E450 (iii) TETRASODIUM PYROPHOSPHATE

E450 (iii) Tetrasodium Pyrophosphate is an inorganic sodium salt of pyrophosphoric acid with the chemical formula Na₄P₂O₇, commercially available in anhydrous and decahydrate forms, used as a multifunctional food additive acting simultaneously as a pH buffer, calcium sequestrant, emulsifying salt, humectant, raising agent, stabilizer, thickener, and dispersing agent in processed foods, pharmaceuticals, toothpaste, detergents, and industrial applications.
E450 (iii) Tetrasodium Pyrophosphate is also known as sodium pyrophosphate, tetrasodium diphosphate, and TSPP, and is composed of the pyrophosphate anion (P₂O₇⁴⁻) and four sodium cations (Na⁺), making it an inorganic salt with strong chelating affinity for divalent metal ions, particularly calcium and magnesium, that underpins its diverse functional roles across food, dental, industrial, and water treatment applications.
E450 (iii) Tetrasodium Pyrophosphate is approved as a food additive in the European Union under Regulation (EC) No 1333/2008 with E number E450(iii), is recognized as Generally Recognized as Safe (GRAS) by the US FDA under 21 CFR 182.6787, 182.6789, and 182.70, and has been assigned a group acceptable daily intake (ADI) of 0–70 mg/kg body weight/day as total phosphate by JECFA (FAO/WHO).

CAS Number: 7722-88-5 (anhydrous); 13472-36-1 (decahydrate)
EC Number (EINECS): 231-767-1 (anhydrous); 603-854-8 (decahydrate)
E Number: E450(iii)
INS Number: 450(iii)
Molecular Formula: Na₄P₂O₇ (anhydrous); Na₄P₂O₇·10H₂O (decahydrate)
Molecular Weight: 265.90 g/mol (anhydrous); 446.09 g/mol (decahydrate)

Synonyms: Tetrasodium Pyrophosphate, Sodium Pyrophosphate, Sodium Diphosphate, Tetrasodium Diphosphate, Tetrasodium Phosphate, TSPP, Anhydrous TSPP, Pyrophosphoric Acid Tetrasodium Salt, Diphosphoric Acid Tetrasodium Salt, Sodium Pyrophosphate Anhydrous, Sodium Diphosphate Tetrabasic, Sodium Pyrophosphate Tetrabasic, Pyrophosphate Sodium Salt, E450(iii), INS 450(iii), Victor TSP, CAS 7722-88-5

E450 (iii) Tetrasodium Pyrophosphate is an inorganic compound in which the pyrophosphate anion (two phosphate groups linked by a P–O–P bridge) is fully neutralized by four sodium cations; its strong affinity for divalent metal ions arises from this P–O–P structure, which can coordinate Ca²⁺, Mg²⁺, Fe²⁺/³⁺, and other ions into stable chelate complexes.
E450 (iii) Tetrasodium Pyrophosphate solutions are moderately to strongly alkaline, with a 1% aqueous solution exhibiting pH 9.8–10.5, making it effective as a buffering agent, protein modifier, and processing aid in a wide range of pH-sensitive food manufacturing operations.

E450 (iii) Tetrasodium Pyrophosphate is a normal endogenous component of human body fluids (pyrophosphate occurs naturally in biological systems), and is not classified as a hazardous substance under GHS/CLP Regulation (EC) No 1272/2008 when used as a bulk inorganic salt, though dust inhalation and eye and skin contact should be avoided.
E450 (iii) Tetrasodium Pyrophosphate is gluten free, vegan, and suitable for all religious groups including Halal and Kosher-certified variants, being derived entirely from inorganic phosphate and sodium sources.

E450 (iii) Tetrasodium Pyrophosphate may be used in combination with other phosphate additives including E338 (phosphoric acid), E339 (sodium phosphates), E340 (potassium phosphates), E341 (calcium phosphates), E343 (magnesium phosphates), E451 (sodium and potassium tripolyphosphates), and E452 (polyphosphates), with the maximum level applying to the sum of all phosphates expressed as P₂O₅.
E450 (iii) Tetrasodium Pyrophosphate belongs to the E450 diphosphate group, which includes seven sub-types: E450(i) disodium diphosphate, E450(ii) trisodium diphosphate, E450(iii) tetrasodium diphosphate, E450(v) tetrapotassium diphosphate, E450(vi) dicalcium diphosphate, E450(vii) calcium dibasic diphosphate, and E450(ix) dimagnesium diphosphate.

