Guar gum

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Guar gum
Guargum.jpg
Identifiers
ChemSpider
  • none
ECHA InfoCard 100.029.567 OOjs UI icon edit-ltr-progressive.svg
E number E412 (thickeners, ...)
UNII
Properties
Density 0.8-1.0 g/mL at 25 °C
Acidity (pKa)5-7
Pharmacology
A10BX01 ( WHO )
Hazards
Safety data sheet (SDS) MSDS
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
X mark.svgN  verify  (what is  Yes check.svgYX mark.svgN ?)

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. [1] The guar seeds are mechanically dehusked, hydrated, milled and screened according to application. [2] It is typically produced as a free-flowing, off-white powder.

Production and trade

The guar bean is principally grown in India, Pakistan, the United States, Australia and Africa. India is the largest producer, accounting for nearly 80% of the world production. [3] In India, Rajasthan, Gujarat, and Haryana are the main producing regions. The US has produced 4,600 to 14,000 tonnes of guar over the last 5 years. [4] [ when? ] Texas acreage since 1999 has fluctuated from about 7,000 to 50,000 acres. [5] The world production for guar gum and its derivatives is about 1.0 million tonnes. Non-food guar gum accounts for about 40% of the total demand. [6]

Properties

Chemical composition

Guar gum is a galactomannan polysaccharide whose backbone structure consists of a linear chain of mannose with short lateral-branches of galactose. Guaran.svg
Guar gum is a galactomannan polysaccharide whose backbone structure consists of a linear chain of mannose with short lateral-branches of galactose.

Chemically, guar gum is an exo-polysaccharide composed of the sugars galactose and mannose. [7] 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. [8]

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. [9] 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). [9] 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. The viscosity attained is dependent on time, temperature, concentration, pH, rate of agitation and particle size of the powdered gum used. The lower the temperature, the lower the rate at which viscosity increases, and the lower the final viscosity. Above 80°, the final viscosity is slightly reduced. Finer guar powders swell more rapidly than larger particle size coarse powdered gum.[ citation needed ] [10]

Guar gum shows a clear low shear plateau on the flow curve and is strongly shear-thinning. The rheology of guar gum is typical for a random coil polymer. It does not show the very high low[ clarification needed ] shear plateau viscosities seen with more rigid polymer chains such as xanthan gum. It is very thixotropic above 1% concentration, but below 0.3%, the thixotropy is slight. Guar gum shows viscosity synergy with xanthan gum.[ clarification needed ] Guar gum and micellar casein mixtures can be slightly thixotropic if a biphase system forms. [9] [11]

Thickening

One use of guar gum is a thickening agent in foods and medicines for humans and animals. Because it is gluten-free, it is used as an additive to replace wheat flour in baked goods. [12] :41 It has been shown to reduce serum cholesterol and lower blood glucose levels. [13]

Guar gum is also economical because it has almost eight times the water-thickening ability of other agents (e.g. cornstarch) and only a small quantity is needed for producing sufficient viscosity.[ clarification needed ] [14] Because less is required, costs are reduced.

In addition to guar gum's effects on viscosity, its high ability to flow, or deform, gives it favorable rheological [ clarification needed ] properties. It forms breakable[ clarification needed ] gels when cross-linked with boron[ citation needed ]. It is used in various multi-phase formulations for hydraulic fracturing, in some as an emulsifier because it helps prevent oil droplets from coalescing,[ citation needed ] and in others as a stabilizer to help prevent solid particles from settling and/or separating[ citation needed ].

Fracking entails the pumping of sand-laden fluids into an oil or natural gas reservoir at high pressure and flow rate. This cracks the reservoir rock and then props the cracks open. Water alone is too thin to be effective at carrying proppant sand, so guar gum is one of the ingredients added to thicken the slurry mixture and improve its ability to carry proppant. There are several properties which are important 1. Thixotropic: the fluid should be thixotropic, meaning it should gel within a few hours. 2. Gelling and de-gelling: The desired viscosity changes over the course of a few hours. When the fracking slurry is mixed, it needs to be thin enough to make it easier to pump. Then as it flows down the pipe, the fluid needs to gel to support the proppant and flush it deep into the fractures. After that process, the gel has to break down so that it is possible to recover the fracking fluid but leave the proppant behind. This requires a chemical process which produces then breaks the gel cross-linking at a predictable rate. Guar+boron+proprietary chemicals can accomplish both of these goals at once.[ citation needed ]

