XANTHAN GUM

XANTHAN GUM

CAS:    11138-66-2

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

SYNONYMS: GUM XANTHAN; GLUCOMANNAN; GLUCOMANNAN MAYO; GALACTOMANNANE; XANTHANGUM,FCC; XANTHANGUM,NF; XANTHATEGUM; Xanthan Gummi; GLUCOMANNAN; GLUCOMANNAN MAYO; GALACTOMANNANE; RHODOPOL 23; XANTHAN; Corn sugar gum; E415; XC Polymer; Xanthomonas campestris; Kelzan; Goma Xantana; gomma; Gomme de Sucre de Maïs; Corn sugar gum; xantan gan; xanthan gum; ksantangam; gam; ksantan gam; xantan gum; xhanthan gum; Xanthan; Xanthan gum; Corn sugar gum; Xanthan; Xanthan gum; Xanthan gum [NF]; Corn Sugar Gum; Gummi Xanthanum; Xanthan Gum Oileld; Xanthan Gum Dispersible; Corn sugar gum; Xanthan; Gum xanthan; UNII-TTV12P4NEE; Xanthan-Gum; 11138-66-2 Xanthan gum; Xanthan gum from Xanthomonas campestris; Biozan R; xanthan; xanthan gum; 9H-Xanthene; XANTHENE; 92-83-1; Xanthan; 10H-9-Oxaanthracene; XANTHAN GUM; Dibenzo[a,e]pyran; NSC 46931; UNII-A762Z8101Y; Dibenzopyran, tricyclic;EINECS 202-194-4; BRN 0133939; AI3-01544; CHEBI:10057; GJCOSYZMQJWQCA-UHFFFAOYSA-N; SBB059332; A762Z8101Y; AK110825; 9H-xanthen; SMR000857210; Xanthane; 9h-xanthen-9-yl; Xanthene, 99%; XANTHAN GUMNF; XANTHANGUMNF; XANTHENE; xanthene; stabiliser, E415, thickenerXANTHAM; XANTHAN;Keltrol F;RHODOPOL 23;GLUCOMANNAN; GUM XANTHAN; XANTHAN GUM; XANTHATEGUM;XANTEMPO(TM); Xanthane gum; Gelatin Guar gum DEHYDROXANTHAN GUM Xanthan gum, acetate UNDECYLENOYL XANTHAN GUM HYDROXYPROPYL XANTHAN GUM XANTHAN GUM; 80 MESH PHARMA GRADE XANTHAN GUM; 80MESH; FOOD GRADE XANTHAN GUM FOOD GRADE XANTHAN GUM (INSTRUCTIONS XANTHAN GUM 200 MESH XANTHAN GUM; 200MESH; FOOD GRADE GUM XANTHAN GLUCOMANNAN GLUCOMANNAN MAYO GALACTOMANNANE; 11138-66-2 Carbohydrates RHODOPOL 23 Polysaccharide XANTHAN XANT; n; Xanthan gum; Corn sugar gum; Xanthan; Xanthan gum; Xanthan gum [NF]; Corn Sugar Gum; Gummi Xanthanum; Xanthan Gum Oileld; Xanthan Gum Dispersible; Corn sugar gum; Xanthan; Gum xanthan; UNIITTV12P4NEE; Xanthan-Gum

CAS Number: 11138-66-2
Chemical formula: C35H49O29 (monomer)
Molar mass: 933.748 g·mol−1

Xanthan gum was discovered by Allene Rosalind Jeanes and her research team at the United States Department of Agriculture, and brought into commercial production by CP Kelco under the trade name Kelzan in the early 1960s. It was approved for use in foods in 1968 and is accepted as a safe food additive in the USA, Canada, European countries, and many other countries, with E number E415, and CAS number 11138-66-2.
Xanthan gum derives its name from the species of bacteria used during the fermentation process, Xanthomonas campestris. This is the same bacterium responsible for causing black rot to form on broccoli, cauliflower, and other leafy vegetables.

