- Guar gum
Guar gum, also called guaran, is a
galactomannan. It is primarily the ground endospermof guar beans. The guar seeds are dehusked, milled and screened to obtain the guar gum. [ [http://www.fao.org/ag/agn/jecfa-additives/specs/monograph3/additive-218.pdf foa.org] ] It is typically produced as a free flowing, pale, off-white colored, coarse to fine ground powder.
Guar gum is extracted from the guar bean, where it acts as a food and water store. The guar bean is principally grown in
Indiaand Pakistan, with smaller crops grown in the U.S.A., Australia, China, and Africa. The drought-resistant guar bean can be eaten as a green bean, fed to cattle, or used in green manure.
olubility and Viscosity
Guar gum is more soluble than
locust bean gumand is a better emulsifier as it has more galactosebranch points. Unlike locust bean gum, it is not self-gelling.Martin Chaplin "Water Structure and Behavior: Guar Gum". April 2006. London South Bank University] However, either boraxor calciumcan cross-linkguar gum, causing it to gel. In water it is nonionicand 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 hydrolysisand 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
viscositybut is strongly shear-thinning. It is very thixotropicabove 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 viscositysynergy with xanthan gum. Guar gum and micellar caseinmixtures can be slightly thixotropic if a biphase system forms. [Lynn A. Kuntz. "Special Effects With Gums". December 1999. Food Product Design]
Guar gum is economical because it has almost 8 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 multi-phase formulations; as an emulsifierbecause it helps to prevent oil droplets from coalescing, and/or as a stabilizer because it helps to prevent solid particles from settling.
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 dissolve. [ [http://www.foodproductdesign.com/archive/2004/1004CS.html foodproductdesign.com] ]
Textileindustry – sizing, finishing and printing
Paperindustry – improved sheet formation, folding and denser surface for printing
Explosives industry – as waterproofing agent mixed with ammonium nitrate, nitroglycerinetc.
Pharmaceuticalindustry – as binder or as disintegrator in tablets
Cosmeticsand toiletries industries – thickener in toothpastes, conditioner in shampoos (usually in a chemically modified version)
* Oil and gas drilling,
Hydroseeding– formation of seed bearing "guar tack" [ [http://www.ssseeds.com/other_products_guar.html Product description: Guar Tack. S&S Seeds Inc. 2006] ]
The largest market for guar gum is in the
food industry. In the US, differing percentages are set for its allowable concentration in various food applications. [ [http://vm.cfsan.fda.gov/%7Edms/eafus.html fda.gov- Food additive list] [http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfCFR/CFRSearch.cfm?fr=184.1339 Maximum Usage Levels Permitted- Guar gum] ] In Europe, guar gum has EU food additive codeE412.
Baked goods- increases doughyield, gives greater resiliency, and improves texture and shelf life; in pastryfillings, it prevents "weeping" (syneresis) of the water in the filling, keeping the pastry crust crisp. [It is primarily used in hypoallergenic recipies that use different types of whole grain flours. Because the consistency of these flours allows the escape of gas released by leavening, guar gum is needed to improve the thickness of these flours, allowing them to rise as a normal flour would. Source: NOW Foods. Guar Gum Nutrition Label. Bloomingdale, IL: n.p., n.d. ]
Dairy- thickens milk, yogurt, kefir, and liquid cheeseproducts; helps maintain homogeneityand texture of ice creams and sherbets
Meat- functions as lubricantand binder.
Dressingand sauces - improves the stability and appearance of salad dressings, barbecue sauces, relishes, ketchups and others
*Misc. - Dry soups, sweet desserts, canned fish in sauce, frozen food items and animal feed.
Nutritional and medicinal effects
Guar gum is a water-
soluble fiberthat acts as a bulk forming laxative, and as such, it is claimed to be effective in promoting regular bowelmovements and relieve constipationand chronic related functional bowel ailments; such as diverticulosis, Crohn's disease, colitisand 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 bacteriafrom the bowel and colon. In addition, because it is soluble, it is also able to absorbtoxic substances (bacteria) that cause infective diarrhea.
Several studies have found significant decreases in human serum
cholesterollevels following guar gum ingestion. These decreases are thought to be a function of its high soluble fiber content.
Guar gum has been considered of interest with regards to both weight loss and diabetic diets. It is a
thermogenicsubstance. [JC Brown & G Livesey. "Energy balance and expenditure while consuming guar gum at various fat intakes and ambient temperatures". Am J Clin Nutr. 1994. 60(6):956-64 (ISSN: 0002-9165)] 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 indexof that meal. In the late 1980s, guar gum was used and heavily promoted in several weight loss products. The USFDAeventually 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. [ [http://www.fda.gov/bbs/topics/CONSUMER/CON00259.html Dietary Supplements: Making Sure Hype Doesn't Overwhelm Science (November 1993) ] ] 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-analysisthat combined the results of 11 randomized controlled trials found that guar gum supplements were not effective in reducing body weight. [Pittler MH, "Ernst E. Guar gum for body weight reduction: meta-analysis of randomized trials". Am J Med. 2001;110(9):724-730.]
Two Japanese studies using rats showed that guar gum supports increased absorption of
calciumoccurring 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
glucosetolerance. Research has revealed that the water soluble fiber in it may help people with diabetesby 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
adjuvantfor 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.
* [http://www.fao.org/ag/agn/jecfa-additives/specs/monograph3/additive-218.pdf GUAR GUM]
* [http://www.lsbu.ac.uk/water/hygua.html Guar Gum]
* [http://www.dineshgum.com MFG OF GUAR GUM]
* [http://www.cybercolloids.net/library/jecfa/index.php?submit=showspec&gum=additive-0765 Guar gum specification]
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Look at other dictionaries:
guar gum — noun a gum from seeds of the guar plant; used to thicken foods and as sizing for paper and cloth • Hypernyms: ↑gum * * * noun : a gum consisting of the ground endosperm of guar seeds that swells and disperses in water and is used chiefly as a… … Useful english dictionary
guar gum — noun Date: 1950 a gum obtained from the endosperm of guar seeds and used especially as a thickening agent and as a sizing material for paper and textiles … New Collegiate Dictionary
guar gum — noun a heteropolysaccharide gum, extracted from the guar bean, that is used as a food additive Syn: E412, thickener, stabiliser, guaran … Wiktionary
guar gum — /ˈgua gʌm/ (say goohah gum) noun a natural thickening agent, produced from the ground beans of the guar plant … Australian English dictionary
guar gum. — See under guar. [1945 50] * * * … Universalium
guar gum. — See under guar. [1945 50] … Useful english dictionary
guar gum — [NF] a gum obtained from the ground endosperms of the leguminous tree Cyamopsis tetragonolobus; used as a tablet binder and disintegrant in pharmaceutical preparations. It can also be used as a source of soluble dietary fiber … Medical dictionary
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