Mathematical modeling of Saccharomyces cerevisiae inactivation under high-pressure carbon dioxide.

High-pressure carbon dioxide inactivation curves of Saccharomyces cerevisiae at different temperatures were analysed using the modified Gompertz model. Comparable lambda and mu values were obtained under pressure treatment as function of temperature. The phase of disappearance (lambda) and the inactivation rate (mu) of S. cerevisiae were inversely related. Higher mu values were obtained at 50 degrees C than at 40, 30 and 20 degrees C under 10.0 MPa CO2 pressure. Increased pressure and temperature had significant effects on the survival of S. cerevisiae. Arrhenius, linear and square-root models were used to analyse the temperature dependence of the inactivation rate constant. For the Arrhenius model the activation energy (E(mu)) was 56.49 kJ/mol at 10.0 MPa, and 55.70, 53.83 and 52.20 kJ/mol at 7.5, 5.0, and 2.5 MPa, respectively. Results of this study enable the prediction of yeast inactivation exposed to different CO2 pressures and temperatures.