Guar Gum
A brief about Guar-Gum:
What is Guar-Gum?
Guar gum, also called guaran, is a galactomannan polysaccharide extracted from guar beans that has thickening and stabilizing properties useful in food, feed, and industrial applications. The guar seeds are mechanically dehusked, hydrated, milled and screened according to application.It is produced as a free-flowing, off-white powder.
Chemical composition?
Chemically, guar gum is an exo-polysaccharide composed of the sugars galactose and mannose. The backbone is a linear chain of β 1,4-linked mannose residues to which galactose residues are 1,6-linked at every second mannose, forming short side-branches. Guar gum has the ability to withstand temperatures of 80 °C (176 °F) for five minutes.
Solubility and Viscosity?
Guar gum is more soluble than locust bean gum due to its extra galactose branch points. Unlike locust bean gum, it is not self-gelling.Either borax or calcium can cross-link guar gum, causing it to gel. In water, it is nonionic and hydrocolloidal. It is not affected by ionic strength or pH, but will degrade at extreme pH and temperature (e.g. pH 3 at 50 °C). It remains stable in solution over pH range 5-7.
Paper Industry
Over ten million kilograms of gums (Guar, Locust Bean, and Tamarind seed gums) are used annually by the paper industry as wet end additives. The gum is added to the pulp suspension at the suction side of the fan pump just before the sheet is formed on either a Fourdriner or cylinder machine. Along with the lignin removed in the pulping process, much of the natural hemicelluloses (mannans and xylans) are removed. Guar replaced and supplements these hemicelluloses in paper bonding with many advantages, which include improved sheet formation with a more random distribution of pulp fibers (fewer fiber bundles), increased mullen or burst strength, increased fold strength, increased tensile strength, increased pick, increased flat crush of corrugating medium, increased machine speed, increased retention of fines, improved finish, decreased porosity.
Pharmaceutical and Cosmetics
Guar has been used as an appetite depressant. Its thickening ability is utilized in various lotions and creams. Coarse Guar gum is often used as a binding and disintegrating ingredient in compressed tablets.
Textile Industry
Guar gum derivatives are used as print-paste thickeners. These derivatives are also used in roller and screen printing, as well as finishing agents. They are more economical that Locust Bean gum derivatives.
Mining Industry
This same hydrogen-bonding action is utilized with the hydrated mineral surfaces of the clay, talc, or shale. Guar acts in froth flotation and potash as an auxiliary reagent, depressing the gangue material.
Derivatives
Recently hydroxyalkyguar has been used in oil well fracturing and aqueous slurry explosives since it is not affected by saturated calcium salt solutions.