Sodium Carboxymethyl Cellulose (CMC Sodium) is a commonly used food additive and a cellulose derivative. It has good water solubility, thickening, stability and emulsification, so it is widely used in the food industry. This article will introduce the properties, uses, application range and related safety issues of sodium carboxymethyl cellulose in detail.

1. Basic properties
Chemical structure
Sodium carboxymethyl cellulose is a cellulose derivative in the form of sodium salt obtained by reacting natural cellulose with chloroacetic acid and treating it with alkali. Its chemical structure contains the basic skeleton of cellulose, and carboxymethyl groups (-CH2COOH) are connected to certain hydroxyl groups of the cellulose molecule through ether bonds. These carboxyl groups make CMC water-soluble and have certain ion exchange properties.

Physical properties
Sodium carboxymethyl cellulose is a colorless or slightly yellow powder, hygroscopic, and can be dissolved in cold or hot water to form a transparent viscous solution. Its solubility is affected by the pH value and salt concentration of the solution. It is usually less soluble in acidic environments and more soluble in alkaline environments.

Functionality
CMC has strong thickening, gelling, stabilizing, emulsifying and suspending functions, which can effectively improve the texture and taste of food. It also has a significant effect on retaining moisture, so it is often used to moisturize food and improve the stability of food.

2. Application in the food industry
Thickening and gelling effect
The most common application of sodium carboxymethyl cellulose is as a thickener. In some beverages, jams, ice cream and condiments, CMC can increase the viscosity of the fluid and improve the texture and taste of the product. By adjusting the amount of CMC used, the consistency and stability of the product can be controlled. In addition, CMC also has certain gelling properties and is often used to make low-fat or low-calorie food substitutes.

Emulsification effect
CMC plays a role in stabilizing the emulsion and improving the stability of the emulsion in emulsification. It can improve the dispersibility of the oil-water phase, so that the oil in the food will not separate or precipitate, thereby improving the appearance and taste of the food. CMC is often used in salad dressings, beverages and various sauces.

Moisturizing effect
In baked goods, CMC can help products such as bread and cakes stay moist and soft. It delays the drying process of food by absorbing and retaining moisture, thereby extending the shelf life of the product.

Food structure improvement
In some low-fat or fat-free foods, CMC can improve the texture of food as a substitute. For example, low-fat dairy products, low-fat yogurt, and imitation meat products can improve their taste by adding CMC to simulate the fat feeling in traditional foods.

Prevent crystallization
CMC can be used in foods such as candy and ice cream to prevent the crystallization of sugar or ice crystals, thereby improving the appearance and taste of food and making it smoother and more delicate.

3. Safety of food additives
Toxicology research
According to current research data, sodium carboxymethyl cellulose is safe for human body within the prescribed usage amount. The World Health Organization (WHO) and the Food and Agriculture Organization of the United Nations (FAO) both consider CMC to be a food-grade additive and have no significant toxic effects. The U.S. Food and Drug Administration (FDA) lists it as a “generally recognized as safe” (GRAS) substance, which means that it is considered harmless to human body under normal use.

Allergic reactions
Although CMC is generally considered safe, some people may have allergic reactions to CMC, which manifests as symptoms such as skin itching and difficulty breathing, especially when consumed in excess. Therefore, some specific groups should avoid excessive consumption, especially for consumers with allergies.

Intake limits
Countries have strict regulations on the use of CMC. For example, in the EU, the use of CMC in food is usually no more than 0.5% (by weight). Excessive intake of CMC may cause some adverse reactions, such as gastrointestinal discomfort or mild diarrhea.

Environmental impact
As a natural plant derivative, CMC has good degradability and less environmental burden. However, excessive use or improper disposal may still have an impact on the environment, especially the pollution of water bodies, so the rational use and handling of CMC products is crucial.

Sodium carboxymethyl cellulose is a multifunctional food additive that is widely used in many fields such as thickening, emulsification, moisturizing, and structural improvement. Its good solubility, thickening, stability and emulsification make it irreplaceable in food processing. Although CMC is generally considered safe, it is still necessary to follow the principle of moderate use to avoid excessive intake. In the food industry, the use of CMC helps improve the quality and taste of products, while providing consumers with healthier, low-fat, and low-calorie food options.