Guar gum


Guar galactomannan Guar gum  [c.457]

MethylceUulose [9004-67-5] and hydroxypropyhnethylceUulose [9004-65-3] are water-soluble gums derived from ceUulose. They possess the abUity to gel upon heating, a property unique among gums. Both products have polymeric backbones of ceUulose, ie, a repeating stmcture of anhydroglucose units. They differ ia the substitutioa units, methoxyl and hydroxypropoxyl, and both may vary depending on the degree of substitution. Degree of substitution influences solubUity and thermal gel point. The properties of ceUulose derivatives can be altered by admixture with other gums. One avaUable mixture has different levels of guar gum, plus added maltodextrias and xanthan.  [c.119]

Gum arabic (acacia) is derived from the acacia tree growa primarily ia Sudan and Senegal. It is a complex of calcium, magnesium, and potassium salts of arabic acid, with a molecular weight of about 250,000. Guar is derived from the endosperm of the guar plant. The guar plant is cultivated commercially ia ladia and Pakistan some is grown ia the southwestern United States. On average, guar gum contains 80% galactomannan, 12% water, and 5% protein.  [c.119]

Guar gum [9000-30-0] derived from the seed of a legume (11,16), is used as a flocculant in the filtration of mineral pulps leached with acid or cyanide for the recovery of uranium and gold (16). It is also used as a retention aid, usually in a chemically modified form (14,17). Starch and guar gum are subject to biological degradation in solution, so they are usually sold as dry powders that are dissolved immediately before use. Starch requires heating in most cases to be fully dissolved.  [c.32]

Gums are classified as natural or modified. Natural gums include seaweed extracts, plant exudates, gums from seed or root, and gums obtained by microbial fermentation (Table 1). Modified (semisynthetic) gums include cellulose and starch derivatives and certain synthetic gums such as low methoxyl pectin, propylene glycol alginate, and carboxymethyl and hydroxypropyl guar gum (see Cellulose Starch).  [c.430]

Harvesting of these gums is expensive however, harvesting from annual plants costs less than from perennial plants or trees. This is clearly demonstrated by the tremendous increase in the use of guar, a gum that is extracted from an annual leguminous plant. Since the beginning of commercial production in 1953, the use of guar has risen rapidly. More guar gum is consumed than all other gums combined.  [c.435]

StmcturaHy, guar gum comprises a straight chain of D-mannose with a D-galactose side chain on approximately every other mannose unit the ratio of mannose to galactose is 2 1 (53). Guar gum has a molecular weight on the order of 220,000 (54).  [c.435]

Guar gum hydrates in either cold or hot water to give high viscosity solutions. Although the viscosity development depends on particle size, pH, and temperature, guar gum at 1% concentration fiiUy hydrates typically within 24 h at room temperature and in 10 min at 80°C. Guar gum solutions are stable over the pH range of 4.0—10.5 with fastest hydration occurring at pH 8.0. Solutions are somewhat cloudy because of the small amount of insoluble fiber and ceUulosic material present.  [c.435]

Guar gum is compatible with other common plant gums, starch, and water-soluble proteins such as gelatin, except for the synergistic viscosity increases given by blends with xanthan gum (55). The presence of salts, water-miscible solvents or low molecular weight sugars can affect the hydration rate. Small amounts of borate, however, cross-link the guar to form mbbery gels (56). These gels can be reversed by adjusting the pH to the acid ranges.  [c.435]

As a result of its properties and low cost, guar gum is the most extensively used gum, both in food and industrial appHcations. In the mining industry, guar gum is used as a flocculant or flotation agent, foam stabilizer, filtration aid, and water-treating agent. In the textile industry, it is used as a sizing agent and as a thickener for dyestuffs. The biggest consumer of guar gum is the paper industry where it faciHtates wet-end processing and improves the properties of the product. Guar gum is used as a thickening and gelling agent for slurry explosives as it readily hydrates in concentrated ammonium nitrate solutions, is easily cross-linked, and acts as a waterproofing agent for the final geUed product (57).  [c.435]

