• How do antioxidants act as food preservative?
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Answers
Answer:
Antioxidants added to food avoid their spoilage during shelving. Food antioxidants are one of the most important conservation technologies. Each group of food antioxidants has specific methods of action and foodstuffs.
Answer:
Explanation:
Antioxidants play a major part in ensuring that our foodstuffs keep their taste and colour and remain edible over a longer period. Their use is particularly important for avoiding oxidation of fats and fat-containing products. When antioxidants are thoroughly mixed with fat or oil, the onset of the final stages of autoxidation when rancidity -development of unpleasant off-flavours and odours- becomes evident, is delayed. Another important reason is that certain vitamins and various amino acids can easily be destroyed by exposure to air, and antioxidants serve to protect them. They also help to slow down the discoloration of fruit and vegetables.
Natural occurring antioxidants
One simple way, for example, of stopping apples going brown is to add a small amount of lemon juice. The ascorbic acid (vitamin C) contained in many citrus fruits is a natural antioxidant and for this reason finds frequent use in food production (E 300-E 304). Vitamin C and its various salts are added to protect soft drinks, jams, condensed milk and sausage.
Other natural antioxidants are the tocopherols
Forms of vitamin E.
(E 306-E309), which are members of the vitamin E family. Tocopherols are found mainly in nuts, sunflower seeds and soya and maize shoots, and they are mostly used for preserving vegetable oils, margarine and cocoa products.
Since both compounds are very popular antioxidants and the requirements for them cannot be met completely from natural sources, ascorbic acid and tocopherols have also been produced artificially for quite some time. It is nowadays possible to copy the molecular structure of these compounds so closely that there are no longer any differences in either structure or effects, which means that these “nature-identical” substances are essentially identical to their originals.
Man-made antioxidants
Man-made antioxidants are used as well as natural ones. The most important artificial antioxidants belong to the group of gallates (E 310-E 312). Gallates are added mostly to vegetable oils and margarine to stop them from going rancid and preserve their taste.
Two other substances, which do not belong to the above groups, are BHA (butylhydroxyanisol, E 320) and BHT (butylhydroxytoluene, E 321).