THE POLYSACCHARIDE GUM FROM ACACIA-TORTUOSA

The polysaccharide gum obtained from Venezuelan Acacia tortuosa contai ns galactose, arabinose, xylose as ti aces, glucuronic acid and its 4- O-methyl analogue. C-13 NMR spectroscopy, in combination with chemical methods, was applied in this study. The preparation of degraded produ cts, via hydrolytic-and Smith-degradations, indicated interesting stru ctural features of the polysaccharide. The core of the structure is es sentially a branched beta-(1 --> 3) galactan. Arabinose, glucuronic ac id and its 4-O-methyl analogue could not be totally removed from the c ore. Arabinose (as furanose and pyranose residues) exist as terminal a nd 3-O-linked, while xylose, glucuronic acid and its 4-O-methyl deriva tive are probably terminal residues. The high content of proteinaceous material in A. tortuosa gum must be investigated in order to determin e whether there are many polysaccharide-protein covalent linkages. (C) 1997 Elsevier Science Ltd.