Lyophilization (Drying Method) Cause Serious Damages to the Cell Viability of Lactic Acid Bacteria
Ibourahema Coulibaly *
Walloon Center for Industrial Biology, Microbial Technology Unit, University of Liège, Gembloux Agro-Bio Tech, Passage des Déportés 2, B-5030 Gembloux, Belgium and Unit and Research in Agroforestry, Laboratory of Microbiology, Bio-Industry and Biotechnology, Jean Lorougnon Guédé University, BP. 150 Daloa, Ivory Coast.
Elisée Kporou Kouassi
Unit and Research in Agroforestry, Laboratory of Microbiology, Bio-Industry and Biotechnology, Jean Lorougnon Guédé University, BP. 150 Daloa, Ivory Coast
Elise N’guessan
Unit and Research in Biochemistry and genetic, Laboratory of Biologicals sciences, University Peloforo Gon Coulibaly, BP. 13280 Korhogo, Ivory Coast.
Jacqueline Destain
Walloon Center for Industrial Biology, Microbial Technology Unit, University of Liège, Gembloux Agro-Bio Tech, Passage des Déportés 2, B-5030 Gembloux, Belgium.
François Béra
Food Technology Unit, University of Liège, Gembloux Agro-Bio Tech, Passages of the Deportees, 2. B-5030 Gembloux, Belgium.
Philippe Thonart
Walloon Center for Industrial Biology, Microbial Technology Unit, University of Liège, Gembloux Agro-Bio Tech, Passage des Déportés 2, B-5030 Gembloux, Belgium and Walloon Center for Industrial Biology, Microbial Technology Unit, University of Liège, B40, B-4000 Liège, Sart Tilman, François BERA, Belgium.
*Author to whom correspondence should be addressed.
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.
Keywords: Probiotics, freeze-drying, free radicals, cellular fatty acid, hydroperoxides, peroxydation, cryoprotectants.