Submitted to: Journal of Food Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 9/26/2003
Publication Date: 10/26/2003
Citation: Shih, F.F., Daigle, K.W. 2003. Antioxidant properties of milled-rice co-products and their effects on lipid oxidation in ground beef. Journal of Food Science. 68:2672-2675. Interpretive Summary: Rancidity due to the spoiling (oxidation) of the fat component in food is a serious problem because it not only lowers the food quality and market value but also could cause health and safety concerns for the consumers. Antioxidants are substances that are capable of inhibiting the oxidation and thus retarding food rancidity. Synthetic antioxidants, prepared chemically in the lab, are effective and available, but natural antioxidants, particularly those from plant sources, are getting attention recently because of a worldwide trend to avoid or restrict the use of synthetic materials in food. This report investigated the potential of antioxidant materials in rice, co-products from the milling of rice, and other selected plant seeds. When they were extracted with methanol, all the extracts showed antioxidant properties. Milled rice co-products, such as brown rice, rice bran and rice hull are particularly promising, because they are not only rich in antioxidant materials, but also plentiful and cheap. When incorporated into ground beef patties, brown rice, rice bran, their extracts and the extract of rice hull were found to effectively retard the rancidity of the beef. Our study showed that these milled rice co-products are good sources of antioxidants and value-added products could be developed from these surplus commodities.
Technical Abstract: 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 58% to 85%, based on the 100% activity at no change in color during the B-carotene bleaching test. A good correlation exists between the antioxidant activity and the total phenolic content of the extracts (R superscript2 = 0.8517). When selected extracts were applied to ground beef patties, 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 showed ability to strongly retard the lipid oxidation.