Soy protein gels based on ultrasonic treatment: Effects of Ca2+ and 11S/7S ratio on gel structures and digestive properties
Ruqi Guo, Xiaoqi Deng, Qinlin Hu, Ying Zhu, Xiuqing Zhu
Abstract
This study aimed to explore the impact of varying Ca 2+ concentrations and 11S/7S ratios on the gel performance of soybean protein gels (SPGs) under ultrasonication (400 W, 15 min) and to clarify the mechanisms involved. Results showed Ca 2+ addition altered the structure of soybean 11S/7S protein gels. Low Ca 2+ levels increased the turbidity, hardness, and water retention of the gels, whereas high levels disrupted the orderly aggregation of 11S/7S proteins, creating a rough, porous network. The effect of Ca 2+ was more pronounced with a higher 11S ratio, significantly influencing turbidity, disulfide bonding, and gel hardness. Conversely, 7S-rich gels showed reduced sensitivity to Ca 2+ . In vitro digestion and SDS-PAGE results indicated that 7S globulin’s α, α’, and β subunits were more digestible than the A and B subunits of 11S globulin. In conclusion, ultrasound combined with Ca 2+ can enhance the cross-linking degree between 11S and 7S globulin, forming a dense network structure.