Study on the mechanism of soy protein isolate and curdlan enhances quality of reduced salt myofibrillar protein gel: insights into water distribution, gel characteristics, and sodium release

This study explores the mechanism by which soy protein isolate (SPI) synergizes with curdlan (Cur) to enhance quality of reduced-salt myofibrillar protein (MP) gels. Comparisons between direct salt-reduced (RS) and salt-reduced gel supplemented with SPI and Cur (MP-SPI-Cur) revealed that the co-addition of SPI and Cur significantly enhanced water retention capacity of the reduced-salt MP gels. The increased bound and free water contents facilitated sodium ion release. The hardness, cohesiveness, and springiness as well as rheological properties of MP-SPI-Cur were all improved, exhibiting excellent elasticity and solid gel characteristics. The formation of dense gel network structure induced an uneven distribution of sodium ions in MP-SPI-Cur. The simulation of oral dynamic process revealed that it released in large quantities at 40 s, and the final conductivity reaches 163.5 us/cm at 120 s, which is consistent with Zero-order release kinetics. FT-IR analysis indicated that combined supplementation promoted an increase in β-sheet content and reconstructed gel chemical forces through strengthened hydrogen bond, hydrophobic interaction and disulfide bond. Correlation analysis revealed a positive correlation between sodium ion diffusivity and gel texture, water-holding capacity, and a negative correlation with ionic bonds. The study demonstrates that SPI and Cur effectively enhance the quality of reduced-salt MP gels and sodium ion release efficiency by synergistically regulating the gel network and chemical forces.<p></p>