Connective tissue differences in the strength of cooked meat across the muscle fibre direction due to test specimen size

Systematic variations in the tensile strenght of cooked beef M. semitendinosus across the muscle fibre direction due to the cross-sectional size of specimens are demonstrated in specimens from (a) longitudinal and (b) transverse slices. The strength perpendicular to the fibre direction of longitudinal slices of thickness 0·25-5·75 mm varied by a factor of 2, thicker slices being stronger. This factor of 2 is in approximate agreement with the difference in strength of transverse versus longitudinal slices across the fibre direction. These variations of strength due to specimen geometry are explained on the basis of the increasing likelihood of including a ribbon of the perimysial connective tissue network which is continuous along the whole length of the test piece in larger samples. The breaking strength of small cross-sectional area specimens is likely to be dominated by the strength of the endomysial-perimysial junction. Larger cross-sectioned specimens, by including continuous strands of the perimysial network, have higher strengths resulting from the necessity to break these strands. These findings highlight the need to specify specimen dimensions in tensile test results. They also show that by manipulating specimen geometry, the relative magnitude of the two mechanisms of connective tissue fracture (endomysial-perimysial separation and perimysial strand fracture) may be assessed.