Journal of food science vol:65 issue:1 pages:155-160
A detailed kinetic study on pressure-temperature inactivation of alkaline phosphatase has been performed in the pressure range 0.1 to 725 MPa at temperatures between 25 and 63 degrees C. Inactivation could be accurately described by a first order kinetic model, allowing D-values to be calculated. According to the thermal death time terminology, z(T)- and z(P)-values were calculated, expressing temperature and pressure dependence respectively. However, at high temperature, pressure dependence could not be calculated unambiguously. D-values firstly increased with increasing pressure up to 300 MPa and then decreased with further pressure increase, showing thermal inactivation to be counteracted by low pressure. Finally, a global model describing the D-value as a function of pressure and temperature has been formulated.