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Guar gum, also called guaran, is primarily the ground endosperm of the seeds from Cyamopsis tetragonolobus (L.) Taub. (Family- Leguminosa) mainly consisting of high molecular weight (50,000-8,000,000) polysaccharides composed of galactomannans; mannose:galactose ratio is about 2:1. The guar seeds are dehusked, milled and screened to obtain the ground endosperm i.e.guar gum[1] .It is typically produced as a free flowing, pale off-white colored, coarse to fine ground powder.Manufacturers define different grades and qualities of guar gum by the particle size, the viscosity that is generated with a given concentration, and the rate at which that viscosity develops.Coarse-mesh guar gums, will typically -- but not always -- develop viscosity more slowly. They may achieve a reasonably high viscosity, but will take longer to achieve. On the other hand, they will disperse better than fine-mesh, all conditions being equal.A finer mesh, like a 200 mesh, requires more effort to get it into solution[2].

Viscosity of 1% solution of Guar Gum ranges from 10 to 2,000 CP as a function of molecular weight and calcium ion content[3].

Guar gum is a galactomannan similar to locust bean gum consisting of a (1 4)-linked β-D-mannopyranose backbone with branchpoints from their 6-positions linked to α-D-galactose (i.e. 1 6-linked-α-D-galactopyranose). There are between 1.5 - 2 mannose residues for every galactose residue[4].

Possessing almost 8 times the water thickening potency as cornstarch, guar gum is economical because only a very small quantity is needed for producing sufficient viscosity. Thus it can be used in various multi-phase formulations; as an emulsifier because it helps to prevent oil droplets from coalescing, and/or as a stabilizer because it helps to prevent solid particles from settling.

Guar gum is more soluble than locust bean gum and is a better emulsifier as it has more galactose branch points. Unlike locust bean gum, it is not self-gelling.^[1] However, either borax or calcium can cross-link guar gum, causing it to gel.^[2][3][4]

In water it is nonionic and hydrocolloidal. It is not affected by ionic strength or pH but will degrade at pH extremes at temperature (e.g. pH 3 at 50°C).^[5] It remains stable in solution over pH range 5-7. Strong acids cause hydrolysis and loss of viscosity, and alkalies in strong concentration also tend to reduce viscosity. It is insoluble in most hydrocarbon solvents.^[6]

Guar gum shows high low-shear viscosity but is strongly shear-thinning. It is very thixotropic above concentration 1%, but below 0.3% the thixotropy is slight. It has much greater low-shear viscosity than that of locust bean gum, and also generally greater than that of other hydrocolloids. Guar Gum shows viscosity synergy withxanthan gum. Guar gum and micellar casein mixtures can be slightly thixotropic if a biphase system forms.^[7][8]

Guar gum retards ice crystal growth non-specifically by slowing mass transfer across the solid/liquid interface. It shows good stability during freeze-thaw cycles.^[9]

Contents 1 Industrial applications 2 Food applications 3 Nutritional and medicinal effects 4 External links 5 References

• Textile industry – sizing, finishing and printing
• Paper industry – improved sheet formation, folding and denser surface for printing
• Explosives industry – as waterproofing agent mixed with ammonium nitrate, nitroglycerin etc.
• Pharmaceutical industry – as binder or as disintegrator in tablets
• Cosmetics and toiletries industries – thickener in toothpastes, conditioner in shampoos (usually in a chemically modified version)
• Textiles
• Oil and gas drilling, well fracturing
• Mining
• Hydroseeding – formation of seed bearing "guar tack"^[10]

The largest market for guar gum (EU food additive code E412) is in the food industry, where guar gum is used as a thickener and binder of free water in sauces, salad dressings, ice creams, instant noodles, pet foods, processed meats, bread improvers and beverages to name some.

Bakery - increases dough yield, gives greater resiliency, and improves texture and shelf life; in pastry fillings, it prevents "weeping" (syneresis) of the water in the filling, keeping the pastry crust crisp.

Dairy - thickens milk, yogurt, kefir, and liquid cheese products; helps maintain homogeneity and texture of ice creams and sherbets

Meat - functions as lubricant and binder.

Dressing and sauces - improves the stability and appearance of salad dressings, barbecue sauces, relishes, ketchups and others

Misc. - Dry soups, sweet desserts, canned fish in sauce, also found in "Natures Treats - Thai Organic Coconut Cream" and frozen food items and animal feed.

Guar gum is generally recognized as safe (GRAS) with differing percentages set for its allowable concentration in various food applications.[5]

Guar Gum is a water soluble fiber that acts as a bulk forming laxative, and as such, it is claimed to be effective in promoting regular bowel movements and relieve constipation and chronic related functional bowel ailments; such as diverticulosis, Crohn's disease, colitis and irritable bowel syndrome, among others. The increased mass in the intestines stimulates the movement of waste and toxins from the system, which is particularly helpful for good colon health, because it speeds the removal of waste and bacteria from the bowel and colon. In addition, because it is soluble, it is also able to absorb toxic substances (bacteria) that cause infective diarrhea.

Several studies have found significant decreases in human serum cholesterol levels following guar gum ingestion. These decreases are thought to be a function of its high soluble fiber content.

Guar gum is of interest with regards to both weight loss and diabetic diets. It is a thermogenic substance.^[11] Moreover, its low digestibility lends its use in recipes as a filler, which can help to provide satiety, or slow the digestion of a meal, thus lowering the glycemic index of that meal. In the late 1980s, guar gum was used and heavily promoted in several weight loss products. The USFDA eventually recalled these due to reports of esophageal blockage from insufficient fluid intake. For this reason, guar gum is no longer approved for use in over-the-counter weight loss aids in the United States. Moreover, a meta-analysis that combined the results of 11 randomized controlled trials found that guar gum supplements were not effective in reducing body weight.^[12]

Two Japanese studies using rats showed that guar gum supports increased absorption of calcium occurring in the colon instead of in the small intestine. This means that lesser amounts of calcium may be consumed in order to obtain its recommended minimum daily intake (RDI). This has obvious implications for reduced calorie diets, since calcium rich dairy products tend to be high in calories.

However, guar gum is also capable of reducing the absorbability of dietary minerals (other than calcium), when foods and/or nutritional supplements containing them are consumed concomitantly with it. However, this is less of a concern with guar gum than with various nonsoluble dietary fibers.

Some studies have found guar gum to improve dietary glucose tolerance. Research has revealed that the water soluble fiber in it may help people with diabetes by binding with glucose in the gastrointestinal tract, thus preventing its absorption.

It also functions as an adjuvant for diabetic drugs that are sometimes employed for the treatment of noninsulin dependent diabetes. The effect is to help lower blood glucose levels. Thus, diabetic patients who are taking drugs should consult their doctors before supplementing with guar gum.

Demand Scenario[6]

World market for guar gum is estimated to be around 150,000 tons/year, 70% of which is produced by India and Pakistan. US consumption is estimated to be around 40,000 tons/year.The export from India is around 115,000 tons and the domestic market is of around 25,000 tons.India exported 33000 tons of guar gum refined split and 84000 tons of guar gum treated and pulverized in 2002-03, which together accounts for an export of 117000 tons of guargum exports valued above Rs. 300 crores.The main demand of guar seed originates from the US petroleum industry and also the oil fields of Middle East.

• GUAR GUM
• Guar Gum
• [http://www.nature.com/news/2004/040920/pf/040920-2_pf.html Swimming in a pool of guar gum slime is as easy as water

• Guar gum specificationPurna sk 11:13, 5 April 2007 (UTC)