DISINTEGRATION OF YEAST-CELLS BY PRESSURIZED CARBON-DIOXIDE

Disruption of yeast cells with high-pressure carbon dioxide at both subcritical and supercritical temperatures (25, 35, and 55-degrees-C) was investigated. The experimental results revealed that yeast cells can be ruptured to a maximal level by carbon dioxide within 5 h at 5000 psi and 15 h at 1000 psi at any of the temperatures studied. In the presence of beta-glucuronidase, the length of time for maximal cell rupture was reduced to 90 min at 5000 psi. Off-flavors of the ruptured yeast cells were removed by carbon dioxide in the process. The functional properties of proteins were preserved, as indicated by enzyme activities in the ruptured cell suspension. An increase in temperature from subcritical to supercritical of carbon dioxide led to a significant enhancement of rapture rates under high pressures, while the functional properties of proteins and the removal of off-flavors were relatively insensitive to the variation of temperature if the process was maintained at or below 35-degrees-C. At higher temperatures, the activities of enzymes began to decay and were lost at about 55-degrees-C under the carbon dioxide pressures of this study.