Uses of E450 (iii) Tetrasodium Pyrophosphate:
E450 (iii) Tetrasodium Pyrophosphate is used in processed cheese manufacturing as an emulsifying salt that disrupts calcium phosphate bridges within the casein network, enabling casein hydration, dispersion, fat emulsification, and prevention of oiling-off during heating, with concentration-dependent effects on firmness, meltability, and rheological behavior.
E450 (iii) Tetrasodium Pyrophosphate is used in processed meat products including sausages, ham, and restructured meats to increase the net negative charge on muscle proteins, promoting protein unfolding and water binding, leading to improved tenderness, reduced cooking loss, enhanced juiciness, and improved texture consistency at typical use levels of 0.1–0.5%.

E450 (iii) Tetrasodium Pyrophosphate is used in seafood processing including frozen fish and shellfish to reduce drip loss during thawing by stabilizing muscle protein structure, limiting protein denaturation, and inhibiting oxidative reactions that cause discoloration and off-flavors; residue limits apply (maximum 0.3 ppm for shrimp and prawns).
E450 (iii) Tetrasodium Pyrophosphate is used in bakery applications as part of chemical leavening systems in combination with sodium bicarbonate, regulating carbon dioxide release to achieve uniform crumb structure and controlled volume expansion; it is also used in flour (up to 15,000 mg/kg in yeast-containing flour) and doughs (up to 12,000 mg/kg expressed as P₂O₅).

E450 (iii) Tetrasodium Pyrophosphate is used in dairy applications including milk-based beverages, dairy desserts, UHT milk, and pasteurized and whipped cream to support mineral balance, protein dispersion, stable pH, and prevention of unwanted calcium salt precipitation.
E450 (iii) Tetrasodium Pyrophosphate is used as a coagulant and thickening agent in noncooked instant puddings, as a dispersant in malted milk and chocolate drink powders, as a crystal formation inhibitor in canned tuna, and as a fat separation reducer in processed cheese.

E450 (iii) Tetrasodium Pyrophosphate is used in toothpaste and dental floss as a tartar control agent, preventing the deposition of calcium and magnesium on teeth and inhibiting tartar formation, with typical concentrations of 1–5%; it is used in the Crest brand as an anti-tartar ingredient.
E450 (iii) Tetrasodium Pyrophosphate is used in soy protein-based meat analogs to remove naturally occurring calcium ions from proteins, accelerate protein gelation, improve texture, and reduce cooking loss at typical concentrations of 0.1–0.5%.

E450 (iii) Tetrasodium Pyrophosphate is used in detergent and cleaning formulations at 5–20% as a chelating agent, water softener, dispersing agent, and pH buffer, and in laundry and dishwashing products at 5–15% as a water softener and soil dispersant.
E450 (iii) Tetrasodium Pyrophosphate is used in water treatment at 1–10 mg/L for corrosion control and mineral chelation, in electroplating at 10–50 g/L as a dispersing agent and rust stain remover, in paint and coatings at 0.5–2% for pigment wetting and dispersion, and in paper processing, oil and gas, and ceramic industries.

E450 (iii) Tetrasodium Pyrophosphate is used as a wool de-fatting agent, metal cleaner, bleaching aid, buffering agent in laboratory applications (EDTA-sodium pyrophosphate extraction buffers for microcystin analysis of soil samples), general sequestering agent, and component of antimicrobial studies.
E450 (iii) Tetrasodium Pyrophosphate is used as a food additive in common products including chicken nuggets, crab meat, canned tuna, marshmallows, ice cream, milk protein products, and convenience foods, and as a food contact substance and food enzyme carrier under EU Regulation 1333/2008.

Benefits or Advantages of E450 (iii) Tetrasodium Pyrophosphate:
E450 (iii) Tetrasodium Pyrophosphate is a multifunctional additive that simultaneously delivers pH buffering, calcium sequestration, emulsification, water retention, and texture modification, reducing the need for multiple separate additives and providing formulation efficiency in high-volume food manufacturing.
E450 (iii) Tetrasodium Pyrophosphate has strong and selective chelating affinity for divalent metal ions (Ca²⁺, Mg²⁺, Fe²⁺/³⁺), enabling precise control of mineral–protein interactions in food systems and providing superior calcium-binding strength compared to STPP, SHMP, TCP, and DSP within the phosphate family.

