Department of Animal Science, University of Nebraska, Lincoln, NE 68583-0908, USA.
J Anim Sci. 2010 Sep;88(9):3084-106. doi: 10.2527/jas.2009-2683. Epub 2010 May 7.
Intramuscular tenderness variation and muscle fiber orientation of beef M. adductor femoris (AF), M. biceps femoris (BF), M. gracilis (GL), M. pectineus (PT), M. sartorius (SR), M. semimembranosus (SM), M. semitendinosus (SO), M. vastus intermedius (VI), M. vastus medialis (VM), and M. vastus lateralis (VL) were investigated. The USDA Choice boxed beef subprimals were purchased and aged for 14 d from boxed date. The AF, BF, GL, PT, SR, SM, SO, VI, VM, and VL (n = 10 each) were fabricated from subprimals. Crust-frozen AF, BF, SO, SM, and VL were cut into 2.54-cm steaks perpendicular to the long axis and grilled (71 degrees C). The PT, SR, VI, and VM were grilled (71 degrees C) as whole muscles, whereas the GL was grilled after cutting into anterior and posterior regions. Grilled muscles were cut into equal size sections perpendicular to long axis of muscles. Location-specific cores were prepared from each steak/section, and Warner-Bratzler shear force (WBSF) was measured. The muscle fiber orientations of BF, PT, and VI were bipennate, SR and SO were fusiform, and AD, SM, VL, GL, and VM were unipennate. The overall mean WBSF values for BF, SO, AF, SM, PT, SR, GL, VI, VM, and VL were 5.62, 4.86, 4.18, 4.90, 3.76, 4.44, 4.75, 4.78, 4.24, and 6.53 kg, respectively. Based on WBSF values, PT was tender, BF and VL were tough, and VM, VI, SM, GL SR, AF, and SO were intermediate. The first 2 proximal steaks of long head BF were more tender than the rest (P < 0.05). In the SO, the tenderness decreased from the middle of the muscle to both ends (P < 0.05). The anterior sides of the long head BF and SO were tougher than their posterior sides (P < 0.05).The first 4 steaks of the SM were more tender than the rest of the muscle (P < 0.05). There was a significant tenderness increment from the middle of the AF and SR to both ends of each muscle (P < 0.05). The medial side of the VI was more tender than its lateral side (P < 0.05). The VM had its smallest shear force value at the most distal end compared with the rest (P < 0.05). Dry or moist heat oven roasting, as compared with grilling, significantly tenderized SO (P = 0.002) and VL (P < 0.0001) muscles. There were no significant WBSF value differences along the PT and between anterior and posterior regions of the GL. Based on WBSF ratings, PT, SR, VM, GL, and VI could be merchandized as single muscle steaks or medallions and the first 2 to 4 steaks of long head BF, SM, and AF could be marketed as premium-quality steaks. This detailed information on intramuscular tenderness and muscle fiber orientation variations of the round muscles could be used in a value added strategy for the beef round.
研究了牛臀中肌（AF）、股二头肌（BF）、股薄肌（GL）、耻骨肌（PT）、缝匠肌（SR）、半腱肌（SM）、半膜肌（SO）、中间肌（VI）、内收肌（VM）和外展肌（VL）的肌内嫩度变化和肌纤维方向。从包装日期起，购买 USDA 优质盒装牛肉次级切块并陈化 14 天。从次级切块中制备 AF、BF、GL、PT、SR、SM、SO、VI、VM 和 VL（各 10 个）。将冷冻的 AF、BF、SO、SM 和 VL 沿长轴垂直切成 2.54 厘米的牛排并烤制（71°C）。PT、SR、VI 和 VM 作为整块肌肉烤制（71°C），而 GL 在切成前、后区域后进行烤制。将烤制的肌肉沿长轴垂直切成等大小的部分。从每个牛排/部分制备特定部位的核心，并测量 Warner-Bratzler 剪切力（WBSF）。BF、PT 和 VI 的肌纤维方向为双羽状，SR 和 SO 为梭形，AD、SM、VL、GL 和 VM 为单羽状。BF、SO、AF、SM、PT、SR、GL、VI、VM 和 VL 的平均 WBSF 值分别为 5.62、4.86、4.18、4.90、3.76、4.44、4.75、4.78、4.24 和 6.53kg。根据 WBSF 值，PT 是嫩的，BF 和 VL 是坚韧的，VM、VI、SM、GL、SR、AF 和 SO 是中等的。长头 BF 的前 2 个近端牛排比其余的更嫩（P<0.05）。在 SO 中，从肌肉中间到两端的嫩度降低（P<0.05）。长头 BF 和 SO 的前侧比后侧更硬（P<0.05）。SM 的前 4 个牛排比其余的更嫩（P<0.05）。从 AF 和 SR 的中间到两端，嫩度显著增加（P<0.05）。VI 的内侧比外侧更嫩（P<0.05）。与其余部分相比，VM 的最远端具有最小的剪切力值（P<0.05）。与烤制相比，干热或湿热烤箱烤制显著嫩化了 SO（P=0.002）和 VL（P<0.0001）肌肉。PT 和 GL 的前后区域之间没有明显的 WBSF 值差异。根据 WBSF 评级，PT、SR、VM、GL 和 VI 可以作为单个肌肉牛排或肉丁进行销售，长头 BF、SM 和 AF 的前 2 到 4 个牛排可以作为优质牛排销售。这些关于圆形肌肉嫩度和肌纤维方向变化的详细信息可用于牛肉圆形的增值策略。
