Influence of Soy Protein Isolate Prepared by Phosphate-Assisted Hydrothermal Cooking on the Gelation of Myofibrillar Protein

The poor solubility and functionalities of soy protein concentrate (SPC) limits its utilization in meat products. Phosphate-assisted hydrothermal cooking (HTC) was applied to refunctionalize SPC in this work. The resultant soy protein isolate (SPI) was used as an ingredient for improving the gelation of porcine myofibrillar protein (MP) which was induced by microbial transglutaminase (MTGase). The addition of sodium tripolyphosphate (STPP) enhanced the refunctionalization efficiency of HTC and increased the phosphorus content in the obtained SPI. Dynamic rheological analysis indicated that this SPI itself could not form a gel with the help of MTGase. However, the SEM observation revealed that the presence of this SPI strengthened the gel network of MP and made it become denser and more ordered. As a result, the mechanical properties and water holding capacity of the MP gel were significantly improved by this SPI prepared by phosphate-assisted HTC.