Effects of soybean protein isolate on protein structure, batter rheology, and water migration in emulsified sausage

This study investigated the effect of mixing soybean protein isolate (SPI) in meat batter on the protein structure and water distribution of emulsified sausages. With SPI (5%) addition, ionic bonds and hydrogen bonds in the batter with SPI (batter–SPI) significantly decreased and increased, respectively. The disulfide bonds in sausage with SPI (sausage–SPI) significantly increased compared with sausage without SPI. Batter–SPI displayed no significant decrease in protein solubility after thermal treatment compared with the control (batter). The water migration did not change significantly as SPI was added. SPI increased the viscosity and shear stress of the emulsified sausage during processing. The rheological analysis showed that the time of degradation temperature of protein ahead in batter–SPI compared with control. Raman spectroscopy revealed a decreased level of α-helix and an increased level of β-sheet during heat treatment. In conclusion, SPI has mainly affected the changes in the protein structure of emulsified sausages. Practical applications Loss of water and oil often occurs in emulsified sausages, which usually led to production and economic losses. Thus, our research investigated how the addition of soybean protein isolate affected the physicochemical properties of minced meat. This study has an important theoretical and practical significance for the active regulation of gel formation process and development of high quality emulsified sausage products.