Sodium carboxymethyl cellulose

Sodium carboxymethyl cellulose (also known as CMC or cellulose gum) is a sodium salt derived from cellulose. It is widely used in the food industry as a viscosity modifier or thickener, and to stabilize emulsions in various products.

Chemical Structure

Sodium carboxymethyl cellulose is a cellulose derivative in which the hydroxyl groups of the original cellulose are etherified with a carboxymethyl group (-CH2-COOH). The degree of substitution (DS) of carboxymethyl groups on the cellulose backbone can vary between 0.7 and 1.2, depending on the manufacturing process.

Production

The production of sodium carboxymethyl cellulose begins with the reaction of cellulose with alkali, typically sodium hydroxide, to activate the cellulose. This is followed by etherification, where monochloroacetic acid or its sodium salt is added to the alkali-cellulose mixture. The resulting product is then washed, dried, and milled to produce sodium carboxymethyl cellulose of the desired particle size.

Applications

Sodium carboxymethyl cellulose has a wide range of applications due to its ability to modify viscosity, form films, and stabilize emulsions. In the food industry, it is used as a thickener, stabilizer, and texture improver in products such as ice cream, baked goods, and dairy products. It is also used in pharmaceuticals as a binder and disintegrant in tablet formulation, and in cosmetics as a viscosity modifier.

In addition to these, sodium carboxymethyl cellulose is used in oil drilling as a viscosity modifier and water retention agent, in papermaking as a binder and strength additive, and in detergents as a soil suspension polymer.

Safety and Regulatory Aspects

Sodium carboxymethyl cellulose is generally recognized as safe (GRAS) by the FDA and is approved for use in food with no limitation other than current good manufacturing practice. It is also approved for use in food by the EFSA and other regulatory bodies around the world.

See Also

• Cellulose
• Food additives
• Emulsion