CMC, also called sodium carboxymethyl cellulose, carboxymethylcellulose or carboxymethyl cellulose, is an anionic polyelectrolyte, soluble in water, whose properties allow applications such as a thickening agent, emulsifier, adhesive binder, wetting, dispersant, etc

In laundry detergents, CMC is used as a soil suspension polymer designed to deposit onto cotton and other cellulosic fabrics, creating a negatively charged barrier to soils in the wash solution.

CMC is also used as a thickening agent, for example, in the oil-drilling industry as an ingredient of drilling mud, where it acts as a viscosity modifier and water retention agent.

CMC is sometimes used as an electrode binder in advanced battery applications (i.e. lithium ion batteries), especially with graphite anodes. 

CMC's water solubility allows for less toxic and costly processing than with non-water-soluble binders, like the traditional polyvinylidene fluoride (PVDF), which requires toxic n-methylpyrrolidone (NMP) for processing. 

CMC is often used in conjunction with styrene-butadiene rubber (SBR) for electrodes requiring extra flexibility, e.g. for use with silicon-containing anodes.

CMC is also used in ice packs to form a eutectic mixture resulting in a lower freezing point, and therefore more cooling capacity than ice.

Aqueous solutions of CMC have also been used to disperse carbon nanotubes, where the long CMC molecules are thought to wrap around the nanotubes, allowing them to be dispersed in water.

In conservation-restoration, it is used as an adhesive or fixative 

Other names

Synonyms: CMC, sodium carboxymethyl cellulose, carboxymethylcellulose, carboxymethyl cellulose, CMC, sodium CMC, or cellulose gum, Carboxymethylcellulose, carmellose, E466

Identifiers

CAS Number

9004-32-4

EC / List no.: 618-378-6

CAS no.: 9004-32-4

Sodium Carboxymethylcellulose

Carboxymethyl cellulose is widely used in food products to absorb and hold water, to control crystal growth, to thicken, as a binder, to increase shelf life, and to provide desired texture or body. 

As Carboxymethyl cellulose is anionic it can form complexes with milk proteins depending on the formulation. 

In addition, high salt concentration has negative influence on viscosity due to masking of electrostatic interactions between CMC chains. 

CMC can be used to control ice crystal growth in ice cream (Regand and Goff, 2003) or as a rheology modifier in yoghurt formulations

CMC's largest volume use is in the preparation of dry pet foods that form their own gravy when warm water is added. 

Its second largest use is in the preparation of ice cream, sherbets, and other frozen desserts. 

CMC is the primary stabilizer in most ice cream products, where it is used to prevent growth of ice crystals. 

Keeping ice crystals small maintains the smooth, creamy consistency of the product. 

CMC also controls sugar crystal size in fondants.

CMC is used when proteins must be stabilized, such as in yogurt, fruit, soy, and other acidic drinks containing protein. 

CMC, a polyvalent anion, can stabilize protein dispersions, especially near their isoelectric pH value where they are least soluble, because the protein molecules will have multiple positive charges and can bind to CMC molecules. 

Using CMC, milk products can be stabilized against casein precipitation when milk is acidified because CMC forms stable soluble complexes with casein at pH values in the range 3–6 where casein is insoluble.

Because of its rapid hydration, it affects hydration of other dry mix components. 

CMC is both a binder and an extrusion aid in the preparation of pet foods and other extruded products. 

In baked goods, like cakes, CMC is added to adjust the consistency of the batter, to increase product volume, to improve the quality of the finished product, to provide moisture retention, and to prolong freshness

CMC (CMC) is an anionic, water-soluble cellulose derivative. 

Solubility of CMC depends on the DP as well as the degree of substitution and the uniformity of the substitution distribution. 

Water solubility of CMC would increase with decreased DP and increased carboxymethyl substitution and substitution uniformity. 

The viscosity of the solution increases with increasing DP and increasing concentration.

