冷却肉贮藏过程中蛋白氧化介导的肌肉水分“态变”机制

Purge loss of chilled meat can result in deterioration of meat quality during storage, and lead to decrease in the yield of meat industry. To analyze the correlation between apparent characteristic features of water holding capacity (WHC) and protein oxidation under controlled oxidation conditions (O2/N2) at 0-4 ℃during storage , porcine longissimus dorsi was selected as the experimental material in this protocol,. Effects of protein oxidation on myofibrillar proteins multistage structures of meat will be investigated, to determine the relationship between changes of protein structure and protein binding water forces during storage. Low field nuclear magnetic resonance (LF-NMR) and hydrogen proton magnetic resonance imaging (MRI) will be applied to track the state, distribution and constitute of myowater in meat, to demonstrate the migration dynamics and behavior changes of muscle myowater, and further clarify the state changes of protein oxidation-mediated meat immobile water shifting to free water. By analyzing the changes of real time electric charge level in oxidation-mediated protein structure with analysis of myofibril protein net charges by ζ-potential and capillary zone electrophoresis（CZE）, to investigate the molecules interaction effects between protein and water and the change regulation of protein-water forces from the points of electrochemistry. Thus to elucidate the internal mechanism on changes of meat WHC and formation of purge loss through transformation of water state, and provide valuable fundamental theoretical basis on controlling of purge loss of chilled meat during storage.

冷却肉贮藏过程中，汁液流失导致其品质降低，造成很大的经济损失。项目以猪背最长肌（longissimus dorsi）为材料，在0-4℃贮藏与控制氧化（不同O2/N2比例）条件下，研究贮藏过程中氧化对肌原纤维蛋白结构的影响，确证氧化介导的蛋白分子结构改变与其水合力变化之间关系；借助低场核磁共振（LF-NMR）及H+核磁成像（MRI）技术，实时跟踪肌肉水分状态、组成与分布，分析冷却肉贮藏过程中水分的迁移动态及其行为变化，阐明肌肉中不易流动水向自由水的“态变”进程；采用Zeta电位分析与毛细管区带电泳（CZE）等方法动态测定不同氧化条件下肌肉蛋白电荷水平，研究氧化介导的肌肉蛋白电化学性质的变化，分析蛋白质-水分的分子间互作及其对蛋白水合力的影响效应，揭示冷却肉贮藏过程中蛋白氧化介导的肌肉中不易流动水向自由水“态变”的机制，回答蛋白氧化引起的贮藏汁液流失形成原因，为生产工艺控制提供理论依据。

冷却肉贮藏过程中，汁液流失导致其品质降低，造成很大的经济损失。本项目以宰后猪背最长肌（longissimus dorsi）为实验材料，研究了0-4℃条件下0%、20%、50%、80%氧气浓度气调包装对冷却猪肉贮藏品质与肌肉持水性的影响；系统分析了猪肉贮藏过程中肌肉水分的迁移动态及行为变化，阐明肌肉中不易流动水向自由水的“态变”进程；基于蛋白组学技术，开展了冷却猪肉贮藏过程中流失汁液全蛋白鉴定，系统分析了不同氧气浓度处理组间的差异蛋白，阐明了不同氧气含量气调包装对冷却猪肉持水力的影响机制；建立了亚油酸/脂肪氧合酶（OLA）、丙二醛（MDA）和羟自由基（·OH）模拟体系，研究了蛋白氧化效应对肌肉蛋白电化学性质的影响，探讨了氧化对蛋白电化学性质作用机制及对蛋白水合力的影响，阐明了肌肉蛋白质水合力的变化规律。该研究通过多层次多角度系统研究冷却肉贮藏过程中氧化对肌肉蛋白结构的影响，回答冷却肉贮藏过程中蛋白氧化介导的汁液流失形成原因，为工艺控制提供理论依据。