WATER‐SOLUBLE ANTIOXIDANT ACTIVITY OF OILSEED PROTEIN DERIVATIVES IN MODEL LIPID PEROXIDATION SYSTEMS OF MEAT

Abstract

ABSTRACTWater‐soluble antioxidant activities of defatted flours, protein concentrates, and protein isolates derived from soybeans, cottonseeds and peanuts were determined. The activity of aqueous extract (0.25%, w/v) of each product was measured by its inhibitory effect on the linoleate peroxidation catalyzed by Met Mb, Fe++‐EDTA (1:1) or beef homogenates. The antioxidative effect varied depending on the kind of oilseeds used, the type of protein derivatives, and the catalytic system employed. Antioxidant activities of the three oilseed flours were significantly different when tested in Fe++‐EDTA and beef homogenate systems, soy flours showing higher activity than either cottonseed or peanut flours. The differences among flours were not significant in Met Mb system where ah the flours were highly antioxidative. Cottonseed concentrate exhibited higher activity than the corresponding soy or peanut products regard less of the catalytic system used. Of the isolates included, those of soybeans and cottonseeds, the former had higher activity than the latter in each system. In general, flour extracts were the most effective of the three types of derivatives. All the aqueous extracts included in the study were more effective for inhibiting Met Mb catalysis of linoleate peroxidation, less effective for Fe++‐EDTA catalysis and least effective for beef homogenate catalysis.