Antioxidant properties of milled-rice co-products and their effects on lipid oxidation in ground beef

Antioxidant properties were analyzed for methanolic extracts of rice seeds, milled-rice co-products, and other selected plant seeds, including cottonseed, soybean, and corn. Values of antioxidant effectiveness ranged from 45% to 86%, based on 100% activity at no change in color during the beta-carotene bleaching test. A correlation exists between the antioxidant activity and the total phenolic content of the rice ingredient extracts (r(2) = 0.81). When selected extracts were applied to ground beef, the lipid oxidation was inhibited by, in relative effectiveness, rice hull > rice bran > brown rice. When applied directly to the beef, both defatted brown rice flour and rice bran strongly retarded the lipid oxidation.