Effects of Marbling Texture on Muscle Fiber and Collagen Characteristics

The objective of this study was to evaluate the effects of marbling texture on muscle fiber morphometrics, adipocyte cross-sectional area, perimysial thickness, collagen solubility, and thermal transition temperature of perimysial collagen of beef strip loin steaks from 3 marbling scores. Beef strip loins (n = 117) were selected from three marbling scores [Top Choice (Modest00 – Moderate100 marbling), Low Choice (Small marbling), and Select (Slight marbling)] to equally represent 3 different marbling texture groups: fine, medium, and coarse, via visual appraisal. There were no marbling texture × marbling score interactions for all traits evaluated. Marbling texture impacted (P 0.05) to both coarse and fine marbled steaks for the same trait. However, marbling texture did not impact (P > 0.05) perimysial thickness. Marbling texture did not affect collagen traits, as no differences (P > 0.05) were found among marbling texture treatments for soluble collagen, insoluble collagen, and total collagen concentrations. Furthermore, all marbling texture groups (fine, medium, and coarse) were similar (P > 0.05) for the peak thermal transition phase of the perimysial fraction of collagen. Marbling score affected adipocyte size, as Top Choice and Low Choice possessed larger (P 0.05) among marbling scores for fiber type; nor were differences found among marbling textures or marbling scores for fiber cross-sectional area. These results indicate that marbling texture does not contribute to differences in collagen characteristics or fiber cross-sectional area that may impact eating quality of beef strip loin steaks.