Structural investigations of the araban from guava, Psidium guajava L

Abstract

The pulp of guava, Psidium guajava L., contains an araban which can be enriched by extraction with 70% ethanol. Hydrolysis of the fully methylated pure araban, obtained during fractionation of the methylated polysaccharide, yielded 2,3,5-tri-, 2,3-di-, and 2-O-methyl-L-arabinofuranose in the molar ratio of 1 : 1.04 : 0.93, together with a small amount of arabinose. A structure has been suggested from these results which was corroborated by results from periodate oxidation studies. Sequence of branching has been confirmed from Barry degradation studies. Information about molecular size has been obtained from light scattering measurements.