Sodium Citrate — Frequently Asked Questions

It acts as an emulsifying salt. Natural cheese holds its casein together with calcium bridges, and when heated it tends to separate into oil and a stringy protein mass. Sodium citrate binds that calcium, so the casein becomes more soluble, hydrates and wraps around the fat droplets, giving a smooth, stable melt. Citrates give a softer, more sliceable body than some phosphates, and blends of the two are common, typically at around 2 % to 3 % of the cheese.

The dihydrate contains about 12 % water of crystallisation; the anhydrous salt contains almost none. Chemically they perform identically once dissolved. The dihydrate is the standard grade for drinks and liquid processes, while the anhydrous form suits dry mixes, tablets and moisture-sensitive products. To switch, 1 kg of anhydrous corresponds to about 1.14 kg of dihydrate.

It raises pH slightly and buffers the citric acid, so the sourness becomes rounder and less sharp, and it holds pH steady during storage. At higher levels its own mildly saline taste becomes noticeable, which is one reason isotonic drinks use it as an electrolyte source. The citric acid to sodium citrate ratio is a key lever in balancing sourness and pH.

Proteins in dairy and plant-based drinks can coagulate when heated or when added to hot, acidic coffee, which shows as feathering or sediment. Sodium citrate buffers against the acidity and binds calcium, which keeps the proteins dispersed. It is often combined with phosphates such as dipotassium phosphate, and the best level is found by testing in the target coffee and water conditions.

Partly. In processed cheese, drinks and some dairy products citrates can take over the buffering and calcium-binding roles, which appeals to manufacturers reducing phosphate. They do not match phosphates in every function: long-chain polyphosphates disperse proteins and bind water in meat more effectively, and the texture of cheese changes with the salt used. Expect to reformulate and trial rather than switch one for one.

Specify trisodium citrate dihydrate or anhydrous, the particle range, the application and the purity standard (E331, FCC, JECFA or a pharmacopoeia). Add the pack size, annual volume and destination, and list the documents required, such as the specification, safety data sheet, batch certificate of analysis and allergen statement, so they are confirmed with the quotation.