Ice crystal growth

Guar gum retards ice crystal growth by slowing mass transfer across the solid/liquid interface. It shows good stability during freeze-thaw cycles. Thus, it is used in egg-free ice cream. Guar gum has synergistic effects with locust bean gum and sodium alginate. May be synergistic with xanthan: together with xanthan gum, it produces a thicker product (0.5% guar gum / 0.35% xanthan gum), which is used in applications such as soups, which do not require clear results. [15]

Guar gum is a hydrocolloid, hence is useful for making thick pastes without forming a gel, and for keeping water bound in a sauce or emulsion. Guar gum can be used for thickening cold and hot liquids, to make hot gels, light foams and as an emulsion stabilizer. Guar gum can be used for cottage cheeses, curds, yoghurt, sauces, soups and frozen desserts. Guar gum is also a good source of fiber with 80% soluble dietary fiber on a dry weight basis. [9]

Grading

Guar gum is analysed for

TestTest MethodTestTest method
ColourTP/09Acid-insoluble residueTP/115
ViscosityTP/10/04Fat contentTP/18
Granulation (mesh)TP/21Ash contentTP/12
Moisture, pHTP/1 and TP/29Gum contentTP/03
ProteinTP/05Heavy metalsTP/13
Insolubles AshTP/11FilterabilityTP/20A

Guar gum powder standards are:

Manufacturing process

Depending upon the requirement of end product, various processing techniques are used. The commercial production of guar gum normally uses roasting, differential attrition, sieving, and polishing. Food-grade guar gum is manufactured in stages. Guar split selection is important in this process. The split is screened to clean it and then soaked to pre-hydrate it in a double-cone mixer. The prehydrating stage is very important because it determines the rate of hydration of the final product. The soaked splits, which have reasonably high moisture content, are passed through a flaker. The flaked guar split is ground and then dried. The powder is screened through rotary screens to deliver the required particle size. Oversize particles are either recycled to main ultra fine or reground in a separate regrind plant, according to the viscosity requirement.[ citation needed ]

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 reduces the hydration of the product. Through the heating, grinding, and polishing process, the husk is separated from the endosperm halves and the refined guar split is obtained. Through the further grinding process, the refined guar split is then treated and converted into powder. The split manufacturing process yields husk and germ called “guar meal”, widely sold in the international market as cattle feed. It is high in protein and contains oil and albuminoids, about 50% in germ and about 25% in husks. The quality of the food-grade guar gum powder is defined from its particle size, rate of hydration, and microbial content.[ citation needed ]

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, such as a 200 mesh, requires more effort to dissolve.[ citation needed ] Modified forms of guar gum are available commercially, including enzyme-modified, cationic and hydropropyl guar. [16]

Industrial applications

Fracturing fluids normally consist of many additives that serve two main purposes, firstly to enhance fracture creation and proppant carrying capability and secondly to minimize formation damage. Viscosifiers, such as polymers and crosslinking agents, temperature stabilizers, pH control agents, and fluid loss control materials are among the additives that assist fracture creation. Formation damage is minimized by incorporating breakers, biocides, and surfactants. More appropriate gelling agents are linear polysaccharides, such as guar gum, cellulose, and their derivatives.

Guar gums are preferred as thickeners for enhanced oil recovery (EOR). Guar gum and its derivatives account for most of the gelled fracturing fluids. Guar is more water-soluble than other gums, and it is also a better emulsifier, because it has more galactose branch points. Guar gum shows high low-shear viscosity, but it is strongly shear-thinning. Being non-ionic, it is not affected by ionic strength or pH but will degrade at low pH at moderate temperature (pH 3 at 50 °C). Guar's derivatives demonstrate stability in high temperature and pH environments. Guar use allows for achieving exceptionally high viscosities, which improves the ability of the fracturing liquid to transport proppant. Guar hydrates fairly rapidly in cold water to give highly viscous pseudoplastic solutions of, generally, greater low-shear viscosity than other hydrocolloids. The colloidal solids present in guar make fluids more efficient by creating less filter cake. Proppant pack conductivity is maintained by utilizing a fluid that has excellent fluid loss control, such as the colloidal solids present in guar gum.

