Properties and product introduction of sodium carboxymethyl cellulose
Sodium carboxymethyl cellulose (CMC), also known as carboxymethyl cellulose. It is a highly polymerized fiber ether prepared by chemically modifying natural cellulose. Its structure is mainly composed of D-glucose units connected by β_(14) glycosidic bonds.
CMC is a white or milky white fiber powder or granule with a density of 0.5g/cm3, almost odorless, odorless, and hygroscopic.
Carboxymethyl cellulose is easily dispersed, forms a transparent colloidal solution in water, and is insoluble in organic solvents such as ethanol.
It can be seen from the structure that there are three hydroxyl groups on each glucose unit, namely C2, C3, and C6 hydroxyl groups. Physical and chemical indicators indicate the degree of substitution of hydrogen on the hydroxyl group of the glucose unit.
Suppose the hydrogens on the three hydroxyl groups on each unit are replaced by carboxymethyl. In that case, the degree of substitution is defined as 7-8, and the highest degree of substitution is 1.0 (food grade can only reach this level). The degree of substitution of CMC directly affects the solubility, emulsification, thickening, stability, acid resistance, and salt resistance of CMC.
When using CMC products, we should fully understand the main index parameters, such as stability, viscosity, acid resistance, viscosity, etc.
Of course, different application industries should use different carboxymethyl cellulose because there are many types of viscosity acting on carboxymethyl cellulose, and the physical and chemical indexes are also different. Only by knowing these can you know how to choose a suitable product.
What are the functions of carboxymethyl cellulose in food?
Carboxymethylcellulose (CMC) is a natural cellulose derivative that is often used in the food industry in its sodium salt, namely Sodium Carboxymethyl Cellulose. After natural cellulose undergoes two-step chemical modification treatment of alkalization and etherification, sodium carboxymethyl cellulose can be prepared.
1.Preparation of Sodium Carboxymethyl Cellulose
Natural cellulose is the most widely distributed polysaccharide in nature, and its sources are abundant, such as cotton, wool, moss, algae, certain microorganisms, etc. After crushing the cellulose-rich raw materials, demineralizing the elements (acid treatment separates the precipitation), etc., the cellulose is first alkalized by reacting with sodium hydroxide (NaOH), after which the alkaline cellulose is etherified with monochloroacetic acid (ClCH2COOH). In this way, sodium carboxymethyl cellulose is produced.
2. The chemical properties of sodium carboxymethyl cellulose and its application in food
Sodium carboxymethyl cellulose is a water-soluble anionic (negatively charged) polymer. Its special chemical structure and properties enable it to thicken and stabilize in the food system to be used as a food additive. It is widely used in various foods. Examples are as follows:
Many beverages have complex ingredients containing protein and lipids, water-soluble substances, and oil-soluble substances (fat-soluble vitamins A, D, E, K, etc.). Sodium carboxymethyl cellulose is dissolved in water to form a stable colloid and interacts with proteins. Under the protection of these colloids, the protein can exist more stably without agglomeration and precipitation; simultaneously, carboxymethyl cellulose can also reduce The surface tension between fat and water, making the fat fully emulsified beverage system more uniform and stable.
Sodium carboxymethyl cellulose has many hydrophilic groups such as -OH, -COONa, etc. Therefore, sodium carboxymethyl cellulose has strong water retention and can absorb and hold a large amount of water. After applying sodium carboxymethyl cellulose to ice cream, it can keep the ice cream system stable and uniform and maintain the shape of the ice cream and slow the melting of the ice cream. Therefore, high-quality ice cream with a high milk fat content (the milk fat in real milk) and without food additives is easy to melt at room temperature. The low-quality, low-fat ice cream, which mainly relies on food additives to maintain the senses and shape, is difficult to thaw at room temperature.
Sodium carboxymethyl cellulose can also be used in baked foods such as bread, cakes, and biscuits. Sodium carboxymethyl cellulose has water retention and can inhibit water evaporation, thereby preventing starch from aging (after the starch loses water, it will often combine to form microcrystalline structure structures that will deteriorate the starchy food taste, commonly known as starch aging). In addition, sodium carboxymethyl cellulose is also a long-chain fibrous molecule with high viscosity. Therefore, it can improve the texture characteristics and crisp taste of baked foods.
The high viscosity and high water retention of sodium carboxymethyl cellulose make it easy to form a film or present a jelly shape. Therefore, it is very suitable for use in jelly, jam, pudding, and other foods, which helps to improve the shape and taste of the product.
