Postmortem degradation of desmin and calpain in breast and leg and thigh muscles from Taiwan black-feathered country chickens.

BACKGROUND: Several studies have reported that the postmortem changes are more rapid in breast muscles (BM) than in leg and thigh muscles (LM) of chickens. However, the reasons for the differences in postmortem proteolysis of BM and LM are still uncertain. The purpose of this study was therefore to compare the postmortem degradation of desmin and calpains in BM and LM from Taiwan black-feathered country chickens at 5 °C.
RESULTS: The pH was lower (P < 0.05) in BM than in LM. Western blot indicated that postmortem desmin degradation was more rapid in BM than in LM. Casein zymograms showed that at-death µ-calpain activity was higher in BM than in LM. As postmortem time proceeded, µ-calpain was activated and autolyzed more extensively in BM than in LM. However, the µ/m-calpain activity remained stable during postmortem storage in both BM and LM.
CONCLUSION: Our results suggest that the more rapid postmortem proteolysis found in BM than in LM at 5 °C similar with the previous study could be mainly explained by both greater amounts and faster activation and autolysis of µ-calpain in BM.