Use of enzymes in the processing of protein products from rice bran and rice flour

Abstract

Large quantities of rice bran and broken rice are generated as co-products during the milling of rice. Rice bran and, to a lesser extent, broken rice are under-utilized. The protein they contain is particularly nutritious and hypoallergenic for use in foods. However, to enhance the use of rice proteins, it is desirable to develop effective methods to separate or concentrate the protein component from these rice co-products. In this investigation, rice bran and rice flour from broken rice were treated with starch and carbohydrate-hydrolysing enzymes including α-amylase, hemicellulase, and cellulase. The enzymatic processing of rice bran resulted in soluble and insoluble rice products, with protein content ranging from 10% to 27%. In the case of rice flour, the starch component was effectively solubilized, and the insoluble fraction was found to contain up to 79% protein. Processing conditions were discussed, and the protein-enriched products were analysed for chemical, physical, and functional properties.