Electron microscopy of bovine muscle: II-The effects of heat denaturation on post rigor sarcolemma and endomysium.

After 1 h at 50°C the collagen fibrils of the endomysium appeared beaded, brought about by their close association with the heat denatured non-collagenous proteins in the extracellular spaces. Heat denaturation of the lipoprotein plasmalemma resulted at 60°C plus for 1 h. The breakdown products of the plasmalemma, large granules, were often associated with the basement lamina, which appeared to survive intact even after 100°C for 1 h. Loss of the plasmalemma and partial thermal shrinkage of the endomysial collagen at higher temperatures (70°C plus) together with a probable loss of plasticity of the myofibrillar masses, resulted in frequent ruptures of the endomysial tube remains. These ruptures, which appeared during the exposure of surfaces prior to SEM observation, were not seen prior to heat treatment.