Optimization, antioxidant activity and bile salts adsorption capacity of the aqueous enzymatic extract from rice bran

Abstract

The optimum extraction conditions of the aqueous enzymatic extract from rice bran (AEERB) were evaluated with respect to γ-oryzanol content and ferric reducing/antioxidant power (FRAP) activity by using response surface methodology. The results showed that the effect of the extraction temperature on γ-oryzanol content and FRAP activity was the most significant. The optimal conditions were determined as follows: Trypsin, 453 U/g at 56°C and pH 7.9 for 2 h at a liquid/solid ratio of 7 : 1. The corresponding γ-oryzanol content and FRAP activity were 0.1749 mg/g and 0.5043 mmol FeSO₄/g, respectively. The antioxidant activities of AEERB were comparable with 2,6-di-tert-buty-4-methylphenol (BHT) or ascorbic acid (AA) at the high concentration. Furthermore, the binding capacities of AEERB to sodium taurocholate and sodium deoxycholate were 24.96 and 13.63 µmol/100 mg, respectively. The results indicated that AEERB is a promising method for developing and applying a value-added RB product.