The Effects of Inulin on Characteristics of Lactobacillus paracasei TD3 (IBRC-M 10784) as Probiotic Bacteria in vitro.

INTRODUCTION Probiotics, as live microbial food ingredients or functional foods, are often related to health promotion and diseases prevention. The growth of these beneficial probiotics was improved by non-digestible food ingredients that are defined as prebiotics. Inulin is one of the known prebiotics that improves the gastrointestinal health.  AIM The aim of this study was to evaluate the functional properties of Lactobacillus paracasei TD3 (IBRC-M 10784) and the effects of inulin as prebiotic on these properties in vitro. METHODS The tolerance of L. paracasei TD3 for low pH and pepsin (stomach condition), bile salt and trypsin conditions (small intestine conditions), antibiotics and pathogenic bacteria were evaluated by different methods. RESULTS Lactobacillus  paracasei TD3 was obtained from TakGene Company. L. paracasei TD3 was resistant to acidic pH higher than 3.5 and was tolerant to pepsin condition lower than 0.723 µg/mL and to bile salts ≤ 0.4% w/v and tripsin condition equal to 72.32 u/g and lower. This strain was resistant to vancomycin, nalidixic acid, colistin and gentamicin while was sensitive to penicillin, streptomycin and tetracycline. L. paracasei TD3 showed antimicrobial activity against S. typhimurium, Sh. dysanteriae, Sh. flexneri and E. coli, respectively. Inulin promoted the growth of L. paracasei TD3 (log CFU) in different conditions and increased the antibacterial activity of L. paracasei TD3 against pathogenic bacteria without changing the tolerance of bacteria to pH and other conditions (P > 0.05). CONCLUSION L. paracasei TD3 (IBRC-M 10784) in combination with inulin can be considered as valuable strain for further investigations in human clinical studies.