Note on Physical and Chemical Properties of Guar Gum in Some Newly Developed Guar(Cyamopsis tetragonolobaL. Taub) Genotypes

Abstract

This study aimed at determination of the physical and chemical characteristics of guar gum in twenty newly developed guar (Cyamopsis tetragonoloba L. Taub) genotypes. For assessment of the physical properties, data were recorded on refractive index, specific rotation, optical density and relative viscosity. The chemical analysis included gum content, pH and sugar profile. The gum content ranged from 23 – 30.33 %, with a 2.08 ratio of mannose to galactose. The relative viscosity ranged from 2055.17 to 3167.9 centipoises, the highest value was detected in Gm22. Moreover, the values of specific rotation, pH, refractive index and optical density of guar gum ranged from43.33°to 81.67°, 6.15 to 7.13, 1.336 to 1.338 and 0.03 – 0.44%, respectively.  It was concluded that a wide range of variability exists among the evaluated genotypes in most of the studied characteristics. Such variation can be exploited in breeding programs for improvement of gum quality.