Abstract:Objective The aim of this study is to explore the effects of dextran with a small molecular weight (SDex) on the viability of intestinal microorganisms.Method The probiotic effects of laboratory-designed SDex containing only α-1,6 glycosidic bonds was evaluated by in vitro fermentation with nine typical intestinal strains, including strains from the genera Bifidobacterium and Lactobacillus, as well as species such as Escherichia coli and Enterococcus faecalis. The microbial proliferation and organic acid production during fermentation were compared among SDex, commercial dextran 20 (Dex 20), and isomalto-oligosaccharides (IMOs).Result SDex and IMOs significantly promoted the proliferation of probiotics such as Bifidobacterium and Lactobacillus as well as the production of organic acids, while Dex 20 showed little effects. SDex did not promote the growth of the conditionally pathogenic bacterium Escherichia coli but showed a less positive effect on the neutral bacterium Enterococcus faecalis than IMOs. Neither SDex nor IMOs significantly affected the lactic acid production. However, SDex promoted acetic acid production while SDex enhanced formic acid production by probiotics.Conclusion SDex demonstrates selective probiotic effects of promoting the proliferation of Bifidobacterium and Lactobacillus while exerting little effect on Escherichia coli, which indicates SDex is essential for replenishing existing prebiotics.
