Potassium nitrite (Potassium nitrite, potassium nitric acid, E249) is the potassium salt of nitric acid.
The chemical formula is KNO2.
Purified potassium nitrite is a white or slightly yellowish crystalline powder. Very well soluble in water and hygroscopic. In air, it is slowly oxidized to potassium nitrate KNO3.
It is used as a color improver and preservative in the food industry in meat and fish products.
When eating foods containing potassium nitrite, there is a strong thirst.
Potassium nitrite as a food additive E249 (preservative) is used similarly to other nitrites and salts (sodium chloride and sodium nitrite),- prevents the formation of botulinum toxin (formed during the vital activity of the Clostridium botulinum bacillus).
When added to meat, it forms nitrosomyoglobin, which has a characteristic red color, which can be observed in most food products (sausages, sausages, etc.).
Potassium nitrite is also used:
- for nitriding in the production of azo-dyes;
- in analytical chemistry for the recognition of amines;
- in photography as a sensitizer.
Potassium nitrite is a common poisonous substance, at a dose of 200 mg per kilogram of weight, 50% of experimental rabbits die. It nitrifies amines under normal conditions to form carcinogens (nitrozoamines). Due to the possible harmful effects of nitrite exposure, their use for canning is not recommended, but it is not always possible to choose an adequate safe replacement.