Effect of Postmortem Aging Period on Quality Properties of Bovine Muscles, Longissimus dorsi, Semimembranosus and Semitendinosus, Held at 2ºC

Abstract

A study was conducted to investigate the effect of postmortem aging period (1, 5, 10, and 15 days) on meat quality of bovine muscles, Longissimus dorsi, Semimembranosus and Semitendinosus, held at 2°C. Fourteen western Baggara bulls were used. The hindquarters were immediately chilled at 2°C for 24 hours, L. dorsi, Semimembranosus and Semitendinosus were cold deboned, each one was divided into four parts and aged immediately after deboning for 1, 5, 10 and 15 days at 2°C. Temperature and pH profile, chemical composition, bacterial load and muscle eating quality were determined. The extractable myofibrillar proteins, the non-protein nitrogen and the water holding capacity were significantly (P≤0.001) increased, while the extractabe sarcoplasmic proteins significantly (P≤0.001) decreased; cooking loss and colour rating scores decreased and tenderness increased numerically with increasing aging period to 15 days. Increasing aging period from 5 to 15 days resulted in low flavour rating and increasd juiciness but non-significantly for the three muscles studied. SDS polyacrylamide gel electrophoresis revealed a gradual decrease and disappearance of the troponin-T and a built up of a 30 kd component seems to be the major changes during postmortem aging. Complete disappearance of toponin-T and appearance of a 30 kd component at day 10 of aging and continue to be observed at day 15.