关键词: 双孢菇多糖, 聚合乳清蛋白, SR-IR, 二维相关光谱, 分子对接

Abstract: Heat-induced whey protein isolate (WPI)-formed polymeric whey protein (PWP) gels are limited in applications due to their high brittleness, while the addition of polysaccharides can significantly improve their properties. Agaricus bisporus polysaccharide (ABP), as an anionic polysaccharide, exhibits excellent biological activities, but the formation mechanism of its composite gels with PWP remains unclear. In this study, experiments including particle size, Zeta potential, surface hydrophobicity, intrinsic fluorescence spectroscopy and surface free sulfhydryl groups were conducted to investigate the effects of ABP concentration (0-4%) on the physicochemical properties of PWP. The results demonstrated that as the ABP concentration increased, the average particle size of PWP-ABP complexes significantly increased from 75.7±6.07 nm to 149.7±6.957 nm (P≤0.05), and the absolute Zeta potential value rose from -35.60±2.64 mV to -45.20±1.40 mV, indicating that ABP enhanced the stability of the complexes through electrostatic repulsion. Simultaneously, surface hydrophobicity decreased from 123.4±3.2 (0% ABP control group) to 68.7±2.5 (4% ABP group), confirming that ABP altered the tertiary structure of PWP via hydrophobic interactions and disulfide bond crosslinking. Further analysis using simultaneous rheology-Fourier transform infrared spectroscopy (SR-IR) revealed that ABP induced a red shift in the amide A region (3200-3600 cm-1) of PWP, suggesting enhanced hydrogen bond formation, while fluctuations in the amide I band (1625 cm-1) were attributed to electrostatic interactions. Molecular docking analysis showed that ABP binds to β-lactoglobulin via hydrogen bonds and two-dimensional correlation spectroscopy further validated changes in O-H stretching vibrations. In conclusion, ABP optimizes the gel network structure of PWP through hydrophobic interactions, hydrogen bonds, and electrostatic interactions, providing a theoretical foundation for developing functional food gel systems.

Key words: Agaricus bisporus polysaccharide, Polymerized whey protein, SR-IR, Two-dimensional correlation spectrum, Molecular docking