This study evaluates the effect of a low‐voltage electrical stimulation (ES) on the tenderness of yak longissimus muscle (LM). Samples from 16 yak bulls were divided into four treatment groups: normal chilling (NC), ES and chilling (ES & C) for 72 s (ES &C 72 s), ES & C for 90 s (ES & C 90 s), and ES & C for 108 s (ES & C 108 s). The temperature, the pH, the glycogen content, the Warner‐Bratzler shear force (WBSF), the myofibril fragmentation index (MFI), and the muscle ultrastructure were determined during the course of postmortem aging. ES caused a rapid decrease in the pH to form a high‐temperature and low‐pH environment. The glycogen content gradually decreased with aging. The WBSF value of the ES & C groups was significantly lower than for the NC group (p  < .05). The MFI values of ES & C groups after 24 hr postmortem aging were significantly higher than for the NC group. We concluded that ES improved yak meat tenderness during postmortem aging and that the different duration time by ES indicated different effects, and its affect was remarkable in the ES & C 90 s.

中文翻译：

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宰后老化过程中低压电刺激对牦牛肉嫩度的影响。

本研究评估了低压电刺激 (ES) 对牦牛最长肌 (LM) 压痛的影响。16 头牦牛的样本被分为四个处理组：正常冷却 (NC)、ES 和冷却 (ES & C) 72 秒 (ES &C 72 s)、ES & C 90 秒 (ES & C 90 s)、和 ES & C 为 108 s (ES & C 108 s)。在死后老化过程中测定温度、pH、糖原含量、Warner-Bratzler 剪切力 (WBSF)、肌原纤维断裂指数 (MFI) 和肌肉超微结构。ES导致pH值迅速下降，形成高温低pH环境。随着年龄的增长，糖原含量逐渐下降。ES & C 组的 WBSF 值显着低于 NC 组 ( p < .05)。24 小时死后老化后 ES 和 C 组的 MFI 值显着高于 NC 组。我们得出结论，ES 在宰后老化过程中改善了牦牛肉的嫩度，并且 ES 的不同持续时间表明了不同的效果，并且其影响在 ES 和 C 90 s 中显着。