CHANGES OF ULTRASTRUCTURE AND THE PHYSICAL-PROPERTIES OF CARP MUSCLE BY HIGH PRESSURIZATION

Pressurized and heated carp muscles were examined by electron microsco py to clarify the effects of high pressure upon their fine structures, in relation to the changes of their physical properties. At pressures over 300 MPa, the striated structure of the myofibrils disappeared. A t 500 MPa the contractile elements of the muscle fibers disintegrated, thus resulting in an appearance of irregular electron-opaque bodies. Heated muscle fibers, on the other hand, showed that the myofibrils co mpletely lost their striations and changed into homogeneous materials. Although high pressure and heat affected the structural profiles of s uch cytoplasmic membrane structures as the mitochondria and endoplasmi c reticulum, no membrane disruption was observed in those structures. The appearance of glycogen granules was not affected by either high pr essure or heating. In addition, the texture values of carp muscles ros e with an increase in pressure, and the viscoelasticity was higher in the pressurized muscles than in the heated muscles.