Enhancement of freeze-thaw stability and gel characteristics in soybean-potato protein Pickering emulsions regulated by polysaccharides: Focusing on physicochemical properties and microstructure.

Polysaccharide modulation is an effective strategy for tailoring the texture and stability of plant-based fat substitutes. This study investigated the modulatory effects of κ-carrageenan, konjac gum, and pullulan at three mass ratios (emulsion:polysaccharide = 5:1, 4:1, 3:1) on the stabilization of Pickering emulsion gels containing potato-soy protein composite nanoparticles. The results indicated that the modulatory effects were dependent on the type of polysaccharide. The pullulan group (3,1) imparted the smallest oil droplet size and optimal freeze-thaw stability to the emulsion; its gel water retention and oil retention reached 98.51% and 99.52%, respectively, with the best elasticity and cohesiveness. The κ-carrageenan group (3,1) maximized gel hardness and storage modulus, forming the network with the highest mechanical strength; konjac gum exhibited effects intermediate between the two. Mechanistically, polysaccharides act as physical fillers that synergize with proteins through steric exclusion and hydrogen bonding, promoting an increase in the content of α-helices and β-sheets; Raman spectroscopy confirmed the absence of covalent cross-linking. The dense, uniform network effectively converts free water into non-free water, reducing water mobility. This study elucidates the structure-property relationship between polysaccharide molecular characteristics and gel network configuration, providing a theoretical basis for designing plant-based fat substitutes with adjustable texture and controllable stability.