CMC use in food
Sodium carboxymethyl cellulose ( carboxymethyl cellulose, sodium CMC) is a carboxymethylated derivative of cellulose, also known as cellulose gum, and is the most important ionic cellulose gum.
CMC is usually an anionic polymer compound obtained by reacting natural cellulose with caustic alkali and monochloroacetic acid. The molecular weight of the compound ranges from several thousand to one million. the unit knot of a molecule
CMC belongs to the modification of natural cellulose. At present, the Food and Agriculture Organization of the United Nations (FAO) and the World Health Organization (WHO) have officially called it “modified cellulose”. The synthesis method of sodium carboxymethyl cellulose was invented by German E.Jansen in 1918, and was patented in 1921 and made known to the world, since then it has been commercialized in Europe.
CMC was only used for crude products, as colloid and binder. From 1936 to 1941, the industrial application research of sodium carboxymethyl cellulose was quite active, and several quite enlightening patents were published. During World War II, Germany used CMC in synthetic detergents as an anti-redeposition agent, And as a substitute for some natural gums (such as gelatin, gum arabic), the CMC industry has been greatly developed.
CMC is widely used in petroleum, geological , daily chemical, food, medicine and other industries, known as “industrial monosodium glutamate”.
01PART
Structural properties of CMC
CMC is a white or slightly yellow powder, granular or fibrous solid. It is a macromolecular chemical substance that can absorb water and swell. When swollen in water, it can form a transparent viscous glue. The pH of the aqueous suspension is 6.5-8.5. The substance is insoluble in organic solvents such as ethanol, ether, acetone and chloroform.
Solid CMC is stable to light and room temperature, and can be stored for a long time in a dry environment. CMC is a kind of cellulose ether. It is usually made from short cotton linter (cellulose content up to 98%) or wood pulp, which is treated with sodium hydroxide and then reacted with sodium monochloroacetate. The molecular weight of the compound is 6400 (± 1000). There are usually two preparation methods: the coal-water method and the solvent method. There are also other plant fibers that are used to make CMC.
02PART
Features and Applications
CMC is not only a good emulsion stabilizer and thickener in food applications, but also has excellent freezing and melting stability, and can improve the flavor of the product and prolong the storage time.
In 1974, the Food and Agriculture Organization of the United Nations (FAO) and the World Health Organization (WHO) approved the use of pure CMC for food after rigorous biological and toxicological studies and tests. The international standard safe intake (ADI) is 25mg/ kg body weight/day.
2.1 Thickening and emulsification stability
Eating CMC can play a role in emulsification and stabilization of beverages containing oil and protein. This is because CMC becomes a transparent stable colloid after being dissolved in water, and the protein particles become particles with the same charge under the protection of the colloid film, which can make the protein particles in a stable state. It also has a certain emulsification effect, so at the same time, it can reduce the surface tension between fat and water, so that the fat can be fully emulsified.
CMC can improve the stability of the product because when the pH value of the product deviates from the isoelectric point of the protein, sodium carboxymethyl cellulose can form a complex structure with the protein, which can improve the stability of the product.
2.2 Increase bulkiness
The use of CMC in ice cream can increase the expansion of ice cream, improve the melting speed, give good shape and taste, and control the size and growth of ice crystals during transportation and storage. The amount used is 0.5% of the total. The ratio is added.
This is because CMC has good water retention and dispersibility, and organically combines protein particles, fat globules and water molecules in the colloid to form a uniform and stable system.
2.3 Hydrophilicity and rehydration
This functional property of CMC is generally used in bread production, which can make the honeycomb uniform, increase the volume, reduce the slag, and also have the effect of keeping warm and fresh; the noodles added with CMC have good water retention, cooking resistance and good taste.
This is determined by the molecular structure of CMC, which is a cellulose derivative with a large number of hydrophilic groups in the molecular chain: -OH group, -COONa group, so CMC has better hydrophilicity than cellulose and water holding capacity.
2.4 Gelation
Thixotropic CMC means that the macromolecular chains have a certain number of interactions and tend to form a three-dimensional structure. After the three-dimensional structure is formed, the viscosity of the solution increases, and after the three-dimensional structure is broken, the viscosity decreases. The thixotropic phenomenon is that the apparent viscosity change depends on time.
Thixotropic CMC plays an important role in the gelling system and can be used to make jelly, jam and other foods.
2.5 Can be used as a clarifying agent, foam stabilizer, increase the taste
CMC can be used in wine production to make the taste more mellow and rich, and the aftertaste is long; in beer production, it can be used as a foam stabilizer for beer, making the foam rich and lasting and improving the taste.
CMC is a polyelectrolyte, which may participate in various reactions in wine to maintain the balance of the wine body. At the same time, it also combines with the crystals that have formed, changing the structure of the crystals, changing the conditions of the crystals in the wine, and causing precipitation. Aggregation of things.