Evolution of hydrophobic polypeptides during the ageing of exudative and non-exudative pork meat

Thirty-six carcasses from 6-month-old pigs were classified in different exudative groups based on measurements of pH2h, pH24h, the colour parameter L∗ and drip loss. A fraction containing polypeptides between 66 and 21 kDa was analysed by reverse phase chromatography at 2-h post-mortem and the evolution of 8 polypeptide fractions followed during ageing and related to meat quality. Three polypeptide (fractions P2, P3 and P4) at 2-h post-mortem showed significant lowest area values in the dark firm and dry class. During ageing, the higher content of P4 in exudative meats at 8-h post-mortem could be due to activation of the cathepsin system. On the other hand, P3 and P4 increased in DFD meats during the first 96-h post-mortem probably due to higher calpain activity. Few differences in polypeptides were related to meat qualities although they are important as precursors of small peptides and free amino acids.