藜麦蛋白对低钠盐体系中猪肉肌原纤维蛋白凝胶特性的影响

分别将3%、6%、9%和12%藜麦蛋白添加到低钠盐（0.40 mol/L NaCl、0.10 mol/L KCl和0.05 mol/L CaCl2）猪肉肌原纤维蛋白（myofibrillar protein，MP）体系中，考察藜麦蛋白添加量对复合蛋白溶液/凝胶的理化性质、蛋白二级结构、化学作用力和微观结构的影响。结果表明：藜麦蛋白的添加提高了MP的凝胶强度、保水性和动态流变特性，这是因为藜麦蛋白提高了复合蛋白溶液的蛋白溶解度和ζ-电位绝对值，降低了蛋白粒径；复合蛋白体系中的化学作用力以二硫键和疏水作用为主，但是藜麦蛋白的添加提高了离子键和氢键含量；藜麦蛋白促进了无规则卷曲向β-折叠和α-螺旋转化，增加了凝胶的稳定性；扫描电镜显示，藜麦蛋白提高了复合凝胶的致密程度。综上，藜麦蛋白作为一种优质植物蛋白，可以增强MP的凝胶特性，特别是当藜麦蛋白添加量为6%～9%时，对低钠盐体系中MP凝胶特性的改善效果较好。

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.