In the food industry, guar gum is appHed as a stabilizer in ice cream and frozen desserts (58), and it is also used as a stabilizer for salad dressings, sauces, frozen foods, and pet foods.  [c.435]

The most unusual property of xanthan gum is the reactivity with galactomaimans, such as guar gum and locust bean gum (80,81). The xanthan gum-locust bean gum combination at low gum concentration (less than 0.1%) has a significantly higher viscosity in solution than would be expected on the basis of the viscosity of the individual components. At higher gum concentrations (greater than 0.2%), a cohesive, thermoreversible gel is formed. Xanthan gum—guar gum combinations provide higher than expected viscosities, but do not form a gel.  [c.436]

Formation Aids. The repulsion of negatively charged fibers in water is not always sufficient to prevent all flocculation, which can result in uneven fiber density in paper. Dispersants can prevent flocculation prior to immobilization of the wet fiber mat on the wine. Polyacrylamide [9003-05-8] poly(ethylene oxide) [25322-68-3] and natural gums, eg, guar gum [9000-30-0] and locust bean gum [9000-40-2] promote even fiber distribution. High molecular weight anionic polymers, such as polyacrylates, lignin sulfonates, and naphthalene sulfonates, can also act as dispersants and enhance sheet formation, but they may impede drainage in some systems (24).  [c.16]

Wet-Web Strength Additives. When the wet sheet is transferred from the forming wire to the press section of the paper machine, it still contains 60—75% water. If there is inadequate sheet strength, breaks occur, resulting in machine downtime and lost production. A number of water-soluble chemical additives have been shown to enhance wet-web strength, including synthetic, eg, anionic polyacrylamides, and natural, eg, locust bean and guar gum, polymers. Several modified natural polymers have also shown promise, including chitosan (30), blocked reactive group starches with acetal protected aldehydes (31), and cationic aldehyde starches produced from them (32). These have replaced the previously successful dialdehyde starch which is made in Japan (31). Since these additives improve wet-web strength indirectly by improving formation and accelerating water removal from the forming sheet, other formation and drainage aids may also improve wet-web strength.  [c.16]

Na.tura.1 Gums. The mucilages from plant roots and stems, most notably guar gum, locust bean gum, and tamarind gum, may be used by papermakers to improve the strength of paper (60). Galactomannan is the effective natural polymer in the materials. These gums, of which guar is the most commercially available, tend to be irreversibly adsorbed on ceUulose pulp fibers and thus augment the hemiceUuloses (qv) formed during refining to impart strength to the paper. Cationic and amphoteric guar derivatives have been produced and used as strength additives in some appHcations, these derivatives are more effective than the naturally occurring gums. Gums are prepared as aqueous solutions before addition to the pulp slurry for ease of handling. In general, gums are used at 0.1—1.0 wt %, based on the dry pulp fibers (see Gums).  [c.19]

Hydrophilic polymers function as water-retention aids by preventing premature dewatering of the coatiag color after it has been appHed to the paper but before the paper has been dried. Water-soluble polymers, eg, CMC, hydroxyethjiceUulose [9004-62-0] guar gum and derivatives, and sodium alginate [9005-38-3] improve the rheological properties of coatiag colors and help keep the colors on the surface of the paper rather than striking into the sheet. Lubricants are added to coatiag colors to improve the lubricity of the wet coatiag color and to improve the properties of the dried coatiag. In particular, lubricants prevent sticking of the dry coatiags to surfaces of calenders. Common lubricants include calcium stearate [1592-23-0] fatty acid esters, sulfonated oils, and wax emulsions.  [c.22]

Guar gum is a nonionic, branched-chain polysaccharide, a galactomaiman that is usually hydroxypropylated for use in drilling (52). It produces viscous solutions in fresh or salt water at concentrations of ca 3—6 kg/m (1—2 lb /bbl). It is used in soHds-free and low soflds muds and degrades rapidly above 80°C, limiting its use to shallow wells.  [c.179]

