Effects of Different Packaging Systems on Beef Tenderness Through Protein Modifications

The main purpose of this study was to investigate effects of three packaging methods on beef tenderness via protein oxidative modifications. Tenderness, protein oxidation, μ-calpain activation, and protein proteolysis of bovine longissimus dorsi (LD) muscle were measured during 10 days (d) of chilled storage. Compared with beef samples from vacuum packaging (VP), beef samples from air packaging (AP) and modified atmosphere packaging (MAP) showed significantly lower free thiol group and higher carbonyl group content, while tenderness was lower after 7 and 10 d of chilled storage, respectively (p < 0.05). μ-Calpain activity was less in beef samples from AP and MAP compared with VP at d 4 and 7 of postmortem storage (p < 0.05). Desmin showed decreased proteolysis in beef samples from AP and MAP compared with VP after 4 and 7 d of storage (p < 0.05). The results above indicated that the reduction in tenderness of beef samples from AP and MAP compared to VP was closely associated with protein modifications including oxidation, proteolysis, and enzyme activation of bovine LD muscle during postmortem storage.