Controlled atmospheric and Modified atmospheric packaging using nitrogen
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Modified atmospheric packaging (MAP) and controlled atmospheric packaging (CAP) extend the shelf life of foods by modifying the gas composition around foods. Nitrogen gas is commonly used in MAP and CAP as an inert filler to reduce oxygen levels and prevent oxidative reactions. For perishable foods, low oxygen levels achieved through nitrogen addition reduce the respiration rate and slow quality deterioration. Nitrogen is also used to displace air during packaging of dry foods like grains and cereals to create an environment lethal to insects and microbes.
Controlled atmospheric and Modified atmospheric packaging using nitrogen
- 1. CONTROLLED AND MODIFIED ATMOSPHERIC PACKAGING • Effect of Nitrogen on storage of durable and perishable commodities By- Debomitra Dey 12/9/2017Handling, Packaging and Storage 1
- 2. INTRODUCTION • CAS/CAP has been used for bulk storage and transportation of fresh fruits and meat, has been in action for over 100 years. • By 1970’s polymeric packages have been available where the gases in the atmosphere can be controlled or modified based on the need. 12/9/2017Handling, Packaging and Storage 2
- 3. • CAP- A controlled atmosphere is an agricultural storage method. An atmosphere in which oxygen, carbon dioxide and nitrogen concentrations as well as temperature and humidity are regulated. • MAP- Modified atmosphere is the practice of modifying the composition of the internal atmosphere of a package; in order to improve the shelf life. • Gases are combined in three ways for use in modified atmospheres: inert blanketing using Nitrogen Gas , semi- reactive blanketing using CO2 / N2 or O2 /CO2 /N2 or fully reactive blanketing using CO2 or CO2 /O2 (Parry 1993; Moleyar and Narasimham 1994). 12/9/2017Handling, Packaging and Storage 3
- 4. MAP (Modified Atmospheric Packaging) • Enclosure of food in package. • Atmosphere is modified or altered . • Increasing shelf life and maintenance of quality of product. 12/9/2017Handling, Packaging and Storage 4
- 5. MAP (Modified atmosphere packaging) • Prolonging shelf life of product. • Air composition in the package in changed. • By alteration of composition the initial freshness can be maintained 12/9/2017Handling, Packaging and Storage 5
- 6. Modified atmosphere • Active or Passive • Active modification- by gas flushing. • Displacement of air with controlled or desired gases. • Passive modification- associated with the consequence of the metabolism of food, viz. respiration, microbial metabolism • Polymeric film, may also contribute to this attribute due to gas permeation. 12/9/2017Handling, Packaging and Storage 6
- 7. MAP • It has been associated with chilling of food products. (exception baked foods) • Chilling is greatly enhanced when employed in combination with modification of gas atmosphere. • As deteriorative actions include aerobic respiration due to reduced O2 levels. 12/9/2017Handling, Packaging and Storage 7
- 8. Vacuum Packaging • Respiring foods, like flesh foods. • Form of MAP. • After initial modification, i.e., removal of air, biological action continues. • For ex. Level of CO2 increases as it produced by respiration of fruits and vegetables or by microorganism. 12/9/2017Handling, Packaging and Storage 8
- 9. Controlled Atmospheric Packaging (CAP) • Enclosure of food. • Impermeable package- gaseous environment. • Gases- N2, O2, CO2, water vapour. • Controlled environment for increasing shelf life. 12/9/2017Handling, Packaging and Storage 9
- 10. More about MAP & CAP • Alteration of concentration of atmospheric gases in storage prevents- ▫ Mould growth ▫ Insecticidal attack ▫ Quality deterioration Alteration- low O2 by adding N2 gas mixture resulting from burning HC or high CO2 environment. 12/9/2017Handling, Packaging and Storage 10
- 11. Advantages • Extend the period of storage. • As no chemicals are used, costs are significantly lower. • Environmental friendly packaging. • Dry conditions are unfavourable for growth of insects; hence, proves to be effective for insecticidal effect. • Additionally 3.2% O2 or 4.3% CO2 is required for complete mortality. 12/9/2017Handling, Packaging and Storage 11
- 12. Advantages and Disadvantages of MAP Advantages Disadvantages • Increase in shelf life: 40-500%. • Reduced economic losses due to longer shelf life. • Provides a high quality product. • No (some) chemical preservative is added. • Odourless and convenient packages. • Sealed packages (Barrier against recontamination) • Cost rises due to addition of gases, packaging materials and machinery. • Temperature control necessary. • Gas formulation differs depending upon the product. • Loss of benefit once packs are opened or if leaks found. • CO2 dissolving may lead to pack collapse and increased drip. 12/9/2017 12 Handling, Packaging and Storage Source- Minimal Processing technologies in Food Industry, CRC Press. 2002
- 13. 12/9/2017Handling, Packaging and Storage 13 STORAGE OF GRAINS • Storage is integral part while stages of transportation of grains from farm to processor to consumer. • Due to inadequate infrastructure the grains are susceptible to infection by pests and insects. • Traditional methods at times fail to offer a longer storage period. • Hence, modern storage methods of packaging are used to prolong shelf life of grains.
