MITOCHONDRIA MODULATION OF POSTMORTEM PROTEOLYSIS AND TENDERIZATION

The overall objective of this proposal is to define the role of mitochondria in postmortem proteolysis and to identify new biomarkers associated with variation in beef tenderness.The central hypothesis for this research is that the variations in beef tenderness may be more thoroughly explained and predicted by mitochondria content and functionality within postmortem muscle. We plan to test our central hypothesis and accomplish the overall objective of this proposal by pursuing the following specific AIMS: 1. Determine mitochondrial role in postmortem calcium homeostasis and its effect on proteolysis. The working hypothesis for this AIM is that functional mitochondria increase calcium sequestering capacity of postmortem muscle and delay the activation of the calpain system. 2. Identify the contribution of mitochondria to postmortem apoptosis and its significance to meat tenderness. The working hypothesis for this AIM is that impaired mitochondrial functionality enhanceapoptosis-induced tenderness. 3. Examine differences in proteomic profiles between muscles with different mitochondria abundance and their relationship with tenderness. The working hypothesis for this AIM is that mitochondria abundance alters proteomic profileof postmortem muscle and hence the extent of proteolysis.