Antioxidant Effects of Soy Protein Hydrolysates on Copper‐catalyzed Methyl Linoleate Oxidation

Oxidation of methyl linoleate in a model emulsion system containing soy protein and copper was studied. The prooxidative effect of soy protein was inhibited following proteolysis. Both the TBA test and diene conjugation measurements showed similar oxidative patterns. The inhibitory effect of the proteolytic treatment was ascribed to the binding of copper by proteolytic products and these copper complexes appeared to be less catalytic than the intact protein‐copper complex. However, the release of bound antioxidant phenolics or copper chelating agents, e.g. phytic acid following proteolysis, may also be involved.