E450 (iii) Tetrasodium Pyrophosphate is an endogenous compound in human body fluids, has a low oral LD50 of approximately 4,000 mg/kg in rats, is GRAS-approved by the FDA, and has been assigned an ADI by JECFA based on extensive safety data, providing a strong regulatory safety foundation for food and dental use.
E450 (iii) Tetrasodium Pyrophosphate has a shelf life of 24 months in original unopened packaging stored under appropriate conditions, providing long supply security for large-scale manufacturing operations.

E450 (iii) Tetrasodium Pyrophosphate is non-flammable, not regulated as dangerous goods under ADR/RID, IMDG, or IATA, and does not contain any organic solvents or toxic combustion byproducts under normal use conditions, simplifying logistics and transport compared to organic food additives.
E450 (iii) Tetrasodium Pyrophosphate is approved in the EU, USA, Turkey, and under JECFA, is available as Halal- and Kosher-certified, and is vegan and gluten-free, supporting broad international market access and compliance.

Features of E450 (iii) Tetrasodium Pyrophosphate:
E450 (iii) Tetrasodium Pyrophosphate is a white crystalline or granular powder in its anhydrous form, and white or colorless crystals that are slightly efflorescent in dry air in its decahydrate form, with no distinct odor and a slightly alkaline characteristic taste.
E450 (iii) Tetrasodium Pyrophosphate has moderate water solubility of approximately 70 g/L (~7%) at 20°C increasing to approximately 230 g/L at 100°C, is completely insoluble in ethanol and ammonia, and has a refractive index of 1.425.

E450 (iii) Tetrasodium Pyrophosphate undergoes slow hydrolysis to orthophosphate in aqueous solution (disproportionation), and the pyrophosphate bond breaks rapidly in acidic environments (pH <4) converting to orthophosphates, which must be considered in acidic formulations.
E450 (iii) Tetrasodium Pyrophosphate exhibits low to moderate hygroscopicity and may cake in humid environments, requiring storage in tightly closed, moisture-proof containers at 15–25°C.

Chemical Properties of E450 (iii) Tetrasodium Pyrophosphate:
E450 (iii) Tetrasodium Pyrophosphate is an inorganic sodium salt of pyrophosphoric acid (H₄P₂O₇) comprising the diphosphate(4−) anion and four sodium(1+) cations, with the molecular formula Na₄P₂O₇ and molecular weight 265.90 g/mol for the anhydrous form.
E450 (iii) Tetrasodium Pyrophosphate has thermodynamic properties: standard enthalpy of formation ΔfH°298 = −3,166 kJ/mol, Gibbs free energy ΔfG° = −3,001 kJ/mol, standard molar entropy S°298 = 270 J/mol·K, and heat capacity C = 241 J/mol·K.

E450 (iii) Tetrasodium Pyrophosphate reacts exothermically with acids, is incompatible with strong oxidizing agents, strong acids, magnesium salts, and calcium salts, and is stable under normal conditions; thermal decomposition above 900°C yields Na₂O, P₂O₅, and phosphorus oxides.
E450 (iii) Tetrasodium Pyrophosphate solutions at 70°C are stable, but prolonged boiling causes hydrolysis to disodium phosphate (Na₂HPO₄); the aqueous solution shows weak alkalinity with characteristic pH 9.8–10.5 (1% solution).

Production of E450 (iii) Tetrasodium Pyrophosphate:
E450 (iii) Tetrasodium Pyrophosphate is produced industrially by the neutralization of phosphoric acid with sodium hydroxide in a 2:1 molar ratio to form disodium phosphate (Na₂HPO₄), followed by dehydration/calcination to yield the pyrophosphate: 2Na₂HPO₄ → Na₄P₂O₇ + H₂O.
E450 (iii) Tetrasodium Pyrophosphate can also be produced by heating disodium phosphate above its melting point (around 250°C) causing condensation of two phosphate groups with elimination of water, and is manufactured in a closed reaction system with annual production capacity of tens of thousands of tonnes per year.

