Study on Physicochemical Properties of Emulsion Gels and Release of Sodium Ions During Oral Processing by Starch Regulation

Emulsion gels, containing the structures of both emulsions and gels, serve as the structural basis for various food products. This study aimed to investigate the effects of different ratios of amylopectin and amylose on the microstructures of soy protein-based emulsion gels and explore their relationship with sodium ions release during oral processing. Emulsion gels were prepared using starch and soy protein. The effects of different amylose and amylopectin addition ratios on the textural properties, rheological behavior, microstructures, and lubrication properties of emulsion gels were characterized using scanning electron microscopy (SEM), texture analyzer, rheometer, and tribometer. Additionally, an oral processing simulator was employed to mimic mastication and assess the release kinetics of sodium ions. The results indicated that the gel exhibited maximum hardness at an amylopectin-to-amylose mass ratio of 6:4, with SEM images showing the densest gel network at this ratio. In contrast, at an amylopectin-to-amylose mass ration of 0:10, the gel exhibited the highest porosity, the lowest hardness, and a significantly increased rate and total release of sodium ions. Furthermore, the tests on the frictional properties of emulsion gels mixed with simulated saliva showed that the increase in amylose content elevated the friction coefficient upon the mixing of gel and saliva, thereby diminishing its lubricative efficiency. These findings aimed to provide a theoretical reference for the design of low-sodium food products.