Effects Of Polysaccharides On The Gel Properties Of Myofibrillar Protein And Soy Protein Composite

Taking meat product cost and nutrition into consideration, soy protein isolated(SPI) and polysaccharides are used more widely in meat product. When SPI and polysaccharides are added at the same time, how to make the meat system maintain good elasticity and hold water capacity is very worthy to study. The existing studies were mostly focused on myofibrillar protein(MP) and SPI, polysaccharides-MP, or polysaccharides-SPI composite gel systems, but polysaccharides-MP-SPI composite gel system was less studied. So the effects of polysaccharides on gel properties of MP-SPI composite under different salt concentrations were explored by the simulation system in this paper. Theoretical basis of improving the quality of the meat products which contain high percentage of SPI and developing low salt meat products may be provided according to this paper.Firstly, the influence of SPI on gel properties of MP was discussed in this paper. At 0.1, 0.3, 0.6 mol/L Na Cl salt concentrations, the influence of 1% and 2% SPI on gel properties of MP was studied. Under the condition of 0.1, 0.3 mol/L Na Cl, low content of soybean protein(3% MP + 1% SPI), had a positive role on MP gel; under the condition of all kinds of salt concentration, if SPI content was further increased in the composite gel, it had a negative effect on gel strength and water holding capacity of the gel.For the objective of comparing the various influence of 6 polysaccharides on the gel properties of MP under different salt concentrations, 6 kinds of polysaccharides respectively were used in this experiment, such as xanthan gum, k-carrageenan, konjac gum, locust bean gum, guar gum and sodium alginate. Polysaccharides were respectively added to the MP at concentrations of 0.1%, 0.5% and 1%. The analysis results showed that at lower salt concentrations, the MP gel elastic modulus, water holding capacity and gel strength were significantly improved due to the addition of polysaccharides; at 0.6 mol/L Na Cl, when the addition amount of locust bean gum and xanthan gum and k-carrageenan was 1%, the maximum G′ of the protein system can be obtained, while three other kinds of polysaccharides had limits of concentration. Gel strength and WHC of MP gel were significantly increased because of locust bean gum and carrageenan.In this paper, the influence of 6 polysaccharides on gel properties of SPI-MP composite under different salt concentrations had been discussed, with the measurements like rheology, gel strength, WHC and gel microstructure observation. Studies found that at 0.1 and 0.3 mol/L Na Cl, for the 1% SPI composite protein gel system, gel strength, elastic modulus, water holding capacity and microstructure were improved after the addition of polysaccharides. Under 0.6 mol/L Na Cl concentration, the gel formation of MP was interfered with the existence of soy protein, and the modulus of elasticity of protein composite system was increased by a moderate amount of polysaccharides, and the interference effect of SPI was reduced; the gel strength and the microstructure of composite protein could be improved by locust bean gum and k-carrageenan.Finally, the speculation on the gel mechanism of polysaccharides-protein composite was discussed. This research took the method of stress relaxation to study the influence of polysaccharides on the composite protein gel. According to the balance elasticity modulus value of the gel, the analysis showed that: at low salt concentration, the number of the system effective grid was increased due to addition of locust bean gum and k-carrageenan. They significantly improved the equilibrium elasticity modulus value of compound protein, and had an advantage of the formation of protein gel. Under high salt concentration, for the SPI:MP(1:3)system, the balance elasticity modulus of protein system was significantly improved by polysaccharides, suggesting that the addition of polysaccharide could increase the MP effective number of grid, and in this way, the SPI interference may be reduced due to polysaccharides in the system, but this function above was not observed by the addition of konjac and guar gum.