Guar gum

Guar gum
Identifiers
CAS number	9000-30-0 Y
ATC code	A10BX01
Properties
Acidity (pKa)	5-7
Hazards
MSDS	MSDS
Y (verify) (what is: Y/N?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Guar gum, also called guaran, is a galactomannan. It is primarily the ground endosperm of guar beans. The guar seeds are dehusked, milled and screened to obtain the guar gum. It is typically produced as a free-flowing, pale, off-white-colored, coarse to fine ground powder.

Production

Guar gum is an extract of the guar bean, where it acts as a food and water store. The guar bean is principally grown in IndiaRajasthan Gujarat are main producing regions. Jodhpur in rajasthan is major Guar trading market and Pakistan, with smaller crops grown in the U.S., Australia, China, and Africa. The drought-resistant guar bean can be eaten as a green bean, fed to cattle, or used in green manure.Guar Beans are also consumed as curry in daily food of the locals.

Guar Gum Powder Standards

HS-Code- 130 232 30

CAS No.- 9000-30-0

EEC No.- E 412

BT No.- 1302 3290

EINECS No. - 232-536-8

Imco Code- Harmles

The major importing countries of Indian Guar Gum and its derivatives are

United States of America Germany France United Kingdom South Africa Netherlands Italy Japan Projected India Seed Crop + Carryover: 4.5 million + 3.0 million bags = 7.5 million bags of 100 kg each (splits/powder production potential of up to nearly 200,000 MT, although there is normally at least 1 million bags of carryover).

(2004 Crops by comparison: India 4 million bags crop + 5 million bags carryover = 9 million bags).

Global Demand: 650,000 MT seeds +/- 10%. Major Importer of Guar Gum

The world market of guar is estimated at 1.5 lakhs tons annually. The major importer countries of the crop are

Canada China Chile Australia Austria Brazil Germany Italy Japan United Kingdom [[File:
Example.jpg]]USA Ireland Sweden Greece Portugal Mexico

Production of Guar in India

India produces 600000 lakh tons of guar annually i.e. the maximum level of production in the world. It contributes to around 80% share in the world’s total production. The major producing regions of this crop in India are

Rajasthan Gujarat Haryana Punjab Uttar Pradesh Madhya Pradesh Tamil Nadu Maharashtra Karnataka Andhra Pradesh

In July 2007, the European Commission issued a health warning to its Member States after high levels of dioxins were detected in a food additive - guar gum - used as thickener in small quantities in meat, dairy, dessert or delicatessen products. The source was traced to guar gum from India that was contaminated with pentachlorophenol (PCP), a pesticide no longer in use. PCP contains dioxins as contamination. Dioxins damage the human immune system.

Trade

According to a Reuters report, India accounts for about 80 percent of the global trade in guar products. India exported 11 billion rupees worth of guar products in 2007/08 financial year ending March 2008. Pakistan trails India in the global trade. Industrial guar gum is the most sought-after guar product, and accounts for about 45 percent of the total demand. Industrial gum is used as a controlling agent in oil wells to facilitate easy drilling and prevent fluid loss.

Properties

Chemical composition

Chemically, guar gum is a 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.

Solubility and viscosity

Guar gum is more soluble than locust bean gum and is a better stabilizer, as it has more galactose branch points. Unlike locust bean gum, it is not self-gelling. However, 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 pH extremes at temperature (e.g. pH 3 at 50 °C). 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.

Guar gum shows high low-shear viscosity but is strongly shear-thinning. It is very thixotropic above 1% concentration, 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 with xanthan gum. Guar gum and micellar casein mixtures can be slightly thixotropic if a biphase system forms.

Thickening

Guar gum is economical because it has almost eight times the water-thickening potency of cornstarch - only a very small quantity is needed for producing sufficient viscosity. Thus, it can be used in various multiphase 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.

Ice crystal growth

Guar gum retards ice crystal growth nonspecifically by slowing mass transfer across the solid/liquid interface. It shows good stability during freeze-thaw cycles.

