Characterization of gums from local acacia species for the food and pharmaceutical uses

Abstract

Gums are widely used to support the pharmaceutical, brewery, food, cosmetics and adhesive industries. Their uses are mainly based on their physicochemical properties and their mucilage. These properties make them act as emulsifiers, suspenders, thickeners, stabilizers, binders, and lubricants. In spite of the tremendous quantities of gums used in industries in Ghana, the chemistry of the locally available gums are not known. The main commercial gums used in industry are from the Acacia senegal, an exotic species. Chemical properties of gums from selected Acacia species - A. Acacia polyacantha, A. sieberiana, and A. dudgeoni were studied. The local gums had acceptable levels of moisture content (which is not more than 15%), less than 1.0% insoluble matter, less than 5% total ash value, and acid insoluble ash. They dissolved in water and sodium hydroxide, but not in most organic solvent. They showed levorotary optical rotation in water, and maintained a relative stable pH with time. The gums did not contain any starch or tannins. It was confirmed from the sugar reactions that their sugar composition were Rhamnose, Arabinose, Galactose, and Glucuronic acid. The viscosities increased with concentration and decreased with time, rose with pH till a pH of about 5 and then fell as the pH increased from 6 to 14. The local gums can be used as suitable substitutes for the commercially imported ones. JOURNAL OF THE GHANA SCIENCE ASSOCIATION Volume 2 No. 1 (2000) pp. 71-79