Vinal gum, a galactomannan from Prosopis ruscifolia seeds: Physicochemical characterization. (October 2015) - Busch, Verónica M.
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 galactomannan with a mannose/galactose ratio of 1.6, with traces of arabinose and glucose residues. The structure was further confirmed by 13 C NMR which showed several similarities between vinal gum and guar gum spectra. The viscosity molecular weight was 1.43 ± 0.04·10 6 Da (obtained from Huggins plot) and the average number molecular weight was 0.7·10 5 Da. Shear continuous rheology studies showed a shear thinning behavior at concentrations higher than 0.04% (w/v) of vinal gum and an apparent viscosity slightly lower than that of guar gum at the same concentration. Mechanical spectra revealed that vinal gum has a typical macromolecular solution behavior with the moduli crossing point that characterized semi-diluted (0.16–0.3% w/v) gum solutions. The present work provides structural, physicochemical and rheological 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. Graphical abstract: Highlights: For the first time, gum from vinal (an Argentinian tree) seeds was characterized. Vinal gum showed a galactomannan structure with a mannose/galactose ratio of 1.6. Vinal gum have a high viscosity molecular weight (1.43 ± 0.04·10 6 Da). The mechanical spectra of vinal gum revealed its macromolecular solution behavior. Vinal gum showed similar structural and rheological properties than guar gum.