Protein gelation properties are important indicators of soybean protein processing quality and application potential. Soybean cultivation in saline-alkali soils constitutes a valuable yet insufficiently exploited agricultural resource with considerable development potential. This study compared four soybean samples: one saline-alkali-tolerant specialty variety and two common varieties grown in saline-alkali soil, and one common variety grown in regular soil. We systematically investigated their structural characteristics and heat-induced gelation behavior. Ultrasound-assisted extraction was optimized using response surface methodology for saline-alkali soybeans (QP). Response surface methodology determined optimal soybean protein extraction conditions: 420 W ultrasonic power, 20 min ultrasonic treatment time, and alkali extraction pH 9.36. After ultrasonic treatment, the protein content of QP increased from 89.56% to 91.61%, while the protein recovery rate increased from 56.00% to 70.33%. Among them, QP exhibited the best gelation performance, with the highest disulfide bond content, favorable rheological properties, and the most compact gel microstructure. Ultrasonic treatment altered the 11S/7S ratio and promoted protein structural rearrangement, accompanied by enhanced disulfide bond formation and intermolecular interactions. The synergistic contribution of these changes facilitated protein aggregation and cross-linking, resulting in the formation of a more compact and continuous three-dimensional gel network and consequently improving the gel properties. These findings reveal the molecular basis of superior gelation properties of saline-alkali soybeans and support their use as high-quality raw materials for plant-protein gels, while ultrasound-assisted extraction effectively improves protein recovery and promotes high-value utilization in functional foods.

Paper Linkage:https://doi.org/10.1016/j.foodhyd.2026.113483