Collagen Solubility and Calcium Concentration and Their Effects on Tenderness in the M. longissimus lumborum
Strip steaks from the McGregor genome project were used to evaluate the effects of sarcomere length, myofibrillar fragmentation index, 3 h postmortem pH, 24 h postmortem pH, marbling, electrical stimulation (ES), sarcoplasmic free calcium concentration, and collagen characteristics on tenderness as measured by Warner-Bratzler shear force (WBS). The WBS values were measured prior to this project so the animals were able to be separated into ?tender? and ?tough? groups using a WBS value of 30 N as the separating point, steaks with a WBS value less than 30 N being ?tender? and the others being ?tough?. It was found that ES sides had lower WBS values, however, ?tough? steaks showed a greater response to ES than ?tender? steaks. ES sides also had higher sarcoplasmic free calcium concentration and lower 3 h postmortem pH. Tenderness is best predicted by treatment (ES versus NON-ES), however, there is some efficacy in using total collagen and collagen solubility in conjunction with treatment.