[Show abstract][Hide abstract] ABSTRACT: The current screening study aimed at identifying promising prebiotic and synbiotic candidates. The fermentation of xylo-oligosaccharides, xylan, galacto-oligosaccharide, fructo-oligosaccharide, polydextrose, lactitol, gentiobiose and pullulan was investigated in vitro. The ability of these established and potential prebiotic candidates to function as a sole carbon source for probiotic (Bifidobacterium and Lactobacillus), intestinal and potential pathogenic microbes (Eubacterium, Bacteroides, Clostridium, Escherichia coli, Salmonella, and Staphylococcus) was assessed in pure cultures. Xylo-oligosaccharides were fermented with high specificity by the tested Bifidobacterium lactis strains and lactitol by lactobacilli, whereas galacto-oligosaccharides, fructo-oligosaccharides and gentiobiose were utilised by a larger group of microbes. Xylan, polydextrose and pullulan were utilised to a limited extent by only a few of the tested microbes. The results of this screening study indicate that xylo-oligosaccharides and lactitol support the growth of a limited number of beneficial microbes in pure cultures. Such a high degree of specificity has not been previously reported for established prebiotics. Based on these results, the most promising prebiotics and synbiotic combinations can be selected for further testing.
[Show abstract][Hide abstract] ABSTRACT: A semi-continuous, anaerobic colon simulator, with four vessels mimicking the conditions of the human large intestine, was used to study the fermentation of xylo-oligosaccharides (XOS). Three XOS compounds and a xylan preparation were fermented for 48 hours by human colonic microbes. Fructo-oligosaccharides (FOS) were used as a prebiotic reference. As a result of the fermentation, the numbers of Bifidobacterium increased in all XOS and xylan simulations when compared to the growth observed in the baseline simulations, and increased levels of Bifidobacterium lactis were measured with the two XOS compounds that had larger distribution of the degree of polymerisation. Fermentation of XOS and xylan increased the microbial production of short chain fatty acids in the simulator vessels; especially the amounts of butyrate and acetate were increased. XOS was more efficient than FOS in increasing the numbers of B. lactis in the colonic model, whereas FOS increased the Bifidobacterium longum numbers more. The selective fermentation of XOS by B. lactis has been demonstrated in pure culture studies, and these results further indicate that the combination of B. lactis and XOS would form a successful, selective synbiotic combination.
[Show abstract][Hide abstract] ABSTRACT: In this study, probiotics Lactobacillus acidophilus NCFM and Lactobacillus rhamnosus HN001 in cheese were studied using models simulating the human gastrointestinal tract with the aim of investigating whether the cheese matrix affected the survival and metabolic properties of these probiotic strains. Probiotics in cheese survived in the simulated upper gastrointestinal tract model, and numbers of L. acidophilus, L. rhamnosus and total lactobacilli were increased in the colonic fermentation simulations of the probiotic cheese when compared with the non-probiotic cheese used as a control. The cheese matrix also beneficially affected cyclooxygenase-gene expression of colonocytes in a cell culture model. Freeze-dried probiotics, which were also analysed in the colonic simulator, showed similar changes in Lactobacillus numbers, although gave a stronger increase and also affected other microbial groups. These results indicate that the probiotic microbes in cheese survive in the gastrointestinal tract and that the cheese matrix does not seem to affect the probiotic survival.
International Dairy Journal 11/2009; · 2.30 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: To investigate the prebiotic potential of two novel candidates, sophorose and panose, with in vitro methods.
The growth of single microbial strains was first assessed for both substrates in pure cultures, and panose was further analysed in the simulated colon model with mixed human faecal culture. Quantitative PCR and flow cytometry were used to determine the microbial group and strain densities after the simulated colonic fermentation of panose, and chromatographic methods were utilized to analyse metabolite concentrations. In pure cultures, sophorose and panose were both fermented only by few beneficial strains, and in the colon simulator, panose gave a significant increase in the numbers of Bifidobacterium and Bifidobacterium lactis, concomitantly decreasing Bacteroides group. Butyrate and acetate production was significantly increased together with decreased markers of protein fermentation as a result of panose fermentation.
Panose had bifidogenic activities in vitro, and these potential beneficial effects should be further assessed in vitro and in vivo.
The current study has provided the first data on pure panose fermentation by the endogenous microbiota and extends our knowledge of the selective fermentation of oligosaccharides by the intestinal microbes.
Letters in Applied Microbiology 07/2009; 49(6):666-72. · 1.63 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Bifidobacteria are important members of the intestinal microbiota and are considered to contribute to maintaining health. However, the level of bifidobacteria colonising the intestine of elderly subjects tends to be lower than in younger adults. Therefore, two Bifidobacterium longum strains, isolated from healthy elderly, were chosen for supplementation of the endogenous Bifidobacterium microbiota in the elderly. Bifidobacteria are generally regarded safe for human consumption. However, since the strains are intended for consumption by the elderly, whom may be more prone to disease, it is important to ascertain their safety. For this purpose, the strains were given to healthy adult volunteers. No side effects were reported and no undesirable changes observed in the immune parameters measured. Based on this study it appears that the two strains are well tolerated by human subjects and there are no reservations about their food use.
Microbiology and Immunology 02/2003; 47(12):911-4. · 1.31 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Probiotics are commonly consumed in the form of supplements and fermented (drink) yogurts. However, alternative carriers are possible and especially cheese seems to be well suited. Selected Lactobacillus strains (L. acidophilus NCFM and L. rhamnosus HN001) were observed to grow during ripening and maintain viability throughout 3 months shelf life. Consumption of 15g of cheese would provide a required daily dose of 109 CFU. Bifidobacterium lactis appeared to be less well suited for application in cheese.
In vitro simulation of digestion showed that in a commercial cheese, the Lactobacillus strains were able to survive conditions similar to those found in the human gastrointestinal tract. Furthermore, the strains were able to modulate the composition and activity of the simulated intestinal microbiota. A subsequent dietary intervention study indicated that consumption of the probiotic cheese was able to increase phagocytosis activity and the fraction of phagocytic cells in healthy elderly volunteers.
The improvement in innate immunity was similar to what was observed earlier for reconstituted milk containing L. rhamnosus HN001; showing that cheese is an equally good and effective carrier for this particular strain as milk. The health effect of the increased phagocytosis remains, however, to be determined.