Effect of thermal treatment on muscle tissue structure and ultrastructure of wild and farmed sea bass, <Emphasis Type="Italic">Dicentrarchus labrax</Emphasis> L

The present work studies the muscle tissue structure and ultrastructure in two populations: wild and farmed sea bass, Dicentrarchus labrax L., in both raw and cooked states. Results found in fresh raw muscle tissue ultrastructure of wild sea bass showed some typical early post-mortem alterations: fibre-to-fibre detachment, detachment of myofibrils to endomysium and swelling of mitochondria and sarcoplasmic reticulum, mainly. In cooked samples of wild and farmed groups, sarcolemma and endomysium were disrupted and coagulated in most of the zones. Myofibrils were detached from sarcolemma–endomysium. Electron-dense aggregates were observed in both subsarcolemmal and interstitial spaces. These granular aggregates also appeared close to sarcolemma and endomysium, like an electron-dense chain. The interstitial material was quantified in both groups, and it was more abundant in farmed than in wild specimens. The size of the cooked fibres was better preserved in wild than in farmed sea bass, which evidences a higher thermal resistance of muscle tissue in wild specimens.