Characteristics and quality of gum arabic from naturally grown Acacia senegal (Linne) Willd. trees in the Central Rift Valley of Ethiopia

Drylands of Ethiopia, including those in the Rift Valley, host good potential for commercial production of natural gums such as gum arabic. However, little researches have assessed the qualities of these gums for their commercial and industrial promotions. The objectives of this study were to assess the (i) quality of guru arabic collected from naturally grown Acacia senegal trees in the Central Rift Valley of Ethiopia and (ii) evaluate these quality characteristics against reported quality attributes of the same kind of gum from known destinations such its the Sudan and with international specifications. Gum samples were collected from randomly identified 10 trees of A. senegal in the study area and composited into one big sample by putting all in one plastic bag. The characteristics analyzed included: color. odor, moisture content, ash content, viscosity, pH, specific rotation, N and tannin contents, and concentration of several metals using standard laboratory procedures. The results yielded moisture content of 15%, ash content of 3.56%, intrinsic viscosity of 1.19 ml g(-1), pH on 25% solution of 4.04, specific rotation of -32.5, nitrogen content of 0.35%, protein content of 2.31%, and with no tannin content. Mineral contents of the gum arabic (g/100 g) are Ca 0.7, Mg 0.2, Na 0.01, K 0.95, Fe 0.001, P 0.6 and non-detectable traces of Pb, Co, Cu, Zli, Ni, Cd, Cr and Mn. These values agree well with values of same quality characteristics of gum arabic reported from Sudan and other exporting countries, and also conform well to international standards in all aspects. Indeed, it is possible to utilize the gum arabic resource of the Central Rift Valley of Ethiopia for commercial and/or industrial purposes. (C) 2008 Elsevier Ltd. All rights reserved.