Antioxidant properties of caseinophosphopeptides and casein hydrolysates.
Chelators are valuable ingredients used to improve the oxidative stability of many processed foods. Caseins and casein peptides have phosphoseryl residues capable of binding prooxidant metals such as iron and may have antioxidant activity. In 5% corn oil-in-water emulsions CPP (25 muM) inhibited the formation of lipid oxidation at both pH 3.0 and 7.0 as determined by lipid hydroperoxides and hexanal. Calcium (0--100 mM) had no influence on the antioxidant activity of CPP. Casein hydrolysates were tested for their antioxidant properties as hydrolysates represent a more economical source of phosphopeptides. Casein hydrolysates were more effective inhibitors of lipid oxidation than CPP at equal phosphorous content (0-- 310 muM) suggesting that antioxidant properties were not uniquely related to chelating prooxidant metals but also to free radicals scavenging activity.