variety of processes. These processes differ primarily
by the type of drying method used. The selection of the optimal method is determined by quality
requirements, raw material characteristics, and economic factors. There are three types of drying processes:
• Sun and solar drying,
• Atmospheric dehydration including stationary or batch processes (kiln,
Oven, and cabinet/tray dryers) and continuous processes (tunnel, continuous belt, fluidized-bed, foam mat,
spray, drum and microwave heated dryers), and
• Sub-atmospheric dehydration (vacuum belt, vacuum drum and freeze dryers).
Sweating
Sweating is a practice of storage of dried product in bins or boxes for equalization of moisture or re-addition
of moisture to a desired level. It is used primarily with some dried fruits and some nuts (almonds and
walnuts).
Packaging
Most product are packaged after drying for protection against moisture, contamination with micro-
organisms, and infestation with insect , although some dried foods (e.g. fruits and nuts) may be held as long
as a year before packaging.
ADVANTAGES OF DEHYDRATED FRUITS AND VEGETABLES
Fruits and vegetables that are properly dehydrated, particularly to a low moisture level (below 5%) have the
following advantages:
1. Dehydration hardly affects the main calorie – providing constituents of fruit. It leaves the mineral
content virtually unchanged. Therefore, the process is helpful in preserving the nutritive content of
the final product. Vitamin losses are no grater with dehydration than with other preservation
methods.

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2. Dried fruits and vegetables have an almost unchanged shelf-life under proper storage conditions and
there is no greater degree of bacteria, enzymatic changes, and mould actions.
3. Transportation, handling and storage costs are substantially lowered, and need of costly refrigeration
during transportation and storage is eliminated Due to their reduction in average weight of 1/7th to
1/9th of the raw material shipping and handling weight is therefore reduced by approximately 90%.
4. They provide consistent product, an important modern marketing requirement. Seasonal variation in
product quality is either absent or at a minimum with low –moisture fruits and vegetables.
5. They provide opportunities for maximum convenience, flexibility, and economics in production
because they can be sized, shaped, formed, etc, to fit almost any requirement. With low moisture
disposal and pollution problems.
6. They utilize the most economical and disposable from of packaging. The two major considerations in
packaging dried fruits and vegetables are the exclusion of moisture and oxygen. Metal cans, plastic
bags, and laminated bags and boxes effectively limit the passage of moisture and oxygen.
7. They offer many distinctive conventional as snack products.
FACTORS AFFECTING DRYING
Food dehydration involves two steps
 to get heat into the product
 to get moisture out of the product.
Surface area
The heat and mass transfer is affected by surface area and higher surface area result into increased rate of
drying. Therefore, the food to be dehydrated is sub divided into small pieces or thin layers which speeds
drying for two reasons. First larger surface area provides more surfaces in contact with the heating medium
and thus, more surface area from which moisture can escape. Second smaller particles or thinner layers
reduce the distance through which heat must travel to the centre of the food and reduce the distance through
which moisture in the centre of the food must travel to reach the surface and escape.
Air velocity
High velocity air, in addition to taking up moisture will sweep it away from the drying foods surface,
preventing the moisture from making a saturated atmosphere which would slow down subsequent moisture
removal.
Dryness of the air
When the food dried in air, then food will dried rapidly due to more absorption and more holding capacity of
moisture by dry air than the moist air. Moist air is closer to saturation and so can absorb and hold less
additional moisture, the extent of dryness of the air also determines how a low moisture content food
product can be dried to low moisture content. Dehydrated food is hygroscopic and each food has own its
equilibrium relative humidity. Equilibrium relative humidity (ERH) is the humidity at a given temperature
where the food will neither lose moisture to the atmosphere nor pick up moisture from the atmosphere.
Dehydration of fruits like plums, apricot, apple, fig, grapes peach.
Grapes: Raisins prepared from grapes are the most important dried fruit product. Muscat and wine
varieties are dipped in boiling solution of 0.5% caustic soda followed by rinsing and sulphuring for 1 hr and
then, drying at 55- 60°C in a dehydrator or sun drying. Ripe bunches of grapes are hung inside the dark
rooms known as Kishmish khanas till berries acquire a greenish or light amber tint colour. Monucca or
raisins is prepared from large seeded Haitha grapes which are lye dipped prior to sun drying.
Apricot: mainly royal and tilton varieties are used for dehydration. Washing, apricots are not peeled before
peeling, cutting and pitting, blanching, sulfuring final product should contain 2000 ppm, and sulfured fruit is
now dried at 63 to 66 degree C in tunnel dryers. The relative humidity is about 50 to 55 % and in this
condition fruit take 15 to 20 hours to dry. After drying grading is performed, now fruit is ready to pack.

101
Apple: Washing, peeling, coring, trimming and slicing into 5 mm thickness, followed by sulphuring for 30
min or immersion in 1-2 % KMS solution for 30 min. This follows the drying at 60-65°C in a mechanical or
solar drier.
Fig: Washing, sulphuring for 1 hr followed by drying at 55 to 60°C in a mechanical or solar drier. In the
case of figs the drying should be more rapid.
Peach: Washing, stone, peaches before drying. The drying process includes washing, removal of pits,
cutting into halves, sulphuring for 30 min followed by drying at 60-65°C in a mechanical or solar drier.
Dehydration of Vegetables: equipment and process for dehydration of peas, cauliflower, potato, methi,
mushroom, tomato etc
Vegetables
Onion and garlic make excellent dehydrated product: onion is dried in the form of flakes and powder
whereas; garlic is dried as cubes and powder. Their use in the dry form has great scope particularly for
export point of view.
Peas: Thomas laxton, tall telephone and tall alderman etc type of varieties are used for dehydration. The
peas should be mature, but still green and tender). (Bruising of the peas will cause off-flavors, but is very
difficult to avoid bruising. Delay between podding and processing also causes off-flavor development. To
limit the degree of off-flavor, harvested peas should be kept iced and processed as quickly as possible. The
podded peas are washed as in cannery practice, preferably using a flotation method. Peas are blanched in
boiling water for 1 to 2 minutes. Long blanching may cause the skin of mature peas to burst. After
blanching, the peas should be cooled under water sprays and inspected for split skins. After traying
dehydration is performed in a parallel flow pre-drying tunnel. The dry bulb temperature at the hot should be
about 830C. Moisture content of the dried product should not exceed 5%.
Cauliflower: Washing, removal of stalks, covering leavers and steams, breaking of curd suitable size pieces,
blanching for 4-5 min. immersion for 1 hr in 1% KMS solution and draining followed by drying at 55-60°C
in mechanical or solar drier.
Carrot: Washing, scrapping, stalks and tips, cutting into 10 mm thick slices blanching for 2-4 min. in
boiling solution of 2% salt followed by drying at 60-65°C in mechanical or solar drier.
Potato: washing, peeling can be performed with lye or with steam. In lye peeling potatoes are completely
submerged for 2 to 3 minutes in 14 to 15 % sodium hydroxide solution at 95 to 101 degree C and cutting
into 10 mm thick slices, blanching in boiling water or steam for 3-4 min. and immersion in 0.5% KMS
solution followed by drying at 60-65°C in mechanical or solar drier. For dehydration tunnel and conveyor
dryers can be used.
Tomato: washing, blanching for 30-60°C, peeling and slicing into 1 cm thick slices followed by drying at
60-65°C in mechanical or solar drier.
Mushroom slices: mushrooms are one of the most important vegetable prepared by dehydration. Steps
include trimming, blanching with SO2 @ 500-1000 ppm for 5-10 min. slicing followed by drying in
mechanical or solar drier.
Ginger: trimming, washing, cutting or slicing and drying in mechanical or solar drier.

