67B-34 |
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Y. CHOI, K. S. Woo, S. J. Seo, and J. Lee. Department of Food Science and Technology, Chungbuk National University, 48 Gaeshin-dong Heungduk-gu, Cheong-ju, 361-763, South Korea Free radicals produced by radiation, chemical reactions and several redox reactions of various compounds may contribute to protein oxidation, DNA damage and lipid peroxidation in living tissues and cells. This oxidative stress may be related to many disorders including cancer, heart disease, atherosclerosis, diabetes and liver cirrhosis. Recent epidemiological studies have indicated that increased consumption of whole grains, fruits and vegetables is associated with reduced risk of chronic diseases. This association may be attributed to the antioxidants from plant foods such as vitamin C, vitamin E, carotenoids, polyphenolic compounds and flavonoids which prevent free radical damages. Whole grains provide significant quantities of energy, protein, dietary fiber, and micronutrients. In addition, it may be a good source of dietary antioxidants including phenolic acid, lignan, phytic acid, vitamin E. The objectives of this study were to determine antioxidant activity of methanolic extracts from some grains and to investigate relationships between antioxidant activities and antioxidant compounds in the samples. DPPH and ABTS free radical-scavenging activity, inhibitory effect of lipid peroxidation, chelating activity and reducing power have been used to compare the relative antioxidant activities of the grains. The concentrations of total polypenolics and carotenoids in extracts were investigated by colorimetric methods and vitamin E analysis was carried out by HPLC. In this study, the methenolic extracts prepared from black rice and sorghum have significantly higher total antioxidant activities and contained polyphenolics than others. Polyphenolic compound was the major naturally occurring antioxidant compounds found in grains. The correlation coefficient between total polyphenolic content and their total antioxidant activity was more than 0.9. No correlation was observed with any other antioxidant compounds such as carotenoids and vitamin E, due to their low concentration compared to the polyphenolics. In conclusion, our results demonstrated the antioxidant activities and antioxidant compounds of some grains. These data could have a direct impact on intake of cereal grains by increasing their awareness of the health benefits of them.
Session 67B, Food Chemistry: Antioxidants and bioactive agents
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