Disodium dihydrogen pyrophosphate has a white monoclinic appearance, crystalline in powder form, with a relative density of 1.862. It decomposes into sodium metaphosphate when heated to above 220 ℃. Easily soluble in water, insoluble in ethanol. When heated in an acidic medium, it hydrolyzes into orthophosphate and has hygroscopicity. After absorbing water, it forms hexahydrate crystals. It can form chelates with Cu2+and Fe2+, and the aqueous solution is hydrolyzed into phosphoric acid by heating with dilute sulfuric acid and inorganic acid.
purpose
It can be used as a functional water retention agent, pH regulator, and metal chelating agent. This product is an acidic salt and is generally not used alone. It is often mixed with sodium pyronate (an alkaline salt that has a specific effect on proteins in meat and can significantly enhance the water holding capacity of meat). This product reacts with sodium bicarbonate to generate carbon dioxide, which can be used as a raw material for rapid fermentation powder. In the food industry, it is used as a rapid fermentation agent, quality improver, etc., and is used as an acidic component in the synthesis of leavening agents such as bread and pastries. Combined with other phosphates, it can be used as a water retaining agent for meat products such as lunch meat, cooked ham, and canned meat, as well as a rehydrating agent for instant noodles.
Preparation method
Disodium dihydrogen pyrophosphate is neutralized by food grade phosphoric acid and soda ash, and the endpoint pH value is controlled to generate sodium dihydrogen phosphate. It is then polymerized and dehydrated at a certain temperature to obtain the finished product.
Dry polymerization two-step method: Food grade soda ash is added to a neutralizer, heated and dissolved under stirring, and then food grade phosphoric acid is added for neutralization reaction. The reaction endpoint pH is controlled to be 4-4.4 to generate sodium dihydrogen phosphate. The solution is filtered at 70-80 ℃, evaporated and concentrated, cooled and crystallized, centrifuged, and dried and dehydrated to anhydrous sodium dihydrogen phosphate at 95 ℃. Then, it is sent to a box type polymerization furnace for heating and melting polymerization, and the material temperature is controlled at 140~200 ℃ for polymerization. The converted acid type sodium pyrophosphate is crushed and packaged to produce edible acid type sodium pyrophosphate.
Storage and transportation conditions
Store in a cool, ventilated, and dry place, protected from moisture and sunlight. Avoid direct sunlight and moisture during transportation.