Intra-species variation of the properties of gum exudates from Acacia Senegal var. Senegal and Acacia seyal var. fistula from Tanzania

Abstract

Gum exudates from Acacia senegal var. senegal and Acacia seyal var. fistula from Tanzania have been analyzed and their inter- and intra-species variation of their properties evaluated. The results show that significant inter-species variation of the properties of the gum exudates from the two species exist, whereas only some parameters show significant intra-species variation. The specific optical rotations of the gum exudates have been found to vary from –43.2^o to –52^o for Acacia senegal var. senegal and +36.0^o to +60.0^o for A. seyal var. fistula. Likewise, the acid equivalent weights (AEWs) have been found to vary from 1093 to 1920 for A. senegal var. senegal and 1063 to 1749 for A. seyal var. fistula. Significant intra-species variation for the tannin content has also been observed for the species studied, whereas the nitrogen content has been observed to vary significantly only in A. seyal var. fistula. The results in this study show that the variation of the properties among batches of commercial Acacia gum may be due to admixture of gums from different Acacia species as well as intra-species variation.

KEY WORDS: Acacia senegal var. senegal, Acacia seyal var. fistula, Gum exudates, Intra-species variation, Inter-species variation

Bull. Chem. Soc. Ethiop. 2003, 17(1), 67-74.