What is the role of chemical cellulose?

Cellulose is a nutrient widely found in various foods, especially many vegetables and fruits are rich in cellulose, but many people may not know the existence of chemical cellulose. In fact, in the chemical industry, cellulose is widely used, especially in the pharmaceutical industry, cosmetics industry, textile industry and many other industries, chemical cellulose is almost indispensable.

Functions of chemical cellulose:

There are many types of cellulose, the most common of which are cellulose nitrate, cellulose acetate and carboxymethyl cellulose. Cellulose nitrate is mainly used to make plastics and gunpowder; cellulose acetate is mainly used in the manufacture of textiles and filter materials; carboxymethyl cellulose is mainly used to produce sodium carboxymethyl cellulose, which has a wide range of uses.

Sodium carboxymethyl cellulose is also known as carboxymethyl cellulose, referred to as CMC or CMC-Na. Sodium carboxymethyl cellulose is made from fibers such as cotton or pulp using a water-based method or a solvent-based method. It is white or slightly yellow fibrous or granular powder or coarse powder, odorless, tasteless, soluble in water, hygroscopic, and divided into three types: FH6 extra high viscosity; FH6 high viscosity and FH6 medium viscosity. It can precipitate from food when the pH is 1-3, and will not precipitate in acid solution when the pH is > 3. However, the viscosity decreases with the increase of pH. When the pH is 5-9, the viscosity changes little. The presence of salts will affect the viscosity of CMC. The heating temperature should be below 80°C. If heated for a long time above this temperature, the viscosity will decrease and insoluble matter will be generated. Adding 0.1% to 0.5% to noodles, instant noodles, and instant rice noodles can make the products expand and lubricate the tissue, have a good taste, and are not easy to deform; adding 0.1% to 0.2% to bread, biscuits, and cakes can prevent water evaporation and aging, prevent oil seepage, and make the product surface smooth and delicate in taste; in meat products, eggs, fruits, and vegetables, spraying a 2% to 3% aqueous solution on the surface of the food forms an extremely thin film, which can store food for a long time, maintain flavor, and prevent fermentation, and can be rinsed with water when eaten; CMC has no nutritional value, will absorb water and swell, and make people feel full, so it can be used as a weight-loss food.

Physical and chemical properties Chemical structure Application Preparation method Identification method Toxicological basis Food industry Usage method Stability and storage conditions Incompatibility taboos Packaging, storage and transportation Cellulose derivatives

Physical and chemical properties

White or slightly yellow powder, odorless, tasteless, easily soluble in water to form a high viscosity solution, the solution is neutral or slightly alkaline, and hygroscopic. Insoluble in many solvents such as ethanol. Relative density is 1.60, relative density of flakes is 1.59, and bulk density is 0.618cm3/g. Refractive index: 1.515. It turns brown when heated to 190-205℃ and carbonizes at 235-248℃. Soluble in water It is a transparent colloid. Its solubility in water depends on the degree of substitution. The dispersibility in water is related to the degree of etherification and its relative molecular mass. The pH of 1% aqueous dispersion is 6.5-8.5. Stable to light, heat and chemicals. Not easy to ferment. It has strong emulsifying power for oils and waxes.

The viscosity of sodium carboxymethyl cellulose solution is affected by its relative molecular weight, concentration, temperature and pH, and it has good compatibility (i.e. synergistic effect) with hydroxyethyl or hydroxypropyl cellulose, gelatin, xanthan gum, carrageenan, locust bean gum, guar gum, agar, sodium alginate, pectin, gum arabic, starch and its derivatives.

At pH 7, the viscosity of sodium carboxymethyl cellulose solution is the highest, and it is relatively stable at pH 4-11.

Carboxymethyl cellulose in the form of alkali metal salts and ammonium salts is soluble in water. Divalent metal ions Ca2+, Mg2+, and Fe2+ can affect its viscosity. Heavy metals such as silver, barium, chromium or Fe3+ can cause it to precipitate from the solution. If the concentration of ions is controlled, such as by adding chelating agent citric acid, a more viscous solution can be formed, thus forming a soft or hard gel.

Chemical structure

A natural high molecular weight compound composed of cellobiose consisting of multiple 2 glucose molecules. There are 3 hydroxyl groups in each glucose in the cellulose macromolecule, and the hydroxyl groups are etherified by carboxymethyl groups. If one hydroxyl group participates in the reaction on average, the degree of etherification DS = 1, the maximum is 3, and the average is 0.4 to 1.5.