Effects of modification methods on microstructural and physicochemical characteristics of defatted rice bran dietary fiber

Rice bran is a by-product produced during rice processing. The present study aims to study the effect of three different modification methods (i.e. enzyme hydrolysis, fermentation, fermentation and enzymatic hydrolysis) on the microstructural and physicochemical characteristics of defatted rice bran dietary fiber. Results showed that all three modification methods influenced rice bran dietary fiber, but fermentation and enzymatic hydrolysis combined modification has the greatest impact. The content of arabinose, xylose, galactose increased significantly (p < 0.05) while the glucose content decreased significantly (p < 0.05). For its microstructural properties, there were more fragments on the surface of dietary fiber, the layered structure was severely damaged, the internal structure exposure was further increased, and the structure exhibited loose and porous morphology. The crystal type of modified rice bran dietary fiber remains unchanged in general while the enzymatic hydrolysis modification has the greatest impact on crystallinity which was decreased by 13.3%. The glucose adsorption capacity of dietary fiber was improved with fermentation and enzymatic hydrolysis modification, significantly (p < 0.05) increased by 66.1% and 57.2% in 100 mmol/L and 200 mmol/L glucose solutions.