Citral is an aliphatic aldehyde found to naturally occur in lemongrass, lemons, and oranges. It is a clear yellow liquid terpene with a strong lemon-like odor and is used as a flavor in perfumery, cologne, and in soaps. It is not endogenous in humans. Citral is the most abundant and important component in all citrus-derived flavoring agents and peels oils.
As a food flavoring additive, the ingredient has "generally recognized as safe" (GRAS) status from FDA. Citral is a common cosmetic ingredient, thanks to its odor-masking property. It has a strong antiseptic effect and boosts preservatives' effectiveness in formulation, prolonging the shelf-life of the preparation.
Citral is a monoterpene that has two geometric isomers occurring naturally:
- Neral (cis-citral; CAS No: 106-26-3; EINECS No: 203-379-2; (Z)-3,7-Dimethylocta-2,6-dienal)
- Geranial (trans-citral; CAS No: 141-27-5; EINECS No: 205-476-5; (E)-3,7-Dimethylocta-2,6-dienal) .
Both isomers are listed in the INCI database separately and have slightly different properties. In natural oils and extracts containing Citral, they appear as a mixture in different ratios depending on plant type.
Citral is a good insect repellant that is even used in some pesticides. Unfortunately, there are a lot of cases of sensitization and allergic reactions from this ingredient.