Influence of storage time on parameters of colour stability of beef

Direct measurements of the oxygen partial pressure profiles at the surface of the longissimus dorsi muscle of six bulls were obtained by means of a solid-state-probe after 1 min and 5 h exposure to air at 5°C. Changes in muscle colour were examined at the same time. The results show the profiles of oxygen partial pressure at the muscle surface after differing storage times (1, 3, 5, 7, 11 and 13 days at 5°C). Up to 5 days post mortem, increases in oxygen partial pressure with lengthening storage periods also led to higher percentages of oxymyoglobin, following exposure to air 1 min to 5 h. Further storage for up to 13 days decreased oxygenation, despite higher oxygen partial pressures. There was no evidence of rapid autoxidation to metmyoglobin during a 5-h period of exposure to air. Obvious connections between oxygenation and measurements of a-value were not found. The Lab-values increased dependent on the length of storage time.