Guar has up to eight times the thickening power of starch. Derivatization of guar gum leads to subtle changes in properties, such as decreased hydrogen bonding, increased solubility in water-alcohol mixture, and improved electrolyte compatibility. These changes in properties result in increased use in different fields, like textile printing, explosives, and oil-water fracturing applications.

Crosslinking Guar

Guar molecules have a tendency to aggregate during the hydraulic fracturing process, mainly due to intermolecular hydrogen bonding. These aggregates are detrimental to oil recovery because they clog the fractures, restricting the flow of oil. Cross-linking guar polymer chains prevents aggregation by forming metal – hydroxyl complexes. The first crosslinked guar gels were developed in the late ‘60s. Several metal additives have been used for crosslinking, among them are chromium, aluminium, antimony, zirconium, and the more commonly used, boron. Boron, in the form of B(OH)4, reacts with the hydroxyl groups on the polymer in a two step process to link two polymer strands together to form bis-diol complexes.

1:1 1,2 diol complex and a 1:1 1,3 diol complex, place the negatively charged borate ion onto the polymer chain as a pendant group. Boric acid itself does not apparently complex to the polymer so that all bound boron is negatively charged. The primary form of crosslinking may be due to ionic association between the anionic borate complex and adsorbed cations on the second polymer chain . The development of cross-linked gels was a major advance in fracturing fluid technology. Viscosity is enhanced by tying together the low molecular weight strands, effectively yielding higher molecular weight strands and a rigid structure. Cross-linking agents are added to linear polysaccharide slurries to provide higher proppant transport performance, relative to linear gels.

Lower concentrations of guar gelling agents are needed when linear guar chains are cross-linked. It has been determined that reduced guar concentrations provide better and more complete breaks in a fracture. The breakdown of cross-linked guar gel after the fracturing process restores formation permeability and allows increased production flow of petroleum products .

Food applications

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. [18] [19] In Europe, guar gum has EU food additive code E412. Xanthan gum and guar gum are the most frequently used gums in gluten-free recipes and gluten-free products.

Applications include:

Nutritional and medicinal effects

Guar gum, as a water-soluble fiber, acts as a bulk-forming laxative. Several studies have found it decreases cholesterol levels. These decreases are thought to be a function of its high soluble fiber content. [23]

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 drugs. The US 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. [24] For this reason, guar gum is no longer approved for use in over-the-counter weight loss drugs in the United States, although this restriction does not apply to supplements. Moreover, a meta-analysis found guar gum supplements were not effective in reducing body weight. [25]

Guar-based compounds, such as hydroxypropyl guar, have been used in artificial tears to treat dry eye. [26]

Allergies

Some studies have found an allergic sensitivity to guar gum developed in a few individuals working in an industrial environment where airborne concentrations of the substance were present. In those affected by the inhalation of the airborne particles, common adverse reactions were occupational rhinitis and asthma. [27]

Dioxin contamination

In July 2007, the European Commission issued a health warning to its member states after high levels of dioxins were detected in guar gum, which was used as a thickener in small quantities in meat, dairy, dessert and delicatessen products. The source was traced to guar gum from India that was contaminated with pentachlorophenol (PCP), a pesticide no longer in use. [28] PCP contains dioxins, which damage the human immune system. [29]

Related Research Articles

Rheology is the study of the flow of matter, primarily in a fluid state, but also as "soft solids" or solids under conditions in which they respond with plastic flow rather than deforming elastically in response to an applied force. Rheology is a branch of physics, and it is the science that deals with the deformation and flow of materials, both solids and liquids.

<span class="mw-page-title-main">Guar</span> Species of flowering plant in the bean family Fabaceae

The guar or cluster bean, with the botanical name Cyamopsis tetragonoloba, is an annual legume and the source of guar gum. It is also known as gavar, gawar, or guvar bean. The genus name Cyamopsis means bean-like. The specific name is from Latin: tetragōnoloba meaning four-lobed.

<span class="mw-page-title-main">Boric acid</span> Weak acid with formula B(OH)₃

Boric acid, more specifically orthoboric acid, is a compound of boron, oxygen, and hydrogen with formula B(OH)3. It may also be called hydrogen orthoborate, trihydroxidoboron or boracic acid. It is usually encountered as colorless crystals or a white powder, that dissolves in water, and occurs in nature as the mineral sassolite. It is a weak acid that yields various borate anions and salts, and can react with alcohols to form borate esters.