For products intended to remain stable dispersions for an extended period, a particle size of 2 p.m or less is desirable. A thickening agent is usuaUy added after the reaction has been completed and the mixture is cooled in order to prevent settling and agglomeration. Examples of thickeners are guar gum, xanthan gum, and hydroxyethylceUulose. The final products are generaUy between 40 and 50% soUds, with a viscosity of 1500 5000 mPa-s(=cP).  [c.298]

Reagent Conditioning. This unit operation is carried out in two stages. Optimum pulp density in both stages is 50—60 wt %. The first stage involves agitating the deslimed ore with a clay depressant or slime blinder to deactivate clay particles that are entrained in the washed ore flowing from the hydraulic desliming operations. Suitable depressants include starches, guar gum, carboxymethyl ceUulose, and polyacrylamides. Depending on the amount of entrained clay and the type of depressant used, dosage rates are 50—500 g of depressant per metric ton of ore processed. Cost-effectiveness is usually the sole criterion in selecting a depressant. After 1 or 2 min of conditioning, the pulp enters the second-stage conditioner.  [c.525]

Cross-Linking of Polyols. Polyols such as natural polysaccharides, eg, cellulose, starch, guar gum and their derivatives, and polyvinyl alcohol and its derivatives can be cross-linked by organic titanates.  [c.164]

Polymer chains of guar gum and its derivatives, in fact of all galactomannans, are readily cross-linked with borate and titanium ions. Gels formed in this way are mbbery in nature.  [c.488]

Commercial locust bean gum is the ground endosperm of the seeds of the locust bean (carob) tree. The general properties of locust bean gum are similar to those of guar gum. Differences are its low cold-water solubiUty and its synergistic gelation with kappa-carrageenan, furceUaran, and xanthan  [c.488]

Job 3090 Exp./Gear/Gen./Ethvlene Plant -190 440 26,400 514 1996  [c.351]

ACR-30 Exp./Gear/Gen./Ethvlene Plant -50 1,116 7,600 5,333 1996  [c.351]

ACR-153 Exp./Gear/Gen./Enerqy Recovery 114 827 15,435 10336 1997  [c.351]

ACR-209 Exp.-Integ-Gear-Gen., MTBE Plant -200 163 28,770 391 1998  [c.351]

Na.tura.1 Products. The use of natural polymers has been known for a long time for example, the soluble protein albumin is used for clarifying wine. Since the 1950s the use of natural products as flocculating agents has steadily declined as more effective synthetics have taken their place. The only natural polymers used to a significant degree as flocculants are starch (qv) and guar gum (see Gums).  [c.32]

Guar Gum. Guar gum [9000-30-0], also a galactomannan, is extracted from the endosperm of the guar plant seed which is grown primarily in India and Pakistan. Guar hydrates rapidly in cold water and is used extensively in ice cream, cheese, and baked goods. Chemically, guar is closely related to locust bean gum and its use began as a result of a shortage of locust bean gum in the 1940s. The high price of guar gum has forced users to look to other materials for thickening agents (85).  [c.443]

Guar Gum. Guar gum [9000-30-0] is derived from the seed of the guar plant, Cjamopsis tetragonolobus a pod-bearing nitrogen-fixing legume grown extensively in Pakistan, India, and on a commercial scale since 1946, in the south-western United States. During processing, the seed coat is removed by heating and milling. The endosperm, comprising approximately 40% of the seed, is then separated from the germ by various milling processes. The final milled endosperm, which is commercial guar gum, has a typical analysis of cmde fiber, 2.5% moisture, 10—15% protein, 5—6% and ash,  [c.435]

Many derivatives of guar, including cationic, carboxymethyl, carboxy-methyUiydroxypropyl and oxidized guar, have been prepared. One in particular, hydroxypropyl guar gum [39421-75-5] is of industrial importance. Derivatization leads to subtle changes in properties, eg, decreased H-bonding, increased solubiHty in alcohol—water mixtures, and improved electrolyte compatibiHty. These changes result in increased use in textile appHcations and Hquid slurry explosives. In addition, the decrease in insolubles in the derivatized product has resulted in appHcation of hydroxypropyl guar gum in oil-weU fracturing appHcations (59).  [c.435]

