Aroma compound
![](https://upload.wikimedia.org/wikipedia/commons/thumb/0/0a/Perfume_shelf_536pix.jpg/220px-Perfume_shelf_536pix.jpg)
Anaroma compound,also known as anodorant,aroma,fragranceorflavoring,is achemical compoundthat has a smell orodor.For an individual chemical or class of chemical compounds to impart a smell or fragrance, it must be sufficientlyvolatilefor transmission via the air to theolfactory systemin the upper part of the nose. As examples, various fragrant fruits have diverse aroma compounds,[1]particularly strawberries which arecommercially cultivatedto have appealing aromas, and contain several hundred aroma compounds.[1][2]
Generally, molecules meeting this specification havemolecular weightsof less than 310.[3]Flavors affect both the sense oftasteandsmell,whereas fragrances affect only smell. Flavors tend to be naturally occurring, and the termfragrancesmay also apply to synthetic compounds, such as those used incosmetics.[4]
Aroma compounds can naturally be found in variousfoods,such as fruits and theirpeels,wine,spices,floral scent,perfumes,fragrance oils,andessential oils.For example, many formbiochemicallyduring theripeningoffruitsand other crops.[1][5]Wines have more than 100 aromas that form as byproducts offermentation.[6]Also, many of the aroma compounds play a significant role in the production of compounds used in the food service industry to flavor, improve, and generally increase the appeal of their products.[1]
Anodorizermay add a detectable odor to a dangerous odorless substance, likepropane,natural gas,orhydrogen,as a safety measure.
Aroma compounds classified by structure
[edit]Esters
[edit]Compound name | Fragrance | Natural occurrence | Chemical structure |
---|---|---|---|
Geranyl acetate | Fruity, Floral |
Rose | ![]() |
Methyl formate | Ethereal | ![]() | |
Methyl acetate | Sweet, nail polish Solvent |
![]() | |
Methyl propionate Methyl propanoate |
Sweet, fruity,rum-like | ![]() | |
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 | ![]() |
Benzyl acetate | Fruity,Strawberry | Strawberries | ![]() |
Methyl anthranilate | Fruity | Grape | ![]() |
Methyl salicylate | Minty,root beer | Wintergreen | ![]() |
Hexyl acetate | Floral,Fruity | Apple,Plum | ![]() |
Linear terpenes
[edit]Compound name | Fragrance | Natural occurrence | Chemical structure |
---|---|---|---|
Myrcene | Woody, complex | Verbena,Bay leaf | ![]() |
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 |
Coriander,Sweet basil,Lavender,Honeysuckle | ![]() |
Nerolidol | Woody, fresh bark | Neroli,ginger Jasmine |
![]() |
Ocimene | Fruity, Floral | Mango,Curcuma amada | ![]() |
Cyclic terpenes
[edit]Compound name | Fragrance | Natural occurrence | Chemical structure |
---|---|---|---|
Limonene | Orange | Orange,lemon | ![]() |
Camphor | Camphor | Camphor laurel | ![]() |
Menthol | Menthol | Mentha | ![]() |
Carvone1 | CarawayorSpearmint | Caraway,dill, spearmint |
![]() |
Terpineol | Lilac | Lilac,cajuput | ![]() |
alpha-Ionone | Violet,woody | Violet | ![]() |
Thujone | Minty | Wormwood,lilac, juniper |
![]() |
Eucalyptol | Eucalyptus | Eucalyptus | ![]() |
Jasmone | spicy, fruity, floral in dilution | Jasmine,Honeysuckle | ![]() |
Note: Carvone, depending on its chirality, offers two different smells.
Aromatic
[edit]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
[edit]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 Flowery |
Feces (diluted) Orange Blossoms |
![]() |
Other aroma compounds
[edit]Alcohols
[edit]- Furaneol(strawberry)
- 1-Hexanol(herbaceous,woody)
- cis-3-Hexen-1-ol(fresh cut grass)
- Menthol(peppermint)
Aldehydes
[edit]High concentrations of aldehydes tend to be very pungent and overwhelming, but low concentrations can evoke a wide range of aromas.
- Acetaldehyde(ethereal)
- Hexanal(green, grassy)
- cis-3-Hexenal(greentomatoes)
- Furfural(burntoats)
- Hexyl cinnamaldehyde
- Isovaleraldehyde– nutty, fruity, cocoa-like
- Anisic aldehyde– floral, sweet, hawthorn. It is a crucial component of chocolate, vanilla, strawberry, raspberry, apricot, and others.
