Trisodium citrate

Trisodium citrate (CAS 68-04-2), also known as TSC and classified as E331iii in food applications, is the trisodium salt of citric acid.

Where is Trisodium citrate used?

• Food and beverage: acidity regulator and emulsifying salt
• Processed cheese: prevents fat separation and improves texture
• Pharmaceuticals: buffer for oral solutions, effervescent tablets and anticoagulant blood collection systems
• Personal care: pH adjuster in creams, shampoos and cleansing products, chelating trace metals
• Water treatment: sequestrant controlling scale-forming calcium and magnesium ions in industrial process water
• It functions as a pH buffer, chelating agent and stabilizer, controlling acidity and sequestering metal ions.
• During HTST pasteurization or UHT processing, prevents coagulation of milk proteins and heat-induced gelation, stabilizes concentrated milk and ensures full solubility in reconstituted milk powder.
• In sausage manufacturing, processed meats and frozen seafood, acts as a moisture retainer and pH stabilizer, improving protein hydration, cooking yield, natural meat color and delaying oxidative rancidity.
• Key component of WHO-standard oral rehydration salts (ORS) formulations to replenish electrolytes lost during severe dehydration.
• The anhydrous form is particularly suitable for dry or moisture-sensitive preparations such as effervescent powders, dry mixes, and tablets.

Good to know: The anhydrous form and the dihydrate are the two commercially standard variants. Recognized grades include FCC, USP, BP and Ph. Eur.; technical grade serves industrial and water treatment applications where food or pharma certification is not required.

Formulation notes

• Trisodium citrate dihydrate is the standard for most food applications such as liquids and gels, while the anhydrous form is used for moisture-sensitive applications such as dry mixes and tablets.

Typical specification

• Anhydrous form offered as a fine powder with USP-NF 2025 compliance and 27.0% sodium.
• High water solubility of approximately 720 g/L at 25°C.
• Loss on drying of 10.0–13.0%.

Regulatory status

• INCI name of trisodium citrate dihydrate is Sodium Citrate.
• The dihydrate is also identified under CAS 6132-04-3.
• Identified by Codex as INS 331(iii).

Storage, packaging and handling

• The anhydrous form is more concentrated because it contains no water, so slightly less is needed, but it is more hygroscopic; the dihydrate form is more stable and easier to handle for most applications.
• Should be stored in cool, dry, well-ventilated warehouses with containers kept tightly closed to prevent moisture absorption and caking, away from direct sunlight, high temperatures and incompatible strong oxidizers.

Frequently asked questions about Trisodium citrate

What are the sulfate and chloride impurity limits for this trisodium citrate?

Sulfate content is less than 50 mg/kg, and chloride content is less than 10 mg/kg.

In which food and cosmetic applications is trisodium citrate dihydrate used for pH control?

In jams, jellies and desserts, trisodium citrate dihydrate is used to control and stabilize pH precisely, ensuring consistent pectin gelation. In cosmetics it is used as a pH regulator where a citrate buffer is preferred over EDTA.

Technical content is compiled and updated by the SoleChem product team from public technical sources; the certificate of analysis (COA) governs product-specific specifications.