Abstract/Summary

Levan, a bacterial exopolysaccharide (EPS), has been suggested to have several biological activities, such as antitumour activity and lowering blood pressure. There has also been interest in its potential prebiotic activity. This study investigated the fermentation profile of a levan fraction from Erwinia sp. 10119 (average DP=137) throughout a three-stage continuous gut model system, in which inulin HP (average DP=40) was included as a comparison. Levan-type fructan was found to selectively stimulate the growth of Bifidobacterium and Eubacterium rectale - Clostridium coccoides group in all fermenter vessels, with significant (p < 0.05) increases in the concentration of both acetate and butyrate. The increases in Bifidobacterium population were significantly (p < 0.05) higher in the models treated with levan-type fructan (0.8–1.24 log cell/mL) compared to the models treated with inulin HP (0.62–0.7 log cell/mL), indicating a stronger bifidogenic effect of levan-type fructan and a prolonged persistence in the colon due to its higher DP.