Phytic acid has been shown previously to form an iron chelate that inhibits iron-catalyzed hydroxyl radical formation and lipid peroxidation. To further characterize its antioxidant properties in model food systems, we investigated the effects of phytic acid on ascorbic acid degradation in aqueous solution and on stability of oil-in-water emulsions. In both systems 1 mM phytic acid provided significant protection against oxidative damage and increased emulsion shelf-life fourfold. To test antioxidant efficacy of phytic acid in a whole food system, its effect on development of warmed-over flavor was determined. Phytic acid substantially inhibited oxygen uptake, malondialdehyde formation and warmed-over flavor development in refrigerated chicken.