I= ISOLATION AND STRUCTURAL STUDIES OF ACACIA GUM EXUDATES FROM THE SPECIES OF GUMMIFERAE
Pakistan Research Repository Home
 

Title of Thesis
ISOLATION AND STRUCTURAL STUDIES OF ACACIA GUM EXUDATES FROM THE SPECIES OF GUMMIFERAE

Author(s)
Seemal Jilani
Institute/University/Department Details
Institute of Chemistry/ University of Punjab
Session
1997
Subject
Chemistry
Number of Pages
241
Keywords (Extracted from title, table of contents and abstract of thesis)
acacia gum exudates, gummiferae, leguminosae, genus acacia, gummiferae glob ferae, gummiferae spicatae, gum arabic, gum acacia

Abstract
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.

Download Full Thesis
1277.48 KB
S. No. Chapter Title of the Chapters Page Size (KB)
1 0 Contents
104.43 KB
2 1 Introduction 1
104.71 KB
  1.1 Gummiferae ‚€“A Series Of Sub Family Mimosoideae Of The Family Leguminosae 1
  1.2 Genus Acacia Of The Family Leguminosae 2
  1.3 Acacia Of Pakistan 3
  1.4 Gum 6
  1.5 Aims And Objects 15
3 2 Chemistry And Uses Of Acacia Gums 16
193.78 KB
  2.1 Composition Of Structure Of Acacia Gums 16
  2.2 Analytical And Comparative Studies Of The Gums Of Acacia 26
  2.3 Composition Of The Proteinaceous Components Of Gum Acacia 32
  2.4 Industrial Applications Of Acacia Gums 38
  2.5 Other Gums 42
4 3 Materials And Methods 45
153.95 KB
  3.1 Chemical And Solvents 45
  3.2 Plant Materials 45
  3.3 Preparation Of Crude Gum 47
  3.4 Purification Of Crude Gum 47
  3.5 Preliminary Examination Of Gums 47
  3.6 Paper Chromatography 54
  3.7 Hydrolysis 54
  3.8 Gas Chromatography Of The Methylated Sugars 67
  3.9 Statistical Techniques 67
5 4 Results And Discussion 68
682.58 KB
  4.1 Physico Chemical Characteristics Of Acacia Gum 68
  4.2 Structural Elucidation 93
  4.3 Chromatography Confirmation Of Gum Structure 178
  4.4 References 191