%0 Journal Article
%T The Resistance to Freeze-Drying and to Storage Was Determined as the Cellular Ability to Recover Its Survival Rate and Acidification Activity
%A Ibourahema Coulibaly
%A Robin Dubois-Dauphin
%A Jacqueline Destain
%A Marie-Laure Fauconnier
%A Georges Lognay
%A Philippe Thonart
%J International Journal of Microbiology
%D 2010
%I Hindawi Publishing Corporation
%R 10.1155/2010/625239
%X The protective effects of the fatty acid composition and membrane action of the acidification activity of two strains of Lactobacillus kept at were studied. The addition of sorbitol, monosodium glutamate and glycerol during storage is causing the decline of acidification and increased concentrations of unsaturated fatty acids observed in both strains. The addition of sorbitol and monosodium glutamate does not alter the fatty acid composition, whatever the strain, but increases the resistance to freeze-drying of L. plantarum CWBI-B1419 and improves survival during storage. The addition of these preservatives and decreased activity of acidification improves the ratio unsaturated. These results indicate that the survival during storage and freeze-drying resistance are closely related to the composition of membrane fatty acids. This behaviour can be interpreted as an adaptation of L. plantarum B1419-CWBI supplemented by cryoprotectant additives such as sorbitol or monosodium glutamate sorbitol and monosodium glutamate as an additive. L. plantarum CWBI-B1419 presents a greater adaptation to culture conditions than L. paracasei ssp. paracasei . 1. Introduction The acidification activity of lactic acid bacteria at the different steps of their production (fermentation, cooling, concentration, cryoprotection, freezing, or freeze-drying) and during storage differs depending on the strain considered and on the operating conditions [1, 2]. The freezing and freeze-drying step is especially critical as it negatively affects both viability and physiological state of the bacteria [3, 4]. The formation of ice crystals induces mechanical damage that leads to cellular death during freezing [5]. In addition, the crystallization of the water leads to a cryoconcentration of the solutes, which induces some osmotic damage [6]. Some agents such as those used in lyoprotection are of undoubted importance for the survival of cells because they can act on biological functions in preserving the integrity of the lipid bilayer by the phenomenon of water replacement, vitrification (glass formation), and depression of membrane transition temperatures (Tm), as reviewed in detail by Castro et al. [7, 8] and Champagne et al. [9]. The same observations with sucrose for survival of Lb. coryniformis Si3 were noticed by Schoug et al. [10]. Adding cryoprotective agents such as sorbitol, monosodium glutamate, and glycerol before freeze-drying process attenuated the damaging effects of freezing, thus improving the bacterial resistance to drying [11, 12]. This protective effect was ascribed to
%U http://www.hindawi.com/journals/ijmicro/2010/625239/