Extraction, characterization and concentration regimes of the natural gum from Triumfetta cordifolia stem bark

Abstract

Gum extracted from the Triumfetta. cordifolia plant is traditionally used for its impressive and versatile properties, but many of its intrinsic characteristics still remain poorly documented. This article presents the extraction, purification and physicochemical characterization of the gum present in the stem bark of the plant on the one hand, and the delineation of its concentration regimes in solution on the other. To this end, fresh stem bark was collected and cold extracted in distilled water, followed by ethanol precipitation. The gum was then characterized by elemental analysis, ICP-AES, FT-IR, ATG and GC-FID. Finally, the intrinsic viscosity was determined and concentration regimes delineated using both capillary viscometry and rheometry. Results revealed a monosaccharide composition rich in uronic acids, making T. cordifolia gum a polyelectrolyte, with a high mineral charge, and physicochemical properties similar to those of other polyelectrolyte gums. T. cordifolia gum solutions showed a relatively high intrinsic viscosity (24.3 ± 2.3 dL g−1) and exhibited three distinct concentration regimes (namely dilute, semi-dilute and concentrated) separated by two critical concentrations (C* = 0.3 g L−1 and C** = 1.4 g L−1). These properties open up new prospects for the use of T. cordifolia gum as a texturizing and structuring agent for a variety of mixtures and complex preparations such as emulsions.