Phytochemicals characterization of solvent extracts from taro-scented japonica rice bran

The major phytochemicals and antioxidant properties of taro-scented rice bran (TaiNung 71; TN71) extracts using 3 different solvents are characterized. Some progress is realized in creating an economic value for rice bran that has long been considered an agricultural waste. Various solvent extracts reveal the presence of phenolic compounds, oryzanols, tocopherols, and tocotrienols. Ethyl acetate (EtOAc) can extract more oryzanols (1.55 ± 0.20 g/kg rice bran). Meanwhile, the methanol (MeOH) extract possesses a higher yield in total contents (15.42 ± 1.41 g/kg bran), which includes phenolic compounds (2.69 ± 0.29 g gallic acid equivalent/kg bran), tocopherols (251 ± 26 mg/kg bran) and tocotrienols (111 ± 4 mg/kg bran). The MeOH extract exhibits more effective antioxidant activity against various oxidative systems in vitro, including the inhibition of linoleic acid peroxidation (33.89%), scavenging of DPPH radicals (83.88%), and reducing power. It is found that the yield, total content in phenolic compounds and tocols of the extracts increase with increasing Synder's polarity value and viscosity, which can then be used as the indices in isolation of the desired rice bran phytochemicals extracts.