Isolation and Study of the Physicochemical Properties of Galactomannans from Plant Materials

Abstract

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 the seeds of 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 55 600–26 200 Da. Studies with 1H and 13C NMR 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 h led to the formation of poly-mannans with a minor content of galactose units. The data can serve to improve isolation and preparation of galactomannan based materials for biomedical purposes.