Muscle fibre orientation and its effect on measurements of tenderness of bovine longissimus dorsi muscle

Summary The muscle fibre orientation within a particular cooked beef steak was found to vary considerably and to be markedly affected by vacuum packaging, freezing and/or cooking. Shear force values, initial-bite tenderness (panel) and cooking loss were highly dependent on, and overall tenderness (panel) was only slightly dependent on muscle fibre orientations. These measures were affected by fibre orientation to a greater extent in tough than in tender meat. At each of three fixed muscle fibre orientation, correlations between tenderness measures were significant (P<0.05), their magnitude depending on the fibre orientation. At a fixed fibre angle correlations of tenderness measures with cooking losses were not significant. However, on a withinanimal basis, cooking loss was related to shear value and to initial-bite tenderness apparently through an effect of fibre orientation. This effect may constitute a major source of variation in the measurement of tenderness and cooking loss.