Oxidation is responsible for the deterioration in the quality of food products, including off-flavors and off-odors. It is affected by processing, packaging and storing methods, as well as product ingredients.
Antioxidants are added to food to prevent them spoiling. Tocopherols, ascorbic acid, carotenoids, flavonoids, amino acids, phospholipids, and sterols are natural antioxidants in foods. Antioxidants delay the onset of oxidation by donating hydrogen atoms to quench free radicals, forming a stable antioxidant radical that is unable to participate in propagation reactions, slowing down oxidation.
Antioxidants inhibit the oxidation of foods by scavenging free radicals, chelating prooxidative metals, quenching singlet oxygen and photosensitizers, and inactivating lipoxygenase.
Foods which contain edible oils will spoil once exposed to oxygen from the air due to oxidation reactions. This chemical change results in a bad flavor and smell from the food. Phenols and the enzyme phenolase are found in the cells of the apple, and when these are exposed to oxygen in the air, for example through slicing, the oxygen causes a reaction.
Oxidation in food
