Lyophilization (Drying Method) Cause Serious Damages to the Cell Viability of Lactic Acid Bacteria

Abstract

Preservation of industrial’s lactic acid bacteria (probiotics) by freeze-drying. Lactic acid bacteria have important nutritional needs and do not have resistance against the environmental conditions surrounding their production (drying, storage, etc.) and their use in vivo (physico-chemical properties of the digestive tract). In this condition, industrials and microbiologists develop regularly research projects of new lactic bacteria able to support the whole of the processes of production, storage and formulation without losing their functional properties. Among various methods of drying (atomization, fluidization and freeze-drying), freeze-drying makes it possible to obtain a thorough dehydration compatible with very long storage times. This method involves changes in product temperature and cause damage to microorganisms because it requires freezing that is not without consequences for cells. On the other side, it causes cellular (peroxydation of the fatty-acids) and genetic (proteins’s modifications) deteriorations. Using cryoprotectants and antioxidants during freeze-drying storage increases appreciably the rate of viability of these cells.