Shackelford S D, Wheeler T L, Koohmaraie M
Roman L. Hruska U.S. Meat Animal Research Center, USDA, ARS, Clay Center, NE 68933-0166, USA.
J Anim Sci. 1997 Sep;75(9):2411-6. doi: 10.2527/1997.7592411x.
The present experiment was conducted to determine 1) the repeatability of Warner-Bratzler shear force and trained sensory panel tenderness ratings in beef round cuts and 2) the effect of location within beef round cuts on shear force and tenderness ratings. Biceps femoris (BF) and semitendinosus (ST) were obtained from the carcasses of youthful (A-maturity), grain-fed, crossbred steers (n = 25) at 16 d postmortem. Steaks were removed from each muscle for determination of shear force and tenderness rating at each of three locations (A = proximal end, B = center, and C = distal end). Tenderness ratings of triplicate samples were slightly more repeatable than shear force for BF (R = .50 vs .30) and ST (R = .60 vs .56). However, all of those estimates of repeatability were much less than values we have obtained for beef longissimus using similar laboratory procedures (R = .79 to .90). Across both muscles and both methods of assessing tenderness, less than 40% of the total variance was accounted for by animal. The variance of tenderness rating among animals was less for BF (.12) and ST (.09) than values we have obtained for beef longissimus (.60). Location did not affect (P > .05) BF shear force; however, BF tenderness ratings were higher (P < .05) for location A (5.5) than for B (5.0) and C (5.2). Location accounted for a higher percentage of the total variance of ST tenderness rating and ST shear force than did animal. Shear force decreased (P < .05) from the proximal end to the distal end of ST (5.1, 4.6, and 3.9 kg for locations A, B, and C, respectively). Also, ST tenderness ratings were lower for location A (4.8) than for locations B (5.6) and C (5.7). Neither method of measuring tenderness was highly repeatable for BF or ST because there was little animal-to-animal variation in tenderness for these round muscles. Thus, there would be little opportunity for segregating round muscles into tenderness classes.
1）牛肉后腿切块中沃纳-布拉茨勒剪切力和经过训练的感官评定小组嫩度评分的重复性；2）牛肉后腿切块内不同位置对剪切力和嫩度评分的影响。从16头屠宰后16天的年轻（A成熟度）、谷物饲养的杂交阉牛（n = 25）的胴体上获取股二头肌（BF）和半腱肌（ST）。从每块肌肉上切下牛排，在三个位置（A =近端、B =中间、C =远端）分别测定剪切力和嫩度评分。对于BF（R = 0.50对0.30）和ST（R = 0.60对0.56），一式三份样品的嫩度评分比剪切力的重复性略高。然而，所有这些重复性估计值都远低于我们使用类似实验室程序对牛肉背最长肌获得的值（R = 0.79至0.90）。在两种肌肉和两种评估嫩度的方法中，动物因素占总方差的比例不到40%。BF（0.12）和ST（0.09）动物间嫩度评分的方差低于我们对牛肉背最长肌获得的值（0.60）。位置对BF剪切力无影响（P > 0.05）；然而，BF位置A（5.5）的嫩度评分高于B（5.0）和C（5.2）（P < 0.05）。位置在ST嫩度评分和ST剪切力总方差中所占的百分比高于动物因素。从ST的近端到远端，剪切力降低（P < 0.05）（位置A、B、C的剪切力分别为5.1、4.6和3.9千克）。此外，ST位置A（4.8）的嫩度评分低于位置B（5.6）和C（5.7）。对于BF或ST，两种测量嫩度的方法重复性都不高，因为这些圆形肌肉的嫩度在动物间差异很小。因此，将圆形肌肉分为不同嫩度等级的机会很小。
