Li Ke, Liu Jun-Ya, Fu Lei, Zhao Ying-Ying, Bai Yan-Hong
College of Food and Bioengineering, Zhengzhou University of Light Industry, Henan Collaborative Innovation Center for Food Production and Safety, Henan Key Laboratory of Cold Chain Food Quality and Safety Control, Zhengzhou 450001, China.
Asian-Australas J Anim Sci. 2019 May;32(5):721-733. doi: 10.5713/ajas.18.0389. Epub 2018 Sep 13.
The objectives of this study were to investigate the thermal gelation properties and molecular forces of actomyosin extracted from two classes of chicken breast meat qualities (normal and pale, soft and exudative [PSE]-like) during heating process to further improve the understanding of the variations of functional properties between normal and PSE-like chicken breast meat.
Actomyosin was extracted from normal and PSE-like chicken breast meat and the gel strength, water-holding capacity (WHC), protein loss, particle size and distribution, dynamic rheology and protein thermal stability were determined, then turbidity, active sulfhydryl group contents, hydrophobicity and molecular forces during thermal-induced gelling formation were comparatively studied.
Sodium dodecyl sulphate-polyacrylamide gel electrophoresis showed that protein profiles of actomyosin extracted from normal and PSE-like meat were not significantly different (p>0.05). Compared with normal actomyosin, PSE-like actomyosin had lower gel strength, WHC, particle size, less protein content involved in thermal gelation forming (p<0.05), and reduced onset temperature (To), thermal transition temperature (Td), storage modulus (G') and loss modulus (G″). The turbidity, reactive sulfhydryl group of PSE-like actomyosin were higher when heated from 40°C to 60°C. Further heating to 80°C had lower transition from reactive sulfhydryl group into a disulfide bond and surface hydrophobicity. Molecular forces showed that hydrophobic interaction was the main force for heat-induced gel formation while both ionic and hydrogen bonds were different significantly between normal and PSE-like actomyosin (p<0.05).
These changes in chemical groups and inter-molecular bonds affected protein-protein interaction and protein-water interaction and contributed to the inferior thermal gelation properties of PSE-like meat.
本研究旨在探究从两类鸡胸肉品质（正常和类似苍白、柔软、渗水 [PSE]）中提取的肌动球蛋白在加热过程中的热凝胶化特性和分子作用力，以进一步加深对正常和类似PSE鸡胸肉功能特性差异的理解。
从正常和类似PSE的鸡胸肉中提取肌动球蛋白，测定其凝胶强度、持水能力（WHC）、蛋白质损失、粒径及分布、动态流变学和蛋白质热稳定性，然后比较研究热诱导凝胶形成过程中的浊度、活性巯基含量、疏水性和分子作用力。
十二烷基硫酸钠-聚丙烯酰胺凝胶电泳显示，从正常和类似PSE的肉中提取的肌动球蛋白的蛋白质谱无显著差异（p>0.05）。与正常肌动球蛋白相比，类似PSE的肌动球蛋白凝胶强度、WHC、粒径较低，参与热凝胶形成的蛋白质含量较少（p<0.05），起始温度（To）、热转变温度（Td）、储能模量（G'）和损耗模量（G″）降低。当从40°C加热到60°C时，类似PSE的肌动球蛋白的浊度、反应性巯基较高。进一步加热到80°C时，反应性巯基向二硫键和表面疏水性的转变较低。分子作用力表明，疏水相互作用是热诱导凝胶形成的主要作用力，而正常和类似PSE的肌动球蛋白之间的离子键和氢键均有显著差异（p<0.05）。
这些化学基团和分子间键的变化影响了蛋白质-蛋白质相互作用和蛋白质-水相互作用，导致类似PSE的肉的热凝胶化特性较差。
