Gum Arabic is a natural plant polysaccharide, a dried exudate of acacia trees (family: Leguminosae). Gum Arabic is the oldest plant polysaccharide in use by man and its use begun around 5000 years ago. Gum Arabic is obtained from acacia trees around the world (around 900 species) but the largest production come from regions of Africa like Sudan, Nigeria, Senegal, and Mauritania [79]
In ancient times, in Egypt use of GA was reported as a mineral pigment adhesive in paint and for embalming mummies (Whistler and BeMiller, 1993). Some species of the Acacia genus are the source of GA. Due to its natural origin and safety record, it is recognized as the most crucial exudate gum. It finds application in food, pharmaceuticals, cosmetics, textile, paper, ink, adhesive, paint and printing. It is mainly produced in sub-Saharan Africa and small quantities in Arabian Peninsula and South Asia. GA is primarily consumed in developing and developed countries. The annual average export of crude and semi-processed gum was about 35,000 tons in 1992–94, which increased to 102,000 tons during 2014–16. During this period, processed gum exports increased from 17,000 tons to 53,000 tons. The value of GA export during 2014–16 was an average of $337 million per year, in which the contribution of crude gum and semi-processed gums were 44 & 56%, respectively (Jales, 2018).
Acacia senegal is a drought-resistant tree found naturally in arid, subtropical and semi-arid climatic zones (Omondi et al., 2010). It is a deciduous, small, spiny shrub and usually branched from the ground of 2–6 or even 12 m high (Fig. 1a) (Duke, 2012). Branches bifurcate repeatedly, and when fully grown, the tree forms a rounded, flat-topped crown. The trunk of the tree has a diameter of about 30 cm and is found covered with greyish-white bark (Gardens, 2016). The tree has alternate pinnately compound leaves, green-grey and 3.5–8 cm long (Fig. 1b). Two glands are present between the uppermost and lowermost pinnate. Leaflets are small, linear to elliptic-oblong, and their tip is either blunt or somewhat pointed. The flowers are found on cylindrical spikes and are yellowish-white in
