A further amendment to the classical core structure of gum arabic (Acacia senegal)

Using the more recently available techniques such as methylation-GC-MS, 1D (H-1, C-13) and 2D (COSY, TOCSY, HMQC and HMBC) NMR spectral analysis, we have revisited the classical structure of gum arabic (Acacia senegal). Methylation and GC-MS analysis confirmed that gum arabic (A. senegal) is a highly branched polysaccharide with the backbone composed of 1,3-linked galactopyransyl (Galp) residues substituted at O-2, O-6 or O-4 positions. The terminal sugar residues are 59.5% of the total sugars. The residues of -> 2,3,6-beta-D-Galp1 ->, -> 3,4-Galp1 ->, -> 3,4,6-Galp1 -> and substitutions at O-2 and O-4 position were not identified in previous studies. (C) 2012 Published by Elsevier Ltd.