USES

Xanthan gum, 1%, can produce a significant increase in the viscosity of a liquid. In foods, xanthan gum is common in salad dressings and sauces. It helps to prevent oil separation by stabilizing the emulsion, although it is not an emulsifier. Xanthan gum also helps suspend solid particles, such as spices. Xanthan gum helps create the desired texture in many ice creams. Toothpaste often contains xanthan gum as a binder to keep the product uniform. Xanthan gum also helps thicken commercial egg substitutes made from egg whites, to replace the fat and emulsifiers found in yolks. It is also a preferred method of thickening liquids for those with swallowing disorders, since it does not change the color or flavor of foods or beverages at typical use levels. In gluten-free baking, xanthan gum is used to give the dough or batter the stickiness that would otherwise be achieved with gluten. In most foods it is used at concentrations of 0.5% or less. Xanthan gum is used in wide range food products, such as sauces, dressings, meat and poultry products, bakery products, confectionery products, beverages, dairy products, others.
In the oil industry, xanthan gum is used in large quantities to thicken drilling mud. These fluids carry the solids cut by the drilling bit to the surface. Xanthan gum provides great "low end" rheology. When circulation stops, the solids remain suspended in the drilling fluid. The widespread use of horizontal drilling and the demand for good control of drilled solids has led to its expanded use. It has been added to concrete poured underwater, to increase its viscosity and prevent washout.
In cosmetics, xanthan gum is used to prepare water gels. It is also used in oil-in-water emulsions to enhance droplet coalescence. Xanthan gum is under preliminary research for its potential uses in tissue engineering to construct hydrogels and scaffolds supporting three-dimensional tissue formation.

Shear thinning

The viscosity of xanthan gum solutions decreases with higher shear rates. This is called shear thinning or pseudoplasticity. This means that a product subjected to shear, whether from mixing, shaking or chewing will thin. When the shear forces are removed, the food will thicken again. In salad dressing, the addition of xanthan gum makes it thick enough at rest in the bottle to keep the mixture fairly homogeneous, but the shear forces generated by shaking and pouring thins it, so it can be easily poured. When it exits the bottle, the shear forces are removed and it thickens again, so it clings to the salad.
Amounts used
The greater the ratio of xanthan gum added to a liquid, the thicker the liquid will become. An emulsion can be formed with as little as 0.1% (by weight). Increasing the amount of gum gives a thicker, more stable emulsion up to 1% xanthan gum. A teaspoon of xanthan gum weighs about 2.5 grams and brings one cup (250 ml) of water to a 1% concentration. 
To make a foam, 0.2–0.8% xanthan gum is typically used. Larger amounts result in larger bubbles and denser foam. Egg white powder (0.2–2.0%) with 0.1–0.4% xanthan gum yields bubbles similar to soap bubbles.
Health
Evaluation of workers exposed to xanthan gum dust found evidence of a link to respiratory symptoms. 
On May 20, 2011, the FDA issued a press release about SimplyThick, a food-thickening additive containing xanthan gum as the active ingredient, warning parents, caregivers and health care providers not to feed SimplyThick, a thickening product, to premature infants. The concern is that the product may cause premature infants to suffer necrotizing enterocolitis.

Safety

According to a 2017 safety review by a scientific panel of the European Food Safety Authority (EFSA), xanthan gum (European food additive number E 415) is extensively digested during intestinal fermentation, and causes no adverse effects, even at high intake amounts. The EFSA panel found no concern about genotoxicity from long-term consumption. EFSA concluded that there is no safety concern for the general population when xanthan gum is consumed as a food additive. 
Preparation
Xanthan gum is produced by the fermentation of glucose and sucrose. The polysaccharide is prepared by the bacteria being inoculated into a sterile aqueous solution of carbohydrate(s), a source of nitrogen, dipotassium phosphate, and some trace elements. The medium is well-aerated and stirred, and the xanthan polymer is produced extracellularly into the medium. After one to four days, the polymer is precipitated from the medium by the addition of isopropyl alcohol, and the precipitate is dried and milled to give a powder that is readily soluble in water or brine. 
It is composed of pentasaccharide repeat units, comprising glucose, mannose, and glucuronic acid in the molar ratio 2:2:1. 
A strain of X. campestris has been developed that will grow on lactose - which allows it to be used to process whey, a waste product of cheese production. This can produce 30 g/L of xanthan gum for every 40 g/L of whey powder. Whey-derived xanthan gum is commonly used in many commercial products, such as shampoos and salad dressings. 
Detail of the biosynthesis

Synthesis originates from glucose as substrate for synthesis of the sugar nucleotides precursors UDP-glucose, UDP-glucuronate, and GDP-mannose that are required for building the pentasaccharide repeat unit. This links the synthesis of xanthan to carbohydrate metabolism. The repeat units are built up at undecaprenylphosphate lipid carriers that are anchored in the cytoplasmic membrane. 
Specific glycosyltransferases sequentially transfer the sugar moieties of the nucleotide sugar xanthan precursors to the lipid carriers. Acetyl and pyruvyl residues are added as non-carbohydrate decorations. Mature repeat units are polymerized and exported in a way resembling the Wzy-dependent polysaccharide synthesis mechanism of Enterobacteriaceae. Products of the gum gene cluster drive synthesis, polymerization, and export of the repeat unit. 

