Abstract: In order to study the effect of ultra-high pressure treatment on the quality of freshly dead Portunus trituberculatus, changes in sensory scores, pH, color difference, myofibrillar protein content, sulphydryl content, surface hydrophobicity and Ca2+-ATPase activity were determined after high pressure treatments. Results showed that sensory scores, pH and whiteness of P. trituberculatus did not significantly change at 150, 200 and 250 MPa compared with the control group (P > 0.05), but significant changes occurred at 300 and 350 MPa (P < 0.05). Moreover, at the higher pressures crab muscle was slightly cooked, producing a unique flavor of cooked crab. At all pressures except 250 MPa for myofibrillar protein content and except 150 and 200 MPa for Ca2+-ATPase activity, both parameters significantly changed (P < 0.05). No significant change was observed in sulfhydryl content of crab myofibrillar protein at 150 and 200 MPa (P > 0.05), whereas surface hydrophobicity was significantly increased (P < 0.05) compared with the control group. Taking into account both sensory scores and biochemistry properties of myofibrillar protein, the quality of P. trituberculatus didn’t significantly changed at 150, 200 or 250 MPa, which can provide a theoretical basis for further studying the effect under ultra-high pressure on the storage quality of P. trituberculatus.

Key words: ultra-high pressure, Portunus trituberculatus, sensory evaluation, myofibrillar protein, biochemical properties