Inulin-type fructans of longer degree of polymerization exert more pronounced in vitro prebiotic effects

We assessed to what extent fructans of different degrees of polymerization (DP) differ in their prebiotic effectiveness towards in vitro microbial communities from the proximal and distal colon. Two short chain fructans - oligofructose (DP 2-20) and inulin (DP 3-60) - were administered to the Simulator of the Human Intestinal Microbial Ecosystem (SHIME) at 2·5 g day⁻¹. The influence of fructan addition towards fermentation activity and microbial community composition from the different SHIME colon compartments were evaluated. Both fructans exerted prebiotic effects with significantly higher butyrate and propionate production and stimulation of lactic acid-producing bacteria. Compared with oligofructose, it was noted that it took more time before significant effects from inulin addition were observed. Yet, the higher short-chain fatty acid production and lower proteolytic activity showed that the prebiotic effects from inulin were more pronounced than oligofructose. Also, the bifidogenic effects from inulin vs oligofructose were higher in the distal colon compartments and this effect was prolonged in the distal colon once the addition was stopped. Inulin has more pronounced prebiotic effects than oligofructose towards both fermentation activity and bacterial community composition in the SHIME model. Its slower fermentation rate and higher prebiotic potency makes inulin a more interesting compound than oligofructose to beneficially influence the microbial community from both the proximal and distal colon regions.