Calcium alginate-resistant starch mixed gel improved the survival of Bifidobacterium animalis subsp lactis Bb12 and Lactobacillus rhamnosus LBRE-LSAS in yogurt and simulated gastrointestinal conditions

The aim of this study was to investigate the protective effect of microencapsulation in calcium alginate-resistant starch mixed gel of a new human isolated strain of Lactobacillus rhamnosus LBRE-LSAS compared with the probiotic strain of Bifidobacterium animalis subsp. lactis Bb12. Influence of microencapsulation was tested under deleterious digestive environment, when challenged to salivary a-amylase, to simulated gastric fluid and to simulated intestinal fluid. Bacterial survival, post-acidifying activity and exopolysaccharides (EPS) content in stored mix yogurt were assessed. Integrity of the beads was acceptable under a-amylase levels largely higher than those found in human saliva. Under simulated gastrointestinal model, viable cell counts of encapsulated cells were significantly higher than those observed with free cells and remained at the recommended levels. Additionally, microencapsulation allowed an improved viability of bacteria and generated higher EPS amounts in mix yogurt stored at 4 degrees C. Our results indicate that calcium alginate-resistant starch beads extend survival under digestive conditions and in yogurt and could be used as an efficient delivery system for probiotics

Association of carob galactomannans with probiotic bacteria in synbiotic fermented milk and colon targeted-release carrier

International audienceFor the first time, this study presented the use of raw locust bean gum (LBG) as a prebiotic, with one probiotic strain in synbiotic fermented milk or combined with Na-alginate as a biopolymer, for a targeted release of bacteria under colon-like conditions. For this purpose, the fermentative characteristics (biomass, pH), bacterial survival, and developed viscosities of the stored fermented milks were determined. The survival rates of microencapsulated bacteria using the emulsion technique under simulated gastrointestinal conditions (stomach: pH 2 + 0.3% pepsin; colon: pH 6.5 + 1% pancreatin + 0.3% bile) were also evaluated. Results showed that all the tested bacteria maintained better biomass and acidifying activities in the presence of LBG, especially at 2%. During cold storage, the viscosities of the LBG-fermented milks were regulated and better appreciated, especially at 2%. Lactobacillus rhamnosus LbRE-LSAS and Bifidobacterium animalis subsp. lactis Bb12 microencapsulated separately in Ca-alginate-raw carob gum maintained good survival rates (51 - 66%) as compared to free cells (21 - 59%) under simulated digestive conditions, and were released under colon-like conditions. Therefore, the formulation of LBG-enriched fermented milks containing probiotic bacteria could represent a very good candidate for industrial application. Ca-alginate-raw LBG beads for the specific release of probiotics in the colon could benefit consumers with celiac disease or other digestive disorders because LBG is naturally gluten-free