关键词: 牛肉, 中间型极限pH值, 嫩度, 钙蛋白酶, 小热休克蛋白

Abstract: Tenderness is one of the most important factors to evaluate the eating quality of beef, and it is also an important factor influencing consumers’ willingness to purchase meat. Compared with beef at high ultimate pH (pHu) (pHu > 6.2) and normal pHu (pHu < 5.8), beef at intermediate pHu (5.8 < pHu ≤ 6.2) has poorer tenderness and requires longer ageing time to achieve the desired tenderness. However, the underlying mechanism for tenderness deterioration is not clear yet. Therefore, in this paper, the causes of tenderness deterioration of beef at intermediate pHu are elucidated by comparing the degree of degradation of cytoskeleton proteins and the functions of endogenous enzyme systems (i.e. calpain, cathepsin, caspase and proteosome) among beef with different pHu, and by determining the expression characteristics of small heat shock proteins in beef at intermediate pHu. The information gathered here will provide a theoretical basis for improving the tenderness of beef with intermediate pHu.

Key words: beef, intermediate ultimate pH, tenderness, calpain, small heat shock proteins