RELATIONSHIP BETWEEN BIOLOGICAL AND PHYSICAL PROPERTIES OF DRY YEAST CELLS
1966 Volume 12 Issue 1 Pages 91-99
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1966 Volume 12 Issue 1 Pages 91-99
By using a series of dry yeasts prepared to have various water contents, the resistivity to heat inactivation and cold medium treatment was studied.
The heat resistance of the samples showed a marked dependence upon the water content, giving activation energies of 80kcal with relatively wet cells and 60kcal with relatively dried cells, respectively. The lowering of the biological activity shown after the rehydration with a cold medium was found to be prevented, at least partially, by preheating the sample at specified temperature before the rehydration procedure. This protective effect disappeared after several hour standing at room temperature, suggesting that the related physical state relaxed with a time constant of hours in order of magnitude.
A domain map is presented to show diagrammatically the relationship between biological properties of the dry yeast and its related physical states in terms of the cell temperature and the cell water content.
