Application of proteomic to investigate the post-mortem tenderization rate of different horse muscles

The aim of this study was to evaluate the effect of post-mortem aging on tenderness development and proteolysis of myofibrillar proteins in 3 different horse muscles. Warner Bratzler shear force decreased during aging in all muscles, showing the lowest values in longissimus lumborum (LL) in all sampling points. Myofibril fragmentation index significantly increased in LL and semimembranosus (SM) muscles throughout aging time whereas in semitendinosus (ST) it increased after 14 days of aging. Proteomics analysis revealed the major content of intact myofibrillar proteins with high molecular weight in ST muscle in the first phase of aging, while, after 14 days a higher accumulation of TnT-derived polypeptides and spots isoforms ascribed to MLC2 and MLC1 proteins were found. Data highlight that aging affects the meat tenderness and proteolysis with different intensities in each muscle and suggest that a more extensive post-mortem proteolysis occurred in ST muscle.