THE ANIONIC GLYCAN FROM THE CACTUS CEREUS-PERUVIANUS - STRUCTURAL FEATURES AND POTENTIAL USES

The columnar cactus Cereus peruvianus provides various compounds of interest that account for most of its 10% dry wt content. Included are acidic gum and cellulose as the highly polymerized carbohydrate components, and a complex waxy lipid fraction. The major gum fraction (1.5 g% of the fresh phytobiomass on single aqueous extraction) is an uronylated rhamnoarabinogalactan whose intrinsic viscosity may exceed 1000 mL/g. Its rheological behavior is, in part, influenced by the native o-acetyl and cation components, mainly Ca2+. A pigment-free powdered gum was obtained by precipitating and washing the fresh mucilage with 2-3 vol of ethanol. The almost protein-free polysaccharide forms viscous solution upon redissolution. The possible uses to be investigated for the pretreated cactus gum will be as an adjuvant in the flocculation of water impurities and in formulation of cosmetics.