冷却肉贮藏和零售过程中的表观色泽稳定性至关重要，通过乳酸盐注射增强技术可有效控制有氧贮藏期间冷却肉的褪色。线粒体介导的乳酸-乳酸脱氢酶系统会促进NADH的再生进而提高高铁肌红蛋白的还原，导致货架期肉色的改善，但具体还原机理尚不清楚。本项目拟以有氧储藏条件下的冷却牛肉为试验材料，采用原位模型和离体模型，研究利用电子顺磁共振波谱技术定量分析冷藏期间肌红蛋白不同氧化状态的变化规律；使用双向电泳结合Western-blotting技术分离和筛选骨骼肌中LDH蛋白，建立LDH同工酶谱，考察LDH抑制剂对表面肉色、LDH活性以及对NADH浓度的影响；研究不同乳酸盐诱导下的乳酸-乳酸脱氢酶系统对牛肉中MetMb还原作用的效果、途径和机理，揭示不同LDH活性与MRA的相关性及其再生NADH的调控机理，探寻宰后冷却牛肉色泽品质的变化规律，为研发控制肉色劣变的新技术提供理论参考。

The apparent color stability of fresh beef is a crucial physical attribute during chilled storage and retail, and Lactate enhancement results in minimizing surface discoloration in injection-enhanced meat products. Lactate-LDH by mitochondrial mediated is the most likely system responsible for generating NADH for metmyoglobin-reducing activity (MRA), but the specific mechanism is unclear. The project intends to systematically study the effect of Lactate-LDH system on color stability in Post-mortem chilled mutton in situ and in vitro, determine the influence of lactate enhancement on LDH enzyme activity,NADH concentration, and MRA, examine the interaction of lactate and LDH to reduce MMb in vitro, Quantitative measurement of the redox state of myoglobin in mutton via electron paramagnetic resonance(EPR), characterize the involvement of LDH isoenzymes in MMb reduction and investigate the effects of LDH Inhibition by oxamate on replenishment of NADH and MRA of meat muscles. Based on assays, to reveal the mechanism of Lactate-LDH system on color stability in Post-mortem chilled beef during aerobic storage. The mechanism will be investigated by EPR spectroscopy, MALDI-TOF-MS, 2-D PAGE, and Western-blotting techniques. Finally, the research results will provide a theoretical reference for development a new technology of minimizing surface discoloration.