A non-Newtonian fluid is a fluid that does not follow Newton's law of viscosity, that is, it has variable viscosity dependent on stress. In particular, the viscosity of non-Newtonian fluids can change when subjected to force. Ketchup, for example, becomes runnier when shaken and is thus a non-Newtonian fluid. Many salt solutions and molten polymers are non-Newtonian fluids, as are many commonly found substances such as custard, toothpaste, starch suspensions, corn starch, paint, blood, melted butter, and shampoo.

<span class="mw-page-title-main">Carrageenan</span> Natural linear sulfated polysaccharide

Carrageenans or carrageenins are a family of natural linear sulfated polysaccharides that are extracted from red edible seaweeds. Carrageenans are widely used in the food industry, for their gelling, thickening, and stabilizing properties. Their main application is in dairy and meat products, due to their strong binding to food proteins. In recent years, carrageenans have emerged as a promising candidate in tissue engineering and regenerative medicine applications as they resemble native glycosaminoglycans (GAGs). They have been mainly used for tissue engineering, wound coverage, and drug delivery.

<span class="mw-page-title-main">Dextrin</span> Chemical compound

Dextrins are a group of low-molecular-weight carbohydrates produced by the hydrolysis of starch and glycogen. Dextrins are mixtures of polymers of D-glucose units linked by α-(1→4) or α-(1→6) glycosidic bonds.

<span class="mw-page-title-main">Xanthan gum</span> Polysaccharide gum used as a food additive and thickener

Xanthan gum is a polysaccharide with many industrial uses, including as a common food additive. It is an effective thickening agent and stabilizer that prevents ingredients from separating. It can be produced from simple sugars by fermentation and derives its name from the species of bacteria used, Xanthomonas campestris.

<span class="mw-page-title-main">Thixotropy</span> Change in viscosity of a gel or fluid caused by stress

Thixotropy is a time-dependent shear thinning property. Certain gels or fluids that are thick or viscous under static conditions will flow over time when shaken, agitated, shear-stressed, or otherwise stressed. They then take a fixed time to return to a more viscous state. Some non-Newtonian pseudoplastic fluids show a time-dependent change in viscosity; the longer the fluid undergoes shear stress, the lower its viscosity. A thixotropic fluid is a fluid which takes a finite time to attain equilibrium viscosity when introduced to a steep change in shear rate. Some thixotropic fluids return to a gel state almost instantly, such as ketchup, and are called pseudoplastic fluids. Others such as yogurt take much longer and can become nearly solid. Many gels and colloids are thixotropic materials, exhibiting a stable form at rest but becoming fluid when agitated. Thixotropy arises because particles or structured solutes require time to organize.

<span class="mw-page-title-main">Gellan gum</span> Gelling and thickening agent

Gellan gum is a water-soluble anionic polysaccharide produced by the bacterium Sphingomonas elodea. The gellan-producing bacterium was discovered and isolated by the former Kelco Division of Merck & Company, Inc. in 1978 from the lily plant tissue from a natural pond in Pennsylvania. It was initially identified as a gelling agent to replace agar at significantly lower concentrations in solid culture media for the growth of various microorganisms. Its initial commercial product with the trademark as Gelrite gellan gum, was subsequently identified as a suitable agar substitute as gelling agent in various clinical bacteriological media.

<span class="mw-page-title-main">Thickening agent</span> Increases the viscosity of a liquid without altering its other properties

A thickening agent or thickener is a substance which can increase the viscosity of a liquid without substantially changing its other properties. Edible thickeners are commonly used to thicken sauces, soups, and puddings without altering their taste; thickeners are also used in paints, inks, explosives, and cosmetics.

<span class="mw-page-title-main">Carboxymethyl cellulose</span> Cellulose derivative grafted with carboxymethyl groups

Carboxymethyl cellulose (CMC) or cellulose gum is a cellulose derivative with carboxymethyl groups (-CH2-COOH) bound to some of the hydroxyl groups of the glucopyranose monomers that make up the cellulose backbone. It is often used in its sodium salt form, sodium carboxymethyl cellulose. It used to be marketed under the name Tylose, a registered trademark of SE Tylose.

<span class="mw-page-title-main">Natural gum</span> Thickening agent

Natural gums are polysaccharides of natural origin, capable of causing a large increase in a solution's viscosity, even at small concentrations. They are mostly botanical gums, found in the woody elements of plants or in seed coatings.

