Vinal gum, a galactomannan from Prosopis ruscifolia seeds: physicochemical characterization

Abstract

Physico-chemical and rheological characterization of the gum extracted from the endosperm of vinal(Prosopis ruscifolia) seeds was performed. The CG-MS analysis revealed that vinal gum is a galactomannanwith a mannose/galactose ratio of 1.6, with traces of arabinose and glucose residues. Thestructure was further confirmed by 13C NMR which showed several similarities between vinal gum andguar gum spectra. The viscosity molecular weight was 1.43 ± 0.04$106 Da (obtained from Huggins plot)and the average number molecular weight was 0.7$105 Da. Shear continuous rheology studies showed ashear thinning behavior at concentrations higher than 0.04% (w/v) of vinal gum and an apparent viscosityslightly lower than that of guar gum at the same concentration. Mechanical spectra revealed that vinalgum has a typical macromolecular solution behavior with the moduli crossing point that characterizedsemi-diluted (0.16e0.3% w/v) gum solutions. The present work provides structural, physicochemical andrheological information of a new galactomannan from an abundant and available non-traditional source,being a starting point for food, pharmaceutical or other industrial potential applications of vinal gum.