In the food industry, locust bean gum is used as a stabilizer in ice cream and in the preparation of processed cheese and extmded meat products. It is also used as an emulsifier and stabilizer of dressings and sauces and overall has similar properties to those outiined for guar gum.  [c.435]

A wide variety of organic polymers serve a number of useful purposes ia drilling fluids, the most important of which are to iacrease viscosity and control filtration rates (Table 5). These polymers are either natural polysaccharides, eg, s. 2nxh.[9005-25-8] (qv),guar gum, xanthan gum [11138-66-2] and other biopolymers (see Gums Microbialpolysaccharides) or derivatives of natural polymers, eg, cehulose (qv), lignosulfonate, and lignite and synthetic polymers, eg, polymers and copolymers of acryflc acid, acrylonittile, acrylamide, and 2-acrylamido-2-methylpropanesulfonic acid (AMPS). The most commonly used polymeric viscosity budders are the cehulosics, xanthan gum, and polyacrylamides.  [c.178]

Guar and Locust Bean Gums. Guaran, the purified polysaccharide from guar gum [9000-30-0], is a galactomaiman [11078-30-1]. It has a man nan backbone, a linear chain of (1 — 4)-1inked P-D-maimopyranosyl units with, on the average, one of every 1.8 mannosyl units substituted with a (1 — 6)-linked a-D-galactopyranosyl unit. The man nan chain is rather evenly substituted with D-galactopyranosyl units but still contains some unsubstituted or smooth regions. Its molecular weight is 220, 000 A 20, 000 daltons (DP 1360 A 125).  [c.488]

Commercial guar gum is not purified guaran but the ground endosperm of guar seeds. Guar gum forms very high viscosity, pseudoplastic solutions at low concentrations. Guar endosperm preparations can be derivati2ed with the same reagents and catalysts used to modify starch and cellulose. The following products are prepared by proprietary processes hydroxypropyl- [39421-75-5], hydroxyethyl- [39465-11-7], sodium carboxymethyl- [51190-15-3], sodiumcarboxymethyl(hydroxypropyl)- [39454-79-0], and 2-hydroxy-3-(trimethylammonio)propyl- [67034-33-7], (made as its chloride salt [65497-29-2]) guar gums. Derivatives are made to control the rate of hydration, peak viscosity, ash content, insoluble material, heat stabiUty, and compatibiUty with other materials.  [c.488]

Microcrystalline ceUuloses ate marketed under the trade name Avicel. The physical characteristics of microcrystalline ceUuloses differ markedly from those of the original ceUulose. The ftee-flowiag powders have particle sizes as smaU as 0.2—10 p.m. Avicel ceUuloses coated with xanthan gum, guar gum, or carboxy-methylceUulose to modify and stabilize their properties are also available. The Avicel products are promoted for use ia low calorie whipped toppiags andiciags andia fat-reduced salad dressiags and frozen desserts (see Fat substitutes).  [c.72]

Water gels, introduced in 1958, were mixtures of ammonium nitrate, TNT, water, and gelatinizing agents (guar gum and a cross-linking agent such as borax). Sometimes aluminum and other metals were used and better gelatinizers have been developed. In addition nonexplosive sensitizers were developed to dilute the TNT. Water gels have the advantages of high yield, high dcL ree of water resistance, plasticity, ease of handling and loading, and good safety chariictcristics  [c.275]


See pages that mention the term Guar gum : [c.457]    [c.314]    [c.24]    [c.444]    [c.430]    [c.369]    [c.191]    [c.192]    [c.486]    [c.486]    [c.486]    [c.443]    [c.70]    [c.73]    [c.351]   
Standard Handbook of Petroleum and Natural Gas Engineering Volume 1 (1996) -- [ c.709 ]