CMC is soluble in water at any temperature. 

Because of its highly hygroscopic nature, CMC hydrates rapidly. 

Rapid hydration may cause agglomeration and lump formation when the CMC powder is introduced into water. 

Lump creation can be eliminated by applying high agitation while the powder is added into the water or preblending the CMC powder with other dry ingredients such as sugar before adding into water.

Due to its high solubility and clarity of its solutions, CMC is commonly used in beverages and beverage dry mixes to provide rich mouthfeel. 

CMC is also used in acidified protein drinks to stabilize protein and prevent it from precipitating. 

Sodium Carboxymethyl cellulose is also added to syrup and sauce formulations to increase viscosity. 

Bakery is another application where Sodium Carboxymethyl cellulose is commonly used to improve the quality and the consistency of the end product. 

In tortilla breads, for example, Sodium Carboxymethyl cellulose is used to improve the process ability of the dough and the textural properties of the end product, including foldability and rollability.

Sodium Carboxymethyl cellulose - usually forms a clear, colourless and tasteless solution. 

Sodium Carboxymethyl celluloseis cold water soluble and some grades have a tolerance to high concentrations of sugar. 

It is available in a wide range of viscosities and has good heat stability. 

Sodium Carboxymethyl cellulose is a good film former.

Ice cream: Sodium Carboxymethyl cellulose is a common stabilizer in ice cream. 

Sodium Carboxymethyl cellulose is cold water soluble and this gives it an advantage in ice cream mixes that are not subject to high temperatures. 

Unlike locust bean gum CMC does not give the ice cream any added melt-down resistance. 

Sodium Carboxymethyl cellulose is more commonly used in the USA than in Europe and this may be related to a higher proportion of the European market being novelty items that benefit from improved melt-down resistance.

Bakery: Sodium Carboxymethyl cellulose is commonly used in cakes, muffins and tortillas to improve the texture of the product by increasing moisture retention.

Beverages: Sodium Carboxymethyl cellulose is used as a stabilizer in fruit drinks and in drink concentrates. 

Fruit drinks typically consist of fruit juice that is diluted with water. 

To improve the taste and texture of the drink a citric acid/citrate buffer is usually added, some extra sugar and CMC can be added to improve the mouthfeel of the drink. 

Low calorie drinks that do not have the viscosity contribution from the added sugar will have a very thin and watery mouthfeel without the addition of a viscosity modifier. 

Uses

Introduction

Sodium Carboxymethyl cellulose is used as a viscosity modifier or thickener, and to stabilize emulsions in various products, both food and non-food. 

It is used primarily because it has high viscosity, is nontoxic, and is generally considered to be hypoallergenic, as the major source fiber is either softwood pulp or cotton linter. 

Non-food products include products such as toothpaste, laxatives, diet pills, water-based paints, detergents, textile sizing, reusable heat packs, various paper products, and also in leather crafting to help burnish edges.[6][7][verification needed]

Enzymology

Insoluble micro granular Sodium Carboxymethyl cellulose is used as a cation-exchange resin in ion-exchange chromatography for the purification of proteins.

The level of derivatization is much lower,[according to whom?] so the solubility properties of micro granular cellulose are retained, while adding sufficient negatively charged carboxylate groups to bind to positively charged proteins.

Moreover, Sodium Carboxymethyl cellulose has also been used extensively to characterize enzyme activity from endoglucanases (part of the cellulase complex); it is a highly specific substrate for endo-acting cellulases, as its structure has been engineered to decrystallize cellulose and create amorphous sites that are ideal for endoglucanase action.

Sodium Carboxymethyl cellulose is desirable because the catalysis product (glucose) is easily measured using a reducing sugar assay, such as 3,5-dinitrosalicylic acid.

Using Sodium Carboxymethyl cellulose in enzyme assays is especially important in screening for cellulase enzymes that are needed for more efficient cellulosic ethanol conversion.

