Individual and combined effects of cold plasma and enzymatic hydrolysis modification on soluble dietary fiber in wheat bran: Structural, physicochemical and functional properties

The individual and combined effects of cold plasma and enzymatic hydrolysis modification on the yield, structural, physicochemical and functional properties of soluble dietary fiber (SDF) derived from wheat bran were investigated. The results indicated that enzymatic hydrolysis and combined modification (cold plasma followed by enzymatic hydrolysis) significantly enhanced the yield of SDF to 15.08 % and 14.65 %, respectively. In terms of structure, all three modifications resulted in partial cleavage of glycosidic and hydrogen bonds, leading to the reduction in the molecular weights of SDFs. The cold plasma-modified SDF displayed a loose lamellar microstructure with small pores, while honeycomb-like pores were observed on the surface of SDF modified by two others. The combined-modified SDF exhibited the most significant structural alterations, which resulted in its lowest viscosity and highest water solubility in all tested SDF. Furthermore, the cold plasmamodified SDF demonstrated the highest alpha-amylase inhibition ability and bile salt adsorption capacity; while the combined-modified SDF showed the best performance in glucose adsorption capacity, cholesterol adsorption capacity and antioxidant capacity. In conclusion, the combination of cold plasma and enzymatic hydrolysis is a promising strategy for improving not only the yield but also the physicochemical and functional properties of SDF in wheat bran.