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Sodium Pyrophosphate （Tetrasodium Pyrophosphate）

Also known as tetrasodium diphosphate

Code GB 15.004; INS 450 （ii）

There are two types of properties: anhydrous and decahydrate. Ten water substances are colorless or white crystals or crystalline powders, while anhydrous substances are white powders. Melting point of 988 ℃, relative density of 1.82, soluble in water, alkaline in aqueous solution (pH of 1% aqueous solution is 10.0-10.2), insoluble in ethanol and other organic solvents. Strong chelating ability with metal ions such as Cu2+, Fe3+, Mn2+, etc. The aqueous solution is stable below 70 ℃, and when boiled, it hydrolyzes into disodium hydrogen phosphate.

Heating disodium hydrogen phosphate at 200-300 ℃ produces anhydrous sodium pyrophosphate, which is dissolved in water and concentrated to obtain crystalline sodium pyrophosphate.

The identification method for this product should be sodium ion reaction and phosphate reaction.

1. Sodium ion reaction: Dissolve 1g of this product in 20mL of water, wet the platinum wire with hydrochloric acid, dip the solution of this product in it and burn it on a colorless flame until colorless. When burned on a colorless flame, it should turn yellow (sodium ion).

2. Phosphate reaction: Dissolve 0.1g of this product in 10mL of water and add 1mL of silver nitrate solution (20g/L) to form a white precipitate. This precipitate is soluble in ammonia and nitric acid solutions, but insoluble in acetic acid solution.

Toxicological basis

1. Oral administration of 4000mg/kg body weight to LD50 rats.

2．GRAS  FDA-21CFR 173.310，181.29； 182.6789.

3. ADI MTDI 70mg/kg body weight (calculated based on total phosphorus from various sources FAO/WHO, 1994).

Use water retention agents, quality improvement agents, pH regulators, metal chelating agents, etc.

1. Precautions for use: Sodium pyrophosphate has a strong ability to mask metal ions such as Cu2+and Fe3+, which can prevent the damage of vitamin C in food.

2. Scope and quantity of use

(1) The "Hygienic Standards for the Use of Food Additives" (GB 2920-1996) in China stipulate that, except for being the same as sodium hexametaphosphate, it can also be used for potato starch, with a maximum usage of 0.025g/kg.

(2) Actual usage reference

① Adding this product to canned meat such as luncheon meat and sausages can improve the water holding capacity of meat products, reduce the loss of nutrients, and enhance the tenderness of meat.

② 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.

For canned mushrooms and duck wings, the pre cooking solution formula added during pre cooking is: 1.02kg of 10% compound phosphate solution (prepared by mixing 85g of sodium tripolyphosphate, 12g of sodium hexametaphosphate, 9g of sodium pyrophosphate, and 900g of water to form a solution of about 1000g), 0.04kg of disodium ethylenediaminetetraacetic acid (EDTA), add boiling water to a total of 100kg, and wait for dissolution and filtration before use.

Used for canned duck four treasures, 1000g of 10% compound phosphate solution is contained in every 100kg of canned duck soup; 500g of compound phosphate solution is contained in every 100kg of canned mushroom stewed duck soup.

③ Canned pork sausage, when chopping and mixing meat, add 2g of compound phosphate per kilogram of meat. The compound phosphate is made of 60% sodium pyrophosphate and 40% sodium tripolyphosphate, pour well and set aside.

④ In foreign countries, fish mince products are usually mixed with tripolyphosphate, and the ratio of tripolyphosphate to pyrophosphate used is 4:6, which is the most effective.

⑤ As a melting agent and emulsifier for cheese, it can release calcium caseinate from the cheese by adding this product, increasing the viscosity of casein and obtaining soft and stretchable products. Generally, this product is used in combination with orthophosphate and pyrophosphate. The dosage varies with the pH of the cheese.

⑥ Soy sauce and soybean paste should be used at a rate of about 0.005% to 0.3% to prevent browning and improve color. Due to the high alkalinity of this product, it can also inhibit the sourness and fermentation of soybean paste.

⑦ Adding 0.05%~0.5% to fruit juice, refreshing drinks, and cold drinks can prevent oxidation and precipitation during storage. For ice cream, there are incremental and emulsifying dispersing effects.

⑧ The extraction of coffee and licorice extract using 1% pyrophosphate and tripolyphosphate increases the coloring components by more than 3% and the extract by more than 10%.