Malic acid is mainly used in food and pharmaceutical industries

Malic acid is commonly used in the preparation of medicines, mordants and tanning agents, and is also commonly used as a reagent for the resolution of racemic basic compounds. It is also a sour agent in food additives, sourness is better than malic acid, lactic acid and so on. Several of its salts have important applications. For example, the Fehling reagent is formulated with potassium sodium tartrate in the laboratory to identify aldehyde functional groups in the structure of organic molecules. Its potassium and sodium salt is also called Rochelle's salt. Its crystals are polarized under pressure to produce a potential difference (piezoelectric effect) on both ends of the surface, which can be made into piezoelectric elements for radio and cable broadcasting. The receiver and pickup. Medically, potassium antimony tartrate (commonly known as tartrate) is used to treat schistosomiasis.