Collagen fibre arrangement in intramuscular connective tissue. Changes associated with muscle shortening and their possible relevance to raw meat toughness measurements

Summary Collagen fibres of ovine and bovine perimysium are shown to have a crimped appearance. The size of the crimp is smaller than in the collagen fibres from tendon (e.g. perimysium 19 μm; tendon 79 μm). The collagen fibres are laid down in a well‐ordered criss‐cross lattice at an angle to the muscle fibre long axis. Muscle contraction changes the angles of this lattice and also changes the crimp length. These changes are related to differences between samples of meat of uniform size such as are tested for toughness. It is demonstrated that any explanation of changes in meat toughness resulting from shortening can no longer be related only to changes in ‘myofibrillar toughness’, but must also include extensive changes in ‘connective tissue toughness’.