<span class="mw-page-title-main">Drilling fluid</span> Aid for drilling boreholes into the ground

In geotechnical engineering, drilling fluid, also known as drilling mud, is used to aid the drilling of boreholes into the earth. Used while drilling oil and natural gas wells and on exploration drilling rigs, drilling fluids are also used for much simpler boreholes, such as water wells.

<span class="mw-page-title-main">Methyl cellulose</span> Chemical compound

Methyl cellulose is a compound derived from cellulose. It is sold under a variety of trade names and is used as a thickener and emulsifier in various food and cosmetic products, and also as a bulk-forming laxative. Like cellulose, it is not digestible, non-toxic, and not an allergen. In addition to culinary uses, it is used in arts and crafts such as papier-mâché and is often the main ingredient of wallpaper paste.

<span class="mw-page-title-main">Hypromellose</span> Cellulose ether used as emulsifier or thickening agent to disperse colloids in water

Hypromellose (INN), short for hydroxypropyl methylcellulose (HPMC), is a semisynthetic, inert, viscoelastic polymer used in eye drops, as well as an excipient and controlled-delivery component in oral medicaments, found in a variety of commercial products.

<span class="mw-page-title-main">Stabiliser (food)</span> Food additive

A stabiliser or stabilizer is an additive to food which helps to preserve its structure. Typical uses include preventing oil-water emulsions from separating in products such as salad dressing; preventing ice crystals from forming in frozen food such as ice cream; and preventing fruit from settling in products such as jam, yogurt and jellies. Some of these food additives may promote the growth of specific microorganisms in the gastrointestinal tract that can ferment them. The following hydrocolloids are the most common ones used as stabilisers:

<span class="mw-page-title-main">Fracking proppants</span> Fracking materials

A proppant is a solid material, typically sand, treated sand or man-made ceramic materials, designed to keep an induced hydraulic fracture open, during or following a fracturing treatment, most commonly for unconventional reservoirs. It is added to a fracking fluid which may vary in composition depending on the type of fracturing used, and can be gel, foam or slickwater–based. In addition, there may be unconventional fracking fluids. Fluids make tradeoffs in such material properties as viscosity, where more viscous fluids can carry more concentrated proppant; the energy or pressure demands to maintain a certain flux pump rate that will conduct the proppant appropriately; pH, various rheological factors, among others. In addition, fluids may be used in low-volume well stimulation of high-permeability sandstone wells to the high-volume operations such as shale gas and tight gas that use millions of gallons of water per well.

Well cementing is the process of introducing cement to the annular space between the well-bore and casing or to the annular space between two successive casing strings. Personnel who conduct this job are called "Cementers".

<span class="mw-page-title-main">Sour cream</span> Fermented dairy product

Sour cream is a dairy product obtained by fermenting regular cream with certain kinds of lactic acid bacteria. The bacterial culture, which is introduced either deliberately or naturally, sours and thickens the cream. Its name comes from the production of lactic acid by bacterial fermentation, which is called souring. Crème fraîche is one type of sour cream with a high fat content and less sour taste.

