Role of cysteine endopeptidases (EC 3.4.22) in rabbit meat tenderisation and some related changes

The role of endogenous cysteine endopeptidases (EC 3.4.22; calpains and cathepsins B, L and H) in rabbit (Oryctolagus cuniculus L.) meat tenderisation and some related changes (formation of the 30 kDa fragment and myofibrillar structure weakening), during ageing (9 days at +4°C), was studied for different types of muscle (I, IIB and IID). The results strongly suggest that cysteine peptidases, possibly calpains, play a major role in rabbit meat tenderisation, myofibrillar structure weakening and formation of the 30 kDa fragment in type II muscles. Cathepsins B, L and H appear to have no role in these changes during rabbit meat ageing. The results also indicate that myofibrillar fragmentation and the contents of the 30 kDa fragment are good ageing indices for rabbit meat. Finally, it is suggested that the weakening of the myofibrillar structure, unlike the formation of the 30 kDa fragment, might be directly involved in rabbit meat tenderisation.