Tenderness of beef m. longissimus lumborum at normal and intermediate ultimate pH before and after a period of ageing

摘要

Abstract Beef tenderness, in terms of Warner‐Bratzler shear force values, was measured following ageing periods of 1 or 20 days for samples of m. longissimus lumborum from pairs of steers or heifers (n = 38) with the two members of each pair being from the same mob. One sample of each pair had an intermediate ultimate pH (pHu 5.7–6.2) and the other a normal pHult (<5.6). Samples of the intermediate pHult group had the expected lower cooking losses and darker colour (lower L?, a?, and b? values). In contrast to previous studies where intermediate pHult has been associated with tougher beef, however, the two groups did not differ in shear‐force values, sarcomere length, or in myofibrillar fragility as measured by a filtration method or by image analysis. Samples for this study were removed from carcasses after rigor mortis had set in, which may have accounted for the sarcomere lengths being longer than in previous studies. It is suggested that the failure to detect a pHult effect on shear force values ma...