Structural characterization of oligosaccharide from Dendrobium officinale and its properties in vitro digestion and fecal fermentation

Oligosaccharides from Dendrobium officinale (DOO) is a kind of new potential prebiotic for health. In this study, structural characteristics, digestion properties and regulatory function on intestinal flora of DOO were investigated. An oligosaccharide, DOO 1-1, was purified by DEAE-Sepharose Fast Flow and Sephadex G-25, and its physicochemical properties were characterized as a glucomannan oligosaccharide with a molecular weight of 1560 Da (DP = 9). In vitro simulated digestion, it proved that the structure of DOO 1-1 was degraded hardly in the simulated gastric and small intestinal fluid. By evaluating the gas, short-chain fatty acids and intestinal microbiota in vitro fermentation, DOO has an excellent regulatory effect on intestinal microbiota, especially promoting the proliferation of Bacteroidetes and Actinobacteria. Therefore, DOO can be used as a potential prebiotic in functional foods.