The Frog and the Peach

Trisodium citrate is a chemical compound with the chemical formula Na₃C₆H₅O₇. It is sometimes referred to by its systematic name, sodium citrate, though this can refer to any of the three sodium salts of citric acid. Trisodium citrate is the most common of these salts and is widely used in a variety of industries, including food, beverage, and pharmaceuticals, due to its properties as a preservative, flavoring agent, and stabilizer.

Properties

Trisodium citrate is a white, crystalline powder that is slightly deliquescent in moist air. It is highly soluble in water, and the solution has a salty, slightly tart flavor. It is less soluble in alcohol. Trisodium citrate has a melting point of about 150°C (302°F) and decomposes upon further heating.

Production

Trisodium citrate is produced primarily from citric acid, which undergoes a neutralization reaction with sodium carbonate (Na₂CO₃) or sodium hydroxide (NaOH). The resulting solution is then evaporated to yield trisodium citrate crystals.

Uses

Food Industry

In the food industry, trisodium citrate is used as a flavor enhancer, to control acidity, and as a preservative. It is found in a variety of food products, including soft drinks, candies, ice cream, and wine. It acts as an emulsifier in cheese making, helping to prevent the separation of fat from the cheese curd, and is also used in the spherification process in molecular gastronomy.

Pharmaceuticals

In pharmaceuticals, trisodium citrate is used as an anticoagulant in blood transfusions, as it prevents blood from clotting. It is also used in oral rehydration solutions and as an alkalizing agent in the treatment of metabolic acidosis.

Other Uses

Trisodium citrate has applications in detergents, where it softens water, allowing detergents to work more effectively. It is also used in the cosmetics industry as a buffering agent to adjust the pH of products.

Health and Safety

Trisodium citrate is generally recognized as safe (GRAS) when used in accordance with good manufacturing practices. However, excessive consumption can lead to an imbalance in the body's electrolytes, leading to conditions such as hypernatremia.

Environmental Impact

As a widely used chemical, the production and disposal of trisodium citrate can have environmental impacts. However, it is considered to be relatively benign compared to many other industrial chemicals.