Bioactive Materials and Antioxidant Properties of Fermented Rice-bran Extract

Abstract

This study suggests that fermented rice bran extract contains natural antioxidants. The contents of bioactive materials (e.g., polyphenolic compounds and flavonoids), antioxidative properties (DPPH (α,α’-diphenyl-β-picrylhydrazyl) free radical scavenging activity, Fe reducing, Cu reducing power, peroxidation of linoleic acid and rat hepatocyte microsome) were tested by in vitro experimental models using fermented rice bran (FRB) extract. The concentrations of phenolic compound and flavonoid were 19.92 ㎎/g and 11.56 ㎎/g, respectively. In oxidation in vitro models using DPPH free radical scavenging activity, (free radical scavenging activity 69.8%) Fe reducing power and Cu reducing power (effect of dose-dependent manner), Fe 2+ /ascorbate induced linolenic acid peroxidation by ferric thiocyanate and thiobarbituric acid (TBA) methods (inhibition activity 81%), and autooxidation of rat hepatic microsomes membrane (lipid peroxidation inhibition activity 38%), antioxidative activities were stronger in FRB extract than FRS (Fermented Rice and Soybean, positive control) extract and, these effects were dose-dependent manner. From these results, FRB extract was shown to have the most potent antioxidative properties and contain the highest amounts of antioxidative compounds such as phenolic compounds and flavonoids. Overall, these results may provide the basic data to understand the antioxidative properties of fermented rice bran for development of functional foods.