Thursday, February 20, 2014

Properties of Guar Gum

The most important property of guar gum is its ability to hydrate rapidly in cold water to attain uniform and very high viscosity at relatively low concentrations. Apart from being the most cost-effective stabilizer and emulsifier it provides texture improvement and water binding, enhances mouth feel and controls crystal formation. The main properties of guar gum are:

.It is soluble in hot & cold water but insoluble in most organic solvents. 
.It has strong hydrogen bonding properties. 
.It has excellent thickening, emulsion, stabilizing and film forming properties. 
.It has excellent ability to control rheology by water phase management. 
.The viscosity of guar gum is influenced by temperature, pH, presence of salts and 
other solids. 

Chemically, guar gum is a straight chain galactomannan, which is 75-85% of the endosperm, has a chain of (1→4)-linked-β-D-mannopyranosyl units with single α-D- galactopyranosyl units connected by (1→6) linkages to, on the average, every second main chain unit (Fig. 4). The ratio of D-mannopyranosyl to D-galactopyranosyl units is about 1.8:1. The average molecular weight of guaran is in the range of 1-2 ×106 dalton. The cis-position is important since adjacent hydroxyl groups reinforce each other in hydrogen bonding reactions. 

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