Effect of Quinoa Protein on Gel Properties of Pork Myofibrillar Protein in Low-Sodium Salt System

In this study, the effects of adding different levels (3%, 6%, 9% and 12%) of quinoa protein on the physicochemical properties, secondary structure, chemical forces, and microstructure of pork myofibrillar protein (MP) in a low-sodium salt system (0.40 mol/L NaCl, 0.10 mol/L KCl and 0.05 mol/L CaCl₂) were investigated. The results showed that the gel strength, water retention and dynamic rheological properties of MP were improved by adding quinoa protein, which increased the solubility and the absolute value of ζ-potential of MP, and reduced the particle size. Disulfide bonds and hydrophobic interactions were the dominant chemical forces in the mixed protein system, but the addition of quinine increased the amount of ionic and hydrogen bonds. Fourier transform infrared (FTIR) spectroscopy showed that quinoa protein promoted the transformation of random coils to β-sheets and α-helixes and enhanced the stability of the MP gel. Scanning electron microscopy (SEM) showed that the quinoa protein increased the compactness of the gel. Therefore, quinoa protein, as a high-quality plant protein, can enhance the gel properties of MP. In particular, adding 6%–9% of quinoa protein is most effective in improving the gel properties of MP.