Trisodium citrate is an inorganic compound with chemical formula Na3C6H5O7. It is commonly referred to as sodium citrate. It has a saline taste and a mildly tart flavour, and because of this, it is known as “sour salt.” It is basically the natural tribasic salt of citric acid and its IUPAC name is trisodium;2-hydroxypropane-1,2,3-tricarboxylate. It appears as white granular crystals and is soluble in water. Due to its biodegradable nature, it can be disposed of together with regular waste.
Trisodium Citrate Dihydrate is manufactured by neutralizing citric acid obtained using a submerged fermentation process. A citric acid fermentation broth is obtained using a hydrocarbon as the principal carbon source for the culture medium. Following which, it is adjusted to a pH from 9 to 13 inclusive with sodium hydroxide, sodium carbonate or sodium hydrogen carbonate. Insolubles are removed from the resultant broth before it is concentrated while maintaining the fluid at a temperature of 50° to 65°C to precipitate sodium citrate dihydrate crystals.
The primary use of trisodium citrate is as a food additive for imparting flavor and acting as a preservative. Its most popular use as a flavoring agent is in club sodas, ready to drink beverages and drink mixes. It is also used as a buffer to regulate acidity and resist changes in pH in food products such as gelatin desserts, milk, etc.
It is used as an anticoagulant in blood transfusions, blood collection tubes as well as the preservation of blood in blood banks. It is also used as an osmotic laxative and an antacid. Other uses include relieving discomfort in urinary tract infections, reducing acidosis in distal renal tubular acidosis.
It is used in boiler descaling for effectively removing the carbonate scale from boilers without removing them from operation and cleaning automobile radiators.