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101
OSMOTIC DEHYDRATION OF FRUITS AND VEGETABLES
Osmotic dehydration: Removal of water through a membrane from higher concentration to lower
concentration.
Reverse osmosis: Reverse osmosis means movement of water through the membrane by applying pressure
on the solute side of the membrane in excesses of the osmotic pressure.
The principle used in this process is that water diffuses from dilute solution to concentrated solution through
a semi-permeable membrane until concentration equilibrium in reached. The driving force water activity
gradient caused due to osmotic pressure. Fruits in general contain more than 75% water and get spoiled very
quickly, if not stored properly. The osmotic dehydration techniques not only enables the storage of the fruits
for a longer period, but also preserves flavor , nutritional characteristics and prevents microbial spoilage.
Osmotic dehydration can remove 50% of the water from fresh ripe fruits e.g. bananas, mangoes, papayas,
apples and other tropical fruits. The final drying of these osmotic dehydrated fruits by vacuum drying
provides a product which has good quality, attributes with respect to appearance, taste, flavor and colour as
compared to sun drying. The product is suitable as a ready to eat snack item. The process of dehydration
consists of three steps
1. Osmotic dehydration
2. Vacuum or air drying

101
3. Packaging
In osmotic dehydration, the fruits are subjected to osmosis by dipping or spreading them in a
aqueous sugar syrup under specific conditions, so that the water from the fruits migrates to sugar syrup.
Major dehydration of the fruit takes place in this process step. The final drying of the fruits to make it
suitable for marketing is carried out by vacuum or air drying depending on the cost considerations.
The different types of osmotic agents such as glucose, sorbitol, sucrose and salts are used according to the
final products. Osmotic dehydration (OD) was most popular method of pretreatment drying for food
materials which caused the reduction of energy costs and better the quality of end products OD was
frequently done by immersing the sample in concentrated solutions of salt or sugar. It was to apply in variety of
fruits by decreasing the moisture contents up to 30%.
Results of drying fruits by osmotic process
Successful-Apple, apricot, banana, boysenberry, cherry (raw, pitted), melon, mango, papaya, peach, pear,
pineapple, plum, raspberry, strawberry
Moderately successful - Cherry (raw, unpitted) blueberry, grapes
Unsuccessful- Citrus fruits, tomato, cherry (frozen)
Osmotic dehydration process
In osmotic dehydration process the fruits are cut into suitable size, dipped in 0.25 per cent sodium metabi-
sulphite solution in a sulphiting tank for 10 to 15 min, at room temperature. Fruit slices are subjected to
osmosis in 70% sugar syrup at 50°C for 3 hours to 18 hours depending upon the commodity. The syrup
should be circulated by a pump and the slices are drained, washed and subjected to drying either in a cabinet
dryer or vacuum dryer at 60°C for about 8 hrs at 736 mm of vacuum. The dry product is packed
immediately. The steps may be change with the types of materials being processed. In sucrose solution, the
osmotic dehydration of mango subjected by temperature (30–50°C), immersion time (60–150 min) and
concentration of solution (40–60% w/w) was studied.
Advantages of the process:
1. It is a low temperature water removal process and hence minimum loss of colour and flavour takes
place
2. Flavour retention is more when sugar or sugar syrup is used as osmotic agent.
3. Enzymatic and oxidative browning is prevented as the fruit pieces are surrounded by sugar, thus
maintaining the colour with little or no use of sulphur dioxide.

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4. Removal of acid from and uptake of sugar by the fruit pieces give a sweeter product than
conventional dried product
5. It partially removes water and thus reduces water removal load at the dryer.
6. It increases solid density due to solids uptake and helps in getting better quality product in freeze
drying.
7. The textural quality of product is better after reconstitution.
8. The storage life of the product is greatly enhanced.
9. Simple equipments are required for the process.
10. The process combined with air or vacuum drying is much cheaper than the freeze drying process.
Applications
The effects of osmotic dehydration as a pre-treatment are mainly related to the improvement of some
nutritional, organoleptic and functional properties of the product. Osmotic dehydration is effective at
ambient temperature, heat damage to colour and flavour is minimized and the high concentration of the
sugar surrounding fruit and vegetable pieces prevents discoloration.
Key Words
Dehydration: Removal of moisture under control conditions of temperature, air flow and humidity.
Drying: Drying of the product under the sun.
Conduction: Transfer of heat with contact particle to particle.
Blanching: Partial pre-treatment in which vegetables are heated in water or live steam to inactivate enzyme
before processing
Sulphuring: Exposing the fruits to the fumes of burning sulphur inside a closed chamber.
Freezing - Freezing process of selected fruits and vegetables: peas, beans, cauliflower,
apricot, mushroom – changes during freezing and spoilage of frozen foods
Freezing as a preservation method probably was observed by prehistoric people during cold weather; and,
until frozen storage cabinets were developed in the late 1800s, naturally occurring snow and ice were used to
freeze foods outside.
It is for the long terms preservation of fruit and vegetables. Low temperatures can be obtained by (a)
refrigeration or chilling (0-50
C) suitable for storage of potatoes, apples and other perishables, and (b)
freezing (−18 to −400
C) suitable for storage of most of the perishables. At temperature below the freezing
point of water (−180 to −400 C) growth of microorganisms and enzyme activity are reduced to a minimum.
Most perishable foods can be preserved for several months if the temperature is brought down quickly
(quick freezing) and the food is kept at these temperatures. Quick frozen foods maintain their quality and
freshness when they are thawed because only very small ice crystals are formed when foods are frozen in
this manner.

