Proteome changes during pork meat ageing following use of two different pre-slaughter handling procedures

The influence of postmortem storage time and pre-slaughter conditions (transport the day before slaughter or immediately before slaughter) on proteome changes of pork meat was investigated over a 72 h ageing period. Intensities of 37 spots varied significantly (p<0.05) with ageing time. Changes indicated proteolysis of troponin T, actin, α-crystallin, myokinase, creatine kinase and mitochondrial ATPase, but also of proteins constitutive of the Z-lines, namely cypher proteins and myozenin. Other modifications were the intensity increase of a full-length protein of the sarcoplasmic reticulum, which may be linked to its increased extractibility after membrane disruption, and a gradual shift in pHi towards alkaline values of some forms of myosin light chains (MLC) 2 and 3. The pre-slaughter conditions affected significantly (p<0.05) 8 spots. Mitochondrial ATPase was over-expressed in the group transported immediately before slaughter, also characterised by a faster pH fall, and the shift in pHi of MLC 2 was more pronounced. The pre-slaughter conditions had no significant effect on the above proteolytic events.