Stabilization of freeze-dried Lactobacillus paracasei subsp. paracasei JCM 8130T with the addition of disaccharides, polymers, and their mixtures

Abstract

Although freeze-drying is a widely used dehydration technique for the stabilizing of unstable lactic acid bacteria, Lactobacillus paracasei subsp. paracasei JCM 8130 (L. paracasei) is destabilized after freeze-drying and subsequent storage. In order to improve the stability of freeze-dried L. paracasei, effects of disaccharides (sucrose and trehalose), polymers (maltodextrin; MD and bovine serum albumin; BSA), and their mixtures on the survival rate of freeze-dried L. paracasei were investigated. The survival rate of non-additive sample decreased slightly after freeze-drying but decreased drastically after subsequent storage at 37 °C for 4 weeks. The reduction was diminished by the addition of disaccharides and polymers. The stabilizing effect of disaccharides was not affected by the co-addition of MD. In contrast, the disaccharide-BSA mixtures had a synergistic stabilizing effect, and the survival rates were largely maintained even after storage. It is suggested that the synergistic effect originates from the conformational stabilization of the dehydrated bacteria.

Assessing the viability of three Lactobacillus bacterial species protected in the cryoprotectants containing whey and maltodextrin during freeze-drying process

“…For example Lacticaseibacillus paracasei subsp. paracasei represented high sensitivity to freeze-drying, but the use of cryoprotectants enhanced bacterial viability in the conditions (Teng et al 2017). In the present study, freeze-drying resulted in reducing the number of L. salivarius 20687, L. plantarum NRRL B-14768, and Lacticaseibacillus rhamnosus GG significantly, which is in line with the result of Carvalho et al (2002).…”

“…As exhibited in Table 2, the viability of L. rhamnosus GG is maximized in the sucrose-containing protectants, while adding peptone or whey fails to affect its viability significantly. The result is in line with that obtained by Teng et al (2017), which exhibits the maximum viability of L. paracasei in the protectant with sucrose. The greater glass-transition temperature of maltodextrin compared to the disaccharides leads to a decrease in the elasticity effects and immobilization of molecule.…”

“…Additionally, the protectants made from skimmed milk, sugar, and amino acid influence the storage period despite their little effect on preserving lactobacilli (Carvalho et al 2002). Numerous studies have reported the protective effect of protectants on bacterium during freeze-drying stage or storage period (Carvalho et al 2004;Martos et al 2007;Teng et al 2017). The proteins of skimmed milk create a protective coverage around bacterial cell (Desai et al 2004).…”

“…The greater glass-transition temperature of maltodextrin compared to the disaccharides leads to a decrease in the elasticity effects and immobilization of molecule. In contrast, the water substitution effect of irregular polymers is less than disaccharides because of possessing the side chains forming steric hindrance and preventing their attachment to other molecules and cell membrane (Teng et al 2017). Based on the results of the previous studies, the water substitution effect in a molecule is considered as more vital for protein stability during freeze-drying compared to the glass transition factor (Liao et al 2004).…”

Combinatorial Effects of Protective Agents on Survival Rate of the Yeast Starter, Saccharomyces cerevisiae 88-4, after Freeze-Drying

“…Depending on the type of protective agent, the protective effect could improve if two or more types are combined rather than adding a single one as the protection mechanism of each protectant is different [8]. Although some combinations of protective agents including skim milk, disaccharides (sucrose and trehalose), proteins (bovine serum albumin), and amino acids have been reported, they have been tested on lactobacilli for use as probiotics [11][12][13]. Concerning yeast, a few studies have reported the combinatorial effects of protective agents.…”