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Process flow of freezing of different fruits and vegetables:-
Preparation for Freezing- Once raw material has been accepted by the inspector at the factory gate
it quickly passes through several procedures in preparation for blanching. These procedures include
washing, cleaning, peeling, dicing, slicing etc. Electronic sorting is used to ensure defect-free product. Peas
are graded through drum sieves and green beans are sized according to their pod diameter through bar
graders.
Blanching-
Blanching is a key factor in
the successful production
of high-quality frozen
vegetables Its purposes
include reduction of
microbial populations,
cleaning the vegetables,
expelling gases from
vegetable tissues (more
important for canning than
freezing), and fixing the
colour and inactivation of
enzymes that would
otherwise cause
deterioration in flavour and
texture during long-term
storage. Most fruits do not
need to be blanched, some,
such as apples, pears,
peaches and apricots,

101
sometimes benefit from such a treatment because oxidative enzymes such as polyphenols oxidase would
otherwise cause darkening of the colour.
,
But most of the vegetables need blanching. Blanching is carried out most commonly by passing the
vegetables through steam or hot water. It should achieve
1. a uniform heat treatment to the individual units of the product;
2. a uniform blanching time to all units of the product;
3. no damage during the blanch and cooling process;
4. a high product yield and quality;
5. low consumption of energy and water.
Hot water blanching is usually carried Hot water blanching is usually carried out between 75°C and 95°C
and for between 1 and 10 min, depending on the size of the individual vegetable pieces. Typical times for
water blanching at 95°C are 2-3 min for green beans and broccoli, 4-5 min for Brussels sprouts and 1-2 min
for peas.
Freezing- In commercial terms, the freezing process involves the removal of heat from plant tissues
until such temperatures are reached that they become stable for an acceptable length of time. Refrigeration
equipment is used to achieve this in the factory and the temperatures reached in cold storage are colder than
-18°C, which gives most fruit and vegetable products a shelf-life greater than 12 months. The International
Institute of Refrigeration recognizes two types of frozen foods:
(i) frozen foods
(ii) (ii) quick-frozen foods
The former applies mainly to meat and poultry products, which are stored and sold at temperatures of -10°C
or colder. Quick-frozen foods are the term applied to products held at -18°C or colder. All vegetables and
most fruits in the UK are quick-frozen.
The most commonly used methods for freezing of fruit and vegetables, particularly high volume
products, are the fluidized bed freezers. These are of two types, one with a fixed bed and the other with one
or more moving stainless steel mesh or perforated plastic belts. The fixed-bed freezer operates by forcing air
at -30°C or colder. In fluidized bed freezer the individual units of vegetable are frozen separately. Tunnel
freezers may be used where the only movement of the product is its conveyance on a tray on a trolley
through the freezer.
Cryogenic freezers using liquid nitrogen or carbon dioxide are also used for freezing vegetables—
particularly where the product is delicate.
Quality Grading- Samples of product are normally taken from fruits and vegetables exiting the freezer
to establish the product quality grade. The standard or specification used will be that determined by the
freezing company or the buyer.
Packaging- Packaging used for frozen vegetables must protect the product from dehydration by
providing an effective barrier to moisture vapour.
ADVANTAGES OF FROZEN FRUITS AND VEGETABLES
1. The fresh vegetables and fruits closely resemble their frozen counterparts in freshness, since the
metabolic activities are arrested to such an extent that all the enzymes are inactivated and
microorganisms are under control.
2. The taste, flavour and colour of fruits and vegetables are preserved to a maximum.
3. They have high nutritive value since the retention of nutrients is maximum.
4. Since frozen vegetables have already been subjected to a heat treatment they require less time for
cooking thus saves considerable time in kitchen and also saves fuel.
5. Greater convenience in handling and preparation.
6. Freezing is a suitable choice for preserving fruit juices containing anthocyanin and carotenoid
pigments since the retention of pigments is maximum.
7. They offer more hygienic food
8. Cent percent edible portion of food of food in each package

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9. Since the degradative effect of heat treatment is bypassed in this, the method of freezing can retain
the pigment of such fruit juices and concentrates in its best form
10. Value for money especially off-season
11. No pollution problem in consuming areas
12. The waste collected during freezing can be utilized for production of value added products.
Limitations
1. Some water soluble nutrients may be lost during freezing as the process involves blanching in
boiling water.
2. Users of quick frozen foods need to invest on freezers to maintain the quality of the product till used.
This adds to the cost of the product.
3. Proper freezing transport facilities have to be developed for each product.
4. Quick freezing can be handled at the industrial level because it involves specialized freezing
equipment, technological know-how, strict quality control which would not be feasible on a small
scale.
5. Sales markets have to be established in all markets with refrigerated display cabinets.
Changes during freezing
Quick-freezing rapidly slows down chemical and enzymatic reactions in foods and stops microbial growth.
A similar effect is produced by sharp freezing, but less rapidly. The physical effects of freezing are of great
importance. There is an expansion in volume of the frozen food and ice crystals form and grow in size.
These crystals are larger in -slow freezing than in quick freezing and more ice accumulates between tissue
cells and may crush the cells.
When water changes state from liquid to solid, there is a 9% increase in volume that is responsible
for many of the inferior textural characteristics of frozen food. It is claimed that ice crystals rupture fruit and
vegetable tissue cells and even microorganisms. Further, freezing is considered to be responsible for killing
microorganisms. The vegetative cells of yeasts and moulds and many Gram-negative bacteria are
susceptible, while Gram-positive bacteria including staphylococci and enterococci are moderately resistant,
while spores of bacilli and clostridia are insensitive to freezing.
QUALITY AND PHYSICAL CHANGES IN FROZEN FOODS
When the food is frozen it undergoes number of quality and physical changes. Chemical and physical
reactions that decrease overall quality continue even in foods stored at -18°C. The losses that occur during a
normal storage period usually exceed any damage that occurs to the food during the initial freezing or
thawing.
(A) Physical changes
Fluctuation in storage temperature results in an increase in the size of ice crystals resulting in physical
damage to the food.
 Recrystallization- Recrystallization is a physical change in which many small ice crystals combine
to form a smaller number of large crystals.
 Sublimation- When water goes from the solid to the gaseous state without passing through the liquid
phase, it is called sublimation. Freezer burn is caused by sublimation of ice from the surface of the
food into the air inside the freezer. Freezer burn can affect the quality so adversely that the food is
discarded.
 Moisture Loss-Moisture loss, or ice crystals evaporating from the surface area of a product,
produces freezer burn. We have already discussed what freezer burn is. This surface freeze-dried
area is very likely to develop off flavours. Packaging in heavyweight, moisture-proof packaging
material will prevent freezer burn.
 Drip Loss-Formation of ice crystals causes a physical pressure on the cell wall. When the pressure
becomes high, it can damage the cell wall and lead to release of intracellular fluid. This is called drip
loss.

