Carboxymethyl cellulose (CMC) is an important natural polymer modified material, widely used in food, medicine, textile, oil drilling and other fields. In the food industry, CMC is widely used in various food formulations due to its excellent thickening, stabilization, film-forming, water retention and bonding properties.

Basic properties of carboxymethyl cellulose
CMC is an anionic water-soluble polymer compound generated by chemical modification of natural cellulose. The carboxylmethyl (-CH2COOH) group on its molecular chain can give it good solubility in water and unique physical and chemical properties. CMC usually exists in the form of its sodium salt, namely sodium carboxymethyl cellulose (CMC-Na), which can form a viscous colloidal solution in water.

Mechanism of action of CMC as a thickener
In food processing, the main function of a thickener is to improve the taste, stability and texture of food by increasing the viscosity of the continuous phase in the food system. The reason why CMC can play a thickening role is mainly because it can dissolve quickly in water to form a high-viscosity solution. When CMC is dissolved in water, the molecular chains unfold and entangle with each other to form a mesh structure, which can effectively hinder the free flow of water molecules, thereby increasing the viscosity of the system.

Compared with other thickeners, the thickening effect of CMC is affected by many factors, including its molecular weight, degree of substitution (i.e. the number of carboxylmethyl groups substituted on each glucose unit), pH value of the solution, temperature, and other components in the food system. By adjusting these parameters, the thickening effect of CMC in food can be controlled to adapt it to the requirements of different foods.

Application of CMC in Food
Due to its good thickening properties, CMC is widely used in various foods. For example, in products such as ice cream, jam, dairy products, beverages, and condiments, CMC can not only increase the viscosity of the product, but also prevent the formation of ice crystals, improve the texture and taste of the product. In addition, CMC can also improve the water holding capacity of dough in flour products and extend the shelf life.

In dairy products and beverages, CMC helps stabilize emulsions and prevent protein coagulation and precipitation, thereby ensuring the uniformity and taste of the product. In sauces and jams, the use of CMC can improve the spreadability of the product, giving it an ideal consistency and smooth texture.

Safety and regulations of CMC
As a food additive, the safety of CMC has been widely recognized. The Joint Expert Committee (JECFA) of the World Health Organization (WHO) and the Food and Agriculture Organization of the United Nations (FAO) has classified it as a “generally recognized as safe” (GRAS) substance, which means that CMC is harmless to the human body at normal usage.

In different countries and regions, the use of CMC is also subject to corresponding regulatory restrictions. For example, in China, the “Standard for the Use of Food Additives” (GB 2760) clearly stipulates the scope of use and maximum dosage of CMC. Generally, the amount of CMC used must be controlled within the prescribed range to ensure the safety and stability of food.

As a versatile thickener, carboxymethyl cellulose occupies an important position in the food industry due to its unique physical and chemical properties. It can not only effectively increase the viscosity of food, but also improve the texture, taste and stability of food. In addition, as a safe food additive, CMC has been widely used in food production around the world. With the development of the food industry, the application prospects of CMC will be broader and it will play a greater role in improving food quality and extending shelf life.