Evaluation of Bovine Myosin Heavy Chain Isoforms and Muscle Fiber Cross-Sectional Area on the Eating Quality of 11 Different Beef Muscles

The objective of this study was to determine the impact of muscle fiber type, diameter, and cross-sectional area (CSA) on the eating quality of 11 different beef muscles. Ten U.S. Department of Agriculture choice shoulder clod (SC), flank (F), knuckle (K), mock tender (MT), top sirloin butt (TS), brisket (B), eye of round (ER), and ribeye (R) were collected in study 1 (n = 80). In study 2, strip loin (SL), tri-tip (TT), and heel (H) were collected from ten USDA low choice beef carcasses (n = 30). Muscle fiber types, CSA, and diameters were determined. Pearson correlation analysis was performed to determine the relationship between muscle fiber type, CSA, diameter, and the eating quality of beef from previously reported studies. Correlation analysis from both studies demonstrated positive correlations between type 1 fibers and many attributes of eating quality such as juiciness and lipid flavor intensity ( P < 0.05). Negative correlations were found between type 2A fibers and those attributes ( P < 0.05) and between type 2X fibers and tenderness measurements ( P < 0.05). Interestingly, a negative correlation was found between muscle fiber CSA and diameter with connective tissue amount ( P < 0.05), and a positive correlation was found between muscle fiber CSA and diameter with tenderness measurements ( P < 0.05) in those same studies.