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 Denaturation- Protein alterations responsible for a decrease in solubility are collectively known as
denaturation. As the ionic concentration increases in freezing, through a reduction in water content,
the proteins form bonds with each other instead of water, and insoluble complexes result. This
change (protein denaturation) may be responsible for increased toughness in frozen foods.
 Freeze Cracking-Generally, light freezing rates lead to small ice crystals and to better quality food
systems. However, some products may crack when submitted to high freezing rates as in cryogenic
fluids. This is particularly seen in mango slices frozen by liquid nitrogen. Pre-cooling prevents freeze
cracking.
(B) Chemical changes
Microbial growth ceases at temperatures below 28°F (-2°C) for most foods, but chemical reactions continue
in foods even at -18°C. Such reactions include lipid oxidation, Maillard and enzymatic browning, flavour
deterioration
Packaging
There are several factors to consider in packaging frozen vegetables, which include protection from
atmospheric oxygen, prevention of moisture loss, retention of flavour, and rate of heat transfer through the
package. There are two basic packing methods recommended for frozen vegetables: dry pack and tray pack.
In the dry pack method, the blanched and drained vegetables are put into meal-sized freezer bags and packed
tightly to cut down on the amount of air in the package. Proper headspace (approximately 2 cm) is left at the
top of rigid containers before closing. For freezer bags, the headspace is larger. Provision for headspace is
not necessary for foods such as broccoli, asparagus, and brussels sprouts, as they do not pack tightly in
containers (Kendall, 2002).
In the tray pack method, chilled, well-drained vegetables are placed in a single layer on shallow trays or
pans. Trays are placed in a freezer until the vegetables become firm, then removed. Vegetables are filled into
containers.
Tray-packed foods do not freeze in a block but remain loosely distributed so that the amount needed can be
poured from the container and the package reclosed (Kendall, 2002).
The technical approach of chapter 1 focuses mainly on the large scale freezing industry. However, it is
important to highlight that all preliminary steps before freezing food products are quite similar whether on a
large or small scale. Furthermore, chapter 3 focuses more on the more suitable approach for small food
freezing industry.
Fruits exposed to oxygen are susceptible to oxidative degradation, resulting in browning and reduced storage
life of products. Therefore, packaging of frozen fruits is based on excluding air from the fruit tissue.
Replacement of oxygen with sugar solution or inert gas, consuming the oxygen by glucose-oxidase and/or
the use of vacuum and oxygen-impermeable films are some of the methods currently employed for
packaging frozen fruits. Plastic bags, plastic pots, paper bags, and cans are some of the most commonly used
packaging materials (with or without oxygen removal) selected, based on penetration properties and
thickness (Gradziel, 1988).
There are several types of fruit packs suitable for freezing: syrup pack, sugar pack, unsweetened pack, and
tray pack and sugar replacement pack. The type of pack is usually selected according to the intended use for
the fruit. Syrup-packed fruits are generally used for cooking purposes, while dry-packed and tray-packed
fruits are good for serving raw in salads and garnishes.
Thawing
During freezing, the outer surfaces contain ice crystals first, followed by the center portions. In thawing, the
outer portions first change from solid ice to liquid water followed by melting of the central portions. Initially
the temperature rise is rapid, but this only occurs before much of the outer surface has changed to the liquid

101
state. When thawing is done with microwaves, conduction is not the major method of heat transfer and this
scenario does not apply.
During thawing, the food passes slowly through temperatures near the melting point where chemical
reactions and recrystallization can occur. Thus, there is more opportunity for the quality of the food to be
decreased during thawing than freezing. Rapid thawing minimizes recrystallization and limits the time cells
are exposed to detrimental concentrations of solutes at high subfreezing temperatures.
Thawing with microwaves is efficient but often uneven and, because parts may become warm, it
should be done just before cooking or serving. Thawing wrapper foods under cool running water is a rapid
and safe method, but due to high water waste, it is not commonly used. Placing wrapped foods in still water
may not be safe if forgotten. Cooking vegetables directly from the frozen state minimize thawing changes,
but will increase the cooking time. For solid blocks of food, this may result in over-cooking outer layers.
Freezing process of selected fruits and vegetables: peas, beans, cauliflower, apricot,
mushroom
Steps for Freezing of Peas
1. Select young, tender beans or peas free of blemishes. The Codex Alimentarius B specification
recommends up to 7.5 mm for extra small peas, up to 8.2 mm for very small peas, up to 8.75 mm for
small peas, up to 10.2 mm for medium peas and over 10.2 mm for large peas.
2. Washing
3. Dehull the peas
4. After shelling, wash the peas or beans thoroughly, lifting them up and down in the water.
5. The next step—blanching—is necessary to stop the action of enzymes, substances that cause
harvested vegetables to decay. If not blanched, peas and butter beans develop off-flavors while
frozen and produce a bad odor when cooked. Blanching times for peas is 1 and a half minutes (90
seconds) - the duration is just long enough to stop the action of the enzymes and kill the bacteria.
Blanching is usually carried out between 75 and 95 °C for 1 to 10 minutes, depending on the size of
individual vegetable pieces
6. Cool the peas- After vegetables are blanched cool them quickly to prevent overcooking. Plunge the
peas into a large quantity of ice-cold water (I keep adding more ice to it). A good rule of thumb:
Cool for the same amount of time as the blanch step.
Fruit Preparation Type of Pack
Apricots Wash, halve, and pit. Peel and slice if desired.
If apricots are not peeled, heat in boiling water for 1/2
minute to keep skins from toughening during freezing.
Cool in cold water, drain.
Pack in 40% syrup, adding 3/4
teaspoon crystalline ascorbic acid per
quart of syrup.
Vegetable Preparation Blanch/Freeze
Beans Wash and trim the ends.
Cut if desired.
Water blanch: Steam
blanch:
Whole: 3 min. Whole: 4
min.
Cut: 2min. Cut: 3min.
Steam blanch: 3 min.
Cabbage Wash and cut into wedges. Water blanch: 3 min.
Steam blanch: 4 min.
Carrots Wash, peel and trim. Cut if desired. Water blanch: 5 min.
Cauliflower Discard leaves; steam and wash. Break into flowerets. Cut Water blanch: Steam

