Composition Analysis of Urechis unicinctus Body Wall Polysaccharide and Its Enrichment and Adsorption Based on MCM-41

In this paper, the polysaccharides from the body wall of Urechis unicinctus was extracted by pepsin, and the composition of the extracted polysaccharides were analyzed. The adsorption of polysaccharides on MCM-41 was studied by the adsorption kinetics, adsorption thermodynamics. The results of composition analysis showed that the content of the total sugar was (78.82%±1.4%), the content of total protein was (10.5%±1.07%), and the content of sulfate radical was (0.52%±0.06%). The monosaccharide mainly contained glucose, mannose, galactose and xylose. The results of infrared spectrum analysis showed that the polysaccharide contained characteristic groups such as O-H, C-O-C, C=O, S=O, which indicated that there were uronic acid in the polysaccharide, and there was substitution of sulfate group. The mesoporous material MCM-41, with the average pore diameter 3.85 nm and the pore volume 1.25 cm³/g, was used to enrich the polysaccharide. It was found that the adsorption kinetics of the polysaccharide on MCM-41 conformed to the pseudo second order adsorption kinetics (PSO) model, in which the external diffusion and intra particle diffusion controlled the adsorption process. The adsorption thermodynamics of the polysaccharide on MCM-41 was consistent with both the Langmuir model and Freundlich model, indicating that the adsorption process of MCM-41 was mainly monolayer and accompanied by the adsorption of multi-layer. It was found that 10% SDS had stronger elution ability, which was caused by the destruction of hydrogen bond interaction between polysaccharide and water. The study on the adsorption mechanism of polysaccharides from the Urechis unicinctus on mesoporous material MCM-41 is expected to provide theoretical guidance for the enrichment and separation of polysaccharides, oligosaccharides, glycoproteins and glycopeptides in food industry.