Citric acid is used as an acidulant in creams, gels, and liquids. Fumaric acid has been used as a food acidulant since 1946. Phosphoric acid, an acidulant, is used as a yeast stimulant. As an acidulant in baking powders, it avoids the undesirable hygroscopic properties of tartaric acid. Malic acid is used in many food products, primarily as an acidulant.