The Gummiferae is a sub-family of the plant family Leguminosae of the genus Acacia. This sub-family comprises of the species which are classified into two series Gummiferae glob ferae and Gummiferae spicatae in Pakistan, eight species of this sub-family are reported to be grown. The species of this sub-family are important sources of valuable chemicals and gums, which have great commercial importance.
Gum exudates obtained from the species of the genus Acacia which are biopolymers in nature are generally called ‚€œ Gum Acacia‚€Ě or as Gum Arabic‚€Ě,. The present major consumers of these biopolymers are food, cosmetic, adhesive, paint, ink, lithography, textile, ceramic glazing and petroleum drilling industries. It is also extensively employed in confectionery, bakery, dairy products and beverages and flavour fixative and flavour emulsifier.
During these studies, gum of six Acacia species were investigated. The gums of A . Arabica, A. Catehu, A. farnesiana , A. Jacquenontii, A. modesta and Senegal were collected for Lahore, Faisalabad, Sheikhupura, Rawalpindi, Peshawar, Karachi, Hyderabad and Qasur. The gum of these of species were analyzed for moisture, ash, nitrogen, crude protein, free titratable acidity, reducing power, mothoxyl content and optical rotation. The ash was further analysed for Zinc, Manganese, Iron, Copper, Cadmium, Sulphate, Magnesium and calcium by using a Hitachi 170-10 atomic absorption spectrophotometer.
Gum of A. Arabica, , A. Ccatehu, A. farmesiana, Ajacquemontii, A. modesta and A. Senegal were tapped, collected and purified. The purified gums were individually hydrolysed with sulphuric and the different classes of compounds were separated.
The degraded gum obtained after autohydrolysis graded hydrolysis and complete hydrolysis of all the six species was fully methylated and hydrolysed. The products separated by paper chromatography and identified through their derivatives are:
2,3,4,6-tetra-O-methyl-D-glactose 2,4,6-tri-O-methyl-D-galactose 2,4,-di-O-methyl ‚€“D-galactose Methylated aldobiuronic acid together with small amount of 2,6-di-O methyl-D-galactose 2-O-methyl-D-galactose and very small amount of 2,3,4-tri-O-methyl-D-galactose and 2,3,-di-O-methyl-L-arabinose The methylated aldobiuronic acid was shown to be.: 2,3,4-tri-O-methyl-6-D-Galactopyranose 2,3,4-tri-O-methyl-ő≤-D-glucopyanside
Reduction of the derived methyl ester, methyl glycoside with sodium borohydride followed by hydrolysis yield.
2,3,4-tri-O-methyl-D-glucose 2,3,-4-tri-O-methyl-D-galactose 2,4-di-O-methyl-D-galactose
It was found that the gums contain a highly branched stable work 1‚†’3 and 1‚†’6 linkages.
The undegraded gum from all the six species were fully methylated and on hydrolysis yielded 7-methylated sugars which confirmed by GLC.
All the gums of six species, studied in the present work contained highly branched backbones of galactose residues in which the main chain was linked 1‚†’3 and side chains were attached by 6‚†’linkages.
All the gums contained the same aldobiuronic acid units in the side chains of the molecules.