Changes in Minerals During Processing of Foods
- 1. Changes in Minerals During Processing of Foods Submitted by Towkir Ahmed Ove M.Sc. In Food Science & Nutrition
- 2. Minerals a mineral is a chemical element required as an essential nutrient by organisms to perform functions necessary for life. Minerals originate in the earth and cannot be made by living organisms. Plants get minerals from soil. Most of the minerals in a human diet come from eating plants and animals or from drinking water.
- 3. kinds of minerals 1) macro minerals Macro means "large" in Greek (and our body needs larger amounts of macro minerals than trace minerals). The macro mineral group is made up of calcium, phosphorus, magnesium, sodium, potassium, chloride, and sulfur. 2) trace minerals A trace of something means that there is only a little of it. So even though your body needs trace minerals, it needs just a tiny bit of each one. Trace minerals includes iron, manganese, copper, iodine, zinc, cobalt, fluoride, and selenium.
- 4. Importance Of Minerals proper composition of body fluids, the formation of blood and bone, the maintenance of healthy nerve function, and regulation of muscle tone, including cardiovascular system.
- 5. EFFECT OF PROCESSING ON MINERALS The bioavailability of minerals is mostly affected by the processes of 1. milling, 2. soaking, 3. cooking, 4. germination, 5. fermentation, and 6. heat processing. All of the above processes influence mineral bioavailability either directly by affecting their solubility or indirectly by destroying the inhibitory effect of phytic acid or tannins.
- 6. 1. Milling Conversion of whole wheat to white flour results in 16--86% loss of iron, zinc, copper, magnesium and selenium The phosphorus content of phytic acid greatly dictates the amounts of minerals absorbed, especially iron and zinc. Although losses of minerals are substantial during milling, mineral bioavailability can improve due to the reduction in the phytic acid. Pearling of sorghum also increases iron absorption due to the reduction in polyphenol and phytate content. Phytic acid, also known as phytates, or IP-6 – is the storage form of phorphorus in plants. Phytic acid binds to minerals such as zinc, iron, magnesium, calcium, chromium, and manganese in the digestive tract, making them unavailable. When we consume foods with phytic acid, our ability to absorb the minerals is impaired and mineral deficiencies and bone loss may result.
- 7. 2. Cooking Though minerals are not lost due to heat, but are usually leached if cooked in boiling water. Zinc and iron losses by conventional cooking of broccoli, spinach, sweet potato. Cooking might improve mineral bioavailability by increasing solubility due to cell wall disruption, protein denaturation and release of organic acids. For example, iron bioavailability increased by at least 200% when vegetables such as broccoli, kale and cabbage were cooked. Hydrochloric acid extractability, an indicator of mineral availability, was greatly enhanced for calcium and zinc by cooking and blanching of spinach and amaranth leaves.
- 8. 3. Soaking, Germination, and Fermentation Mineral availability from cereal grains can be improved by hydrolyzing phytates during processing. Calcium, zinc, iron, manganese and copper availability increased when pearl millet was fermented. Reduction of phytate by germination and fermentation was shown to improve iron availability from soy beans and wheat products. Sorghum, due to its high content of phytate and tannins, has minerals of poor availability. However, tannin levels can be reduced by soaking and germination, both of which improve iron and zinc availability from sorghum products.
- 9. continued Fermentation improves the bioavailability of minerals not only by reducing the phytate content but also by producing lactic acid which improves mineral solubility. Fermentation of milk with Staphylococcus thermophilus and Lactobacillus bulgaricus increased zinc availability from 6.3% to 12.5%. The increase in zinc solubility was attributed to the fermentation of lactose to lactic acid which either increased zinc solubility or decreased the binding of zinc to casein.
- 10. 4. Storage Freezing cooked vegetables for six months had no effect on iron or zinc availability. One of the factors limiting the expanding consumption of beans is the development of a textural defect when beans are stored under relative humidities and high temperatures prevalent in tropical countries.
- 11. 5. Fortification Iron bioavailability from infant cereals can be improved by adding ascorbic acid, a well-known enhancer of iron absorption. The effectiveness of ascorbic acid in increasing iron absorption depends on the type of food and the amount of inhibiting factors present in the food. Fifty mg of ascorbic acid increased iron absorption from infant cereals, maize, rice and wheat. Ascorbic acid was less effective in enhancing iron absorption from quinoa because of its high phytate and polyphenol content.
- 12. 6. Heat Processing More than 50% if the manganese, cobalt, and zinc may be lost during canning of spinach, beans, and tomatoes, if the liquid is not consumed. Use of hard water for processing and cooking can result in an increase in the calcium or magnesium content of foods, while use of softened water can result in an increase in the sodium content. Cooking and baking can destroy ascorbic acid and its effect on iron availability. In vitro studies have shown that Maillard reaction products, produced during browning, bind with zinc. The degree of binding is related to the extent of browning and the nature of the proteins found in the food.
- 13. Continued Extrusion processing of cereals can cause an increase in iron content due to contamination from the extruder. The process can also increase mineral bioavailability by reducing the phytate content of food. Extrusion cooking reduced the phytic acid content of cereals from 66-79% to 2~50% of the total inositol phosphates, resulting in increased iron bioavailability.
- 14. Conclusions All foods that processed are subjected to nutrient losses. However, processing can increase nutrient bioavailability due to inactivation of anti nutritive factors. In conclusion, food processing practices can generally be beneficial in terms of increasing mineral availability but sometimes they can impose detrimental effects if proper treatment is not met.
- 15. Thank You