Antioxidants
Antioxidants are the substances that can delay onset, or slow the rate of oxidation of autoxidizable materials. By virtue of this property, they provide protection against oxidative changes in fats and oils. They act by reacting with the free radicals and thereby terminate the propagation of chain reaction. The antioxidant reacts with the fatty acid free radical or with the peroxy free radical. Literally hundreds of compounds, both natural (including vitamins C and E, vitamin A, selenium (a mineral) and a group known as the carotenoids) and synthesized, have been reported to possess antioxidant properties. Their use in foods, however, is limited by certain obvious requirements not the least of which is adequate proof of safety. The main lipid soluble antioxidants currently used in food are monohydric or polyhydric phenols with various ring substitutions. For maximum efficiency, primary antioxidants are often used in combination with other phenolic antioxidants or with various metal sequestering agents.