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Preparation Method

Sodium pyrophosphate is produced by drying an aqueous solution of disodium hydrogen phosphate to obtain anhydrous disodium hydrogen phosphate, which is then dehydrated and polymerized at high temperatures. There are two methods: one-step method and two-step method. The one that completes drying and polymerization in one device is called one-step method, and the one that completes drying and polymerization in two devices is called two-step method. The one-step method has simple equipment and a short process, but the quality is not very stable. The two-step equipment is more complex, the process is longer, and the product quality is more stable. Sodium pyrophosphate used in the food industry mostly adopts the two-step method. The reaction equation is:

Na2HP04·12H20→Na2HP04+12H20

2Na2HP04→NaIP207+H20[3]

Application of Sodium Pyrophosphate

(1) Canned poultry such as duck four treasures, mushroom duck wings, and mushroom stewed duck are prone to releasing hydrogen sulfide during heating. Hydrogen sulfide reacts with iron ions inside the can to produce black iron sulfide, which affects the quality of the finished product. Adding composite phosphates has a good chelating effect on metal ions and can improve the quality of finished products.

(2) Canned pork sausage, add compound phosphate (60% sodium pyrophosphate, 40% sodium tripolyphosphate) when chopping and mixing meat.

(3) Used abroad for fish mince products, composite phosphates (sodium pyrophosphate 60%, sodium tripolyphosphate 40%).

(4) Can be used as a melting agent and emulsifier for cheese, which can release calcium ions from calcium caseinate in cheese, increase the viscosity of casein, and obtain soft and stretchable products. Generally, sodium pyrophosphate, orthophosphate, and pyrophosphate are used in combination, with a dosage not exceeding 0.9% (calculated as P).

(5) Used for soy sauce and soybean paste, with a usage rate of about 0.005%~0.3%, it can prevent soybean paste from browning and improve color