E450 (iii) Tetrasodium Pyrophosphate is available in anhydrous form (food grade purity ≥95–96.5%, P₂O₅ 52.5–54.0%) and decahydrate form (Na₄P₂O₇·10H₂O), and is packaged in 25 kg Kraft or PP woven bags, 500–1,000 kg big-bags, and 25 kg HDPE pails.
E450 (iii) Tetrasodium Pyrophosphate quality control verifies purity (Na₄P₂O₇ on dry basis), P₂O₅ content, pH, water-insoluble matter, fluoride, chloride, sulfate, heavy metals (Pb, As, Hg, Cd), iron, calcium, and microbiological parameters including total plate count, yeast, mold, E. coli, and Salmonella.

Material Safety Data Sheet (MSDS) of E450 (iii) Tetrasodium Pyrophosphate:

Handling of E450 (iii) Tetrasodium Pyrophosphate:
E450 (iii) Tetrasodium Pyrophosphate should be handled only by personnel trained and familiar with handling of inorganic chemicals, in accordance with good industrial hygiene and safety practices and in compliance with the applicable Safety Data Sheet.
E450 (iii) Tetrasodium Pyrophosphate handling requires avoiding skin and eye contact and breathing of dust, and avoiding handling which leads to dust formation; the alkaline pH (9.8–10.5 in solution) causes skin and eye irritation.

SDS of E450 (iii) Tetrasodium Pyrophosphate:

Stability and Reactivity of E450 (iii) Tetrasodium Pyrophosphate:

Chemical stability:
E450 (iii) Tetrasodium Pyrophosphate is stable under normal storage conditions below 37°C in sealed, dry containers.

Reactivity:
E450 (iii) Tetrasodium Pyrophosphate reacts exothermically with acids and may react with strong oxidizing agents, magnesium salts, and calcium salts.
E450 (iii) Tetrasodium Pyrophosphate slowly hydrolyzes to orthophosphate in aqueous solution; the pyrophosphate bond breaks rapidly in acidic conditions (pH <4).

Conditions to avoid:
Moisture and humidity (causes caking).
Strong oxidizing agents.
Strong acids (exothermic reaction, hydrolysis of pyrophosphate bond).
Calcium and magnesium salts (chelation reactions).
Temperatures above 37°C for storage.
Temperatures above 900°C (thermal decomposition).

Incompatible materials:
Strong oxidizing agents.
Strong acids.
Strong bases (concentrated).
Magnesium salts.
Calcium salts.
Oxidant chemicals.
Edible chemicals (store separately).

Hazardous decomposition products:
Sodium oxide (Na₂O) — above 900°C.
Phosphorus pentoxide (P₂O₅) — above 900°C.
Phosphorus oxides — above 900°C.

Handling and Storage of E450 (iii) Tetrasodium Pyrophosphate:

Handling:
Handle in accordance with good industrial hygiene and safety practices.
Avoid skin and eye contact and inhalation of dust; use personal protective equipment.
Avoid handling that leads to dust formation.
Use warm water for solution preparation (solubility ~70 g/L at 20°C; increases with temperature).
Wash hands thoroughly after handling and before eating, drinking, or smoking.
Do not eat, drink, or smoke in handling areas.

Storage:
Store in a cool (15–25°C), dry, well-ventilated area; temperature must not exceed 37°C.
Keep in tightly sealed, moisture-proof original containers.
Store separately from strong oxidizing agents, strong acids, and edible chemicals.
E450 (iii) Tetrasodium Pyrophosphate may cake in humid environments; store in dry conditions.
Shelf life: 24 months in unopened original packaging under appropriate storage conditions.
Packaging: 25 kg Kraft bag with PE liner, 25 kg PP woven bag with PE liner, 500–1,000 kg big-bag, 25 kg HDPE pail.

First Aid Measures of E450 (iii) Tetrasodium Pyrophosphate:

Inhalation:
Move affected person to fresh air.
Seek medical attention if respiratory irritation, coughing, or discomfort persists.

Skin contact:
Wash thoroughly with soap and plenty of water for at least 15 minutes.
Remove contaminated clothing.
Seek medical attention if irritation develops or persists; the alkaline pH can cause skin irritation.

