Perimysium thickness as an indicator of beef tenderness

Eight bovine muscles were evaluated to determine if perimysium thickness (PT) differed among muscles and carcasses and was affected by electrical stimulation (ES). In addition, the effect of PT on Warner-Bratzler shear (WBS) of steaks divided into tenderness groups was evaluated. Muscle and carcass affected (P<0.05) PT, but PT was not significantly affected by ES. Correlation coefficients revealed that PT would be a poor indicator of WBS when used alone (r=0.13). When analyzed within electrical stimulation treatment, PT was correlated (P<0.05) to WBS of NES (r=0.21) carcasses and not significantly related to WBS of ES carcasses. Within tenderness groups, PT accounted for 4.5%, 9.5%, 20.0%, and 4.0% of the variation in WBS force at 3, 7, 14, and 21 d, respectively. These results indicate that PT can be used in conjunction with other myofibrillar components of tenderness to account for some variation in WBS values of cooked beef steaks.