Separation, Purification and Structural Analysis of Non-Starch Polysaccharides from Chickpea Seeds

After removal of starch by enzymatic treatment and deproteinization by the Sevag method, the crude polysaccharides extracted from chickpea seeds were fractionated by DEAE Cellublose-52 and Sephadex G-75 column chromatography into neutral and acidic polysaccharides. The structure, monosaccharide composition and morphology of the purified polysaccharides were obtained by UV absorption spectroscopy, gas chromatography (GC), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The results showed that both polysaccharides exhibited no absorption peak at 260 or 280 nm, interpreting the absence of nucleic acids, proteins and peptides. Monosaccharide composition analysis showed that the neutral polysaccharide consisted of rhamnose, fucose, arabinose, xylose, mannose, galactose and glucose at a molar ratio of 2.48:1:3.92:0.87:32.82:18.79:28.06, while the acidic polysaccharide was composed of rhamnose, fucose, arabinose, xylose, mannose, galactose and glucose at a molar ratio of 2.22:1:3.92:2.10:5.92:15.99:8.57 (both with fucose as the standard). Their FTIR spectra indicated characteristic absorption peaks of polysaccharides. SEM indicated that the structure of the neutral polysaccharide was linear whereas the acidic polysaccharide was lamellar and curly. © 2019, China Food Publishing Company. All right reserved.