宰后蛋白氧化介导的肌肉水分迁移机制研究

The water migration of post-mortem muscle can result in purge loss, which can lead to weight loss and reduce of the juiciness, tenderness and appearance quality of meat, and thus can affect the yield of meat. At present the studies of muscle water holding capacity (WHC) were mostly concentrated on the post-mortem glycogen anaerobic metabolism and the effects of endogenous enzyme, the relationship between purge loss and protein oxidation in the mature process of post-mortem muscle is rather poorly documented. This project uses post-mortem porcine longissimus dorsi as the experimental material, to analyze the changes of protein oxidation apparent characteristic features of post-mortem muscle which subjected to different oxidation conditions, determine the water NMR relaxation of muscle, and to clarify the influences of the protein oxidation-mediated charge effects on the muscle water holding capacity. By using SDS-PAGE protein electrophoresis, differential scanning calorimetry (DSC) and circular dichroism (CD) analysis, combining with scanning electron microscopy (SEM) and transmission electron micrographs (TEM) to clarify the effects of oxidation-mediated protein cross-linking polymerization on the microscopic space structure of the muscle bundles, and to reveal the relationship between protein oxidation and muscle hydraulic conductivity. Using controlled Fe3+-H2O2-Vc oxidation system to imitate myofibrillar protein oxidation to confirm the protein oxidation-mediated charge effects and space effects. By check experiment and simulation test verification to reveal the role of protein oxidation on the formation of muscle flowing water's "pool" and "drip channel". The results of this project will elucidate the mechanism of protein oxidation-mediated water migration and provide a new theoretical basis to control purge loss of post-mortem muscle.

畜禽宰后肌肉中水分从肌原纤维内空间向细胞外空间迁移导致汁液流失与品质劣变。宰后肌肉水分变化研究多集中在肌糖原酵解与内源酶作用效应方面，而蛋白氧化引起的肌肉持水性变化与水分迁移机制尚需研究。项目以宰后猪背最长肌为材料，研究肌肉蛋白在不同氧化条件下介导的蛋白水合力变化对肌肉持水性的影响，揭示肌肉中不易流动水向自由流动水的"态变"机制，阐明蛋白氧化与肌肉汁液流失的内在联系；研究肌原纤维蛋白氧化对其空间构象的影响，分析蛋白交联-聚合效应在水分运移通道形成中的作用，探明蛋白氧化与肌肉导水性的关系；采用羟自由基体系对肌原纤维蛋白进行控制氧化，揭示蛋白氧化电荷效应和空间效应对凝胶持水性的影响机制。通过控制氧化试验与模拟验证，回答蛋白氧化在肌肉可流动水"库"与水分通道形成中的作用，借助水分迁移动态过程分析，阐明蛋白氧化介导的肌肉水分迁移机制，为宰后肌肉汁液流失控制提供依据。

本项目以宰后猪背最长肌为材料，研究了肌肉蛋白在不同氧化条件下介导的蛋白水合力变化对肌肉持水性的影响，揭示了肌肉中不易流动水向自由水流动的“态变”机制，阐明了蛋白氧化与肌肉汁液流失的内在联系；研究了肌原纤维蛋白氧化对空间构象的影响，分析了蛋白交联-聚合效应在水分运移通道形成中的作用，探明了蛋白氧化与肌肉导水性的关系；采用羟自由基体系对肌原纤维蛋白进行控制氧化试验与模拟验证，回答了蛋白氧化在肌肉可流动水“库”与水分通道形成中的作用；借助水分迁移动态过程分析，阐明蛋白氧化介导的肌肉水分迁移机制；探讨了宰后肌肉尸僵-成熟过程中，μ-calpain介导的肌原纤维蛋白-水分作用变化关系，阐明了肌肉成熟过程中内原酶调控机制，为冷却肉汁液流失工艺控制提供依据。