The influence of dissolved CO_2 concentration on the death kinetics of Saccharomyces cerevisiae

摘要

Aims: The effects of temperature and concentration of dissolved CO_2 on the inactivation of Saccharomyces cerevisiae were investigated using a plug-flow system. Methods and Results: Several combinations of pressure (4, 6, 8, 10 mega-Pa (MPa)) and temperature (30, 34, 36, 38 ℃) were used. The D-values obtained were 0.14 min at 8 MPa and 38 ℃, and 0.15 min at 10 MPa and 36 ℃. The log D-values were related linearly to the treatment temperature and to the dissolved CO_2 concentration. The thermal resistance constant (Z_(CO_2)(T)) was 9.5 ℃ in the media, including significant levels of CO_2, and the CO_2 resistance constant was z_(temp).(γ) = 7.2 γ. Conclusions: This work has shown that inactivation followed first-order death kinetics, and the effects of temperature and CO_2 concentration were consistent through the critical temperature and pressure of CO_2. Therefore, it is feasible to estimate D-values at any temperature and any CO_2 concentration. Significance and Impact of the Study: Non-thermal inactivation of micro-organisms in acidic beverages could be realized by the present technique.