Hydrodynamic and rheological properties of Irvingia gabonensis gum

The polysaccharide displayed typical polyelectrolyte behaviour in solution. The intrinsic viscosity at infinite ionic strength, a measure of the hydrodynamic volume of the uncharged polysaccharide molecule, was obtained as 4.9 dl/g. The macromolecules have a semi flexible backbone with a Smidsrod stiffness parameter of 0.085. The polysaccharide exhibited non-Newtonian behaviour at all the concentrations (0.2% to 3.0% (w/v)) investigated. Cox-Merz plots showed that η(γ˙) and η*(ω) were closely superimposable except at low shear rates and higher concentrations, where η* > η. The high Mw (1.56 × 106 g/mol) and its random coil conformation show I. gabonensis polysaccharide has potential for application as a thickener.