Soy protein gels based on ultrasonic treatment: Effects of Ca and 11S/7S ratio on gel structures and digestive properties.

This study aimed to explore the impact of varying Ca 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 addition altered the structure of soybean 11S/7S protein gels. Low Ca 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 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. 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 can enhance the cross-linking degree between 11S and 7S globulin, forming a dense network structure.