White A, O'Sullivan A, Troy D J, O'Neill E E
Teagasc, The National Food Centre, Castleknock, Dublin 15, Ireland.
Meat Sci. 2006 May;73(1):151-6. doi: 10.1016/j.meatsci.2005.11.021. Epub 2006 Jan 19.
The aim of this study was to monitor the effects of the alteration of the pre-rigor environment of the bovine LD muscle using controlled temperature regimes in order to gain an insight into the early post-mortem pH/temperature/time interactions which are important from the point of view of tenderness and to identify possible reasons for inconsistencies in beef tenderness. LD muscles (n=12) were hot-boned within 90min post-slaughter, cut into three pieces which were randomly placed in polyethylene bags and submerged in water baths pre-set at the following temperatures; 0, 5, 10, 15, 20 and 25°C for 8 h post-mortem then stored at 2°C for up to 14-days post-mortem. The rate of pH decline increased with increasing temperature. Muscles incubated at 0 and 5°C were cold shortened however not all of these muscles were tough as indicated by Warner Bratzler shear force values (WBSF). A pH range of 5.9-6.2 at 3 h post-mortem (pH(3)) produced consistently tender beef where cold-shortening was avoided. Cold shortened muscles showed the greatest variation in tenderness at 14 days post-mortem and underwent the greatest amount of tenderisation (ΔWBSF) and proteolysis between days 2 and 14 post-mortem. Proteolysis of cold shortened muscle may induce variation in tenderness in these muscles.
本研究的目的是通过控制温度条件来监测牛背最长肌宰前环境改变的影响，以便深入了解宰后早期pH/温度/时间的相互作用，这从嫩度角度来看很重要，并确定牛肉嫩度不一致的可能原因。宰后90分钟内对背最长肌（n = 12）进行热剔骨，切成三块，随机放入聚乙烯袋中，然后浸入预先设定为以下温度的水浴中：0、5、10、15、20和25°C，宰后8小时，然后在2°C下储存直至宰后14天。pH下降速率随温度升高而增加。在0和5°C下孵育的肌肉出现冷收缩，然而，如沃纳·布拉茨勒剪切力值（WBSF）所示，并非所有这些肌肉都很坚韧。宰后3小时（pH(3)）时pH值在5.9 - 6.2范围内可产生始终嫩化的牛肉，且避免了冷收缩。冷收缩的肌肉在宰后14天时嫩度变化最大，并且在宰后第2天至第14天期间嫩化（ΔWBSF）和蛋白水解程度最大。冷收缩肌肉的蛋白水解可能导致这些肌肉嫩度的变化。
