What are the main uses of sodium citrate
The effect of sodium citrate
Sodium citrate is widely used in food , beverage, and spice industries as acidulant, flavoring agent, preservative, preservative, buffer, and chelating agent. It is used as antioxidant, plasticizer and detergent in chemical industry, cosmetic industry and washing industry. It is used as an anticoagulant in the pharmaceutical industry.
Sodium citrate, also known as sodium citrate, is an organic compound, a sodium salt , its chemical formula is Na3C6H5O7, the appearance is white to colorless crystals, and it has the taste of soapy water. Soluble in water and glycerol, insoluble in alcohols and other organic solvents. Deliquescence, weathering in hot air.
It is used as flavor and stabilizer in the food and beverage industry; in the pharmaceutical industry as an anticoagulant, expectorant and diuretic; in the detergent industry, it can replace sodium tripolyphosphate as a non-toxic detergent. Auxiliary; also used in brewing, injection, photographic drugs and electroplating.
Lemon juice contains a large amount of citric acid. The combination of citric acid and calcium ions forms a soluble complex, which can relieve the effect of calcium ions on blood coagulation, and can prevent and treat hypertension and myocardial infarction. So it can play an anticoagulant effect.
When taking fresh blood clinically, it is necessary to add some sterilized sodium citrate or sodium oxalate to prevent blood coagulation, so sodium citrate and sodium oxalate are called anticoagulants.
After all, sodium citrate is a chemical substance. Many people worry that eating it will be harmful to the human body. In fact, it is not. Sodium citrate is an alkaline substance. Regular consumption can balance the pH value of the human body. It is a normal pH value for the human body. , and alkaline is very good for relieving the fatigue of the human body after exercise. Sodium citrate is edible.
Second, the precautions of sodium citrate
1. Edible danger
Citric acid is an edible acid, which can enhance the normal metabolism in the body, and the appropriate dose is harmless to the human body. Adding citric acid to some foods tastes good and can promote appetite. In China, citric acid is allowed to be used in jams , beverages, cans and candies . Although citric acid has no direct harm to the human body, it can promote the excretion and deposition of calcium in the body. For example, long-term consumption of foods containing citric acid may lead to hypocalcemia and increase the risk of duodenal cancer. Children show unstable nervous system, excitability, and autonomic disorder; adults show tetany, muscle spasm, paresthesia, itching and gastrointestinal symptoms.
Based on the effect of citric acid on calcium metabolism, people who often eat canned food, beverages, jams, and sour candies, especially children, should pay attention to calcium supplementation, drink more raw milk, fish head, fish bone soup, and eat small shrimp skins, etc. , so as not to lead to insufficient blood calcium and affect health, gastric ulcer, hyperacidity , dental caries and diabetes patients should not eat citric acid regularly. Citric acid cannot be added to pure milk, otherwise it will cause pure milk to coagulate. The dairy industry often mixes citric acid into a solution of about 10% and adds it to a low-concentration milk solution, which should be stirred quickly when adding.
2. Industrial Hazards
Health Hazards: Concentrated citric acid solutions are irritating to mucous membranes. In industrial use, contacts may cause eczema;
Explosion Hazard: Citric acid is flammable. Powder and air can form explosive mixture, which may cause fire and explosion in case of open flame, high heat or contact with oxidant.
3. Storage conditions
Citric acid monohydrate loses crystal water in dry air or when heated to about 40 degrees, slightly deliquescent in humid air, and dilute citric acid aqueous solution can ferment when standing. Therefore, solid monohydrate or anhydrous should be stored in an airtight container and stored in a cool and dry place.
3. Physical and chemical properties of sodium citrate
1. Physical properties
At room temperature, citric acid is colorless translucent citric acid crystals or white granules or white crystalline powder, odorless, extremely sour in taste, and slightly deliquescent in humid air. It can exist in the form of anhydrous or monohydrate: when citric acid is crystallized from hot water, anhydrous is formed; when crystallized in cold water, a monohydrate is formed. When heated to 78 °C, the monohydrate will decompose to give an anhydrate. Citric acid is also soluble in absolute ethanol at 15 degrees Celsius. The crystal form of citric acid varies with different crystallization conditions. There are anhydrous citric acid C6H8O7 and citric acid 2C6H8O7.H2O, C6H8O7.H2O or C6H8O7.2H2O containing crystal water.
