High Pressure Thawing of Fish (Whiting): Influence of the Process Parameters on Drip Losses

Atmospheric thawing and pressure-assisted thawing were applied to frozen fish prior to heat treatment (80 °C/20 min). The influence of the pressure level (between atmospheric pressure and 200 MPa), of the freezing rate, of the pressurization rate, and of the pressure holding time was studied in comparison with a thawing process at atmospheric pressure. High freezing rate (0.77 vs.0.14 °C/min), high pressurization rate (100 vs. 42 MPa/min) reduced the thawing drip losses at a given pressure. A decrease in the drip volume for high pressure thawing compared to atmospheric thawing was obtained only by prolonging the pressure holding time. This parameter was most influential in reducing the drip loss. Electrophoresis analysis of thawing drips and of sarcoplasmic proteins of fish fillets showed a modification of the line 48 kDa proteins whose intensity decreased from 150 MPa.