Abstract: In order to clarify the effect of high concentrations of soymilk on the quality of tofu, in this study, we prepared tofu from high concentrations of soymilk (containing 9.2%–12.2% solids) cooked and subsequently diluted to 8.0%, and compared the quality of the tofu samples. We also compared the physicochemical properties and rheological properties during coagulation of the cooked soymilks and analyzed the cause of the difference in the quality of the tofu samples. The results showed that as the concentration of soymilk increased, the hardness and chewiness of tofu decreased compared with the control group (with 8.0% solids), showing the maximum value at a solid content of 9.2%; however, little difference in elasticity, yield, water content or water-holding capacity was observed. Furthermore, we found that the percentage of protein particles in soymilk was the smallest (26.2%), and the surface hydrophobicity was the largest at a solid content of 9.2%. The average particle size, the absolute value of zeta potential, and the proportion of B subunit increased with increasing concentration of soymilk, whereas the ratio of α to α’ showed a downward trend. Through analysis of the change in the rate of soymilk coagulation, it was found that the higher the soymilk concentration, the earlier soymilk coagulation began and the faster the rate of coagulation. This study suggests that high concentrations of soymilk can promote the aggregation of soymilk proteins during cooking, thereby helping to improve the processing characteristics of soymilk and soymilk gels, which can provide a theoretical basis for actual production.

Key words: cooking high concentrations of soymilk; aggregation; soymilk; tofu; quality