Microbial Transglutaminase Catalyzed the Cross-Linking of Myofibrillar/Soy Protein Isolate Mixtures

The effects of temperature and ionic strength on the cross-linking of myofibrillar protein isolate (MPI)/soy protein isolates (SPI) catalyzed by microbial transglutaminase (MTGase) were studied. The SPI treated with MTGase formed a substantial amount of cross-linking at temperatures 50C. All the SPI constituents except the basic subunits (B) of glycinin were cross-linked and formed polymers. For MPI/SPI mixtures heated with MTGase, the actin band was gradually reduced within the temperature range from 20 to 90C. The addition of KCl gradually reduced the protein band changes and the myosin heavy chain and actin bands became less noticeable detected by the sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The rheological results indicated that the treatment of MPI with MTGase significantly improved the elasticity of the MPI gels, irrespective of the incubation time. MTGase treatment significantly enhanced the gel properties of the mixed MPI/SPI protein gels. Practical ApplicationsMyofibrillar proteins are the main contributors imparting textural attributes and functional properties to muscle foods. Defining the performance of myofibrillar proteins during heat-induced gelation is beneficial in maintaining quality and developing processed meat products and processes. A better understanding of the gelation properties of protein (muscle and nonmuscle) in the presence or absence of microbial transglutaminase, would contribute to improving its industrial utilization and the quality of meat products.