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Guar gum is the ground endosperms of the guar plant, Cyamopsis tetragonolobus (L.) Taub., Leguminosae which is cultivated in Asia Minor and in portions of the Southwest United States. The water soluble fraction (85%) of guar flour is called guaran which consist of linear chains of (14)-fl-D-mannopyranosyl units with –D- galactopyranosay units attached by (1-6) linkages. The typical ratio of D-galactose to D-mannose is 1:2.
Guar gum will disperse and swell almost completely in cold or hot water to form a viscous sol. It is insoluble in organic solvents. Guar gum is a nonionic polymer compatible with most plant hydrocolloids and modified water soluble polymers. Some multivalent salts, such as borate ions, will cross-link with hydrated guar gum to form cohesive structural gels.
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Sodium carboxymethylcellulose (CMC) is a water-soluble derivation of the most abundant polymer in nature, cellulose. The main reason for using CMC/cellulose gum in a formulation is to increase its viscosity. This feature makes CMC/cellulose gum functional in the following ways:
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It acts as a thickener, binder, stabilizer, protective colloid, suspending agent, and rheology, or flow control, agent.
- It forms films that are resistant to oils, greases, and organic solvents
- It dissolves rapidly is cold or hot water.
- It is suitable for use in food systems.
- It is physiologically inert.
- It is an anionic polyelectrolyte.
Xanthan Gum is a natural biopolymer produced by the culture fermentation of Xanthomonas campestris on a polysaccharide backbone. The xanthan gum molecule is similar to cellulose with side chains linked to every other glucose unit consisting of a glucuronic acid unit between two mannose units. P compounds are attached to some single unit side chains by ketal linkages.
Xanthan gum is readily soluble in cold or hot water and form highly viscous, heat stable solutions with high tolerance in strong acidic and basic environments. Xanthan gum is insoluble in organic solvents with the exception of a few water miscible alcohols.
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