Etching–Hydrophobicity Modification of Soybean Dreg Insoluble Dietary Fibers and Their Pickering Emulsion Stabilization Mechanisms

Soybean dregs are one of the main by-products during the processing of traditional soybean products, which are rich in insoluble dietary fiber. Insoluble dietary fiber has high mechanical strength and stability. After a certain treatment, it can have the po-tential to stabilize Pickering emulsions. In this research, high-purity soybean dregs insoluble dietary fibers (HPSIDF) were modified by alkaline H₂O₂, with oleic acid (OA) modified in a green synergistic modification. The surface of HPSIDF was etched to in-crease the reaction sites for hydrophobic modification. The hydrophobic modification was then used to enhance the emulsification properties, and finally, the performance of the particles in Pickering emulsions and the emulsification mechanism were analyzed. The absolute value of the ζ-potential of the hydrophobically modified high-purity soybean dregs insoluble dietary fiber (O-HPSIDF) increased from 15.87 mV to 37.27 mV. The stability of the Pickering emulsion stabilized by O-HPSIDF was greatly en-hanced, the droplet size of the emulsion decreased, the distribution was more uniform, and the emulsifier particles were able to form a network structure at the interface, which formed a certain mechanical strength for the emulsion.