- an organic compound, C4H6O6, existing in four isomeric forms, the common or dextrorotatory isomer being a white, crystalline, water-soluble powder or transparent crystals: used in effervescent beverages, baking powders, confections, photography, and tanning.
- a colourless or white odourless crystalline water-soluble dicarboxylic acid existing in four stereoisomeric forms, the commonest being the dextrorotatory (d-) compound which is found in many fruits: used as a food additive (E334) in soft drinks, confectionery, and baking powders and in tanning and photography. Formula: HOOCCH(OH)CH(OH)COOH
