In conclusion, calcium chloride injection and freezing activate calpain-2 earlier postmortem in both muscles and calcium injection improves LL tenderness.
The present results suggest that meat tenderness in Nellore cattle does not directly depend on the expression of the CAPN1 and CAPN2 genes, but is associated with the expression of other genes such as CAST2, HSP90AA1, DNAJA1 and HSPB1.
Our results indicate that both calpain-1 and calpain-2 may contribute to the postmortem improvement of beef tenderness, with calpain-1 being responsible for the tenderness improvement early postmortem and calpain-2 responsible for additional tenderization during extended aging.