- 14. Hydrobaric Storage • Placing food in environment: pressure, air temperature, humidity controlled. • Change in rate of air is closely regulated. • Only O2 is required, as O2 concentration is directly proportional to pressure. • Research is been carried out for its effect on flesh foods and other perishables. • Not employed commercially. 12/9/2017Handling, Packaging and Storage 14
- 15. Gases used in MAP NITROGEN: Nitrogen is an inert gas and is used to exclude air and, in particular, oxygen. Used as a balance gas (filler gas) to make up the difference in a gas mixture, to prevent the collapse of packs containing high-moisture and fat-containing foods, caused by the tendency of these foods to absorb carbon dioxide from the atmosphere. For modified atmosphere packaging of dried snack products 100% nitrogen is used to prevent oxidative rancidity. • CO2 • O2 • Argon 12/9/2017Handling, Packaging and Storage 15
- 16. Nitrogen gas in packaging • Inert, Tasteless Less prone to pass into product or out of product ▫ Used as filler , cushion, replacing O2 ▫ as alternative to vacuum packaging ▫ product is fragile ▫ To limit collapse caused by CO2 absorption ◦ Doesn’t possess bacteriostatic activity ◦ Not very soluble in water, used for displacing Oxygen 12/9/2017Handling, Packaging and Storage 16
- 17. MAP of Durable products • Grains are dry, cannot support growth of bacteria (Jay, 1992) • Insects and moulds cause major spoilage of grains. • Anoxic environment lethal effect on insects and pests. • MAP alternative to use of chemical fumigants and insecticides, as they have carcinogenic effects. • Insects and Moulds develop resistance against insecticides and chemical fumigants. • Resistance to MAP may seldom occur, as it is dependent upon several biotic and abiotic factors. 12/9/2017Handling, Packaging and Storage 17
- 18. Modified Atmosphere Packaging for grains • Factors for control of insects in stored commodities: (Storey, 1979) ▫ Large area available to displace existing atmosphere in large bulk. Atmosphere lethal to storage pests within reasonable time. Should have no harmful effect on quality of treated commodity. ▫ Storage system should have adequate gas holding capacity. 12/9/2017Handling, Packaging and Storage 18
- 19. Effect of Nitrogen on storage of grains • Studies conducted by Shejbal in 1980, trials with cereal grains with N2 is advantageous at all temperature and moisture content up to 30°C and 19% compared to storage in air. • Oilseeds storage life is prolonged when stored with environment with higher N2 than air. • Disadvantage associated with N2 fumigation & storage technique related to storage facility. 12/9/2017Handling, Packaging and Storage 19
- 20. Application of N2 • Shredded lettuce gas flushed- 5% O2 , 5% CO2, 90% N2, vv) – prevent browning prior to atm equilibration (Ballantyne et a1 (1988b)). • Beverages- drop of N2 is added, into beer and carbonated drinks before seaming ▫ N2 used as filler, flushing out O2, this helps increasing shelf life, retains aroma and reduces can corrosion. 12/9/2017Handling, Packaging and Storage 20
- 21. 12/9/2017Handling, Packaging and Storage 21 Herbert et al, 2013 Growth of spoilage microflora under N2 concentration
- 22. Effect of N2 (perishable product) • Normally, the concentration of O2 in a pack is kept very low (1-5%) by use of Nitrogen Gas Generators to reduce the respiration rate of fruits and vegetables (Lee and others 1995). • Reducing the rate of respiration by limiting O2 prolongs the shelf life of fruits and vegetables by delaying the oxidative breakdown of the complex substrates which make up the product. 12/9/2017Handling, Packaging and Storage 22
- 23. MAP in Minimally processed products • Packaging allows manufacturer to impose a barrier between food and external environment. • Immediate environment can be altered, sums up MAP. • Few chemical preservative maybe added for minimally processed product. • CO2 is highly soluble in water, tends to be absorbed by moist food. 12/9/2017Handling, Packaging and Storage 23
- 24. MAP in Minimally processed products • For packaging of moist foods, N2 may be added. • On the other hand, disadvantage associated with N2: No bacterostatic effect Dangerous alternative, if food susceptible to bacterial growth 12/9/2017Handling, Packaging and Storage 24
- 25. 12/9/2017Handling, Packaging and Storage 25 N2 gas used for processing of Blueberries
- 26. N2 in Packaged cereal products • Dry product. • Ready to eat cereals – excludes light and O2. • CO2 along with N2 can be used to prevent Lipid Oxidative, that causes rancidity in products. • Ready to eat cereal products have high ratio of unsaturated to saturated fats. 12/9/2017Handling, Packaging and Storage 26
- 27. N2 in packaging of Fresh Pasta products • Falls in category of REPFED. • Gas comp for storage of Pasta- 100% N2 or 70-80% Co2 and 20-30% N2. • Survey study for Staphylococci spp in wet pasta product under (20:80) mixture from five different processor showed that 12% of fresh products were contaminated with S.aureus. • The result indicated that proper refrigertaion was essential to ensure safety of MAP wet pasta. 12/9/2017Handling, Packaging and Storage 27
- 28. References • Sahay K.M., Singh K.K., Unit Operations of Agricultural Processing. • Robertson G., Food Packaging- Practices and Principles. • Food Packaging Technology Handbook. • Church I J, Parsons A L, 1995 Modified Atmosphere Packaging Technology : A Review, J Sci Food Agric 1995,67,143-152 • Vicente M. Gomez-Lopez, Decontamination of Fresh and Minimally Processed Produce • C.M.D. Man, Adrian A. Jones, Shelf Life Evaluation of Foods 12/9/2017Handling, Packaging and Storage 28