Effects of NaCl/KCl ratios on structural and properties changes in soy-potato protein mixed gel

To reduce the sodium salt content in protein gel-based foods, this study investigated the effects of different Na-K ratios on the gelation properties and structural changes of soy protein isolate (SPI) and potato protein isolate (PPI) composite gels. The results showed that the composite gel properties were further enhanced with increasing Na-K ratio in the SPI/PPI gel system. Specifically, when the Na-K ratio was 1:1, the SPI/PPI composite gel exhibited the highest gel strength, gel elasticity, WHC, storage modulus (G′), and β-sheet content, whereas the α-helix content and β-turn content were the lowest. Scanning electron microscopy images revealed a dense and uniform network structure of the composite gel. The addition of low concentrations of Na⁺ and K⁺ improved the network structure and water-holding capacity of the SPI/PPI gel during the heat-induced gelation process. However, excessively high Na-K ratios weakened the gel properties.