Production and Physicochemical Properties of Rice Bran Protein Isolates Prepared with Autoclaving and Enzymatic Hydrolysis

The objectives of this study were to increase the protein purity in the rice protein isolate, and to enhance the functional properties of the extracted rice bran protein via enzymatic hydrolysis and/or high temperature treatment. Washing the isolates with 30% ethanol solution achieved significant improvements in the protein contents (77.62%) of the rice bran protein isolates. The highest improvement in solubility was detected in the isolate autoclaved after enzymatic hydrolysis, up to 97.4% at a pH of 10.0. A combined modification of the method involving autoclaving and protease-hydrolysis improved the emulsion activity of the isolate at pH values above 6.0. The autoclaving and enzymatic hydrolysis increased the foaming capacity of the isolate, but reduced the foam stability at all pH ranges except 5.0. Enzymatically hydrolyzed isolates evidenced lower minimum concentrations of gel formation proteins and higher gel strengths than were detected in the other isolates.