猪宰后背最长肌中μ-calpain、pH和骨架蛋白变化与持水性的关系

Relationship Among Changes of μ-calpain, pH and Skeleton Proteinand Water Holding Capacity of Post-mortem Pork

为研究宰后猪肉中pH、μ-calpain、肌间线蛋白(desmin)和整联蛋白(integrin)变化与持水性的关系,将20条不同汁液流失的猪背最长肌样品按汁液流失率的高低,分成高汁液流失组(High drip loss;H组,drip loss≥5.01%,n=10)和低汁液流失组(Low drip loss;L组,drip loss≤4.00%,n=10)。分别于宰后45 min,3、9、12和24 h测定所选背最长肌pH、μ-calpain活性和desmin、integrin的表达量。结果表明:H组的汁液流失率极显著高于L组(P<0.01),3~24 h的desmin表达量均高于L组(P<0.05),45 min、12 h和24 h的μ-calpain活性低于L组(P<0.05),integrin(45 min、3 h和12 h)的表达量和pH(45 min~12 h)均低于L组(P<0.05)。desmin的表达量与汁液流失率呈正相关,而pH、μ-calpain活性和integrin的表达量与汁液流失率均呈负相关。pH、μ-calpain活性、desmin和integrin的表达量分别解释了汁液流失变异的78.1%、42.4%、70.3%和71.7%。上述结果表明:pH、μ-calpain、desmin和integrin都会对汁液流失产生影响;pH是对汁液流失率的影响最大的单变量。

To investigate the relationship between pH,μ-calpain,desmin and integrin changes and water holding capacity in postmortem pork,20 samples of longissimus dorsi with different drip loss were divided into High drip loss group(Hgroup drip loss≥5.01%,n=10)and Low drip loss group(L-group drip loss≤4.00%,n=10).pH,μ-calpain activity and expression levels of desmin and integrin were determined in 45 min,3,9,12 and 24 h after slaughter.The results showed that the drip loss of H-group was significantly higher than L-group(P<0.01),desmin expression level(3~24 h)was higher than that of L group(P<0.05),the activity ofμ-calpain(12 h and 24 h)was lower than that of L group(P<0.05),integrin expression level(45 min,3 h and 12 h)and pH(45 min~12 h)was lower than that of L group.The expression of desmin was positively correlated with the drip loss,while the expression of integrin,the activity ofμ-calpain and pH were negatively correlated with the driploss.pH,the express level ofμ-calpain autolysis,desmin and integrin explained 78.1%,42.4%,70.3%and 71.7%of the variation in drip loss,respectively.The results showed that pH,μ-calpain,desmin and integrin all had an effect on drip loss,pH is the single variable that has the greatest influence on drip loss.