Unraveling Mitochondrial Proteome Changes Of Chinese Luxi Yellow Cattle Beef And Its Relationship To Meat Discoloration During Post-mortem Storage Analyzed

In recent years,China's beef consumption,production and beef imports show a significant growing trend.The quality of beef is getting more and more attention by consumers.The meat color is one of the important factors in the quality of beef.Flesh color determines the purchasing power of the consumer.So improving beef meat color for the meat industry is an urgent problem to be solved.There are many factors that affect the flesh color.The effect of mitochondrial function on the flesh color is relatively mature.However,during the whole mitochondrial metabolism,its effect on the stability of meat color is controversial.So it is important to clarify the mechanism of mitochondrial metabolism in the process of beef storage and display period.Eight rhizomes of Luxi cattle were selected as experimental samples.The longest muscle parts were cut into 2.54 cm thick steak and vacuum packed.They were stored at 4 ? for 21 days,and were randomly selected from 1,4,7,14,21 days.The dietary color,pH value,metmyoglobin content,MRA,NADH were measured and proteomics analysis were performed by 2-D electrophoresis,and then re-permeated at each storage time point Oxygen packaging,simulated market after storage using tray packing in showcase sales.Steak with oxygen permeable membrane packaging into the display cabinet display 7 days,were measured 0,4,7 days of the meat color indicators,pH,metmyoglobin content,MRA.The main results of this experiment:With the prolongation of storage days,there was no significant difference in the pH value of beef,which was significantly higher at 14 days and 21 days of storage time.There is no significant fading on store beef in the vacuum packaging;the meat color showed a certain improvement in the early stages,but with the extension of time,the show period of beef fade becomes more serious.With the storage time and display time,metmyoglobin content showed an increasing trend.But the proportion of the increase in the display period is much greater than the storage period of beef.At the same time,with the storage time and display time prolonged,beef metmyoglobin reduction force showed a decreasing trend;NADH showed a significant decrease trend.Therefore,due to the accumulation of metmyoglobin in beef,the beef appeared corresponding browning phenomenon.By comparing the storage of beef mitochondrial proteomics during the storage period,there were 16 proteins that were significantly different during the whole storage period.There were related to the flesh color: heat shock protein beta-1,adenylate kinase 1,methionine adenosine(AA 1-214),peroxidative oxidase 4,eukaryotic translation elongation factor 1,?2,prosome,macropain subunit,?-type,voltage-dependent anion selective channel Protein 1,heat shock protein ?-1,acyl-Co A synthase long chain family member 1,glycerol-3-phosphate dehydrogenase 1(soluble),phosphoglycerate kinase 1,elongation factor Tu,peroxidative redox Enzyme 2.Heat shock protein has a protective effect on the cells,controlling the degree of peroxidation inside the mitochondria,which can delay the oxidation of myoglobin.During the storage period,the expression of heat shock protein was down-regulated,and the redox balance within the mitochondria was broken,and the reaction was toward the direction of the metmyoglobin,resulting in discoloration of the color.Energy metabolism enzymes are the main enzymes in the mitochondria.Due to the down-regulation of these enzymes,the mitochondrial activity is decreased,the content of NADH in the beef is reduced,the reducing power of the metmyoglobin is decreased,and the beef is browning.