Grading

Guar Gum is analysed for

Test Test Method Test Test Method Colour TP/09 Acid insoluble residue TP/30 Viscosity TP/10/04 Fat content TP/18 Granulation(Mesh) TP/21 Ash content TP/12 Moisture, pH TP/1 and TP/29 Gum content TP/03 Protein TP/05 Heavy metals TP/13 Insolubles Ash TP/11 Filterability TP/20A

Guar Gum Manufacturing Process

Depending upon the requirement of end product various processing techniques are used. The commercial production of Guar gum is normally undertaken by using process of roasting, differential attrition, sieving and polishing.

The stage wise process of manufacturing food grade guar gum is as under. It is very important to select guar split in this process. The split will be screened to clean and then it will be soaked to prehydrate in a double cone mixer. Prehydrating stage is very important in the process as it derives the rate of hydration of the final product.

The soaked splits, which has reasonably high moisture content, will be passed through Flacker to take them. The flaked guar split will be ground to desired particle size followed by drying of the material. The power will be screened through rotary screens to deliver required particle size. The oversize will be either recycle to main Ultra fine or regrind in separate regrind plant, as per viscosity requirement.

This stage helps to reduce the load at the grinder. The soaked splits are difficult to grind. Direct grinding of those generates more heat in the grinder which is not desired in the process as it results in insoluble or reduced hydration of the product. Through heating, grinding & polishing process the husk is separated from the endosperm halves and the refined Guar Gum split are obtained. Through grinding process the refined Guar split are then treated and converted into powder.

During the split manufacturing process, husk & germ are obtained which are used as a cattle feed as they are rich in protein. It is widely sold in the international market as “Guar Meal” and has contents of “Oil & Albuminoids”. These contents are about 50% in germ whereas it is about 25% in husks. Quality of the food grad guar gum powder is defined from its particle size, rate of hydration and the microbial in it. E412 guar gum is an important natural food supplement with high nutritional value. Manufacturers define different grades and qualities of guar gum by the particle size, the viscosity 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 dissolve.

Modified forms of guar gum that are available commercially include enzyme-modified, cationic and hydropropyl guar.

Industrial applications

• 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; main ingredient in some bulk-forming laxatives
• Cosmetics and toiletries industries – thickener in toothpastes, conditioner in shampoos (usually in a chemically modified version)
• Oil and gas drilling, hydraulic fracturing
• Mining
• Hydroseeding – formation of seed-bearing "guar tack"
• Medical institutions, especially nursing homes - used to thicken liquids and foods for patients with dysphagia

Food applications

The largest market for guar gum is in the food industry. In the U.S., differing percentages are set for its allowable concentration in various food applications. In Europe, guar gum has EU food additive code E412.Xanthan (ZAN than) gum and guar (gwar) gum are the most frequently used gums in gluten-free recipes and gluten-free products.

Applications include:

• In baked goods, it 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.
• In dairy products, it thickens milk, yogurt, kefir, and liquid cheese products, and helps maintain homogeneity and texture of ice creams and sherbets
• For meat, it functions as a binder.
• In condiments, it improves the stability and appearance of salad dressings, barbecue sauces, relishes, ketchups and others.
• It is also used in dry soups, instant oatmeal, sweet desserts, canned fish in sauce, frozen food items and animal feed.

Nutritional and medicinal effects

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.^{[citation needed]}

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.^{[citation needed]}

Guar gum has been considered of interest in regard to both weight loss and diabetic diets. It is a thermogenic substance. 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 U.S. Food and Drug Administration eventually recalled these due to reports of esophageal blockage from insufficient fluid intake, after one brand alone caused at least 10 users to be hospitalized, and a death. 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 guar gum supplements were not effective in reducing body weight.

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

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

Some studies have found guar gum to improve dietary glucose tolerance. Research has revealed the water-soluble fiber in it may help people with diabetes by slowing the absorption of sugars by the small intestine. Although the rate of absorption is reduced, the amount of sugar absorbed is the same overall. This helps diabetic patients by lowering the amount of insulin needed to keep the blood glucose at a normal level.

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.

References

Notations

• Guar gum specification