Analytical Studies on the Gum Exudates from Anogeissus leiocarpus

Abstract

Anogeissus leiocarpus gum samples were collected randomly as natural exudates from 3 different locations in Sudan, namely Abojebiha (season 1994-1995), Elfula and Rosaries (season 1996-1997). Physicochemical properties of gum samples (moisture, ash, nitrogen, protein, specific rotation, relative viscosity, refractive index, equivalent weight, pH, uranic acid, reducing sugar and tannin content). Results showed significant differences within each location in most parameters studied except in the refractive index values which was found to be constant in all samples (1.334). The effect of location on the properties of gum samples was also studied and the analysis of variance showed insignificant differences (p<0.05) in all properties studied except in ash content and this may be due to the differences in the type of clay soil which found in the three different locations. The general characteristics of Anogeissus leiocarpus gum might be described as the mean value of all properties studied of all gum samples of the three different location as follows: 9.2% moisture, 3.4% ash, 0.72% nitrogen, 4.74% protein%, -35.5° specific rotation, 1.68 relative viscosity, 4.2 pH, 1.334 refractive index, 14.3% uranic acid, 0.44% reducing sugar 1336.0% equivalent weight and 0.68% tannin content. UV absorption spectra of gum samples were determined and the maximum absorption points were found the same ranging between wave length 243 and 285. Cationic composition of gum samples was also determined and the results showed that magnesium (Mg) has the highest value in all samples followed by iron (Fe), sodium (Na), potassium (K), calcium (Ca), zinc (Zn) and trace amount of manganese (Mn), copper (Cu), nickel (Ni), cadmium (Cd) and lead (Pb). Functionality (water holding capacity and emulsifying stability of Anogeissus leiocarpus gum were studied. The water holding capacity value was found to be 65.5% and emulsifying stability value was found to be 1.008 insignificant differences were observed between Anogeissus leiocarpus gum and Acacia senegal gum for the 2 parameters studied.