Citral


Citral, or 3,7-dimethyl-2,6-octadienal or lemonal, is either a pair, or a mixture of terpenoids with the molecular formula C10H16O. The two compounds are geometric isomers. The E-isomer is known as geranial or citral A. The Z-isomer is known as neral or citral B.

Occurrence

Citral is present in the oils of several plants, including lemon myrtle, Litsea citrata, Litsea cubeba, lemongrass, lemon tea-tree, Ocimum gratissimum, Lindera citriodora, Calypranthes parriculata, petitgrain, lemon verbena, lemon ironbark, lemon balm, lime, lemon, and orange.

Uses

Citral has a strong lemon odor. Neral's lemon odor is less intense, but sweeter. Citral is therefore an aroma compound used in perfumery for its citrus effect. Citral is also used as a flavor and for fortifying lemon oil. It also has strong antimicrobial qualities, and pheromonal effects in acari and insects.
Citral is used in the synthesis of vitamin A, lycopene, ionone, and methylionone, to mask the smell of smoke.

Health and safety information

Two studies showed 1–1.7% of people to be allergic to citral, with allergies frequently reported. Citral on its own is strongly sensitizing to allergies; the International Fragrance Association recommends that citral only be used in association with substances that prevent a sensitizing effect. Citral has been extensively tested, with no known genotoxicity or carcinogenic effect.