Calcium sulphate‐induced soya bean protein tofu‐type gels: influence of denaturation and particle size

Soya bean protein isolate (SPI) dispersions (7.25%, w/v) were heated at 65, 75, 85 or 90 °C for different time periods to produce SPI aggregates with diverse degrees of denaturation and particle size to investigate the effects on calcium sulphate (CaSO₄)‐induced tofu‐type gel. The results revealed that gel hardness and water‐holding capacity correlated positively with the degree of denaturation of glycinin (11S) and the particle size of the SPI aggregates. The formed gels showed more uniform and denser network structures with increasing degrees of denaturation and particle size of SPI. Hydrophobic interaction was speculated to be the crucial factor for the retention of gels prepared by SPI whose degree of denaturation by 11S was lower than 4.35%. However, disulphide bonds probably played a more important role in the retention of gels generated by SPI with the 11S denaturation degree of >84.47%. Moreover, the bulk density of the protein aggregates might determine the gel structures to a certain extent.