Gelling properties of myofibrillar protein–soy protein and k-carrageenan composite as affected by various salt levels

Abstract

In order to increase use of soybean protein in meat products, the objective of this research was to investigate the effects of k-carrageenan on the gel properties of the myofibrillar protein (MP)–soybean protein isolate (SPI) composite with various salt levels. The results showed that the addition of SPI in a small amount improved the gelation and WHC of MP-SPI composite gel, and incorporation of k-carrageenan enhanced WHC at low NaCl concentration (0.1 mol/L and 0.3 mol/L). The observation results of the environmental scanning electron microscope (ESEM) suggested that the strong WHC of k-carrageenan and the filling of soybean protein promoted the gelation forming. It was related to the positive effects on the elastic modulus, gel strength and WHC of MP mixing with a small amount of soybean protein and larger content of k-carrageenan. However, at a high salt concentration (0.6 mol/L), SPI showed negative effects on the gel strength and WHC of composite MP-SPI. The gel strength and WHC of mixed MP-SPI were reinforced with the addition of k-carrageenan. In conclusion, the results of this research showed that the interactions in the system of the k-carrageenan-MP-SPI composite were significantly influenced by salt concentration. Low concentration of soybean protein and high level of k-carrageenan at low-salt concentration improved composite gel properties.