Effects of high pressure treatment on physicochemical characteristics of fresh oysters (Crassostrea gigas)

The effects of high pressure (HP) treatment (at 100-800 MPa for 10 min at 20 °C) on physicochemical characteristics of depurated oysters were investigated. HP-treated oysters had higher pH and lightness (Hunter L) values than untreated oysters; the magnitude of changes increased with treatment pressure. HP-induced changes in colour generally imparted a cooked, more voluminous and juicy appearance to the raw oyster tissue. After treatment, oyster muscles became detached from their shells, essentially resulting in shucking. As assessed by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE), denaturation of oyster adductor muscle proteins occurred as a consequence of HP-treatment. The moisture content of oysters increased while ash and protein contents decreased, relative to untreated oysters, with increasing treatment pressure up to 800 MPa.