Aroma compound

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.

Contents

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
Banana plant
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 Bitter 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 Belladonna
Indole Fecal
Flowery
Feces
Jasmine
Skatole Fecal Feces

Other aroma compounds

Alcohols

Aldehydes

Esters

Ketones

Lactones

Thiols

Miscellaneous compounds

Aroma compound receptors

Animals that 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 that detect air-borne aroma compounds.

In mammals, olfactory receptors are expressed on the surface of the olfactory epithelium in the nasal cavity.

Safety

'Fragrance' was voted Allergen of the Year in 2007 by the American Contact Dermatitis Society. The composition of fragrances are usually not disclosed in the label of products, hiding the actual chemicals of the formula, which raises concerns among some consumers.[2]

References

  1. ^ a b D. Glindemann, A. Dietrich, H. Staerk, P. Kuschk, (2005). "The Two Odors of Iron when Touched or Pickled: (Skin) Carbonyl Compounds and Organophosphines". Angewandte Chemie International Edition 45 (42): 7006–7009. doi:10.1002/anie.200602100. PMID 17009284. 
  2. ^ Toxic chemicals linked to birth defects are being found at alarming levels in women of childbearing age

See also