The prebiotic, oligofructose-enriched inulin modulates the faecal metabolite profile: An in vitro analysis

Scope: Health benefits of prebiotic administration have been judged mainly from the increased numbers of bifidobacteria and the enhanced production of short-chain fatty acids in the colon. Only a few studies have focused on the capacity of prebiotics to decrease the proteolytic fermentation, which might contribute to health as well. Methods and results: The influence of the prebiotic oligofructose-enriched inulin (OF-IN) on the pattern of volatile organic compounds was characterized using an in vitro faecal model. Faecal slurries, obtained from healthy subjects, were anaerobically incubated at 37 degrees C with and without different doses of OF-IN (2.5, 5, 10, or 20 mg) and changes in the metabolite pattern and pH were evaluated. A total of 107 different volatile organic compounds were identified and classified according to their chemical classes. The concentration of esters and acids significantly increased with increasing doses of OF-IN. Similar effects were observed for some aldehydes. To the contrary, OF-IN dose-dependently inhibited the formation of S-compounds. Also, the generation of other protein fermentation metabolites such as phenolic compounds was inhibited in the presence of OF-IN. Conclusion: Our results confirmed a clear dose-dependent stimulation of saccharolytic fermentation. Importantly, a significant decrease in toxic protein fermentation metabolites such as sulphides attended these effects.