Rice bran water extraction through autoclaving and sonication protein content and amino acid profile

Abstract

Rice bran is one of the co-products from rice milling process that has high protein content among many other beneficial minerals and nutrients. Recently there are a few novel water-based extraction methods introduced such as subcritical and hydrothermal extraction. However simpler methods of water extract such as autoclaving and sonication can produce comparable results. Therefore in this study, a method is introduced to extract protein from raw rice bran by mixing full-fat unstabilized rice bran with water (5%, w/v) and autoclaved at 140°C for 15, 30, 45 and 60 min. Soluble protein content and amino acid profile of the extracts were analyzed. 60 min autoclaving time produced extract with the best soluble protein content of 8.41 g/100 g±0.022 and the best amino acid profile with highest content of essential and conditional amino acids, 1.64 g/100 g±0.002 and 1.40 g/100 g±0.001, respectively. Therefore this selected extract was further treated by sonicating the rice bran-water mixture for 5 min before or/and after the autoclaving. Based on the soluble protein content results, combination with sonication does not improve protein extraction.