CHARACTERIZATION OF A HEAT-STABLE ANTIOXIDANT COPURIFIED WITH THE SUPEROXIDE-DISMUTASE ACTIVITY FROM DRIED PEAS

Heat-stable antioxidant activity co-purified with the pea superoxide dismutase (SOD) activity is believed to be due to bound phenolic compounds. Digestion with trypsin showed that the native SOD protein structure was not required for the expression of the thermostable antioxidant activity. Part of the bound phenolic compounds can be removed from the SOD protein by alkaline hydrolysis. The dissociated phenolic fraction was able to inhibit the autoxidation of linoleic acid by more than one week. Incubation of the phenolic fraction with bovine SOD (BSOD) and serum albumin (BSA) resulted in the transfer of thermostable antioxidant activity to the SOD protein but not to serum albumin. The results indicate that pea SOD can act as a carrier for certain pea phenolic compounds and thus facilitate a protein-bound thermostable antioxidant.