Effect of prebiotic carbohydrates on growth, bile survival and cholesterol uptake abilities of dairy-related bacteria
Résumé
BACKGROUND Three strains of lactic acid bacteria and one probiotic Bifidobacterium strain sourced from milk origin were considered to select for the best synbiotic-like combination for cholesterol uptake ability. For that purpose, fermentative characteristics, bile salt hydrolase activity, bile survival and cholesterol removal were assessed in the presence of different carbohydrates. RESULTS Carbohydrate fermentability was highly variable among the different strains, and lactulose was the only prebiotic to favour growth of all strains, whereas pectin led to low population regardless of the strain. Bile survival of bacteria could be improved by the preferred carbon source and was related to their bile salt hydrolase activities. All together, our results showed that the most advantageous synbiotic-like combinations to achieve cholesterol uptake abilities were Lactobacillus delbrueckii subsp. bulgaricus LB 340 with raffinose, Streptococcus thermophilus TA040 or Lactobacillus rhamnosus LBRE-LSAS with lactulose, and Bifidobacterium animalis subsp. lactis Bb12 with mannitol. CONCLUSION The suggested synbiotics may represent new promising functional dairy additives.