Effect of calcium chloride on heat-induced Mesona chinensis polysaccharide-whey protein isolation gels: Gel properties and interactions

Salt ions play an important role in the quality structure of food and sensory properties. This study aims to investigate the effects of different concentrations of calcium chloride (0–0.012 mol/L) on the gel properties and interactions of heat-induced Mesona chinensis polysaccharide (MCP)-whey protein isolate (WPI) mixed gels. It was found that the apparent viscosity decreases gradually with the increase of calcium ion concentration, especially when the calcium ion concentration reaches 0.012 mol/L, the apparent viscosity is the lowest. The water holding capacity of the mixed gel decreased from 86.25% to 32.05% and the network structure of the gel became looser, which was consistent with low-field magnetometry results and the variation of microstructure. In the in vitro digestion experiments, the addition of 0.003 mol/L calcium chloride was effective in reducing the degradation of the gel. The results of chemical bonding analysis indicated that hydrogen bond and hydrophobic interactions were the key forces that promoting gel formation and maintaining the gels network structure. This study showed that calcium ions could change the contribution of hydrogen bonding, disulfide bonds, and hydrophobic interactions to the gelation process.