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

Abstract

For 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.