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into 2.5 cm (1 inch) pieces blanch:
Whole: 5 min. Whole: 7 min
Mushrooms Sort and cut large mushrooms. May be frozen without heat
treatment.
Peas Shell garden peas. Water blanch: Steam
blanch:
1-1/2 min. 1-1/2 min.
Whole: 5 min.
Pieces: 2-3
min.
commodity Temperature (°F) Rel. humidity (percent)
Approximate
storage life Freezing point (°C)
FRUITS
Apples 30–40 90–95 1–12 months -1.5
Apricots 31–32 90–95 1–3 weeks -1.05
Grapes, American 31–32 85 2–8 weeks -1.23
VEGETABLES
Beans green or snap 40–45 95 7–10 days -0.72
Cauliflower 32 95–98 3–4 weeks -0.70
Greens, leafy 32 95–100 10–14 days —
Mushrooms 32 95 3–4 days -0.9
Peas, green 32 95–98 1–2 weeks -0.61
KEY WORDS
 Freezing point: Temperature at which the liquid congeals into the solid state at a given pressure and
temperature.
 Refrigerated storage: Refers to storage temperatures above freezing point of water i.e. about 16 to –
2°C.
 Quick freezing: Quick freezing is defined as the process where the temperature of the food passes
through the zone of ice crystal formation in 10 minutes or less. The process removes quick removal
of water and small ice crystals are formed in the process.
 Slow freezing: Slow freezing involves slow removal of water and process may take 3-72 hours.
 Fluidized bed freezing: A method of freezing used for particulate items such as peas, diced carrots,
corn and berries. The freezer employs a bed with a perforated bottom through which refrigerated air
is blown vertically upwards.

101
 Blanching: Blanching is a common heat pre-treatment commonly used before processing most
vegetables. The main aim is to inactivate enzymes responsible for deterioration in food.
 Sublimation: The change of state from ice to water vapour or water vapour to ice. Unpackaged
frozen material changes to gaseous form e.g. dry ice (frozen carbon dioxide) when exposed to
extreme cold air.
 Freeze burn: It refers to a defect which develops during frozen storage. Moisture loss due to
sublimation from surface leads to discolouration in form of patches of light coloured tissues. This
can be controlled by humidification or lowering of storage temperature or better packaging.
Food Laws and FPO standards for fruits and vegetable products
Food is the basic need of all living organisms. Hence, its quality should be given top priority. Processing of
the food and food products is usually done at mass scale. So, there are always the possibilities of food being
adulterated. Secondly, the consumer must get the product for which he has paid. The processors may add
any prohibited preservative or permitted preservative in excess of the prescribed limits. So, it is essential to
set the minimum quantities of desirable characteristics required and the maximum quantities of undesirable
components that the food should contain. Food processing involves number of unit operations and material
handling. So, standards are formed and number of agencies and organizations are involved at national and
international level to make the standards implement and regulate them.
There are several ways of arriving at the standards for product quality but four methods are
commonly used;

101
1. Legal standards: Standards, which are established by government bodies.
2. Company or voluntary standards: Set by the various segments of food industry. Voluntary
standards generally represent a consumer image and may become a trademark of product quality.
3. Industry standards: An organized group attempts to establish given limits of quality for any food
product. Normally these become effective by pressure from marketing organizations or by specific
commodity groups where legal standards are not involved.
4. Consumer or grade standards: The consumer standards represent the consumer requirements of a
product and are generally based on experience of the industry with its consumer.
Out of these, the legal standards are the most important. These standards also encourage the safety and
quality of products by manufacturer making sure that the product meets the standards.
INDIAN STANDARDS
The Government of India is fully aware of the possibilities of food being adulterated. The main agencies
involved in this are described below.
Prevention of Food Adulteration Act (PFA)
One of the early acts to be promulgated in food laws and standards was the Prevention of Food
Adulteration Act of 1954, which has been in force since June 1, 1955, amended 1964 and again in 1976. The
objective of this act was to ensure that food articles sold to the customers are pure and wholesome. It is also
intended to prevent fraud or deception and encourages fair trade practices.
The Act prohibits the manufacture, sale and distribution of not only adulterated foods but also foods
contaminated with toxicants and misbranded foods. A central committee for food standards has been
constituted under the Act. The Food Health Authority is appointed at state level who is the Director of
Public Health and Preventive Medicine. He is responsible for the good quality and standards of foods
available to the consumers. Under FHA is the Local Health Authority (LHA). There is a Local Health
Authority appointed in each city in every state.
Fruit Products Order (FPO)
The Government of India promulgated a Fruit Products order in 1946. In 1955, the order was
revised. FPO certification India is effective since 1955 but became mandatory only in 2006 after Food
Safety and Standards Act. The Fruit Products Order (FPO) lays down statutory minimum standards in
respect of the quality of various fruits and vegetable products and processing facilities. The FPO is enforced
by the Department of Health. Presently there is a little over 5198 units registered under the Fruit Products
Order. Most of the units fall in the cottage or small-scale sector. A few modern processing plants have, now
come up and many more are in the pipeline.
Meat Food Products Order (MFPO)
Regulation for the production of meat products are covered by the Meat Food Products Order, 1973. It
provides means to:
1. Detect and destroy meat of diseased animals.
2. Ensure that the preparation and handling of meat and meat products be conducted in a clean and sanitary
manner.
3. Prevent the use of harmful substances in meat foods.
4. See that every cut piece of meat is inspected before sale to ensure its wholesomeness.
The order also lays down rules and conditions for the procedure to be adopted for the selection of disease-
free animals, slaughterhouse practices.
Bureau of Indian Standards (BIS)
Bureau of Indian Standards (BIS) is the National Standards Organization established as a Society in
1947 as Indian Standards Institution and subsequently made a statutory body as BIS under Bureau of Indian
Standards Act 1986. The Bureau comprises of members representing industry, consumer organizations,

