Effect of soybean protein isolate and egg white mixture on gelation of chicken myofibrillar proteins under salt/-free conditions

Abstract

Non-meat proteins are widely used in the meat processing, and the final product is greatly affected by salt. This study presented the combined use of soybean protein isolate (SPI) and egg white (EW) on the gelation of chicken myofibrillar protein (MP) with or with NaCl. Gel properties were determined with the use of texture profile analysis, cooking loss, intermolecular forces, rheological properties, scanning electron microscopy and low field nuclear magnetic resonance (LF-NMR) measurements. Non-meat proteins improved the MP gel quality when it was without NaCl, except for the increased cooking loss caused by 1.2% SPI. The effect of non-meat proteins on MP gel quality was more obvious at 0.3 mol/L NaCl, including the improvement of gel hardness by SPI and the reduction of cooking loss by EW. When the added non-meat proteins changed from 1.2% SPI to 0.3% EW-0.9% SPI, the gel hardness significantly decreased (P < 0.05). Its storage modulus was even lower than that of the pure MP, and uneven protein aggregates and pores were observed in the microstructure. This was because the SPI aggregates were wrapped by EW, and the SPI-EW aggregates led to the local aggregation of MP and the uneven structure of MP gel.