Physicochemical and antioxidative characteristics of rice bran protein extracted using subcritical water as a pretreatment and stability in a functional drink model during storage

Abstract

Industrial hexane-defatted rice bran, a waste byproduct from the rice bran oil industry, was treated with subcritical water conditions followed by alkaline extraction and enzymatic hydrolysis. The extracted content included rice bran protein (RBP), rice bran protein hydrolysate (RBPH), and rice bran hydrolysate (RBH). The highest protein content, protein recovery, total phenolic content, and antioxidant activity, determined by ABTS, DPPH, FRAP, and MIC were seen in RBH. The essential amino acids index of RBH was 48%. FTIR spectra confirmed RBH consisted of protein and phenolic hydroxyl group. RBH was selected for application in the development of a functional drink, and quality was determined during storage. A functional drink supplemented with RBH contained quality protein, with high antioxidant activity and stability during storage. These results show that RBH extract has potential as a novel protein and antioxidant source that could be used in the development of functional food and drinks.