It is used as a food additive, also known as E224. It is restricted in use and may cause allergic reactions in some sensitive persons.
Potassium metabisulfite is an inhibitor of the polyphenol oxidase enzyme
Potassium metabisulfite, K2S2O5, also known as potassium pyrosulfite, is a white crystalline powder with a pungent sulfur odour. The main use for the chemical is as an antioxidant or chemical sterilant. It is a disulfite and is chemically very similar to sodium metabisulfite, with which it is sometimes used interchangeably. Potassium metabisulfite is generally preferred out of the two as it does not contribute sodium to the diet.
Potassium metabisulfite is sometimes added to lemon juice as a preservative.
Potassium metabisulfite is used in the textile industry for dyeing and cotton printing.
Potassium metabisulfite is sometimes used to precipitate gold from solution in aqua regia (as an alternative to sodium sulfite).
It is a component of certain photographic developers and solutions used in photographic fixing.
It is used as a bleaching agent in the production of Coconut cream.
It is used in some pickles as a preservative.
It is used in tint etching iron-based metal samples for microstructural analysis