冻融对早胜牛肉品质及微细结构的影响

Effects of Freezing-thawing on Muscle Quality and Microstructure of Zaosheng Cattle Meat

为探讨反复冻融对早胜牛肉品质的影响,选取2.0～2.5岁阉割牛背最长肌,随机分成6组,称重,真空包装,进行不同次数的反复冷冻—解冻试验,分别检测原料肉解冻损失、煮制损失、失水率、熟肉剪切力及pH,并观察原料肉显微超微结构的变化。结果显示,随着反复冻融次数的增加,原料肉解冻损失和煮制损失极显著增加,失水率只在第1次冻融后显著增加,剪切力先显著增加后再降低,pH随着冻融次数增加而显著降低,肌纤维结构混乱,肌束及肌原纤维间隙增加,肌节略微缩短,线粒体肿胀、空泡样变,Z线错位排列,甚至溶解、消失。结果表明,反复冻融严重破坏了早胜牛肉的组织结构,显著降低了肉品质。

In order to study the effects of repetitive freezing-thawing on beef quality,2.0-2.5 years old bullock Zaosheng cattle were selected,longissimus dorsi（LD） were collected and cut into 6 samples randomly,weighted and vacuum packed and repetitively freezing-thawing different times,then thawing loss（TL）,cooking loss（CL）,water loss（WL）,shear force（SF）,pH and microstructure were studied.The results showed that compared with fresh beef,repetitive freezing-thawing significantly increased the TL and CL;WL were increased significantly after freezing-thawing once;SF were significantly increased when freezing-thawing twice and then decreased;Freezing-thawing increased the space between muscle fiber,confused fiber bundles,and shortened sarcomere,vacuolated structure formation in the mitochondria,blurred even disappeared Z disc.The results demonstrated that repetitive freezing-thawing seriously damaged the structure of beef and declined the muscle quality of Zaosheng cattle.