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 as its sodium salt, sodium carboxymethyl cellulose.

Uses :

CMC is used in food under the E number E466 as a viscosity modifier or thickener, and to stabilize emulsions in various products including ice cream. It is also a constituent of many non-food products, such as toothpaste, laxatives, diet pills, water-based paints, detergents, textile sizing, and various paper products. 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.  . CMC is used extensively in gluten free and reduced fat food products.

CMC is also used in pharmaceuticals as a thickening agent.

CMC powder is widely used in the ice cream industry. It is used to make ice creams without churning mechanism or extreme low temperatures thereby eliminating the need of the conventional churners or salt ice mixes. CMC is used in bakery products like breads and cake preparation. The use of CMC gives loaf a much improved quality at a reduced cost to the baker economizing on the fat component. CMC is also used as an emulsifier in producing high quality biscuits. Due to CMC, fat disperses uniformly in the dough and hence CMC improves the release of the dough from the moulds and cutters to achieve well-shaped biscuits without any distorted edges. It can help to reduce consumption of egg yolk or fat used in making biscuits, thus achieving economy. Use of CMC in candy preparation ensures smooth dispersion in flavour oils, improves texture & quality. They are used in chewing gums, margarines and peanut butter as emulsifier, also it is used in leather crafting to burnish the edges. It is edible.

wikipedia