Influence of Interactions Between Drawing Soy Protein and Myofibrillar Proteins on Gel Properties

Drawing soy protein (DSP) exhibits a well-defined fibrous structure, conferring significant market potential. This study investigates the interactions between DSP and myofibrillar proteins (MP) and their effects on gel properties. Porcine myofibrillar protein (MP) was used as the raw material, and mixed systems were prepared by incorporating different concentrations of DSP at 0%, 2%, 4%, 6%, and 8% to evaluate their physicochemical properties and gel characteristics. The results demonstrated that the addition of DSP enhanced the gel strength, hardness, and water-holding capacity (WHC) of MP, thereby improving the overall properties and water retention of the gels. Among them, the trend of change was most obvious when the addition amount was 6%. The gel strength increased by 196.5%, the water retention capacity improved by 68.3%, and the hardness rose by 33.3%. Furthermore, as the addition amount of DSP increases, the total thiol content decreases, the hydrogen bond content increases, and the surface hydrophobicity enhances. This leads to a more compact arrangement of protein molecules, which is conducive to a denser and more stable solution and improves the stability of the protein solution. The α-helical structures in the proteins progressively transformed into β-turn structures, exposing more amino acid side chains and inducing conformational changes in MP, resulting in denser and more uniform gel network structures. The most pronounced changes were observed at a 6% addition level. These findings contribute to diversifying meat products and provide a theoretical basis for improving the WHC and yield of emulsified meat products in pork processing.