The eating quality of pork: 1. The influence of ultimate pH

Twenty pork carcasses were selected at 13 h post mortem (pm) to contain longissimus lumborum (LL) muscles that possessed a large variation in ultimate pH. On the LL ultimate pH, colour, water holding capacity, sarcomere length, percent intramuscular fat and shear force (at 3 and 7 days pm) were assessed. In addition, eating quality (tenderness, juiciness and flavour) was determined at 5 till 8 days p.m. by a 25-member taste panel. Ultimate pH varied from 5.42 to 6.25 (mean : 5.71) and was, as expected, significantly related to colour and water holding capacity. The PSE condition was not observed. Shear forces, particularly at 7 days pm, were highly correlated with panel judgements of tenderness (r=-0.78) and juiciness (r=-O.74). No significant relationships were found for sarcomere length or intramuscular fat with shear forces and panel judgements. Ultimate pH was positively related to sensory tenderness (r=0.78) and juiciness (r=0.68), but not to flavour (r=O.02). Furthermore, ultimate pH appeared to be more highly related to shear force at 7 days (r=-0.70) than at 3 days (r=-0.43) pm. This suggests that ultimate pH had an effect on ageing rate. The results indicate that carcasses can be selected for eating quality (tenderness and juiciness) by using ultimate pH.