Proteome analysis of early post-mortem changes in two bovine muscle types: M. longissimus dorsi and M. semitendinosis.

To study early post-mortem changes in muscle tissues from bull calves, cytosole proteins from two muscles: M. longissimus dorsi (LD) and M. semitendinosis (ST) at 0 and 24 h after slaughter were analysed by 2-DE. Principal component analysis (PCA) and rotation testing were used to analyse the protein patterns in the two muscles in order to select protein spots that were significantly different at the two time-points. Selected proteins were identified by MALDI-TOF/TOF. Five proteins, namely cofilin, lactoylglutathione lyase, substrate protein of mitochondrial ATP-dependent proteinase SP-22, HSP 27 and HSP20, were changed in both LD and ST muscles during post-mortem storage. Fifteen additional protein changes were observed in either LD or ST muscles, and some of these changes have not previously been observed to change during post-mortem storage of bovine muscles. Further studies will reveal the relevance of these biomarkers for meat quality.