Fragrances
Published: 09/27/2010
An aroma compound, also known as odorant, aroma, fragrance or flavor, is a chemical compound that has a smell or odor. A chemical compound has a smell or odor when two conditions are met: the compound needs to be volatile, so it can be transported to the olfactory system in the upper part of the nose, and it needs to be in a sufficiently high concentration to be able to interact with one or more of the olfactory receptors.
Aroma compounds can be found in food, wine, spices, perfumes, fragrance oils, and essential oils. For example, many form biochemically during ripening of fruits and other crops. In wines, most form as byproducts of fermentation. Odorants can also be added to a dangerous odorless substance, like propane, natural gas, or hydrogen, as a warning. Also, many of the aroma compounds play a significant role in the production of flavorants, which are used in the food service industry to flavor, improve, and generally increase the appeal of their products.
Aroma compounds classified by structure
Esters
Compound name
Fragrance
Natural occurrence
Chemical structure
Methyl formate
Ethereal
Methyl acetate
Sweet, nail polish
Solvent
Methyl butyrate
Methyl butanoate
Fruity, apple
Pineapple
Ethyl acetate
Sweet, solvent
Wine
Ethyl butyrate
Ethyl butanoate
Fruity, orange
Pineapple
Isoamyl acetate
Fruity, banana
Pear
Pentyl butyrate
Pentyl butanoate
Fruity, pear
Apricot
Pentyl pentanoate
Fruity, apple
Octyl acetate
Fruity, orange
Linear terpenes
Compound name
Fragrance
Natural occurrence
Chemical structure
Myrcene
Woody, complex
Verbena, bay
Geraniol
Rose, flowery
Geranium, lemon
Nerol
Sweet rose, flowery
Neroli, lemongrass
Citral, lemonal
Geranial, neral
Lemon
Lemon myrtle, lemongrass
Citronellal
Lemon
Lemongrass
Citronellol
Lemon
Lemongrass, rose
Pelargonium
Linalool
Floral, sweet
Woody, lavender
Coriander, sweet basil
Lavender
Nerolidol
Woody, fresh bark
Neroli, ginger
Jasmine
Cyclic terpenes
Compound name
Fragrance
Natural occurrence
Chemical structure
Limonene
Orange
Orange, lemon
Camphor
Camphor
Camphor laurel
Terpineol
Lilac
Lilac, cajuput
alpha-Ionone
Violet, woody
Violet
Thujone
Minty
Cypress, lilac
Juniper
Aromatic
Compound name
Fragrance
Natural occurrence
Chemical structure
Benzaldehyde
Almond
Eugenol
Clove
Clove
Cinnamaldehyde
Cinnamon
Cassia
Cinnamon
Ethyl maltol
Cooked fruit
Caramelized sugar
Vanillin
Vanilla
Vanilla
Anisole
Anise
Anise
Anethole
Anise
Anise
Sweet basil
Estragole
Tarragon
Tarragon
Thymol
Thyme
Thyme
Amines
Compound name
Fragrance
Natural occurrence
Chemical structure
Trimethylamine
Fishy
Ammonia
Putrescine
Diaminobutane
Rotting flesh
Rotting flesh
Cadaverine
Rotting flesh
Rotting flesh
Pyridine
Fishy
Indole
Fecal
Flowery
Feces
Jasmine
Skatole
Fecal
Feces
Other aroma compounds
Alcohols
Furaneol (strawberry)
1-Hexanol (herbaceous, woody)
cis-3-Hexen-1-ol (fresh cut grass)
Menthol (peppermint)
Aldehydes
Acetaldehyde (pungent)
Hexanal (green, grassy)
cis-3-Hexenal (green tomatoes)
Furfural (burnt oats)
Esters
Fructone (fruity, apple-like)
Hexyl acetate (apple, floral, fruity)
Ethyl methylphenylglycidate (strawberry)
Ketones
Dihydrojasmone (fruity woody floral)
Oct-1-en-3-one (blood, metallic, mushroom-like)[1]
2-Acetyl-1-pyrroline (fresh bread, jasmine rice)
6-Acetyl-2,3,4,5-tetrahydropyridine (fresh bread, tortillas, popcorn)
Lactones
gamma-Decalactone intense peach flavor
gamma-Nonalactone coconut odor, popular in suntan lotions
delta-Octalactone creamy note
Jasmine lactone powerful fatty fruity peach and apricot
Massoia lactone powerful creamy coconut
Wine lactone sweet coconut odor
Sotolon (maple syrup, curry, fenugreek)
Thiols
Ethanethiol, commonly called Ethyl mercaptan (added to propane or other liquefied petroleum gases used as fuel gases)
Grapefruit mercaptan (grapefruit)
Methanethiol, commonly called Methyl mercaptan (Durian or leek)
2-Methyl-2-propanethiol, commonly called tertiary-butyl mercaptan is added as a blend of other components to natural gas used as fuel gas.
Miscellaneous compounds
Methylphosphine and dimethylphosphine (garlic-metallic, two of the most potent odorants known)[1]
Nerolin (orange flowers)
Tetrahydrothiophene (added to natural gas)
2,4,6-Trichloroanisole (cork taint)
Substituted pyrazines
Aroma compound receptors
Animals which are capable of smell detect aroma compounds with olfactory receptors. Olfactory receptors are cell membrane receptors on the surface of sensory neurons in the olfactory system which detect air-borne aroma compounds.
In mammals, olfactory receptors are expressed on the surface of the olfactory epithelium in the nasal cavity.
