超声处理对类PSE鸡肉分离蛋白结构和乳化特性的影响

碱溶酸沉法得到的类苍白松软渗水（pale, soft and exudative，PSE）鸡肉分离蛋白功能特性较差，研究不同超声功率（0、150、300、450 W）对类PSE鸡肉分离蛋白（以下简称类PSE分离蛋白）结构和乳化特性的影响及其相关性。结果表明：随着超声功率的增加，类PSE分离蛋白的粒径和ζ电位绝对值显著降低（P＜0.05），粒径分布逐渐从双峰分布转变为单峰分布；十二烷基硫酸钠-聚丙烯酰胺凝胶电泳显示蛋白组成成分没有发生明显变化，而肌球蛋白重链和肌动蛋白的条带强度总体上增强；圆二色谱显示α-螺旋和无规卷曲相对含量增加，β-折叠和β-转角相对含量降低；自由巯基含量、表面疏水性和荧光强度明显增加；通过扫描电子显微镜进一步证实超声处理改变了分离蛋白的结构，并且减小分离蛋白尺寸；超声处理后，类PSE分离蛋白溶解性、乳化活性和乳化稳定性显著提高（P＜0.05）；同时，相关性分析和主成分分析结果表明，超声处理后类PSE分离蛋白乳化特性的提高与其结构的改变存在高度相关性。综上，超声处理能够改变类PSE分离蛋白的结构并提高其乳化特性，为类PSE鸡肉深加工提供一定的参考依据。

Effect of High Hydrostatic Pressure Treatment on Morphological,Thermal and Rheological Properties of Oat Starch

Functional properties of pale soft exudative (PSE)-like chicken protein isolate prepared by sequential alkali dissolution and acid precipitation are poor. In this context, the effects of different ultrasonic power levels (0, 150, 300 and 450 W) on the structure and emulsifying properties of PSE-like protein isolate as well as the correlation between them were analyzed. The results showed that the particle size and the absolute value of zeta potential of the protein isolate were decreased significantly (P < 0.05) with the increase in ultrasonic power, and the particle size distribution gradually changed from bimodal to unimodal distribution. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) showed that the protein composition was not obviously changed, while the band intensity of myosin heavy chain and actin were generally increased. Circular dichroism (CD) spectroscopy showed that the relative contents of α-helix and random coils were increased significantly, and the relative contents of β-sheet and β-turn were reduced. The content of free sulfhydryl groups, surface hydrophobicity and fluorescence intensity were increased obviously. Scanning electron microscopy (SEM) further confirmed that ultrasonic treatment changed the structure of the protein isolate and reduced its particle size. After ultrasonic treatment, the solubility, emulsifying activity, and emulsifying stability of the protein isolate were significantly improved (P < 0.05). Meanwhile, correlation analysis and principal component analysis (PCA) showed that there was a high correlation between the improvement in the emulsifying properties of the protein isolate and its structural changes after ultrasonic treatment. In summary, ultrasound treatment can change the structure of PSE-like protein isolate and improve its emulsifying properties, which provides a certain reference for the deep processing of PSE-like chicken.