EFFECT OF HIGH HYDROSTATIC-PRESSURE ON THE TEMPERATURE-DEPENDENCE OF SACCHAROMYCES-CEREVISIAE AND ZYGOSACCHAROMYCES-ROUXII

The inactivation kinetics of two yeasts, Saccharomyces cerevisiae CCRC 20271 and Zygosaccharomyces rouxii CCRC 21873, were determined at com binations of different hydrostatic pressures (0.1-300 MPa) and tempera tures (35-55 degrees C). First order kinetics were applicable to both yeasts under the conditions used, except that slight deviations occurr ed for Z. rouxii at combinations of 35-40 degrees C and 150-300 MPa. A t pressures of 0.1 to 100 MPa S. cerevisiae was more resistant to heat and also to pressure than Z. rouxii. The Arrhenius plots of the speci fic death rates for both yeasts at various pressures showed similar ye t distinct patterns. The average activation energy (E(a)) for Z. rouxi i was about 1.51 +/- 0.08 x 10(5) J/mol and was apparently independent of pressure, however, E(a) values of S. cerevisiae were roughly divid ed into two groups of parallel lines, one obtained at pressures of 0.1 -100 MPa was 1.65+/-0.61 x 10(4) J/mol, the other was 1.23 +/- 0.17 x 10(5) J/mol at 150-300 MPa. Consequently, the combined effect of press ure and temperature on the survival of the yeasts appeared to be addit ive, but this effect tended to increase stepwise for S. cerevisiae as the pressure increased. (C) 1997 Elsevier Science Ltd.