Nature and Preparation method
White crystalline powder. The relative density is 1.86, and the refractive index is 1.510. It is soluble in water (lOg/lOOmL, 20 ℃) and ethanol. It is hygroscopic, the aqueous solution is acidic, and the pH value of 1% water is 4~4.5. It is decomposed into sodium metaphosphate at 220 ℃. The water solution is hydrolyzed into phosphoric acid when heated with dilute inorganic acid. Acid sodium pyrophosphate is slightly hygroscopic and forms six crystal hydrates after absorbing water. When heated to above 220 ℃, it decomposes to generate sodium metaphosphate.
Add food-grade soda ash into the neutralizer, heat and dissolve it under stirring, and then add food-grade phosphoric acid for neutralization reaction. Control the pH of the reaction end point to 4~4.4 to generate sodium dihydrogen phosphate. Filter the solution at 70~80 ℃, evaporate and concentrate the filtrate, cool and crystallize, centrifuge, and dry and dehydrate it at 95 ℃ to become anhydrous sodium dihydrogen phosphate. Then it is heated at 140~200 ℃ for polymerization and converted into disodium dihydrogen pyrophosphate.
Application
It is used as a starter for baking food and controlling fermentation speed;
It is used for instant noodles to reduce the rehydration time of finished products, without sticking and rotting;
It can be used for biscuits and pastries, shorten the fermentation time, reduce the product damage rate, loosen and tidy the gap, and extend the storage period.
Essential information
Major manufacturers include:ICL Performance、Suqian Modern Chemical、Shifang Juyuan Chemica、Innophos and so on. The main regions of production and consumption include North America, Europe, Japan, Southeast Asia and India. According to product characteristics, the product is divided into industrial grade and food grade.In industry, this product is mainly used as adhesive, dispersant and metal ion composite agent. As a fast starter and quality improver in the food industry. For example, adding barbecue food can control fermentation speed and improve production intensity; It is used as an acidic component of synthetic leavening agent such as bread and pastry, which can prolong the storage time. In addition, the loose and tidy space can also reduce the breaking rate of biscuits and pastries.