References

  1. ↑ Thombare, Nandkishore; Jha, Usha; Mishra, Sumit; Siddiqui, M.Z. (July 2016). "Guar gum as a promising starting material for diverse applications: A review". International Journal of Biological Macromolecules. 88: 361–372. doi:10.1016/j.ijbiomac.2016.04.001. PMID   27044346 – via Elsevier Science Direct.
  2. ↑ "foa.org" (PDF). Archived from the original (PDF) on 27 September 2007. Retrieved 18 April 2011.
  3. ↑ "GUAR MARKET - GROWTH, TRENDS, COVID-19 IMPACT, AND FORECASTS (2022 - 2027)". www.mordorintelligence.com/. Retrieved 20 October 2022.
  4. ↑ Guar in West Texas http://lubbock.tamu.edu/files/2013/06/Guar-Production-Industry-Texas-May2013-Trostle.pdf
  5. ↑ Trostle, Calvin (18 May 2012). "Guar Update, West Texas" (PDF). Texas AgriLife Research & Extension Center. Archived (PDF) from the original on 9 October 2022. Retrieved 5 February 2017.
  6. ↑ "The Ultimate Guide To The Industrial Uses of Guar Gum". www.guarresources.com. 3 June 2021. Archived from the original on 22 December 2022. Retrieved 22 December 2022.
  7. ↑ "Alliance in Mumbai, India". www.allianceingredients.in. Retrieved 4 February 2022.
  8. ↑ "Guar Gum Powder | INDIAN HYDROCOLLOIDS". www.inhyco.com. Retrieved 4 February 2022.
  9. 1 2 3 4 Martin Chaplin "Water Structure and Behavior: Guar Gum". April 2012. London South Bank University
  10. ↑ https://apeda.gov.in/apedawebsite/six_head_product/Guargum_final_Profile.pdf [ bare URL PDF ]
  11. ↑ Lynn A. Kuntz. "Special Effects With Gums". December 1999. Food Product Design
  12. ↑ Fenster, Carol (8 January 2014). Gluten-Free 101: The Essential Beginner's Guide to Easy Gluten-Free Cooking. Houghton Mifflin Harcourt. ISBN   978-1-118-53912-5.
  13. ↑ "Guar Gum Uses, Benefits & Dosage - Drugs.com Herbal Database". Drugs.com. Retrieved 3 May 2018.
  14. ↑ "Advanced Food Science II" (PDF). Advanced Food Science. 2 (1): 12.
  15. ↑ Campo-Quintero, Valentina; Rojas-Gaitán, Juan José; Ramírez-Navas, Juan Sebastián (8 May 2022). "Efecto de la adición de carragenina, goma guar y metilcelulosa en los parámetros de calidad de un helado con licor". Ciencia & Tecnología Agropecuaria. 23 (2). doi: 10.21930/rcta.vol23_num2_art:2209 . ISSN   2500-5308. S2CID   248686988.
  16. ↑ Ashford's Dictionary of Industrial Chemicals, Third edition, 2011, page 4770
  17. ↑ Ram Narayan (8 August 2012). "From Food to Fracking: Guar Gum and International Regulation". RegBlog. University of Pennsylvania Law School. Archived from the original on 22 August 2012. Retrieved 15 August 2012.
  18. ↑ fda.gov- Food additive list Archived 21 February 2008 at the Wayback Machine
  19. ↑ Maximum Usage Levels Permitted- Guar gum
  20. ↑ Source: NOW Foods. Guar Gum Nutrition Label. Bloomingdale, IL: n.p., n.d.
  21. ↑ Lewis, JH (1992). "Esophageal and small bowel obstruction from guar gum-containing "diet pills": analysis of 26 cases reported to the Food and Drug Administration". Am. J. Gastroenterol. 87 (10): 1424–8. PMID   1329494.
  22. ↑ "Supplier and Exporter of Guar Meal Korma and Roasted Korma". 3 December 2022. Retrieved 12 December 2022.
  23. ↑ Brown, Lisa; Rosner, Bernard; Willett, Walter; Sacks, Frank (1999). "Cholesterol-lowering effects of dietary fiber: a meta-analysis". The American Journal of Clinical Nutrition. 69 (1): 30–42. doi: 10.1093/ajcn/69.1.30 . PMID   9925120 . Retrieved 4 August 2017.
  24. ↑ "Supplements: Making Sure Hype Doesnþt Overwhelm Science (original date unknown)". fda.gov. Archived from the original on 5 May 1997.
  25. ↑ Pittler, MH (2001). "Ernst E. Guar gum for bodyweight reduction: meta-analysis of randomized trials". Am J Med. 110 (9): 724–730. doi:10.1016/s0002-9343(01)00702-1. PMID   11403757.
  26. ↑ Pucker AD, Ng SM, Nichols JJ (2016). "Over the counter (OTC) artificial tear drops for dry eye syndrome". Cochrane Database Syst Rev. 2016 (2): CD009729. doi:10.1002/14651858.CD009729.pub2. PMC   5045033 . PMID   26905373.
  27. ↑ "AllergyNet - Allergy Advisor Find". Allallergy.net. Archived from the original on 31 March 2013. Retrieved 19 February 2013.
  28. ↑ "Commission Regulation (EU) No 258/2010". 25 March 2010. Archived from the original on 13 February 2013. Retrieved 14 July 2012.
  29. ↑ "Dioxins and their effects on human health". 1 May 2010. Retrieved 8 February 2012.
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