The effect of different edible fungal polysaccharides on the stability of whey protein isolate solution near isoelectric point

Whey protein isolate (WPI) is unstable near isoelectric point with simultaneous precipitation or phase separation, which negatively affects its application. In the current study, four kinds of edible fungal polysaccharides were selected to improve the WPI stability through non-covalent interaction. The addition of edible fungal polysaccharides significantly improved the WPI stability. Zeta potential analysis showed that edible fungal polysaccharides reduced the zeta potential of WPI. The analysis of rheological properties showed that complex solutions exhibited higher viscosity and behaved as pseudoplastic fluids. Bio-layer interferometry demonstrated the interactions between edible fungal polysaccharides and WPI, and the K-D between Tremella fuciformis (TFP) and WPI was the lowest. LC-MS/MS results indicated that the peptide fragments "VGINYWLAHK" and "TPEVDDEALEKFDK" in alpha-lactalbumin and beta-lactoglobulin were probably binding regions interacted with the four kinds of edible fungal polysaccharides. Furthermore, molecular docking results inferred GLN43 and GLU127 were the major residues in the alpha-lactalbumin and beta-lactoglobulin.