29B-5 |
Antioxidant activity of selected plant extracts |
N. S. HETTIARACHCHY, D. J. Feliz, and R. Cai. Dept. of Food Science, Univ. of Arkansas, 2650 N. Young Ave., N-218 Food Science Bldg., Fayetteville, AR 72704-5690 Antioxidants offer high potential to increase product self-life by reducing the rate of lipid oxidation and hydrolysis through sequestering and stabilization of free radicals. Synthetic antioxidants have shown the potential for health concern in large amounts. In addition, consumers show a preference for natural ingredient sources due to health concerns. It is therefore desirable to find methods for increasing product self-life through the use of natural antioxidants. The objective of this investigation was to evaluate antioxidant activity of selected plant extracts produced using 70% ethanol extraction, water extraction, and extracts of commercial sources. Cowpea, ginger, black tea, green tea, rice bran, and fenugreek extracts were prepared by extraction with 70% ethanol or water. Commercial extracts including grape seed, gotu kola, ginkgo leaf, rosemary, and synthetic antioxidants BHT and TBHQ were also included for comparison. Antioxidant testing was conducted by conjugated diene method in which the formation of conjugated diene from methyl linoleate in the presence of antioxidants was compared to control with no antioxidant by colorimetric method. Our results showed that cow pea, black tea, green tea, rice bran, and fenugreek ethanol extracts inhibited 92.3%, 95%, 99%, 98.3%, and 72.4% the formation of conjugated diene respectively, while black tea, green tea, ginger, and coriander water extracts inhibited 99.2%, 93.7%, 92.7%, and 91.3%, respectively. Commercial water extracts from grape seed, gotu kola, ginkgo leaf, and rosemary inhibited 99.8%, 99%, 91.2%, and 98.8%, respectively. Both BHT and TBHQ inhibitions were 100%. Our data demonstrated that these plants extracts have the potential to minimize/prevent lipid oxidation and extend self-life in lipid-containing food products.
Session 29B, Food Chemistry: Lipids, antioxidants and emulsifiers
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