Influence of Different Bleeding Times on Structural and Physicochemical Characteristics of Beef from Halal-Slaughtered Cattle

The bleeding process during slaughter significantly influences meat quality by affecting post-mortem biochemical and structural changes. In this study, the effects of three different bleeding durations (5, 10, and 15 min) during Halal cattle slaughter on the biochemical properties of expelled blood and selected physicochemical, structural, and textural characteristics of beef Longissimus dorsi thoracis muscle were evaluated. Blood loss increased significantly with prolonged bleeding times, with 15 min resulting in the highest bleeding efficiency (p<0.05). Biochemical analyses revealed that total protein and urea concentrations in blood decreased significantly with longer bleeding times, while glucose and lactate dehydrogenase (LDH) levels increased at 10 min bleeding and declined at 15 min bleeding durations. In the beef samples, proximate composition, pH, water activity, and CIE lightness (L*), redness (a*), yellowness (b*), chroma and hue values showed no significant differences between the bleeding durations. However, meat hardness increased significantly (p<0.05) with longer bleeding times, which was supported by scanning electron microscopy (SEM) observations showing more compact and organized muscle fiber structures in samples subjected to 10 and 15 min bleeding in comparison to the 5-min group. Fourier Transform Infrared Spectroscopy (FTIR) further confirmed changes in proteins and nucleic acids associated with bleeding time. The results obtained from this study suggest that a 15-min bleeding duration improves bleeding efficiency and without compromising beef chemical and colour properties. This study highlights the importance of optimizing bleeding duration during Halal slaughter to enhance beef quality and shelf-life.