Solution properties of the xyloglucan polymer from Afzelia africana.

In this paper we describe the solution properties of a new xyloglucan polysaccharide extracted from the African legume Afzelia africana Se. Pers. The polysaccharide is of high weight-average molecular weight (Mw), but application of the "pressure cell" method enabled a range of Mw fractions to be prepared. Results from the light scattering/intrinsic viscosity measurements on these fractions suggest that like other xyloglucans from tamarind and detarium it occurs in solution as a polymeric coil, with a small amount of excluded volume. Measurement of dilute and semidilute solution rheology suggests that, like these polymers, and the related galactomannan series, it forms viscous solutions at higher concentrations via entanglements.