Abstract:With the aim to investigate the effects of adding three polysaccharide types and concentrations of pectin, xanthan gum and κ-carrageenan (0.002g/mL,0.004g/mL,0.006g/mL) on the gel properties and molecular forces of soy protein (SPI)-chlorogenic acid (CA) hydrogels, the infrared spectra, molecular forces, rheology, water distribution and microstructure of SPI-CA/polysaccharide ternary gels were measured. Finally, the interaction mechanism between different polysaccharides and SPI-CA and the differences and similarities of different polysaccharides on the improvement of SPI-CA gel properties were confirmed. The results showed that the addition of xanthan gum and κ-carrageenan increased the β-sheets content of the protein from 24.59% to 24.87%~26.65% and significantly decreased the content of random coil (P<0.05), which was beneficial to the formation of the gel network structure. The addition of all three polysaccharides significantly enhanced the hydrogen bonding interactions in the gels and the binding ability of immobilized water (T21) in the gels. Compared with pectin and xanthan gum, the addition of κ-carrageenan resulted in stronger hydrogen bonding interactions in the gels, shorter relaxation time of T21, and denser gel structure. The storage modulus (G′), loss modulus (G″), hardness and chewiness of the gels were positively correlated with the concentration of κ-carrageenan. The addition of appropriate amounts of pectin and xanthan gum can form stable gels, but overfilling with pectin and xanthan gum can reduce the thermal stability of the gels and destroy the gel network structure. The results can provide theoretical support for introducing different polysaccharides to improve the gel properties of soy protein-chlorogenic acid hydrogels.