Effects of astragalus polysaccharide on the physicochemical properties of heat-induced whey protein gels by simultaneous rheology and Fourier transform infrared spectroscopy

This study investigated the physicochemical properties of gels induced by heat treatment in the presence of 10% polymerized whey protein (PWP) and different concentrations (1%-4%) of astragalus polysaccharide (AGPS). The results of the particle size, zeta potential, surface hydrophobicity, intrinsic fluorescence, surface free sulfhydryl, rheological and differential scanning calorimetry showed that AGPS improved the tertiary structure stability of PWP. Simultaneous rheology and Fourier transform infrared spectroscopy traced the breaks of aromatic groups and the formation of PWP-AGPS hydrogels through hydrogen bonding and electrostatic interactions during heat process. The correctness of the experimental results was verified via molecular docking and 2-dimensional correlation spectroscopy. Cryogenic scanning electron microscopy images showed that the interaction between PWP and AGPS caused the denser microstructure of hydrogels. In summary, AGPS could promote gelation and improve the physicochemical properties of PWP-AGPS hydrogels. The findings of this study provided a theoretical basis for the application of protein-polysaccharide hydrogels in the food industry, offering insights for practical use.