Eye contact:
E450 (iii) Tetrasodium Pyrophosphate causes serious eye irritation; rinse immediately with plenty of water for at least 15 minutes while holding eyelids open.
Remove contact lenses if present and easy to do.
Seek immediate medical attention after significant eye contact.

Ingestion:
Rinse mouth with water.
Drink plenty of water.
Do not induce vomiting unless instructed by medical personnel.
Seek medical attention if you feel unwell; oral LD50 in rat is approximately 4,000 mg/kg indicating low acute toxicity.

Firefighting Measures of E450 (iii) Tetrasodium Pyrophosphate:

Suitable extinguishing media:
Any extinguishing media appropriate for surrounding fire.

Specific hazards:
E450 (iii) Tetrasodium Pyrophosphate is non-flammable.
Above 900°C, thermal decomposition produces Na₂O, P₂O₅, and phosphorus oxides.

Protective equipment for firefighters:
Wear self-contained breathing apparatus (SCBA) and full protective clothing.

Firefighting instructions:
Cool exposed containers with water spray.
Prevent contaminated firefighting water from entering drains or waterways.

Accidental Release Measures of E450 (iii) Tetrasodium Pyrophosphate:

Personal precautions:
Avoid inhalation of dust; wear appropriate respiratory protection.
Avoid skin and eye contact; spilled material may create a slipping hazard when wet.
Use appropriate personal protective equipment.

Environmental precautions:
Prevent large quantities of E450 (iii) Tetrasodium Pyrophosphate from entering drains or waterways; phosphate release may contribute to eutrophication.

Methods for cleaning up:
Sweep or vacuum dry spilled material into properly labeled waste containers.
Avoid creating dust; do not use compressed air for cleanup.
Dispose according to local regulations.

Exposure Controls / Personal Protective Equipment of E450 (iii) Tetrasodium Pyrophosphate:

Engineering controls:
Provide adequate local exhaust ventilation where dust may be generated during weighing, bagging, or mixing.
NIOSH REL: TWA 5 mg/m³.

Eye protection:
Wear safety glasses or chemical splash goggles where dust or splashing is possible.

Hand protection:
Wear chemical-resistant gloves for prolonged or repeated handling.

Skin and body protection:
Wear suitable protective clothing to prevent skin contact with alkaline dust or solution.

Respiratory protection:
Wear a dust respirator (NIOSH-approved) where dust generation cannot be avoided; inhalation of dust may cause mechanical irritation to the respiratory tract.

Hygiene measures:
Wash hands and face thoroughly after handling E450 (iii) Tetrasodium Pyrophosphate and before eating, drinking, or smoking.
Avoid handling which generates dust.

Identifiers of E450 (iii) Tetrasodium Pyrophosphate:
E Number: E450(iii)
INS Number: 450(iii)
CAS Number: 7722-88-5 (anhydrous); 13472-36-1 (decahydrate)
EC Number: 231-767-1 (anhydrous); 603-854-8 (decahydrate)
Molecular Formula: Na₄P₂O₇ (anhydrous); Na₄P₂O₇·10H₂O (decahydrate)
Molecular Weight: 265.90 g/mol (anhydrous); 446.09 g/mol (decahydrate)
IUPAC Name: Tetrasodium diphosphate
InChIKey: FQENQNTWSFEDLI-UHFFFAOYSA-J
PubChem CID: 24403 (anhydrous); 3084150 (decahydrate)
ChEBI: CHEBI:71240
ChemSpider: 22813
RTECS: UX7350000
UNII: O352864B8Z
CompTox (EPA): DTXSID9042465
ECHA InfoCard: 100.028.880
HS Code: 283529
P₂O₅ Content: ~53%
GHS Signal Word: Warning
GHS Pictogram: GHS07 (Exclamation mark); GHS05 (Corrosive — some SDS sources)
GHS Hazard Statements: H302 (harmful if swallowed, some SDS); H315 (causes skin irritation); H318/H319 (eye irritation/damage); H335 (respiratory irritation)
NIOSH REL: TWA 5 mg/m³
US FDA: GRAS (21 CFR 173.310, 175.210, 175.300, 181.29, 182.6787, 182.6789, 182.70); food standards 21 CFR 133.169, 133.173, 133.179
SCOGS Report: No. 32
EU: Food additive E450(iii) approved under Regulation (EC) No 1333/2008; specifications in Commission Regulation (EU) No 231/2012
JECFA ADI: 0–70 mg/kg body weight/day (total phosphate)
Turkey: Approved under Turkish Food Codex Food Additives Regulation
Halal/Kosher: Available
Vegan/Vegetarian: Suitable (inorganic origin)
Gluten-free: Yes

