Gum Arabic / Gum Acacia
The dried exudate (gum) from Acacia Senegal and related species (Acacia Seyal)
Gum Arabic
Origin
Collection (origin) and Processing (Europe)
Structure
– chemical composition
Properties
– functional characteristics and influences
Applications
Important Quality Parameters
Comparison of the different grades
Our qualities
Gum Arabic – Origin
South of Sahel zone, mainly Sudan, Chad and Nigeria
Gum Arabic – Collection
Tapping
Cleaning
Sieving
Gum Arabic – Processing
Dry
– powder
– granular
Wet
– spraydrying
– rollerdrying
Gum Arabic – Structure
Complex polysaccharide
– neutral or weakly acid
– containing nitrogenous material (amino acids)
– chemical composition vary slightly
– contained sugar monomers in a ratio of 3:3:1:1 are
• galactose, arabinose, rhamnose and glucoronic acid
– highly branched molecule with great variation in molecular mass
Gum Arabic – Properties
readily dissolves in cold water
odourless
tasteless
viscosity is a function of concentration
Solutions of Gum Arabic below 40 %
– react like Newtonian liquid
• viscosity is shear rate independent
Solutions of Gum Arabic at higher concentrations
– show pseudoplastic characteristics
• shear thinnig
reversible decrease of viscosity with increasing shear forces
weakly acid character in water (pH 4.5)
pH of the solution affects the viscosity
viscosity decreases in the presence of electrolytes (salts)
comparison with other thickening agents shows lower viscosity of Gum Arabic solutions even at higher concentrations
emulsifier for essential oils and flavours
– proteins adsorb on the surface of the oil droplets
– formed emulsions remain stable for a long period of time
Disadvantage:
prolonged heating ( > 70 °C) of Gum Arabic solutions causes precipitation of the proteinous components !!!
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