Investigation of the effects of commercial carcass suspension (24 and 48 h) on meat quality in high oxygen modified atmosphere packed beef steaks during chill storage

Hanging for 24 or 48 hours (h) of intact carcasses in the chill store cooler prior to further processing occurs periodically at processor level due to demand for product. The aim of the study was to investigate the effects of commercial carcass suspension (24 and 48 h) on meat tenderness attributes in modified atmosphere packed beef steaks during chill storage. A secondary objective was to investigate protein oxidation reactions occurring and the subsequent meat tenderness consequences. Carcasses were hung for 24 or 48 h in order to reproduce commercial short term storage of meat at processor level. Experimental gas atmospheres used in packs consisted of; 40%, 50%, 60%, 70% and 80% oxygen, with all packs containing 20% CO2 and the remainder being provided by the filler gas N2. Steaks from the 24 h suspended carcasses were tougher than those from 48 h suspended muscle. Additionally, packaging systems with high oxygen had a negative influence on tenderness (instrumental) and consumer determined juiciness in cooked beef steaks. The carbonyl content and TBARS numbers increased to the greatest extent in high oxygen packed samples. Protein oxidation was directionally and significantly correlated (P < 0.01) to the higher O2 treatments. Protein and lipid oxidation also occurred to a greater extent in the samples from the 48 h treatment, possibly due to physical matrix differences in the meat compared to the 24 h treatment. Meat from the 48 h treatment appeared less red than meat from the 24 h treatment.