Rancidification is the decomposition of fats and other lipids by oxidation. Rancid foods and oils develop highly reactive chemicals which produce unpleasant and obnoxious odors and flavors, and destroy nutrients in food. Under some conditions, rancidity, and the destruction of vitamins, occurs very quickly.

Antioxidants are often added to fat-containing foods in order to retard the development of rancidity. Natural anti-oxidants include ascorbic acid (Vitamin C) and tocopherols (Vitamin E). Chemical antioxidants include BHA (butylated hydroxyanisol), BHT (butylated hydroxytoluene) and ethoxyquin. The natural anti-oxidants tend to be short-lived; the chemical anti-oxidants are potential carcinogens.

See also

• Food preservation
• Preservative
• Putrefaction
• Fermentation