Influence of temperature and drying rate on the dehydration inactivation of Lactobacillus plantarum.

The objective of this work was to study the influence of drying temperature and drying rate on the dehydration inactivation of Lactobacillus plantarum. Drying methods with different temperatures and different characteristic drying times were used. Residual activities of 70-85% were realized after convective or vacuum drying of a layer at 30°C as opposed to 30-50% at 4°C. Spray drying (fast drying) and vacuum drying at higher water activity (aw) values (slow drying) both resulted in lower residual activities. These experiments agreed with the following hypothesis: during drying at 30°C a physiological adaptation of the cell takes place which is time dependent. This work provides a tool for improvement of the production of dried L. plantarum.