101
scientific and research institutions, professional/technical institutes, central ministries, State Government
and Members of Parliament.
The functions of Bureau are;
1) Standard Formulation.
2) Certification: Product, Quality Management System, Eco Mark, Environment Management System,
Hallmarking of Gold Jewellery, Hazard Analysis and Critical Control Points.
3) Laboratory: Testing, Calibration and Management.
4) Standards Promotion.
5) Consumer Affairs.
6) Awareness and Training Programs.
There are 14 Technical departments engaged in formulation of Standards. So far 17000 Standards have
been formulated in different technological areas depending upon the National priority. These standards are
evolved through the consensus from sectors such as industry, Consumers, testing and laboratory experts and
Government organization by co-opting them in the related technical committees, sub-committee and panels.
The standards are reviewed time-to-time and continuously updated to match the technological changes
taking place. The BIS has formulated 1133 standards which pertain to food products.
AGMARK Standard
The word Agmark is derived from Agricultural Marketing. The AGMARK standard was set up by
the Directorate of Marketing and Inspection of the Government of India by introducing an Agricultural
Produce Act in 1937. The word ‘AGMARK’ seal ensures quality and purity. The quality of a product is
determined with reference to the size, variety, weight, colour, moisture, fat content and other factors are
taken into account. It covers the following commodities:
• Pulses
• Cereals, 1966, 2001
• Makhana
• Vegetable oils
• Fruits and vegetables
• Roasted Bengal gram
• Vermicelli, Macroni and Spaghetti
Any officer of the Central Government or a State Government, or any authority, authorized by the
Central Government, may, if he has reason to believe that any provision of this Act or the rules made there
under has been, or is being, contravened, enter any premises at any reasonable time and make necessary
inspection of, and search for, the agricultural produce in relation which such contravention has been, or is
being made. The officer can seize and penalize the firm for not meeting the standards.
Milk and Milk Product order (MMPO)
The Govt. of India had promulgated the Milk and Milk Product Order (MMPO) 1992 on 9.06.1992.
According to this order, it is essential for a dairy plant to process more than 10,000 liters of milk per day or
handle more than 500 tones of milk solids per annum. The production, collection, transportation,
distribution and supply of milk and milk products are controlled by the Milk and Milk Products Order,
1992. The order sets sanitary requirements for dairies, machinery and premises and includes quality
control, certification, packing, marking and labeling standards for milk and milk products. The standards
specified in the order also apply to imported products. Govt. of India has amended Milk and Milk Product
Order 1992 from time to time in order to make it more liberal and oriented to facilitate the dairy
entrepreneurs. The Govt. of India has notified the amendment proposals in the official gazette on
26/03/2002.Every person the business of handling, processing or manufacturing milk or milk products
should provide proper labeling based on the certification by a certified officer. The label on the package of
milk or milk products should contain –
(a) The name, trade name or description of the article contained in the package
(b) The name and business address the holder of registration certificate and number

101
(c) The net weight or number or volume of contents as may be the case
(d) The batch or code number, except in case of package less than 60g or 60ml.
(e) The day, month and year of manufacture of the packing milk and month and year of manufacture for
packing of milk products
(f) The date of manufacture for packages containing sterilized milk and infant milk food
Export (Quality Control & Inspection) Act, 1963
The Export Inspection Council is responsible for the operation of this Act. Under the Act, a large
number of exportable commodities have been notified for compulsory pre-shipment inspection. The quality
control and inspection of various export products is administered through a network of more than fifty
offices located around major production centers and ports of shipment. In addition, organizations may be
recognized as agencies for inspection and /or quality control. Recently, the government has exempted
agriculture and food products, fruit products and fish and fishery products from compulsory pre-shipment
inspections; provided that the exporter has a firm letter from the overseas buyer stating that the overseas
buyer does not require pre-shipment inspection from official Indian inspection agencies.
The Edible Oils Packing (Regulation) Order, 1998
The order came into force on 17th September 1998 and is regulated by the Department of Sugar and
Edible oil under Ministry of Food and Consumer affairs. “Edible oil” means vegetable oils and fats but does
not include any margarine, vanaspati, bakery shortening and fat spread as specified in PFA and rules made
there under, for human consumption
The Standards of Weights and Measures Act, 1976
The Standards of Weights and Measures, 1956 was first enactment by which the uniform standards
of weights and measures, based on the metric system were established. The Standards of Weights and
Measures are administered by the ministry of Consumer affairs, Food and Public Distribution All weights or
measures must be recorded in metric units and certain commodities can only be packed in specified
quantities (weight, measure or number). These include baby and weaning food, biscuits, bread, butter,
coffee, tea, vegetable oils, milk powder, and wheat and rice flour.
FSSAI, 2006
The Government has established Food Safety and Standards Authority of India under Food Safety
and Standards Act, 2006. The Act was needed to bring out a single statutory body for food laws, standards
setting and enforcement so that there is one agency to deal and no confusion in the minds of consumers,
traders, manufacturers and investors which was due to multiplicity of food laws. The priorities of the FSSAI
is laying down science based standards for articles of food and to regulate their manufacture, storage,
distribution, sale and import, to ensure availability of safe and wholesome food for human consumption
INTERNATIONAL STANDARDS
Quality of food is major concern worldwide. So, each country has formulated its own standards and created
agencies for strict quality control measures of the food products. Some of them are internationally accepted
as standards. A brief description of some these standards are given in this section.
 Association of Official Agricultural Chemists (AOAC)
AOAC is an independent association devoted to promoting methods validation and quality measurements in
the analytical sciences. The AOAC methods are recognized worldwide as an authoritative resource, because