Properties of E450 (iii) Tetrasodium Pyrophosphate:
Physical state (20°C): Solid
Appearance: White or colorless crystalline powder or granules (anhydrous); colorless transparent crystals slightly efflorescent in dry air (decahydrate)
Odor: Odorless
Taste: Slightly alkaline, characteristic
Melting point (anhydrous): 988°C (lit. 988–995°C)
Melting point (decahydrate): 79.5°C (loses crystal water)
Boiling point (anhydrous): Decomposes
Boiling point (decahydrate): 93.8°C (loses water of crystallization)
Density: 2.534 g/cm³ (anhydrous, 25°C)
Solubility in water (0°C): 2.61 g/100 mL
Solubility in water (25°C): 6.7 g/100 mL (~70 g/L)
Solubility in water (100°C): 42.2 g/100 mL
Solubility in ethanol: Insoluble
Solubility in ammonia: Insoluble
Refractive index: 1.425
Crystal structure: Monoclinic (decahydrate)
pH (1% solution, 25°C): 9.8–10.5
Hygroscopicity: Low to moderate
Stability: Stable at 70°C in aqueous solution; hydrolyzes to Na₂HPO₄ on prolonged boiling
Thermal decomposition: Above 900°C → Na₂O + P₂O₅ + phosphorus oxides
Flash point: Non-flammable
Heat capacity: 241 J/mol·K
Std molar entropy (S°298): 270 J/mol·K
Std enthalpy of formation (ΔfH°298): −3,166 kJ/mol
Gibbs free energy (ΔfG°): −3,001 kJ/mol
GHS Classification: H315, H318/H319, H335 (Warning)

Specifications of E450 (iii) Tetrasodium Pyrophosphate — Food Grade (EU E450iii):
Appearance: White crystalline powder or granules
Purity (Na₄P₂O₇, dry basis): ≥95.0%
P₂O₅ content: 52.0–54.0%
Loss on drying (105°C, 2h): ≤1.0%
Loss on ignition: ≤0.5% (anhydrous); 38–42% (decahydrate)
pH (1% solution, 25°C): 9.8–10.5
Water-insoluble matter: ≤0.2%
Fluoride (F⁻): ≤10 ppm
Chloride (Cl⁻): ≤0.05%
Sulfate (SO₄²⁻): ≤0.05%
Heavy metals (as Pb): ≤10 ppm
Lead (Pb): ≤2 ppm (food grade); ≤1 mg/kg (EU Commission Regulation 231/2012)
Arsenic (As): ≤3 ppm; ≤1 mg/kg (EU)
Mercury (Hg): ≤1 ppm
Cadmium (Cd): ≤1 ppm
Iron (Fe): ≤50 ppm
Calcium (Ca): ≤0.05%
Total microbial count: ≤1,000 CFU/g
Yeast and mold: ≤100 CFU/g
E. coli: Negative in 10 g
Salmonella spp.: Negative in 25 g
Storage: Cool (15–25°C), dry, tightly sealed, moisture-proof containers
Shelf life: 24 months in original sealed packaging
Packaging: 25 kg Kraft/PP woven bag; 500–1,000 kg big-bag; 25 kg HDPE pail

Names of E450 (iii) Tetrasodium Pyrophosphate:
E450(iii)
Tetrasodium Pyrophosphate
Sodium Pyrophosphate
Tetrasodium Diphosphate
Sodium Diphosphate
Tetrasodium Phosphate
Sodium Pyrophosphate Anhydrous
Sodium Diphosphate Tetrabasic
Sodium Pyrophosphate Tetrabasic
Diphosphoric Acid Tetrasodium Salt
Pyrophosphoric Acid Tetrasodium Salt
Pyrophosphate Sodium Salt
TSPP
Anhydrous TSPP
INS 450(iii)
Victor TSP
CAS 7722-88-5
CAS 13472-36-1 (decahydrate)