LAUSR

BACKGROUND Protein oxidation is widespread in biochemical systems. The objective of the study was to investigate the differences in protein oxidation, μ-calpain activity, desmin proteolysis and protein solubility of beef psoas major (PM) and semi-membranosus (SM) muscles under three packaging systems during postmortem ageing. At 24 h postmortem, beef muscles were packaged respectively in air-permeable film overwrap (AP), vacuum pack (VP) or modified atmosphere (MAP, 80% O2 + 20% CO2 ), and then displayed for 10 days at 4 °C. RESULTS Carbonyl group values and thiol group content were significantly influenced by packaging type and storage time. The SM muscles from AP and MAP showed greater μ-calpain activity compared to VP. Desmin of PM and SM from AP and MAP samples showed decreased proteolysis compared with VP. CONCLUSION The results suggested that the inhibition of μ-calpain activity of beef samples from AP and MAP could be closely associated with protein oxidation which further lowered the level of desmin degradation compared to VP. © 2017 Society of Chemical Industry.