E297 - Fumaric acid

Fumaric acid or trans-butenedioic acid is the chemical compound with the formula HO2CCH=CHCO2H. It is produced in eukaryotic organisms from succinate in complex 2 of the electron transport chain via the enzyme succinate dehydrogenase. It is one of two isomeric unsaturated dicarboxylic acids, the other being maleic acid. In fumaric acid the carboxylic acid groups are trans -E- and in maleic acid they are cis -Z-. Fumaric acid has a fruit-like taste. The salts and esters are known as fumarates. Fumarate can also refer to the C4H2O2−4 ion -in solution-. - Wikipedia