Abstract
Pressure shift freezing consists in cooling a biological substance (mainly containing water) under pressure without phase change followed by a sudden release of the pressure. The high supercooling obtained during the quasi adiabatic depressurisation permits to achieve a rapid and uniform ice nucleation. The ice fraction formed during the pressure release of a sample of pure water has been calculated using a mathematical model. In addition, this fraction was experimentally evaluated by isothermal calorimetry. The calculations and measurements were carried out at 3 different initial points of the ice I melting curve. A relatively good agreement is observed between the experimental and calculated ice ratio which were between 0.117 and 0.402 (kg ice/kg ice-water mixture) for an initial temperature-pressure values of -10°C/1 15 MPa and -21°C/210 MPa respectively.