Citral

Citral is a naturally occurring aroma chemical, a mixture of two geometric isomers: geranial (trans-citral) and neral (cis-citral). It is an acyclic monoterpene aldehyde with the formula C10H16O, responsible for the lemon odor characteristic of many essential oils.

Citral occurs in several essential oils, most notably lemongrass (Cymbopogon citratus), as well as lemon and orange oils. Commercial supply comes from natural extraction of these oils and from chemical synthesis using terpenoid precursors; the final product is typically a mixture of geranial and neral in varying proportions. In industry, citral can be produced or enriched by processes that transform related terpenoids, yielding a concentrate enriched in the two isomers.

In flavor, fragrance, and consumer products, citral provides a strong lemon note and is used in foods, beverages, confectionery, and cosmetics, as well as in cleaning agents. It serves as a versatile building block for fragrance synthesis, including conversion to ionones and other citral-derived aroma compounds.

Citral is volatile and can degrade upon exposure to air and light, forming oxidation products and polymers. It is a skin sensitizer and is listed as a fragrance allergen in many regulatory frameworks, with labeling considerations for cosmetics and other products containing it.