秦川牛肉冷藏期间能量代谢变化及其对肉品质的影响

为探究秦川牛肉在冷藏期间能量代谢机理及其对肉品质的影响。采用4D-非标记定量蛋白质组学法研究不同贮藏期（0、4、8 d）秦川牛背最长肌中蛋白质组学变化，采用高效液相色谱法检测能量物质的变化。结果表明：与能量代谢相关的三磷酸腺苷（adenosine triphosphate，ATP）合酶亚基δ和ATP合酶亚基γ在贮藏第8天时较第0天分别上调1.516（P＝0.017）、1.579 倍（P＝0.037）；NADH脱氢酶[泛醌]1β亚复合物亚基5在贮藏第8天时较第4天调整0.497 倍（P＝0.023）；琥珀酸-辅酶A连接酶[ADP形成]亚基β在贮藏第8天时较第0天调整0.762 倍（P＝0.000 7）；NADH脱氢酶[泛醌]1α亚复合物亚基6在贮藏第4天时较第0天上调1.467 倍（P＝0.026）；细胞色素c氧化酶亚基7A1在贮藏第8天时较第4天调整0.692 倍（P＝0.024）。以上6 种蛋白表达丰度的变化通过线粒体电子传递、呼吸链复合物I装配、ATP生物合成等过程影响ATP等能量物质合成和运输过程，导致冷藏期间肌细胞中能量物质供应不足，进而影响肉品质的变化：在贮藏0～8 d期间ATP含量降低了95.07%，影响了肌红蛋白的转化，导致褐变出现；促使无氧糖酵解在产能的同时产生乳酸，引起肌肉酸化；导致细胞凋亡，肌原纤维蛋白水解促使肌肉嫩度变化。

Changes in Postmortem Energy Metabolism of Qinchuan Cattle Meat during Chilled Storage and Its Effects on Meat Quality

In order to explore the mechanism of postmortem energy metabolism in Qinchuan cattle muscle during cold storage and its effect on meat quality, this study investigated the proteomic changes in the Longissimus dorsi muscle of Qinchuan cattle during different storage periods (0, 4 and 8 days) using 4D label-free quantitative (4D-LFQ) proteomics, and high performance liquid chromatography (HPLC) was used to detect the changes of energy substances. The results showed that ATP synthase subunit δ and ATP synthase subunit γ, both related to energy metabolism, were up-regulated by 1.516 (P = 0.017), and 1.579 times (P = 0.037), respectively on day 8 compared with those on day 0, NADH dehydrogenase [ubiquinone] 1β subunit 5 was down-regulated by 0.497 times (P = 0.023) on day 8 compared with that on day 4 and succinate CoA linker [ADP formation] subunit β was down-regulated by 0.762 times (P = 0.000 7) on day 8 compared with that on day 0, NADH dehydrogenase [ubiquinone] 1 α subunit 6 was up-regulated by 1.467 times (P = 0.026) on day 4 compared with that on day 0, and cytochrome c oxidase subunit 7A1 was down-regulated by 0.692 times (P = 0.024) on day 8 compared with that on day 4. The changes in the expression abundance of the above six proteins could affect the synthesis and transportation of ATP and other energy substances through mitochondrial electron transport, respiratory chain complex I assembly, ATP biosynthesis and other processes, thereby resulting in insufficient supply of energy materials in muscle cells during cold storage, and consequently affecting the change of meat quality. ATP content was reduced by 95.07% after 8 days of storage, affecting myoglobin transformation, leading to the occurrence of browning, promoting anaerobic glycolysis to produce energy and lactic acid, causing muscle acidification, and leading to cell apoptosis and finally myofibrillar protein hydrolysis to promote muscle tenderness changes.