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

摘要

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 Bbl2. 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 ℃. 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.