2. Chemical properties
Structurally, citric acid is a tricarboxylic acid compound and thus has similar physical and chemical properties to other carboxylic acids. When heated to 175°C, it will decompose to produce carbon dioxide and water, leaving some white crystals. Citric acid is a strong organic acid with 3 H+ that can be ionized; it can be decomposed into various products by heating, and react with acids, alkalis, glycerol, etc.
Fourth, the main use of sodium citrate
1. For food industry
Because citric acid has a mild and refreshing sour taste, it is widely used in the manufacture of various beverages, soft drinks, wine, candy, snacks, biscuits, canned juice , dairy products and other foods. In the market of all organic acids, citric acid has a market share of more than 70%, flavoring agents, and can also be used as antioxidants for edible oils. At the same time, it improves the sensory properties of food, enhances appetite and promotes the digestion and absorption of calcium and phosphorus in the body. Anhydrous citric acid is used in large quantities in solid beverages. Citric acid salts such as calcium citrate and ferric citrate are calcium and iron fortifiers in certain foods. Esters of citric acid, such as triethyl citrate, can be used as non-toxic plasticizers to manufacture plastic films for food packaging, acidulants and preservatives in beverage and food industries.
2. Used in chemical and textile industries
In chemical technology, citric acid can be used as a reagent for chemical analysis, as an experimental reagent, a chromatographic analysis reagent and a biochemical reagent; as a complexing agent, masking agent; used to prepare buffer solutions. Using citric acid or citrate as a builder can improve the performance of washing products, can quickly precipitate metal ions, prevent pollutants from re-attaching to the fabric, maintain the necessary alkalinity for washing; disperse and suspend dirt and ash; It is an excellent chelating agent to improve the performance of surfactants; it can be used as a reagent for testing the acid resistance of architectural ceramic tiles.
Formaldehyde pollution of clothing is a very sensitive problem. Citric acid and modified citric acid can be made into a formaldehyde-free anti-wrinkle finishing agent for the anti-wrinkle finishing of pure cotton fabrics. Not only the anti-wrinkle effect is good, but also the cost is low.
3. For environmental protection
Citric acid-sodium citrate buffer is used for flue gas desulfurization. China is rich in coal resources, which constitute the main part of energy. However, there has been a lack of effective flue gas desulfurization technology, resulting in serious atmospheric SO2 pollution. Research on effective desulfurization process is a top priority. Citric acid-sodium citrate buffer solution is a desulfurization absorbent with great development value due to its low vapor pressure, non-toxicity, stable chemical properties, and high absorption rate of SO2.
4. For livestock production
Adding citric acid to piglet feed can lead to early weaning, improve feed utilization by 5% to 10%, and increase sow litter size. Adding 1% to 2% citric acid to the diet of growing-finishing pigs can increase daily gain, reduce feed to meat ratio, improve protein digestibility, reduce back fat thickness, and improve meat quality and carcass characteristics. Rare earth citrate is a new type of high-efficiency feed additive, suitable for pigs, chickens, fish, shrimps, cattle, sheep, rabbits, silkworms and other animals. It can promote animal growth, improve product quality, improve disease resistance and survival rate. Improve the feed conversion rate and shorten the feeding cycle.
5. Used in cosmetics
Citric acid is a kind of fruit acid. Its main function is to speed up keratin renewal. It is often used in lotions, creams, shampoos, whitening products, anti-aging products, and acne products. The renewal of keratin is helpful for the exfoliation of melanin in the skin, the reduction of pores, and the dissolution of blackheads.
6. For sterilization
The combined action of citric acid and 80°C temperature has a good effect on killing bacterial spores, and can effectively kill bacterial spores polluted in the pipeline of the hemodialysis machine. Lemon, known as the "King of Western Food", has a strong bactericidal effect and is good for food hygiene. Coupled with the fragrance of lemon, people have always liked to use it to make cold dishes, which are not only delicious and refreshing, but also increase appetite.
7. For medicine
In the formation of prothrombin activator and the subsequent coagulation process, calcium ions must be involved. Citrate ions and calcium ions can form a soluble complex that is difficult to dissociate, thereby reducing the concentration of calcium ions in the blood and hindering blood coagulation. This product is used as an in vitro anticoagulant during blood transfusion or laboratory blood sample anticoagulation.