101
of thorough and rigorous testing characterization. They are written in U.S. Code of Federal Regulation and
are also adopted by other national and international standards organizations.
 United States Department of Agriculture (USDA)
It is the main body of food standards in USA. Regulations and directives are developed by USDA to ensure
compliance with all relevant federal laws of USA, executive orders, directives, and policies. The regulations
also protect and promote U.S. agricultural health, administer the Animal Welfare Act, carry out wildlife
damage management activities, and ensure that America's agricultural exports are protected from unjustified
trade restrictions.
 Food and Drugs Administration (FDA)
The Food and Drug Administration of USA is one of the oldest and most respected consumer protection
agencies. FDA safeguards the USA food supply by making sure that all ingredients used in foods are safe,
and that food is free of contaminants like disease-causing organisms, chemicals, or other harmful
substances. The agency must approve new food additives before they can be used in foods. FDA regulates
all medical devices, including simple items like thermometers to very complex technologies such as heart
pacemakers and dialysis machines.
 International Standards Organization (ISO)
ISO prepared a document called ISO 9000 series in 1987 (modified in 1994) as a guideline for all
organizations on managing quality and standard. It covers quality, quality policy, quality management,
quality system, quality control, quality assurance, quality improvement, product, service, process and
customer. The ISO series is given below;
ISO 9000-1,2,3,4 : Quality management and quality assurance
ISO9004-1: Quality management and quality system elements subcontractor
ISO9004-2: Guidelines for services
ISO9004-3: Guidelines for processed materials
ISO9004-4: Guidelines for quality improvement
ISO9004-5: Guidelines for project management
ISO9004-6: Guidelines for quality plans
ISO9004-7: Guidelines for configuration management
ISO 10011-1,2,3 : Guidelines for auditing quality system
ISO 10012-1,2 : Quality assurance requirements for measuring equipment
ISO 10013: Guidelines for developing quality manual
ISO 10014: Guidelines for economic effect of quality
ISO 10015: Continuing education and training guidelines
 Codex Alimentarius
The term Codex Alimentarius is taken from Latin and means food code. The FAO/WHO Codex
Alimentarius Commission was established to implement the joint FAO/WHO Food Standard Program.
About 150 countries including India are member of the commission. The purpose of this program is to
protect the health of consumers and to ensure fair practice in the food trade. The Codex contract Point in
India is the Directorate General of Health Services (DGHS) in the Ministry of Health. Ministry of Food
processing Industries is also closely associated with the activities of Codex Alimentarius.
 Hazard Analysis and Critical Contort Point (HACCP)
Hazard Analysis and Critical Control Point (HACCP) is an important quality assurance system. This system
ensures that the products are safe and have good quality. It is science based and systematic, identifies
specific hazards and measures for their control to ensure the safety of food. The HACCP system consists of
following seven principles;
1. Conduct a hazard analysis.
2. Determine the Critical Control Points (CCPs).
3. Establish critical limits.
4. Establish a system to monitor control of CCP.
5. Establish the corrective action to be taken when monitoring indicates that a particular CCP is not under
control.
6. Establish procedures for verification to confirm the HACCP system is working effectively.

101
7. Establish documentation concerning all procedures and records appropriate to these principles and their
application.
 Good Manufacturing Practices (GMP)
 GMP provides quality assurances that off-the-shelf testing cannot. It provides continual measures of
quality that can uncover problems and fluctuations as they occur before the product is shipped. GMP
comprise a variety of practices that ensure quality including things such as:
• Raw materials quality assurance
• Record-keeping of substances throughout the manufacturing process
• Standards for cleanliness and safety
• Qualifications of manufacturing personnel
• In-house testing
• Production and process controls
• Warehousing and distribution
Virtually every manufacturer adheres to an in-house GMP standard, which varies from producer to producer.
List of Main International Standards and Statutes:
1. International Standards Organization (ISO)
2. Codex Alimentarius Commission (CAC)
3. World Health Organization (WHO)
4. Food and Agricultural Organization (FAO)
5. World Trade Organization (WTO)
6. World Organization for Animal Health (WOAH)
7. European Union Standards (EU standards)
8. Food and Drugs Administration (FDA), USA
9. International Plant Protection Organization (IPPO)
10. International Commission on Microbiological Specifications for Foods (ICMSF)
FPO Standards for different fruit and vegetables products

101

101
KEY WORDS
AOAC: Association of official Analytical chemists.
Certificate: A document providing evidence of status of qualification.
Critical control point: Any point in the process where loss of control may result in a health risk.
Food safety: A judgment of acceptability of the risk involved in eating a food; of risk is relatively low, a
food substance may be considered.
GMP: Good manufacturing practices guidelines that a company uses to evaluate the design and construction
of food processing plants and equipment.
HACCP: Hazard Analysis Critical Control Point; a preventive food safety system.
Standards: Set up and established by authority as a rule for the measure of quantity, weight, extent, value,
or quality. Set by different agencies to specifically describe a food; to be labeled as such, a food must meet
these specifications.
TQM: Total quality management.
NABL: National Accreditation Board for Testing and Calibration Laboratories.
FRAC: Food Research and Analysis Centre, an organization to improve public polices in USA.

101
By-products utilization
Fruits are consumed mostly raw and fresh, while the vegetables are usually consumed after cooking.
We also know that fruits and vegetables can easily spoil. This spoilage occurs at the time of harvesting,
handling, transportation, storage, marketing and processing.
Fruits and vegetables are rich source of vitamins, carbohydrates and minerals and even the inedible
portion is rich in nutrients. In most of the countries up to 80 per cent of the total production of fruits and
vegetables are processed.
However, in India, only around 2 per cent of the total production is processed and that too mostly at
cottage and small scale.
The processing waste generated by these factories can be categorized into solid or liquid wastes.
Solid wastes comprise of peels, skins, fragments, pits, spillage, trimmings, cores, fibre and seeds. Liquid
wastes include mainly the wash water coming out of factory after processing operations like raw material
washing, container washing, blanching, sterilization, cooling and plant and machinery clean up.
If we do not attend to these wastes, they become a source of pollution and contamination. But if we
attend to these wastes in scientific manner these can become a rich source of vital constituents like
carbohydrates, proteins, fats, minerals, natural colours, pectin, oils, biogas fuel, etc.
When we process the fruits and vegetables for juices, squashes, jams, jellies, canning and other
products, we get large quantities of left over materials. These are called solid wastes. During processing
fruits and vegetables produce different kinds of waste material which are described below:
i) Fruit wastes
a) peel, rag, pulp and seeds in citrus
b) peel, stones, and pulper waste in mango
c) rind and seeds in jack fruit
d) peel, core, seeds in guava
e) seeds, and skins in grape
f) pomace of apple
g) apricot kernel, shell and skin
h) peel, core, trimmings, shreds and leaves of pineapple
i) peel, pseudo stem, leaves of banana
j) over ripe and blemished fruits
k) cull fruits and unmarketable surplus
ii) Vegetable wastes
a) tomato seeds, skins and trimmings
b) asparagus wastes from canning
c) vines and pods from pea canning
d) wastes from dryers
e) peel and cores solids of potato
BY-PRODUCTS FROM FRUIT AND VEGETABLE WASTES
The solid waste obtained from processing of fruits and vegetables is not really a waste but sometimes is an
asset. A number of by-products may be obtained from the waste. Some of the important products prepared /
obtained from solid waste.
Possible by-products from solid wastes in fruit processing units
i) Fat- On an average stone content in mango is about 15 per cent. The estimated fat content in
mango kernel is more than 10 per cent.
ii) Magaz is a seed kernel. You can obtain magaz by decorticating the seeds of cucumber, pumpkin,
water melon, musk melon, etc. These have a big market in confectionary, bakery, ice creams and

