Sodium acid pyrophosphate, also known as disodium dihydrogen pyrophosphate, disodium pyrophosphate is usually widely used in food processing. It is white powder or granules in appearance, soluble in water but not soluble in ethanol. The aqueous solution can be hydrolyzed into phosphate acid by heating with dilute inorganic acid, which has hygroscopicity and can form into six crystalline hydrates after absorpting water. When it is heated to above 220℃，it can be decomposed and form sodium metaphosphate. In general, it is packed with outer woven bag and inner bag, the net weight of each bag can be different based on different manufacturers, customers can choose different specification according to their own needs.
| Items | Sodium Acid Pyrophosphate (SAPP) |
| Appearance | White crystal or crystalline power |
| Purity, % ≥ | 96% |
| Acidity(ml,0.1N NaOH 2.0g) | ≤0.2 |
| Heavy metals | ≤0.001% |
| Loss on drying | ≤1.5% |
| Moisture | ≤0.3% |
| Sulphate Ash | ≤0.1% |
Used as baking powder, the fermentation speed can be fast or slow based on different uses. It can control fermentation speed and increase production intensity in baking products. For instant noodles, it can reduce the rehydration time of finished products, and make it not sticky. For biscuits and pastries, it can shorten the fermentation time, reduce products damage rate, make the loose gap neat, as well as extend the storage period. For meat and aquatic products processing, it can be used as quality improver.