Glycolysis Analysis Of Different Ultimate PH Beef During Early Postmortem Time

In recent years,the consumption of beef,beef production and imports of beef products,showing significant growth in the state,more and more consumers are concerned about the quality of beef and its influence factors.There is a kind of heterogeneous quality beef :DFD(Dark,Firm & Dry).In beef production process,due to the poor quality of this kind of beef,meat processing enterprises got huge economic loss each year,while two heterogeneous meat generate directly related to the ultimate pH value.The relationship between the heterogeneity of meat and ultimate pH is the relationship between the process and the rate of anaerobic glycolysis in the early stage of post-slaughter.The substrate of anaerobic glycolysis in the early stage of post-slaughter are glycogen,glucose,6-P-glu and so on,the rate of anaerobic glycolysis have significantly associate with glycolytic key kinase activity.So its meaningful to analysis the relationship between glycolysis and beef quality in the early stage of post-slaughterThe experiment analysis the energy level(glycolytic potential,lactic acid content)in different ultimate pH group of beef,and analysis differently ultimate pH group of beef glucose metabolism to determine its internal mechanism.This experiment select 90 Chinese yellow cattle as samples,firstly take samples from longissimus lumborum dorsi of beef in 1h,3h,6h,12 h,24h and frozen in liquid nitrogen,and then divide the sample into three groups according to the pHu value in the 24 h.High ultimate pH group(pH value> 6.1);middle ultimate pH group(5.8 <p H value <6.1);low ultimate pH group(5.4 <p H value <5.8).Each group selected six biological samples to determine its indicators.The result shows there are sinificant difference between different ulimate pH value group,the glycogen and glycolysis potential content of high ulimate pH value group is siginificant lower than low ulimate pH value group.Glycogen as a important substrate of glycolysis,postslaughter glycolysis and the generate of lactate is the main reason which cause the decline of pH value.The initial content of lactic acid show that no significantly difference between three pHu groups,and with the post-slaughter glycolysis,there are significant difference of lactic acid content between low pHu and high pHu group in 24 h.The amount of lactic acid which generate in high ultimate pH lower than normal,which means in high pHu group the generated of lactic acid is not enough to decreased pH to the normal range.Hexokinase and pyruvate kinase activity in high ultimate pH group was significantly lower than the low ultimate pH group.It can be understood as specifically,the higher enzyme activity represents a high rate of glycolysis,while the anaerobic glycolysis of glycogen final product is lactic acid,which represents a relatively high rate of lactic acid production.Producing lactic acid will cause pH decline rapidly,so that at the same time,the pH value in the low ultimate pH beef group was significantly lower than the high ultimate pH group.Hexokinase,pyruvate kinase activity showed significant differences at various time points,the trend to increased first and then decreased.As the concrete can be understood as the maturation time,rapid consumption of the ATP will increases hexokinase,pyruvate kinase activity by one or more ways,so that hexokinase,pyruvate kinase peaked at three hours,then with the pH decreases and gradually deviated from the optimum pH of the key enzyme in the glycolytic,thus making hexokinase,pyruvate kinase activity is decreased.