Chemical Properties

viscosity of 1% solution 1,200-1,600 mPas

Chemical Properties

Xanthan gum occurs as a cream- or white-colored, odorless, freeflowing, fine powder.

Uses

Xanthan Gum is a gum obtained by microbial fermentation from the xanthomonas campestris organism. it is very stable to viscosity change over varying temperatures, ph, and salt concentrations. it is also very pseudoplastic which results in a decrease in viscosity with increasing shear. it reacts synergistically with guar gum and tara gum to provide an increase in viscosity and with carob gum to provide an increase in viscosity or gel formation. it is used in salad dressings, sauces, desserts, baked goods, and beverages at 0.05–0.50%.

In foods, pharmaceuticals, and cosmetics as stabilizer and thickening agent. For rheology control in water-based systems. In oil and gas drilling and completion fluids.

Xanthan gum (corn starch gum) serves as a texturizer, carrier agent, and gelling agent in cosmetic preparations. It also stabilizes and thickens formulations. This gum is produced through a fermentation of carbohydrate and Xanthomonas campestris.

Production Methods

Xanthan gum is a polysaccharide produced by a pure-culture aerobic fermentation of a carbohydrate with Xanthomonas campestris. The polysaccharide is then purified by recovery with propan-2-ol, dried, and milled.

Pharmaceutical Applications

Xanthan gum is widely used in oral and topical pharmaceutical formulations, cosmetics, and foods as a suspending and stabilizing agent. It is also used as a thickening and emulsifying agent. It is nontoxic, compatible with most other pharmaceutical ingredients, and has good stability and viscosity properties over a wide pH and temperature range. Xanthan gum gels show pseudoplastic behavior, the shear thinning being directly proportional to the shear rate. The viscosity returns to normal immediately on release of shear stress.
Xanthan gum has been used as a suspending agent for conventional, dry and sustained-release suspensions. When xanthan gum is mixed with certain inorganic suspending agents, such as magnesium aluminum silicate, or organic gums, synergistic rheological effects occur. In general, mixtures of xanthan gum and magnesium aluminum silicate in ratios between 1 : 2 and 1 : 9 produce the optimum properties. Similarly, optimum synergistic effects are obtained with xanthan gum : guar gum ratios between 3 : 7 and 1 : 9.

Although primarily used as a suspending agent, xanthan gum has also been used to prepare sustained-release matrix tablets. Controlled-release tablets of diltiazem hydrochloride prepared using xanthan gum have been reported to sustain the drug release in a predictable manner, and the drug release profiles of these tablets were not affected by pH and agitation rate. Xanthan gum has also been used to produce directly compressed matrices that display a high degree of swelling due to water uptake, and a small amount of erosion due to polymer relaxation. It has also been used in combination with chitosan, guar gum, galactomannan, and sodium alginate to prepare sustained-release matrix tablets. Xanthan gum has been used as a binder, and in combination with Konjac glucomannan is used as an excipient for controlled colonic drug delivery. Xanthan gum with boswellia (3 : 1) and guar gum (10 : 20) have shown the best release profiles for the colon-specific compression coated systems of 5- fluorouracil for the treatment of colorectal cancer. Xanthan gum has also been used with guar gum for the development of a floating drug delivery system.It has also has derivatized to sodium carboxymethyl xanthan gum and crosslinked with aluminum ions to prepare microparticles, as a carrier for protein delivery. Xanthan gum has been incorporated in an ophthalmic liquid dosage form, which interacts with mucin, thereby helping in the prolonged retention of the dosage form in the precorneal area. When added to liquid ophthalmics, xanthan gum delays the release of active substances, increasing the therapeutic activity of the pharmaceutical formulations.
Xanthan gum can be used to increase the bioadhesive strength in vaginal formulations. Xanthan gum alone or with carbopol 974P has been used as a mucoadhesive controlled-release excipient for buccal drug delivery. Modified xanthan films have been used as a matrix system for transdermal delivery of atenolol. Xanthan gum has also been used as a gelling agent for topical formulations incorporating solid lipid nanoparticles of vitamin A or microemulsion of ibuprofen. A combined polymer system consisting of xanthan gum, carboxy methylcellulose and a polyvinyl pyrolidone backboned polymer has been used for relieving the symptoms of xerostomia. Xanthan gum can also be used as an excipient for spray-drying and freeze-drying processes for better results. It has been successfully used alone or in combination with agar for microbial culture media.