101
beverages. Apricot kernel is sweet in taste. It looks like almond. It is used in confectionery along
with almond.
iii) Starch-Mango kernel obtained after decorticating the seed and banana pseudo stem are good
sources of starch. Banana plants provide about 5 per cent edible starch. Presently more than
1,40,000 tonnes of starch is available from mango seed kernel and 4-5 tonnes starch per thousand
banana plants is available.
iv) Tutti-Frutti- The papain extracted papaya and water melon rind after removal of green portion is
most suited for the production of tutti-frutti. The tutti-frutti is used in cakes, ice cream, bakery
products, etc.
v) Amchur / pickle- Large quantities of dropped green mangoes may be used for the preparation of
pickles, amchur and raw mango slices.
vi) Food grade flavours- Citrus are a good source of flavour. It is a by-product from shaved citrus
peel.
vii) Chutney- You can utilize fresh apple pomace, grape pomace, mango and tomato wastes to
prepare chutney of various tastes and colours.
viii) Edible oil- You can obtain edible oil from apricot kernel, grape seed and citrus seed. Apricot oil
and kernel paste are used like almond oil and paste in cosmetics and pharmaceutical preparations.
Grape oil is used to produce grape resins of lustrous appearance. Tomato seed oil is golden in
colour. It is used as salad oil.
ix) Cheese and halwa- Guava core, seeds and peel are utilized for the preparation of cheese and
halwa. There are certain varieties of banana which have thick peel. The pulpy portion from the
thick peel is scraped and used to make cheese.
x) Flour and fortified atta- You can prepare flour of jack fruit seeds, mango kernel and residues
left after extracting juice or the unmarketable surplus of fruits like anola and jamun, and
vegetables like carrot, radish, spinach, tomato, bitter gourd, etc., by drying and powdering. The
flour may be blended with cereal flour. This powder can be mixed with the wheat flour in 1.5 to
3.0 proportions. This flour contains 5.56-11.5 per cent protein, 16.1 per cent fat, 0.35 per cent
minerals and 69.2 per cent carbohydrate.
xi) Jam and jelly- You can use apple pomace to make jelly. White apricot kernel is added to apricot
jam to make it more attractive.
xii) Marmalade- You know that marmalade is prepared from citrus peel. The process involves
washing of fruit peel, slicing or comminuting the peel, boiling to tenderize and remove bitterness,
cooking with sugar or fruit syrup, and adding pectin.
xiii) Candied peel- You can prepare candied peel from orange or grape fruit peel. The diced peel is
equilibrated and cooked in sugar syrup and food dyes are added.
xiv) Citrus purées and bases- You can utilize citrus pulp and unconsumed fruits to manufacture
purees and bases. Preparation generally involves grinding, pasteurizing.
xv) Amla seed can be dried and used in ayurvedic preparations.
i) Black or brown seeds of ripened okra are roasted and used as a substitute for coffee.
INDUSTRIAL PRODUCTS FROM FRUIT AND VEGETABLE WASTES
Apart from utilizing the solid waste for preparation of some products as discussed above, it could also be
used for the preparation of some industrial products. Some of these products are described below:
i) Industrial oil- Cashew shell contains about 20 per cent oil and resin. You can use this oil for
insulation of electric wiring, break lining and preparing foundry moulds and cores. Other sources
of sweet and bitter oil are the waste of wild apricots (chulli), peach kernels, citrus seed and
tomato seed. These oils are used in cosmetics and pharmaceutical, and after refining in food
items.
ii) Pectin- Pectin is a by-product of mango and citrus peel, apple pomace, raw papaya, cashew
apple, etc. Pectin is used for making jam, pharmaceutical preparations and industrial uses.

101
iii) Essential oil- citrus wastes are a rich source of essential oil
iv) Natural colour- Industries are now extracting colours from blue grape skins, kokum (Garcinia
indica), phalsa (Grewia subinaequalis), jamun, safflower, etc.
v) Cups and plates- A banana plant contains 20-25 green leaves. Farmers harvest banana along
with the plant. The green and dried leaves are used to prepare disposable cups and plates to serve
meals.
vi) Other industrial uses- Beside the products described above, there are numerous other items
which can be prepared from the fruit and vegetable wastes. The few important ones are:
 Citric acid from lemon peel
 Varnish and resin from tomato peel
 Surfactantants, wetting agents and detergents from tomato seed meal
 Citrus seed and mango kernel oils for soaps and detergents
 Glucosides and bioflavins anti-oxidants from citrus peel
 Papaya latex for proteolytic enzyme papain
 Paper pulp from banana stem
 Fibre from pineapple leaves, mango peel and apple pomace wastes and by-products
obtainable from fruits and vegetables are a good source of cattle and poultry feed.
KEY WORDS
By products: Any material or product contingent upon or incidental to a manufacturing process.
Processing waste: Any material generated as waste, in a food processing operation.
Packaging waste: Any material generated as waste from a fruit/ vegetable packaging.
Peel: Outer covering of any fruit or vegetable.
Core : The innermost or centremost part of fruit containing the seeds.
Seed: It is a part of plant capable of developing into another such plant.
Pomace : Waste material obtained during processing of fruits like apple, citrus, etc.
Stem : Stalk of fruit/vegetable or plant.

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