电刺激对宰后不同部位牦牛肉成熟过程中微观结构及嫩度影响.docVIP

电刺激对宰后不同部位牦牛肉成熟过程中微观结构及嫩度影响 　　摘 要：为研究电刺激对宰后牦牛肉成熟过程中肌肉微观结构及嫩度的影响，采用肌肉组织结构HE染色法、肌肉超微结构透射电镜观察法及剪切力测定法分别测定宰后不同处理（电刺激、未电刺激）条件下，牦牛冈上肌（supraspinatus，SU）、背阔肌（latissimus dorsi，LD）和半腱肌（semitendinosus，ST）3 个部位肉成熟0 h、1、2、3、5、7、14 d时的肌肉组织学特性、超微结构及剪切力的变化。结果表明：电刺激组3 个部位牦牛肉的肌纤维直径和肌纤维横截面积下降幅度以及肌间距离的增加幅度均显著高于未电刺激组；2 个处理组LD的肌肉组织学特性变化均最快，且电刺激组LD的肌原纤维破坏、溶解、小片化及Z线断裂现象较未电刺激组明显；成熟14 d时，电刺激组SU、LD和ST的剪切力下降百分比较未电刺激组分别高出2.93%、9.47%和5.08%。综上所述，电刺激处理能够显著加快宰后牦牛肌肉组织的破坏程度及嫩化速率，且LD的宰后嫩化较其他2 个部位快。 　　关键词：电刺激；牦牛；肌肉微观结构；嫩度 　　Abstract： In an effort to study the effect of electrical stimulation on the microstructure and tenderness of different yak muscles during postmortem aging， the histological characteristics and microstructure of supraspinatus （SU）， latissimus dorsi （LD） and semitendinosus （ST） muscles from yak carcasses with and without electrical stimulation （ES） were examined at 0?C14 days postmortem by HE staining and transmission electron microscopy （TEM） and the shear force was also measured. The results showed that ES caused a significantly greater decrease in muscle fiber diameter and cross-sectional area and a significantly greater increase in intermuscular fiber space for all three muscles compared to the untreated control group. For both the treatment and control groups， the histological characteristics of LD changed the fastest of the three muscles， and the former group showed significant destruction， dissolution and fragmentation of LD muscle fibers and significant rupture of the Z line than did the latter. At 14 days postmortem， the shear force of SU， LD and ST in the ES group was 2.93%， 9.47% and 5.08% higher compared with the control group， respectively. To sum up， this study demonstrated that electrical stimulation could significantly accelerated the destruction and tenderization of yak muscle tissue during postmortem aging and that LD could be tenderized faster than SU and ST. 　　Key words： electrical stimulation； yak； muscle microstructure； tenderness 　　DOI：10.7506/rlyj1001-812