Relationship Between Postmortem Changes Of Desmin And Integrin And Water Holding Capacity Of Pork

This subject was subsidized by the National Natural Science Foundation of China(31171711)Waterholding capacity, the ability of fresh meat to retain moisture, is arguably one of the most important quality characteristics of raw products.In this paper, we selected20Black Dahe pigs of the same age and management,10of these pigs were treated by transport stress. Others were had a rest48h before slaughter.twenty samples were divided into lower drip loss group （drip loss<2%,range:0.38%‐1.45%）and higher drip loss group (drip loss>2%,range:2.16%‐4.10%) with cluster analysis.Temperature,PH, drip loss and extracellular space in longissimus dorsi muscle were measured at postmortem.change of cytoskeletal proteins(desmin,integrin),μ‐calpain enzymatic activities in longissimus dorsi musclewere measured with western blots at postmortem,so as to analyze the relationship between drip loss and other index.Analyzed the Influence mechanism of postmortem changes of cytoskeletal proteins to drip loss of pork, the mechanism of μ‐calpain decompose cytoskeletal proteins. Our resultsas follows:1PH at1h,6h,9h,24h,5d and7d postmortem were negatively correlated with drip loss(P<0.05);2In time dose,cytoskeletal proteins(desmin,integrin) of two kinds of samples reduced.Specifically,intensity of intact desmin was not significant deviated betweenhigher drip loss group samples and lower drip loss group samples(P>0.05).intensity of intact desmin were not significant deviation at1‐24h postmortem(P>0.05).intensity of intact desmin were significant deviation at day1‐day7postmortem; intensity of intact integrin were significant deviated between higher drip loss group samples and lower drip loss group samples at1h‐6h postmortem(P<0.05).intensity of intact integrin from lower drip loss samples were not significant deviation at1h‐24h postmortem (P>0.05),butintensity of intact integrin from lower drip loss group samples were significantdeviation at day1‐day7postmortem(P<0.05).intensity of intact integrin from higher drip loss samples were not significant deviation at1h‐5d postmortem(P<0.05),but intensity of intact integrin from higher drip loss group samples were significantdeviation at day7 postmortem(P<0.05).Desmin had lowly correlate with drip loss; At1h,6h,24h postmortem,drip loss was signifying correlate with integrin (P<0.05),drip loss was negatively correlated with integrin at3h postmortem(P<0.01).so,the more degradation of integrin,the more drip loss.3Autolysis of μ‐calpain was positively correlated with intensity of intact desmin. autolysis of μ‐calpain was negatively correlated with intensity of intact integrin.intensity of intact integrin was negatively correlated with drip loss. the degradation of integrin is contribution to form drip loss channel between muscle cell membrane and muscle fiber.it promotes to drip loss.4Extracellular space from higher drip loss samples at6h,9h and24h postmortem were extremely larger than those from lower drip loss samples.extracellular space during postmortem was positively correlated with drip loss (P<0.01).so we drew the inference:in this case,the contraction of myofibrils was too early and too large.5the high levels of the activation ofμ‐calpain and the high levels of desmin degradation were associated with large extracellular space and high drip loss values.the high levels of the activation ofμ‐calpain and the high levels of integrin degradation were associated with large extracellular space and high drip loss values.