KGM对鲢肌球蛋白热诱导展开与聚集的影响及其对凝胶网络的作用机制研究

The gel property of freshwater fish limits the development of surimi industry. Various hydrocolloids are used to enchance the gel property of freshwater fish surimi, however, the mechanism is not clarified until now. The action mechanism between the hydrocolloids and proteins could not be explained clearly only using rheological method. As result, the application of hydrocolloid in the surimi industry was limited. Konjac glucomannan (KGM) with different degrees of deacetylation (DDs) are used to silver carp myosin gel. The effect of KGM on the rate of unfolding and aggregation of myosin induced by thermal treatment are investigated using infrared spectroscopy (IR), Raman spectroscopy, and circular dichroism spectroscopy (CD). The chemical forces (hydrophobic interactions, disulfide bonds, hydrogen bonding, ionic bond, etc.) are determined to investigate the action between KGM and myosin during heat-induced gelation. Atomic force microscopy, and differential scanning calorimetry are also used to detect the action between KGM and myosin.The three-dimensional network structure of KGM and myosin are studied using scanning electron microscopy, microscopic tissue slicing method, and Monte Carlo simulation. Water states of gel system are studied by LF-NMR to investigate the effect of KMG on the rate of unfolding and aggregation of myosin, and also to explain the network of the mixture gel. Based on the above, the effect of KGM on the dynamic equilibrium of unfolding and aggregation of myosin during heat treatment will be clarified. The form of KGM network exists in the network of myosin gel also will be explained. Furthermore, effect of KGM on the change of myosin microstructure including secondary structure and tertiary structure will be clarified. It is very important that this project to state the mechanisms of hydrocolloid improving the gel capacity and network stability of myosin. Expected results of this project will rich theory of the interaction between polysaccharide and protein macromolecules. And it also will provide theoretical guidance for the development of recombinant protein food such as the freshwater fish surimi and other polysaccharides / protein food. Finally, it will promote the healthy development of freshwater fish farming and processing industry.

亲水胶体已被用来提高淡水鱼糜类产品的凝胶特性，其本质原因不明确，目前仅从流变物性学角度无法阐明多糖/蛋白相互作用机理，从而限制了其应用与鱼糜产业发展。本研究选择效果较高的魔芋葡甘聚糖（KGM）和鲢肌球蛋白为对象，利用红外光谱、激光拉曼光谱、圆二色谱、流变仪、原子力显微镜、低场核磁共振、化学力测定、差示扫描量热仪、扫描电镜和组织显微切片等技术，结合通过热诱导改变肌球蛋白初始结构制备不同变性程度肌球蛋白的方法，对KGM（不同脱乙酰度）影响肌球蛋白展开与聚集速率和混合凝胶体系的网络结构进行研究，探索KGM改善肌球蛋白凝胶形成能力和网络结构有序性的作用途径，对阐明KGM与肌球蛋白的相互作用及提高鱼糜凝胶特性的作用机理具有重要意义。预期结果将能丰富多糖和蛋白质大分子的相互作用理论，为淡水鱼糜制品以及其他多糖-蛋白类调理食品的开发提供理论指导，促进淡水鱼养殖业和加工产业健康发展。

亲水胶体已被用来提高淡水鱼糜类产品的凝胶特性，其本质原因不明确，目前仅从流变物性学角度无法阐明多糖/蛋白相互作用机理，从而限制了其应用与鱼糜产业发展。本研究选择效果较高的魔芋葡甘聚糖（KGM）和鲢肌球蛋白为对象，利用红外光谱、激光拉曼光谱、圆二色谱、流变仪、原子力显微镜、低场核磁共振、化学力测定、差示扫描量热仪、扫描电镜和组织显微切片等技术，结合通过热诱导改变肌球蛋白初始结构制备不同变性程度肌球蛋白的方法，.阐明了魔芋葡甘聚糖（KGM）对鲢鱼肌肉蛋白热凝胶聚集行为的影响及其机制，研究了KGM（不同脱乙酰度）对鲢肌肉蛋白展开与聚集过程中的分子间作用力的影响；揭示了KGM（不同脱乙酰度）对鲢肌肉蛋白展开与聚集过程中的水分分布与迁移的影响；阐明了KGM对鲢鱼肌肉蛋白网络形成和凝胶特性的影响机制。.结果显示在鱼糜蛋白质凝胶化过程中，由于KGM乙酰基基团脱除的程度不同，其结合水能力、疏水相互作用以及凝胶稳定性存在差异，可能通过影响鱼糜蛋白质凝胶化过程的水分状态与分布、蛋白质二级结构和蛋白质分子间作用力特别是疏水作用来影响蛋白质的展开与聚集的相对速率，最终影响鱼糜凝胶化过程，从而影响鱼糜凝胶的宏观特性。因此，适宜的乙酰基脱除更有利于KGM改善鲢鱼糜的凝胶网络结构，为KGM在鱼糜制品生产中的而应用提供了指导，结果丰富了多糖和蛋白质大分子的相互作用理论，为淡水鱼糜制品以及其他多糖-蛋白类调理食品的开发奠定了基础。