Virginia Tech, School of Animal Sciences, Blacksburg, VA 24061, USA.
Department of Animal Science, College of Animal Science and Food Engineering, University of São Paulo, Pirassununga, SP 13635-900, Brazil.
Meat Sci. 2023 Dec;206:109344. doi: 10.1016/j.meatsci.2023.109344. Epub 2023 Sep 20.
Reduction in muscle glycogen triggered by adverse antemortem handling events alters postmortem energy metabolism and results in a high ultimate pH and dark, firm and dry beef, often referred to as 'dark-cutting'. However, the relationship between atypical dark (AT) beef, postmortem energy metabolism and underlying tissue characteristics remains somewhat unclear. Cattle harvested in the US and Canada representing normal (pH < 5.6), AT dark (pH 5.6-5.8) and dark cutting (DC; pH > 5.8) beef were analyzed for tissue characteristics related to energy metabolism. Results show AT dark beef is more oxidative but similar to normal beef in glycolytic potential and nucleotide abundance. Mitochondria DNA content (P < 0.05, Canada; P < 0.005, US) and oxidative enzymes for DC and AT dark beef were greater (P < 0.01; Canada and US) compared to normal beef. Myoglobin tracked (P < 0.01) with color classification. These findings show both DC and AT beef are inherently more oxidative and raise the possibility that more oxidative muscle may be more prone to develop dark beef.
不良宰前处理事件引发的肌肉糖原减少会改变死后能量代谢，导致最终 pH 值升高、肉质呈深色、坚实和干燥，通常称为“暗切”。然而，非典型暗切（AT）牛肉、死后能量代谢和潜在组织特征之间的关系仍有些不清楚。分析了来自美国和加拿大的正常（pH<5.6）、AT 暗切（pH5.6-5.8）和暗切（DC；pH>5.8）牛肉的与能量代谢相关的组织特征。结果表明，AT 暗切牛肉更具氧化性，但与正常牛肉的糖酵解潜力和核苷酸丰度相似。线粒体 DNA 含量（加拿大，P<0.05；美国，P<0.005）和 DC 和 AT 暗切牛肉的氧化酶活性更高（加拿大和美国，P<0.01），与正常牛肉相比。肌红蛋白与颜色分类相关（P<0.01）。这些发现表明，DC 和 AT 牛肉本质上更具氧化性，并提出了更具氧化性的肌肉可能更容易产生暗切牛肉的可能性。
