Disodium pyrophosphate
Description
Disodium pyrophosphate (CAS 7758-16-9), also known as SAPP and sodium acid pyrophosphate, is an inorganic phosphate salt used across food manufacturing and water treatment as a buffering, leavening, and sequestering agent.
Approved as E450a in the EU, it controls pH, binds metal ions, and stabilizes formulations where precise acidity management is critical. In baked goods, SAPP acts as a leavening acid in baking powder and self-rising flour.
It reacts with sodium bicarbonate to generate controlled CO₂ release during baking. Potato processors rely on it to inhibit after-cooking darkening by chelating iron and other trace metals that trigger enzymatic discoloration.
In seafood and meat processing, it functions as a moisture stabilizer and texture modifier, reducing drip loss in frozen products. Water treatment operations use it to sequester hardness ions and control scale formation.
Disodium pyrophosphate is supplied as a white crystalline powder or granules, with granule grades available for improved flowability in dry blending operations. Standard market grades include food-grade material.
This material conforms to FCC and E450a specifications, as well as technical-grade material for industrial applications. Buyers should confirm the slow-acting or fast-acting leavening profile when sourcing.
The reaction rate varies by grade, making it essential to select the correct version for specific baking applications. This ensures consistent texture and volume in the final manufactured food products.
Physical Properties
| Melting Point | decomposes 220°C [MER06] |
| Density | (hexahydrate) 1.86 |
| Appearance | white powder |
| Color | White to Off-White |
| Form | white powder |
| Water Solubility | Fully miscible in water. Insoluble in alcohol and ammonia. |
| Vapor Pressure | 0Pa at 20℃ |
| pH | 3.5-4.5 (20℃, 0.1M in H2O, freshly prepared) |
| Log P | -3.420 (est) |
Safety & Handling (Learn More)
Trade & Regulatory
| Storage Class | 11 - Combustible Solids |
| WGK (Germany) | 2 |
Documentation
Other Names
disodium diphosphate|Sodium acid pyrophosphate|Disodium dihydrogen pyrophosphate|Disodium dihydrogen diphosphate|Diphosphoric acid, disodium salt|Disodium acid pyrophosphate|H5WVD9LZUD|Pyrophosphoric acid, disodium salt|SAPP|E450a
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