目的:探讨畜禽肉宰后能量代谢的差异及其可能的原因.方法:于宰后45 min测定鸡肉、灰白(pale soft exudative,PSE)猪肉、正常猪肉和牛肉中糖原、ATP/ADP/AMP含量及乳酸脱氢酶(lactate dehydrogenase,LDH)活性,并提取肌浆和肌原纤维蛋白进行十二烷基硫酸钠-聚丙烯酰胺凝胶电泳(sodium dodecyl sulfate-polyacrylamide gel electrophoresis,SDS-PAGE)和液相色谱-串联质谱鉴定,分析各组肉的磷酸化水平差异.结果:牛肉中糖原含量显著高于其他组(P＜0.05),正常猪肉组糖原和ATP含量显著高于PSE猪肉组和鸡肉组(P＜0.05),而PSE猪肉组的LDH活性显著高于其他组(P＜0.05);肌浆蛋白SDS-PAGE ProQ染色表明,宰后45 min PSE猪肉组中6个条带的磷酸化水平显著低于正常猪肉组(P＜0.05),而另有6个条带的磷酸化水平显著高于正常猪肉组(P＜0.05).牛肉组和鸡肉组中分别有3个和1个条带的磷酸化水平偏低,1个条带和8个条带的磷酸化水平明显偏高.而肌原纤维蛋白电泳表明,牛肉中大部分蛋白质的磷酸化水平处于最高值,而鸡肉组处于最低值,猪肉介于两者之间;PSE猪肉组中7个条带的磷酸化水平显著低于正常猪肉(P＜0.05);6个条带的磷酸化水平显著高于正常猪肉(P＜0.05).结论:宰后异质肉的形成受宰后糖原和ATP消耗速率、LDH活性的影响,同时与肌肉中糖酵解酶的磷酸化水平有关.
Energy Metabolism and Protein Phosphorylation of Pork, Beef and Chicken during the Early Postmortem Period
Objective:To explore the major cause for abnormal meat.Methods:At 45 min postmortem,chicken,pale soft exudative (PSE) pork,normal pork and beef were taken for the analysis of glycogen,ATP/ADP/AMP contents,lactate dehydrogenase (LDH) activity.At the same time,myofibrillar and sarcoplasmic proteins were extracted and separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE),and the bands of interest were identified by liquid chromatography-tandem mass spectrometry (LC-MS/MS).The difference in band intensity was evaluated.Results:Glycogen was higher in beef than three other meats (P ＜ 0.05).Glycogen and ATP contents were higher in PSE pork than normal pork and chicken (P ＜ 0.05).LDH activity in PSE pork was much higher than all other groups (P ＜ 0.05).SDS-PAGE with ProQ staining indicated that,at 45 min postmortem,the phosphorylation levels of sarcoplasmic proteins from 6 bands were lower in PSE pork than those of normal pork (P ＜ 0.05),while sarcoplasmic proteins from other 6 bands had higher phosphorylation levels than normal pork (P ＜ 0.05).In addition,3 bands in beef and 1 bands in chicken had lower phsophorylation levels,whilst higher phsophorylation levels were observed for 1 bands in beef and 8 bands in chicken.For myofibrillar proteins,the majority of bands in beef had highest phosphorylation levels,the lowest phosphorylation levels were found for chicken (P ＜ 0.05),and pork was in the middle.Similarly,7 bands in PSE pork had lower phosphorylation levels than normal pork (P ＜ 0.05),while 6 bands had higher phosphorylation levels than normal pork(P ＜ 0.05).Conclusion:The rates of glycolysis and ATP depletion,and LDH activity had a great contribution to PSE pork,which is also associated with protein phosphorylation of glycolytic enzymes.
国家科技期刊平台
NSTL
万方数据
维普
