Pike M M, Ringkob T P, Beekman D D, Koh Y O, Gerthoffer W T
School of Veterinary Medicine/202, University of Nevada, Reno, Nevada 89557-0104, USA.
Meat Sci. 1993;34(1):13-26. doi: 10.1016/0309-1740(93)90015-A.
Post-mortem (PM) glycolytic rate in beef M. longissimus thoracis et lumborum (LTL) was controlled by applying low-voltage electrical stimulation (ES) for 1 min at different stages along the slaughter line. The ES treatments were as follows: (1) No electrical stimulation (NES); (2) 75 V to one side of the carcass immediately after splitting; (3) 20-40 V during exsanguination; (4) 75 V either during or following exsanguination. The study utilized 40 bulls and 40 steers. Loin steaks were aged in vacuum pouches 2, 4, 8 and 16 days PM. Quadratic equations utilizing pH at 3 h (pH(3)) gave the best estimate of Warner-Bratzler (WB) shear force for 2, 4, 8 and 16 day steaks. The rate of glycolysis is the primary determinant of LTL tenderness in this study. Temperature may only be important through its influence on early PM glycolytic rate. Optimum tenderness was produced by stimulating carcasses or sides to produce a pH(3) of 6·0. ES application to the carcass either just before or after splitting (treatment 2) produced more desirable and consistent pH(3) responses than either NES or ES during exsanguination. Aging has a differential effect whereby the WB shear values from tougher (leaner bulls) 2 day steaks improve to a greater degree, so they are not different from more tender (fatter steers) steaks by 16 day PM.
通过在屠宰线上的不同阶段对牛肉胸腰段最长肌（LTL）施加1分钟的低电压电刺激（ES），来控制宰后（PM）糖酵解速率。ES处理如下：（1）无电刺激（NES）；（2）劈半后立即对胴体一侧施加75V电压；（3）放血期间施加20 - 40V电压；（4）放血期间或放血后施加75V电压。该研究使用了40头公牛和40头阉牛。腰大肌牛排宰后在真空包装袋中熟化2、4、8和16天。利用3小时时的pH值（pH(3)）的二次方程能对2、4、8和16天熟化牛排的沃纳 - 布拉茨勒（WB）剪切力给出最佳估计。在本研究中，糖酵解速率是LTL嫩度的主要决定因素。温度可能仅通过其对宰后早期糖酵解速率的影响才具有重要性。通过刺激胴体或半边胴体使pH(3)达到6.0可产生最佳嫩度。在劈半前或劈半后对胴体施加ES（处理2）比放血期间施加NES或ES产生更理想且更一致的pH(3)反应。熟化具有不同的效果，即来自更坚韧（更瘦的公牛）的2天熟化牛排的WB剪切值改善程度更大，因此到宰后16天时它们与更嫩（更肥的阉牛）的牛排没有差异。