Xanthan gum is also used as a hydrocolloid in the food industry, and in cosmetics it has been used as a thickening agent in shampoo. Polyphosphate with xanthum gum in soft drinks is suggested to be effective at reducing erosion of enamel.

Safety Profile

When heated to decomposition it emits acrid smoke and irritating fumes.

Safety

Xanthan gum is widely used in oral and topical pharmaceutical formulations, cosmetics, and food products, and is generally regarded as nontoxic and nonirritant at the levels employed as a pharmaceutical excipient.
The estimated acceptable daily intake for xanthan gum has been set by the WHO at up to 10 mg/kg body-weight.
No eye or skin irritation has been observed in rabbits and no skin allergy has been observed in guinea pigs following skin exposure. No adverse effects were observed in long term feeding studies with rats (up to 1000 mg/kg/day) and dogs (up to 1000 mg/kg/day). No adverse effects were observed in a three-generation reproduction study with rats (up to 500 mg/kg/day).
LD50 (dog, oral): >20 g/kg
LD50 (rat, oral): >45 g/kg
LD50 (mouse, oral): >1 g/kg
LD50 (mouse, IP): >50 mg/kg
LD50 (mouse, IV): 100–250 mg/kg

Xanthan gum is a stable material. Aqueous solutions are stable over a wide pH range (pH 3–12), although they demonstrate maximum stability at pH 4–10 and temperatures of 10–60°C. Xanthan gum solutions of less than 1% w/v concentration may be adversely affected by higher than ambient temperatures: for example, viscosity is reduced. Xanthan gum provides the same thickening, stabilizing, and suspending properties during long-term storage at elevated temperatures as it does at ambient conditions. In addition, it ensures excellent freeze–thaw stability. Solutions are also stable in the presence of enzymes, salts, acids, and bases. Vanzan NF-ST is especially designed for use in systems containing high salt concentrations as it dissolves directly in salt solutions, and its viscosity is relatively unaffected by high salt levels as compared with general purpose grades.

The bulk material should be stored in a well-closed container in a cool, dry place.

Incompatibilities

Xanthan gum is an anionic material and is not usually compatible with cationic surfactants, polymers, or preservatives, as precipitation occurs. Anionic and amphoteric surfactants at concentrations above 15% w/v cause precipitation of xanthan gum from a solution.
Under highly alkaline conditions, polyvalent metal ions such as calcium cause gelation or precipitation; this may be inhibited by the addition of a glucoheptonate sequestrant. The presence of low levels of borates (<300 ppm) can also cause gelation. This may be avoided by increasing the boron ion concentration or by lowering the pH of a formulation to less than pH 5. The addition of ethylene glycol, sorbitol, or mannitol may also prevent this gelation.
Xanthan gum is compatible with most synthetic and natural viscosity-increasing agents, many strong mineral acids, and up to 30% inorganic salts. If it is to be combined with cellulose derivatives, then xanthan gum free of cellulase should be used to prevent depolymerization of the cellulose derivative. Xanthan gum solutions are stable in the presence of up to 60% water-miscible organic solvents such as acetone, methanol, ethanol, or propan-2- ol. However, above this concentration precipitation or gelation occurs.

The viscosity of xanthan gum solutions is considerably increased, or gelation occurs, in the presence of some materials such as ceratonia, guar gum, and magnesium aluminum silicate. This effect is most pronounced in deionized water and is reduced by the presence of salt. This interaction may be desirable in some instances and can be exploited to reduce the amount of xanthan gum used in a formulation.
Xanthan gum is incompatible with oxidizing agents, some tablet film-coatings, carboxymethylcellulose sodium, dried aluminum hydroxide gel, and some active ingredients such as amitriptyline, tamoxifen, and verapamil.