Analysis of the microscopic interactions between processed Polygonatum cyrtonema polysaccharides and water

The dissolution and microscopic interactions of processed Polygonatum cyrtonema polysaccharides in water are extremely important because they strongly influence the process to extract these polysaccharides from water. In this paper, molecular dynamics simulation methods were used to analyse the influence of extraction temperature, concentration and molecular weight on the radial distribution function (RDF), mean square displacement (MSD), diffusion coefficient (D), radius of gyration (R_g), and microstructure of processed Polygonatum cyrtonema polysaccharides in water as well as the intrinsic viscosity (η), hydrogen bond characteristics and microscopic interactions in the solutions. The research results showed that the extraction temperature, concentration and molecular weight of the polysaccharides had important effects on the RDF, MSD, D, R_g, η, hydrogen bond characteristics and the microstructure of the polysaccharide molecules, but there were some major differences. The order of the influence of the factors affecting the dissolution of polysaccharides in water was temperature > concentration > molecular weight. Extraction temperature, material fluid ratio and molecular weight had greater influence on the fluidity and dissolution state of the polysaccharides in water. As the solute concentration and molecular weight increased, hydrogen bonds between polysaccharides and water inhibited their dissolution and diffusion. Properly increasing the temperature, reducing the concentration and selecting low molecular weight polysaccharides enhanced the dissolution and diffusion of the polysaccharides in the solution system. Molecular weight was the main factor affecting the η of the polysaccharide solutions. These results can provide theoretical guidance for the extraction or tea brewing process of Polygonatum cyrtonema polysaccharides in future work.