Oxalic acid Oxalic acid Oxalic acid is an organic compound with the formula CHO. It is a colorless crystalline solid that forms a colorless solution in water. Its condensed formula is HOOCCOOH, reflecting its classification as the simplest dicarboxylic acid. Its acid strength is much greater than that of acetic acid. Oxalic acid is a reducing agent and its conjugate base, known as oxalate (), is a chelating agent for metal cations. Typically, oxalic acid occurs as the dihydrate with the formula CHO·2HO. It occurs naturally in many foods, but excessive ingestion of oxalic acid or prolonged skin contact can be dangerous.
Malic acid also a component of some artificial vinegar flavors, such as "salt and vinegar" flavored potato chips. In citrus, fruits produced in organic farming contain higher levels of malic acid than fruits produced in conventional agriculture. The process of malolactic fermentation converts malic acid to much milder lactic acid. Malic acid occurs naturally in all fruits and many vegetables, and is generated in fruit metabolism. Malic acid, when added to food products, is denoted by E number E296. Malic acid is the source of extreme tartness in United States-produced confectionery, the so-called "extreme candy". It is also used with or in