Modification of black soybean (Glycine max(L.)merr.) residue insoluble dietary fiber with ultrasonic, microwave, high temperature and high-pressure, and extrusion

Recent studies have emphasized the modification of Insoluble Dietary Fiber (IDF) to enhance its physicochemical properties and functional performance. This study systematically examined the effects of ultrasonic treatment, microwave irradiation, high-temperature and high-pressure processing, and screw extrusion on the physicochemical characteristics, in vitro antioxidant activity, and adsorption capacities of High-Purity Insoluble Dietary Fiber (HPIDF) derived from black bean residues. Although these physical modifications did not alter the functional group composition or crystalline structure of HPIDF, they significantly enhanced its porosity, water-holding capacity (WHC), oil-holding capacity (OHC), and adsorption capacities for glucose, cholesterol, bile salts, and metal ions. Notably, HPIDF treated under high-temperature and high-pressure conditions exhibited the highest adsorption capacities: 9.86 mmol/g for glucose, 8.69 mg/g (pH 2) and 9.69 mg/g (pH 7) for cholesterol, 0.183 g/g (pH 2) and 0.127 g/g (pH 7) for sodium cholate, and 0.699 mg/g (pH 2) and 0.774 mg/g (pH 7) for Cr2+. •The insoluble dietary fiber was modified by various physical methods.•The antioxidant activities of physically modified IDFs were compared in vitro.•The adsorption capacity of metal ions of physically modified IDFs was compared.