热聚集行为调控肌球蛋白-血清白蛋白复合体系凝胶性能的机制

The meat products qualities can be improved significantly with the interaction between plasma protein and muscle proteins. Preliminary studies shows that there are synergistic interaction and antagonistic interaction between myosin and serum albumin which can be regulated by the heat-induced aggregation. That is the key of the gel performance of the plasma protein mixed products. However, the mechanisms of regulating the synergistic interaction or antagonistic interaction through the aggregation behavior during the heating processing were not clear. Thus, this project intends to focus on the processing of the myosin-serum albumin system transferred from the sol to the gel, begin with the effects of protein charged states on the aggregation behavior, and analyze the relationship between the protein molecular space structure and gel microstructure during the gel formation. The rules that the aggregation structure influence the mixed gel properties will be explained. SS linked products of heat-induced aggregation are planning to identified, and the main reaction modes of the SS linked products and cysteines involved in this reaction will be revealed. Based on those, mechanism of heat-induced aggregation regulating the gel properties of myosin-serum albumin mixed system will be answered. These researches will enrich the theory of mixed gel formation, and provide the theoretical foundation for the quality control technique of plasma protein mixed products.

血浆蛋白可与肌肉共同作用形成良好的凝胶，显著改善肉制品品质。前期研究表明：肌球蛋白与血清白蛋白之间可发生受其热聚集行为调控的协同或拮抗相互作用，而这正是决定血浆蛋白-肌肉复合制品凝胶性能优劣的关键。但是，热诱导过程中热聚集行为是如何调控其凝胶性能的，目前还尚不清楚。因此，本项目以肌球蛋白-血清白蛋白复合溶胶-凝胶转变体系为研究对象，验证蛋白质荷电状态对蛋白质聚集行为的影响，分析凝胶形成过程中蛋白质分子空间构象的变化以及凝胶微细结构的变化，阐明聚集体结构对复合凝胶宏观性能的影响规律，明确热聚集反应生成的二硫键连接产物，揭示二硫键形成的主导作用方式与作用位点，在分子水平上阐明热聚集行为调控肌球蛋白-血清白蛋白复合体系凝胶性能的机制，丰富和发展肌肉蛋白复合凝胶形成理论，为有效控制血浆蛋白复合型肉制品质量提供理论参考。

血浆蛋白可与肌肉共同作用形成良好的凝胶，显著改善肉制品品质，解析血浆蛋白-肌肉复合制品凝胶性能形成机制是将屠宰副产物血浆蛋白应用于凝胶类肉制品的一项基础研究。本项目以肌原纤维蛋白/肌球蛋白-血清白蛋白模拟体系为研究对象，通过分析其质构、保水性、流变性、蛋白质二级结构和三级结构、粒径、Zeta电位等变化，研究由pH介导的蛋白质荷电状态与血浆蛋白的引入比例对复合蛋白的热聚集行为、分子空间构象及凝胶表观性能的影响机制。研究结果表明：（1）不高于1/2的血清白蛋白替代，可以改善肌原纤维蛋白/肌球蛋白的凝胶强度或保水性，并仍保持肌球蛋白流变曲线的“几”字形特点。（2）形成肌原纤维蛋白-血清白蛋白复合凝胶的主要作用力为二硫键与疏水相互作用，由pH介导的静电作用可通过影响复合体系中蛋白质的聚集程度而形成不同的凝胶表观性能。（3）不高于1/2血清白蛋白的引入可降低复合体系中蛋白质的聚集程度，并得到适宜的α-螺旋与β-折叠比例，增加了蛋白质空间结构的松散程度，获得了适宜的疏水性氨基酸暴露程度，从而改善了凝胶强度。（4）肌球蛋白与血清白蛋白之间的相互作用为随机性交联反应，反应涉及了肌球蛋白重链的所有部位，轻链结构不参与热聚集反应。研究结果丰富和发展了肌肉蛋白复合凝胶形成理论，可为有效控制血浆蛋白复合型肉制品质量提供理论参考。.