Sodium Citrate

About This Product

Sodium citrate in food use normally means trisodium citrate, E331(iii) in the EU and UK, usually supplied as the dihydrate (CAS 6132-04-3, Na3C6H5O7·2H2O, 294.10 g/mol) and less often as the anhydrous salt (CAS 68-04-2). The mono- and disodium citrates, E331(i) and E331(ii), are separate, more acidic products. Trisodium citrate is a white, odourless crystalline granule or powder with a mild saline taste, very soluble in water and slightly alkaline in solution.

Its main functions are buffering, sequestration of calcium and other metal ions, and emulsification of cheese proteins. In soft drinks and sports drinks it pairs with citric acid to hold pH steady and soften sourness. In processed cheese and cheese sauces it acts as an emulsifying salt, binding calcium so that casein hydrates and emulsifies the fat into a smooth melt; blends of citrates and phosphates are typically used at around 2 % to 3 % of the cheese. In dairy and plant-based drinks and creamers it stabilises proteins against heat and against feathering in hot coffee, and in gelatine and pectin confectionery it protects the gel from acid during depositing. It is also used in jams, meat products and some infant and clinical nutrition formulations.

The dihydrate is the standard grade for liquid systems. The anhydrous form suits dry mixes, tablets and low-moisture products; 1 kg of anhydrous trisodium citrate corresponds to about 1.14 kg of dihydrate. Particle size is agreed for dry blending, with fine granular grades mixing most evenly.

Buyers usually agree the assay on the anhydrous basis, water content for the form supplied, pH of a 5 % solution, oxalate, lead and other heavy metals, and the particle range. The grade should conform to the E331(iii) purity criteria in Regulation (EU) No 231/2012 and its GB equivalent, or to FCC, JECFA or a pharmacopoeia for other uses.

Sodium citrates are authorised in many food categories, frequently at quantum satis, but check Annex II of Regulation (EC) No 1333/2008 and the UK retained equivalent for your product, especially for foods for infants and young children, which follow stricter rules. On the label it appears by function, such as acidity regulator: sodium citrate, or emulsifying salt: E331. Its sodium, about 23 % of the dihydrate by weight, counts towards the salt declaration.

Store sealed in a dry place at stable temperature. The dihydrate can lose water in hot, dry conditions and cake when it later reabsorbs moisture. When you enquire, state which citrate you need (trisodium, dihydrate or anhydrous), the particle range, the application, the standard required, the pack size, annual volume and destination, and the approval documents you need.