ACACIA GUM > composition AND STRUCTURE print

Acacia gum is a natural polysaccharide belonging to the complex arabinogalactan family.
(Synonyms: Gum acacia; Gum arabic; acacia gum; Indian gum )
This native substance has an average molecular weight between 300 and 800 kDa. It is composed for 95% of the dry weight of polysaccharides and for 1 to 2% depending on the specie of proteins.
Acacia Gum is composed of three different fractions that vary for their molecular weight and protein content :

  • 1% of the total mass is a glycoprotein,
  • 1 to 10% is the arabinogalactan-protein, and
  • 90 to 99% is arabinogalactan.
 

The « wattle blossom » model represents the ramified and compact structure of Acacia gum :
Arabinogalactans are ramified on a protein skeleton. The polysaccharidic fraction is composed of a linear chain of galactose ß 1,3 linked. This chain is ramified in position 1,6 with chains of galactose and arabinose. Rhamnose, glucuronic acid or methyl glucuronic acid units are found as chain terminations.

AVERAGE COMPOSITION OF ACACIA GUM

Sugar composition after hydrolysis

 

•  Galactose

35 - 45 %

  

•  Arabinose

25 - 45 %

 

•  Rhamnose

4 - 13 %

 

•  Glucuronic acids

6 - 15 %

 

Molecular weight average

350 000

  

pH solution at 25 %

4.4

  

Intrinsec viscosity

12 ml/g

 

Brookfield viscosity, solution at 25%, 60 rpm

70 cP

  

Protein Content

1 - 2 %

 

Total ashes
(Potassium, Calcium & Sodium Salts)

3 - 4 %

 

Arabinogalactan (AG)

89 - 98 %

 

Arabinogalactoprotein (AGP)

1 - 10 %

 

Glyco Proteins (GP)

Less than 1 %