The aim of the study is isolation of galactomannan from plant materials and investigation of their physical and chemical properties. Polysaccharides generally consisting of galactomannan were isolated and purified from galactomannans from these eds the plants Sophora japonica and Gleditsia triacanthos by cold and hot extraction methods. Galactose and mannose contents of the galactomannans isolated were quantitatively characterized and physical and chemical properties of the polysaccharides were studied. In addition, polysaccharides isolated were enzymatic hydrolyzed and changes in the monosaccharide composition in the hydrolysis process were studied. The characteristic viscosities of the initial and hydrolyzed galactomannans were 4.85–3.80 dl/g, respectively. Molecular weights of the galactomannans, after treatment with the enzyme, changed in a range of 55600–26200 Da. Studies with 1H NMR and 13CNMR spectroscopy methods showed decreases in galactoside content of the hydrolyzed galactomannans, indicating the primary course of hydrolysis occurs by the side chain of the macromolecule. Increase in duration of enzymatic hydrolysis more than 24 hours led to the formation of poly-mannans with a minor content of galactose units. The obtained data can serve to improve isolation and preparation of galactomannan based materials for biomedical purposes.
Cotton cellulose has been sulfated in the presence of organic solvents (methanol, ethanol, iso-propanol and via chlorosulfonic acid-pyridine complex, and a mixture of concentrated sulfuric acid and ethanol) and the effects were studied by polarized light microscopy, electron microscopy, IR spectroscopy, and X-ray diffraction. Sorption-desorption behavior of the sulfonated cellulose was also observed. These processes enhance interfibrillar swelling, weaken intermolecular hydrogen bonds, and loosen the packing density of microfibrils. As a result, the accessibility of esterification reagents was improved depending on the activation method. Microscopic studies showed that the surface of the initial cotton cellulose is wrinkled. The fibrillar structure of the primary fiber wall was not observed. In the case of cotton cellulose, sulfation changed its crimped fibers with different thicknesses, length and defects which were visible in a polarized light as bright luminescence. Fibers become short, thick, and straightened. Moreover, degree of anisotropy and crystallinity of the modified fibers decreased. Their size and degree of crimping are dependent on condition of modification. All pre-activation processes were successful. Thickness of fibers was increased up to 20% and the length was decreased to one-third or one-fourth. The sorption capability of cellulose was increased 2.1–3.4-fold in pre-activated samples, which is due to the increasing specific surface area (45.0–109.1 m2 g-1). Volume and radius of the pores increased up to 0.1164–0.410 m3 g-1 and 36.2–133.3 Å, respectively.
27 September 2021 in Chemistry of plant raw material
The article is devoted to the study of polysaccharides isolated from the basidiomycete raw material I. hispidus and studying their physical and chemical properties. Water-soluble polysaccharides were isolated from mushroom raw materials by the method of sequential water extraction and the yield was 9.44%. Polysaccharides were separated into neutral fractions by ion exchange chromatography and purified from proteins and peptides. During the separation process, it was determined that the polysaccharide sample consisted of homogeneous polysaccharides, while the carbohydrate content of the purified polysaccharide sample was 99.4%. The carbohydrate composition of polysaccharides was determined, it was found that the polysaccharide consists mainly of glucose residues and contains minor amounts of fructose and rhamnose residues. Molecular weight and molecular weight distribution were determined by size exclusion chromatography. The Mw of the polysaccharide sample obtained was 18.7 kDa, the polydispersity index was 1.3. The results of IR-, 1H- and 13C NMR spectroscopic studies have shown that the polysaccharide, according to its structural characteristics, belongs to the β-glucan type polysaccharide having β-(1,3) and β-(1,6)-glycosidic bounds.