Influence of ultimate pH on biochemistry and quality of Longissimus lumborum steaks from Nellore bulls during ageing

摘要

Ultimate pH (pH_u) is an indicator that influences post-mortem meat quality. We studied physiological and biochemical changes of steaks obtained from Nellore bulls (Bos indieus) during post-mortem ageing. To this, Longissimus lumborum (LL) muscles were classified into three groups: Normal-pH_u (≤5.79), Interme-diate-pH_u (5.80-6.29) and High-pH_u (≥6.30) groups, portioned into steaks, vacuum packaged and matured at 2 °C for 0, 7, 14, 21 and 28 days. High-pH_u steaks exhibited impaired colour stability and were darker compared to the other groups. High- and Normal-pH_u steaks showed improved tenderness and myofibrillar fragmentation linked to proteolysis. Intermediate-pH_u steaks were associated with a lower meat tenderness and decreased collagen solubility. High-pH_u steaks retained a high pH during ageing and increased water-holding capacity. These findings provide evidence that highlight pH_u as a strategy for the classification of pH_u-dependent beef quality from Nellore bulls that can be adopted by the Brazilian meat industry.