Although sodium citrate can technically refer to three chemical compounds – whether it’s mono-, di- or tri-sodium citrate – trisodium citrate will be further detailed as its uses and benefits outweigh the other two. Trisodium citrate, itself, exists in three forms: anhydrous, dihydrate and pentahydrate. Trisodium citrate is the sodium salt of citric acid as it takes the three hydrogen atoms away from the hydroxyl groups of citric acid and replaces it with sodium ions. It has a sour, saline taste, which explains its use as a safe food additive for enhancing flavour.
*N.B. “Trisodium citrate” and “sodium citrate” may be used interchangeably throughout this page’s description.
Less than two decades after the turn of the 20th century, Alfred Hustin and Luis Agote – Belgian and Argentine physicians, respectively – found that sodium citrate was a suitable anticoagulant when dealing with blood transfusions. In order to yield trisodium citrate, however, you must add a largely-pure sodium hydroxide or sodium carbonate with citric acid. Complete neutralization occurs followed by the crystallization of trisodium citrate pellets or powder. The non-toxic and biodegradable granular crystals that form are then used for food or industrial operations, among other things.