Scheffler T L, Gerrard D E
Department of Animal Sciences, Purdue University, 915 W. State Street, West Lafayette, IN 47907, United States.
Meat Sci. 2007 Sep;77(1):7-16. doi: 10.1016/j.meatsci.2007.04.024. Epub 2007 May 10.
Pale, soft and exudative (PSE) pork represents considerable economic losses for the industry due to its limited functionality and undesirable appearance. During the past several decades, exhaustive research covering various aspects of the food chain has established genotyping procedures, recommended handling practices, and quality indicators in order to reduce the incidence of inferior pork quality. Despite these efforts, there is still a relatively high occurrence of PSE pork. Development of pork quality attributes is largely governed by the rate and extent of postmortem pH decline. The combination of high temperature at low pH or abnormally low ultimate pH causes denaturation of sarcoplasmic and myofibrillar proteins, resulting in paler color and reduced water holding capacity. The pH decline is closely related to muscle energy availability and demand at or around slaughter. The postmortem degradation of glycogen through glycogenolysis and glycolysis provides ATP to help meet energy demand and decreases pH by generating lactate and H+. Therefore, the flux of metabolites through glycolysis, the involvement of energy signaling pathways that modulate glycolytic activity, and the inherent metabolism of different fiber types are critical factors influencing pH decline and pork quality. Further, recent work implicates adenosine monophosphate-activated protein kinase (AMPK) as a major energy sensor for the cell, and thus may be involved in the control of postmortem metabolism. The intent of this paper is to review the biochemistry controlling postmortem energy metabolism in pig muscle and explore new information generated using genetic mutations in order to define the fundamental mechanisms controlling the transformation of muscle to meat.
苍白、松软且有渗出液（PSE）的猪肉因其有限的功能和不佳的外观给行业带来了相当大的经济损失。在过去几十年里，针对食物链各个方面进行了详尽研究，建立了基因分型程序，推荐了处理方法和质量指标，以降低劣质猪肉品质的发生率。尽管做出了这些努力，PSE猪肉的发生率仍然相对较高。猪肉品质特性的形成在很大程度上取决于宰后pH值下降的速率和程度。低pH值下的高温或异常低的最终pH值相结合会导致肌浆蛋白和肌原纤维蛋白变性，从而使肉色变浅并降低持水能力。pH值下降与屠宰时或屠宰前后肌肉能量的可用性和需求密切相关。糖原通过糖原分解和糖酵解的宰后降解提供ATP以帮助满足能量需求，并通过产生乳酸和H+降低pH值。因此，代谢物通过糖酵解的通量、调节糖酵解活性的能量信号通路的参与以及不同纤维类型的固有代谢是影响pH值下降和猪肉品质的关键因素。此外，最近的研究表明，腺苷单磷酸激活的蛋白激酶（AMPK）是细胞的主要能量传感器，因此可能参与宰后代谢的控制。本文旨在综述猪肌肉宰后能量代谢的生物化学调控，并探索利用基因突变产生的新信息，以确定控制肌肉转化为肉的基本机制。
