Wheeler T L, Savell J W, Cross H R, Lunt D K, Smith S B
Texas Agricultural Experiment Station, Texas A&M University, College Station 77843-2471.
J Anim Sci. 1990 Dec;68(12):4206-20. doi: 10.2527/1990.68124206x.
To study possible mechanisms for differences in meat tenderness, 10 purebred Hereford and 10 American Grey Brahman steers were fed a typical feedlot diet and slaughtered when ultrasound measurements indicated that they had approximately 1 cm of fat thickness at the 12th rib. Longissimus muscle from Brahman cattle was less (P less than .05) tender after 7, 14, 21, 28 and 35 d postmortem than muscle from Hereford cattle, but muscle from Hereford cattle showed greater improvement in tenderness from 7 to 14 d postmortem than muscle from Brahman cattle (interaction P less than .05). Cathepsin B or cathepsin B+L activities and the myofibrillar response to elevated ionic strength were not different between breeds, but both could be related to the postmortem increase in tenderness of both breeds. Calcium-dependent protease activity, as modulated by calcium-dependent protease inhibitor, seems to play a major role in the inherent tenderness differences between breeds.
为研究肉质嫩度差异的可能机制，选取10头纯种赫里福德牛和10头美国灰婆罗门牛，给它们饲喂典型的育肥牛日粮，当超声测量显示第12肋处脂肪厚度约为1厘米时进行屠宰。婆罗门牛的背最长肌在宰后7、14、21、28和35天比赫里福德牛的肌肉嫩度更低（P<0.05），但赫里福德牛的肌肉在宰后7至14天的嫩度改善程度比婆罗门牛的肌肉更大（交互作用P<0.05）。品种间组织蛋白酶B或组织蛋白酶B+L活性以及肌原纤维对离子强度升高的反应并无差异，但二者均可能与两个品种宰后嫩度的增加有关。钙依赖性蛋白酶抑制剂调节的钙依赖性蛋白酶活性似乎在品种间固有嫩度差异中起主要作用。
