Why can aldehydes and ketones have fruity aromas?

Many aldehydes and ketones are frequently responsible for the characteristic flavors and pleasant, fruity aromas found in fruits and vegetables.12

The perception of these aromas is a complex process involving the olfactory system. For a substance to be perceived as odorous, it must be sufficiently volatile to be carried by air currents into the nostrils. Once inhaled, these molecules interact with specific olfactory receptors located in the nasal epithelium. Humans possess a large family of these receptor genes, and each receptor molecule is capable of responding to a specific family of odorants.34

While no single chemical or physical property has been identified that universally elicits a specific odor, the scent of these compounds is influenced by both the arrangement of atoms within the molecule and the presence of specific functional groups. In the case of aldehydes and ketones, the carbonyl functional group plays a central role in their chemical identity and reactivity, contributing to the diverse range of scents they impart, such as the aroma of cherries, almonds, or cheeses.312