Isolation and Characterization of the Hemicelluloses Polysaccharides of Scots Pine (Pinus Sylvestris) Wood

Many natural polysaccharides have biological activity, which allows them to be used for obtaining medicines. Development of new methods for the isolation of polysaccharides from plant materials, as well as investigation of their properties and structure constitute a topical task. In this study, polysaccharide galactoglucomannan (GGM) was isolated from pine wood for the first time by the peroxide delignification in the acetic acid-water medium in the presence of (NH4)6Mo7O24 catalyst. The GGM yield was 10.1 wt % of the wood sample and 58.1 wt % of the hemicelluloses content in the wood. Using 13C NMR method it was found that the degree of GGM acetylation was 0.23 with substitution at C2 and C3 atoms of the pyranose ring. According to the X-ray phase analysis data, GGM has an amorphous supramolecular structure. Polysaccharide glucoxylan (GX) was isolated by alkaline extraction from the cellulosic product of the peroxide delignification in a yield of 4.3 wt % of the wood sample and of 24.5 wt % of the hemicelluloses content in the wood. Glucoxylan does not contain acetyl groups (IR and NMR spectroscopy data); it has a crystalline supramolecular structure and is poorly soluble in water. The composition and structure of the isolated polysaccharides were studied by chemical analysis methods, as well as by IR spectroscopy, 1H, 13C, 2D HSQC NMR spectroscopy, gas chromatography, and X-ray phase analysis.