Interactions between Longzhua polysaccharides autoclave-extracted and walnut protein and their role in walnut oil...

This study investigates the autoclave extraction of polysaccharides from Longzhua mushroom and resulting flexible-chain polysaccharides (LMP-A). The extraction yield, structure, mechanical properties of the LMP-A were then assessed and compared with those of hot-water-extracted polysaccharides (LMP-H). The interactions between LMP-A and walnut proteins (WP) were examined, and the effects of these interactions on the dispersion stability of WP in water were assessed. An LMP-A-WP-walnut oil (WO) emulsion was constructed and assessed. Extraction yield of LMP-A reached 44.07%, significantly higher than that of LMP-H (P < 0.05). Both of polysaccharides showed similar group structures, but LMP-A had a higher molecular weight (1.486 × 10⁶ g/mol) and intrinsic viscosity (17.21 g/dL). LMP-A displayed an irregularly coiled morphology in aqueous systems. Consistent with the conformation parameter (ρ) analysis, LMP-A were identified as flexible chains polysaccharides, whereas the LMP-H exhibited a rigid-chain structure. LMP-A interacted with WP primarily through electrostatic interactions, and LMP-A-WP complexes considerably enhanced the dispersion stability of the WP in water. A stable LMP-A-WP-WO emulsion was successfully prepared using a one-step high-speed shearing method. The stabilization mechanism was attributed to the synergistic effects of the interfacial adsorption of LMP-A-WP complexes, polysaccharide cross-linking, and the WO filling effect.