Achievement of rapid osmotic dehydration at specific temperatures could maintain high Saccharomyces cerevisiae viability.

Various methods have been tried to prevent cell mortality during dehydration, but the reasons why microorganisms die when submitted to dehydration and rehydration are not well understood. The aim of this study was to further investigate the reasons for yeast mortality during dehydration. Osmotic dehydration and rehydration of Saccharomyces cerevisiae W303-1A were performed at different temperatures. Two different approaches were used: isothermic treatments (dehydration and rehydration at the same temperature), and cyclic treatments (dehydration at an experimental temperature and rehydration at 25 degrees C), with significant differences in viability found between the different treatments. Dehydration at lower and higher temperatures gave higher viability results. These experiments allowed us to propose a hypothesis that relates mortality to a high water flow through an unstable membrane during phase transition.