Effects of acid treatment on the physicochemical and functional properties of wheat bran insoluble dietary fiber

Background and Objectives Wheat bran is a by-product of the wheat milling industry but most are used as animal fodder or discarded. To extend the applications of wheat bran, the structural, physicochemical, and functional properties of sulfuric acid-modified wheat bran insoluble fibers (WBIDF) produced using 1%, 2%, 4%, and 8% H2SO4 and 1.5% potassium hydroxide were investigated. Findings Due to cell wall disintegration, 1.0% and 2.0% H2SO4 treatments increased the concentration of soluble dietary fiber. Scanning electron microscopy indicated that acid treatment disrupted WBIDF structure, removed starch granules from the surface, and significantly reduced starch content. Higher H2SO4 concentrations increased WBIDF crystallinity due to hydrolysis of hemicellulose and amorphous cellulose. Acid treatment below 2% not only enhanced the water holding, water swelling, oil binding, and cation exchange capacities of WBIDF, but also increased cholesterol, sodium cholate, and glucose adsorption capacities and alpha-amylase inhibition activity. Conclusions Acid-modified WBIDF has potential as a functional food ingredient. Significance and novelty Acid treatment can be used to disrupt the microstructure of wheat bran to improve its functional properties. These findings can be utilized to improve the technological functionality of wheat bran as a high fiber ingredient for food applications.