Sodium Carboxymethyl cellulose was misused in early work with cellulase enzymes, as many had associated whole cellulase activity with Sodium Carboxymethyl cellulose hydrolysis.

As the mechanism of cellulose depolymerization became better understood, it became clear that exo-cellulases are dominant in the degradation of crystalline (e.g. Avicel) and not soluble (e.g. CMC) cellulose.

Food science

Sodium Carboxymethyl cellulose is used in food under the E number E466 or E469 (when it is enzymatically hydrolyzed), as a viscosity modifier or thickener, and to stabilize emulsions in various products, including ice cream.

Sodium Carboxymethyl cellulose is also used extensively in gluten-free and reduced-fat food products.

Sodium Carboxymethyl cellulose is used to achieve tartrate or cold stability in wine, an innovation that may save megawatts of electricity used to chill wine in warm climates. 

It is more stable than metatartaric acid and is very effective in inhibiting tartrate precipitation. 

It is reported that KHT crystals, in presence of Sodium Carboxymethyl cellulose, grow slower and change their morphology.

Sodium Carboxymethyl cellulose molecules, negatively charged at wine pH, interact with the electropositive surface of the crystals, where potassium ions are accumulated. 

The slower growth of the crystals and the modification of their shape are caused by the competition between Sodium Carboxymethyl cellulose molecules and bitartrate ions for binding to the KHT crystals.

Specific culinary uses

Sodium Carboxymethyl cellulose powder is widely used in the ice cream industry, to make ice creams without churning or extremely low temperatures, thereby eliminating the need for conventional churners or salt ice mixes.

Sodium Carboxymethyl cellulose is used in baking breads and cakes. 

The use of Sodium Carboxymethyl cellulose gives the loaf an improved quality at a reduced cost, by reducing the need of fat. 

Sodium Carboxymethyl cellulose is also used as an emulsifier in biscuits. 

By dispersing fat uniformly in the dough, it improves the release of the dough from the moulds and cutters, achieving well-shaped biscuits without any distorted edges. 

It can also help to reduce the amount of egg yolk or fat used in making the biscuits. 

Use of Sodium Carboxymethyl cellulose in candy preparation ensures smooth dispersion in flavor oils, and improves texture and quality. 

Sodium Carboxymethyl cellulose is used in chewing gums, margarines and peanut butter as an emulsifier.

In veterinary medicine, Sodium Carboxymethyl cellulose is used in abdominal surgeries in large animals, particularly horses, to prevent the formation of bowel adhesions.

In laundry detergents, it is used as a soil suspension polymer designed to deposit onto cotton and other cellulosic fabrics, creating a negatively charged barrier to soils in the wash solution.

Sodium Carboxymethyl cellulose is also used as a thickening agent, for example, in the oil-drilling industry as an ingredient of drilling mud, where it acts as a viscosity modifier and water retention agent.

Sodium Carboxymethyl cellulose is sometimes used as an electrode binder in advanced battery applications (i.e. lithium ion batteries), especially with graphite anodes. 

Sodium Carboxymethyl cellulose's water solubility allows for less toxic and costly processing than with non-water-soluble binders, like the traditional polyvinylidene fluoride (PVDF), which requires toxic n-methylpyrrolidone (NMP) for processing. 

Sodium Carboxymethyl cellulose is often used in conjunction with styrene-butadiene rubber (SBR) for electrodes requiring extra flexibility, e.g. for use with silicon-containing anodes.

Sodium Carboxymethyl cellulose is also used in ice packs to form a eutectic mixture resulting in a lower freezing point, and therefore more cooling capacity than ice.

Aqueous solutions of Sodium Carboxymethyl cellulose have also been used to disperse carbon nanotubes, where the long Sodium Carboxymethyl cellulose molecules are thought to wrap around the nanotubes, allowing them to be dispersed in water.

In conservation-restoration, it is used as an adhesive or fixative