Abstract:
Using dandelion roots as a raw material, dandelion root polysaccharides (DRP) were extracted using a complex enzymatic hydrolysis method, and the extraction process was optimized. The four polysaccharide components, denoted DRP-a, DRP-b, DRP-c, and DRP-d were separated using diethylaminoethyl column chromatography, and the structural characteristics and
in vitro antioxidant activities of these five polysaccharides were investigated.
In vitro digestion experiments were conducted on the components having the best antioxidant activity after separation to explore the variation patterns of total carbohydrates and reducing sugars during
in vitro digestion. The results showed that using an enzymatic hydrolysis time of 1.6 h, enzyme addition ratio of 5:2, enzyme dosage of 3.5%, and pH of 4.30 was optimal, yielding 23.46% polysaccharides. All five compounds produced the typical absorption peaks of polysaccharides and were mainly composed of seven monosaccharides: rhamnose, glucuronic acid, galacturonic acid, glucose, mannose, arabinose, and galactose. The molecular weight of DRP-a was 8763 Da, those of DRP-b and DRP-c were 6396~51090 and 8067~52713 Da respectively, and that of DRP-d was 12389~229349 Da. Among the five polysaccharides, only DRP had a triple-helical structure, as well as an irregular fragmented surface morphology. DRP-a had a spherical packing structure, whereas DRP-b, DRP-c, and DRP-d had smooth and irregular fragmented structures.
In vitro antioxidant experiments demonstrated that all five polysaccharides had good antioxidant capacities. The total sugar and reducing sugar contents of DRP-d after
in vitro oral, stomach, and small intestine simulated digestion did not change significantly, indicating that DRP-d is stable during digestion, and, thus, reaches the intestinal tract to exert its effects. Overall, the findings clarify the digestive characteristics of dandelion polysaccharides. Further, the results indicate that dandelion polysaccharides could be developed and utilized as prebiotics.