Fumaric acid

Fumaric acid is a dicarboxylic organic acid that occurs naturally as an essential intermediate in the Krebs cycle — the central pathway of aerobic energy metabolism in virtually all organisms. It is the trans-isomer of maleic acid and has a sharp, clean, intensely sour flavour, with greater acidifying power per gram than citric acid or malic acid. In food it functions as an acidulant, pH regulator, and raising-acid component in baked goods, beverages, and confectionery, where its high acidity and dry powder form make it technologically convenient.

JECFA evaluated fumaric acid in 1969 and established an ADI of 6 mg/kg body weight per day, a group ADI that also covers its sodium, potassium, and calcium salts (E365–E367). The body handles fumaric acid through direct entry into the Krebs cycle, making it one of the most metabolically integrated food acidulants available. No accumulation, toxic metabolites, or specific organ toxicity was identified in the evaluation. Typical dietary exposure from food applications is well within the ADI.

Fumaric acid is approved throughout the EU and globally as an acidulant and raising acid. Its low hygroscopicity — it resists absorbing moisture from the air — makes it particularly valuable in dry powder mixes, baking powders, and instant beverage formulations that must remain free-flowing during storage. As a leavening acid in baking powder, it reacts relatively slowly with bicarbonate at room temperature but rapidly upon heating, providing "double-action" properties that give bakers flexibility in timing. On ingredient labels it appears as fumaric acid or E297. Consumers can safely encounter fumaric acid in a broad range of everyday food products without concern.