Influence of one-step enzymatic modification on the structure, physicochemical, and functional properties of dietary fiber from corn husk rich in (hemi)cellulose

Abstract

This study systematically evaluated enzymatic modification of corn husks rich in hemicellulose using different sources of cellulases for producing soluble dietary fiber (SDF) by comparing the differences in yields and characteristics of obtained polysaccharides, thereby developing a novel one-step enzymatic modification process without starch and protein removal pretreatment that was commonly used in traditional enzymatic modification processes. It was shown that Trichoderma reesei cellulases showed a better modification effect than Penicillium oxalicum cellulases, especially T. reesei SCB-18 cellulase, producing high-yield SDF with superior physicochemical and structural characteristics and functional properties such as high water-holding capacity and adsorption capacities for cholesterol and nitrite ion, good thermal stability, low crystallinity, and molecular weight through this one-step process. Increased porous structure and functional groups in the SDFs, which were caused by the degradation of cellulose and hemicelluloses in corn husk, should partially explain the improvement in physicochemical and functional properties. This study also evaluated the physicochemical and functional properties of insoluble dietary fiber (IDF) obtained by this process. It provides a simple and feasible enzymatic modification process to produce SDF and IDF from corn husks efficiently and at a low cost, thereby realizing the high-value application of corn husks.