COMPOSITION AND RHEOLOGICAL PROPERTIES OF CASHEW TREE GUM, THE EXUDATE POLYSACCHARIDE FROM ANACARDIUM-OCCIDENTALE L

Anacardium occidentale gum from Brazilian plants has a higher galactos e content and lower arabinose and rhamnose content than those gums fro m India and Papua. The other constituents (glucose, mannose and glucur onic acid) are similarly distributed. GPC of cashew gum detected the p resence of 6% polysaccharide-protein complex, 42% polysaccharide of M( pk) 1.6 x 10(4). The whole gum is a low viscosity polysaccharide with an activation energy of flow for solution at 2 and 3% (similar to 16 k J mol(-1)), characteristic of systems with little intra and intermolec ular interactions. Experiments on the effects of NaCl, CaCl2 and AlCl3 on the reduced viscosity, as well as the effect of salt concentration on the specific viscosity, indicated that the affinity between A. occ identale gum and metal ions follows the order: Al-3 > Ca2+ > Na+.