Coriander aldehyde, also known as (E)-2-decenal, is an unsaturated aliphatic aldehyde primarily responsible for the characteristic aroma of fresh coriander leaves (Coriandrum sativum). It arises from the enzymatic or oxidative breakdown of unsaturated fatty acids in the plant. This compound imparts a green, citrusy, and sometimes soapy or pungent note to the herb's scent profile. It is widely used in flavor and fragrance industries to replicate coriander or citrus notes in food products and perfumes. Chemically, it features a trans double bond at position 2 and an aldehyde functional group, making it reactive in Maillard reactions and prone to oxidation.