Structural and physicochemical characterization of a novel water-soluble polysaccharide isolated from Dorema ammoniacum

In this paper, structure, chemical composition and physicochemical properties of the novel polysaccharide Amuniacum gum (AMG) were assessed. The AMG had 12.21% moisture, 3.76% ash, 0.31% protein, 73.06% carbohydrate, 1.24% fat and 10% uronic acids. The elemental analysis indicated the absence of sulfur. The HPLC demonstrated the presence of galactose and arabinose as dominant sugars. The X-ray diffraction (XRD) pattern of the native gum indicated a semicrystalline structure. Furthermore, gel permeation chromatography (GPC) showed that the average molecular weight included 35 kDa. The Fourier transform infrared (FTIR) spectroscopy showed the presence of hydroxyl, carboxyl and methyl groups. Moreover, 1H and 13C NMR analysis demonstrated that AMG included a backbone of β-D-Galp residues and was mainly branched through 4-O-methyl-α-D-glucopyranosyl units. Results of thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) indicated that the thermal decomposition of AMG occurred at nearly 278 °C. In conclusion, these results highlight that the novel gum can be used in food and pharmaceutical industries.