- Cuminaldehyde(4-propan-2-ylbenzaldehyde) – Spicy, cumin-like, green
Esters
[edit]- Fructone(fruity, apple-like)
- Ethyl methylphenylglycidate(Strawberry)
- alpha-Methylbenzyl acetate(Gardenia)
Ketones
[edit]- Cyclopentadecanone (musk-ketone)[7]
- Dihydrojasmone(fruity woody floral)
- Oct-1-en-3-one(blood, metallic, mushroom-like)[8]
- 2-Acetyl-1-pyrroline(fresh bread, jasmine rice)
- 6-Acetyl-2,3,4,5-tetrahydropyridine(fresh bread, tortillas, popcorn)
Lactones
[edit]- gamma-Decalactoneintense peach flavor
- gamma-Nonalactonecoconut odor, popular in suntan lotions
- delta-Octalactonecreamy note
- Jasmine lactonepowerful fatty-fruity peach and apricot
- Massoia lactonepowerful creamy coconut
- Wine lactonesweet coconut odor
- Sotolon(maple syrup,curry,fenugreek)
Thiols
[edit]- Thioacetone(2-propanethione) A lightly studied organosulfur. Its smell is so potent it can be detected several hundred meters downwind mere seconds after a container is opened.
- Allyl thiol(2-propenethiol; allyl mercaptan; CH2=CHCH2SH) (garlicvolatiles andgarlic breath)[9]
- (Methylthio)methanethiol (CH3SCH2SH), the "mouse thiol", found in mouse urine and functions as asemiochemicalfor female mice[10]
- Ethanethiol,commonly called ethyl mercaptan (added topropaneor other liquefied-petroleum gases used as fuel gases)
- 2-Methyl-2-propanethiol,commonly calledtert-butyl mercaptan, is added as a blend of other components to natural gas used as fuel gas.
- Butane-1-thiol,commonly called butyl mercaptan, is a chemical intermediate.
- Grapefruit mercaptan(grapefruit)
- Methanethiol,commonly called methyl mercaptan (after eatingAsparagus)
- Furan-2-ylmethanethiol,also called furfuryl mercaptan (roastedcoffee)
- Benzyl mercaptan(leek or garlic-like)
Miscellaneous compounds
[edit]- Methylphosphineanddimethylphosphine(garlic-metallic, two of the most potent odorants known)[8]
- Phosphine(zinc phosphidepoisoned bait)
- Diacetyl(butterflavor)
- Acetoin(butter flavor)
- Nerolin(orange flowers)
- Tetrahydrothiophene(added tonatural gas)
- 2,4,6-Trichloroanisole(cork taint)
- Substitutedpyrazines
Aroma-compound receptors
[edit]Animals that are capable ofsmelldetect aroma compounds with theirolfactory receptors.Olfactory receptors are cell-membranereceptorson the surface ofsensory neuronsin theolfactory systemthat detect airborne aroma compounds. Aroma compounds can then be identified bygas chromatography-olfactometry, which involves a human operator sniffing the GC effluent.[11]
Inmammals,olfactory receptors areexpressedon the surface of the olfactory epithelium in thenasal cavity.[5]
Safety and regulation
[edit]![](https://upload.wikimedia.org/wikipedia/commons/thumb/4/4c/Epikutanni-test.jpg/220px-Epikutanni-test.jpg)
In 2005–06, fragrance mix was the third-most-prevalentallergeninpatch tests(11.5%).[12]'Fragrance' was votedAllergen of the Yearin 2007 by the American Contact Dermatitis Society. An academic study in the United States published in 2016 has shown that "34.7 % of the population reported health problems, such as migraine headaches and respiratory difficulties, when exposed to fragranced products".[13]
The composition of fragrances is usually not disclosed in the label of the products, hiding the actual chemicals of the formula, which raises concerns among some consumers.[14]In the United States, this is because the law regulating cosmetics protectstrade secrets.[15]
In the United States, fragrances are regulated by theFood and Drug Administrationif present in cosmetics or drugs, by theConsumer Products Safety Commissionif present in consumer products.[15]No pre-market approval is required, except for drugs. Fragrances are also generally regulated by theToxic Substances Control Act of 1976that "grandfathered" existing chemicals without further review or testing and put the burden of proof that a new substance is not safe on theEPA.The EPA, however, does not conduct independent safety testing but relies on data provided by the manufacturer.[16]
A 2019 study of the top-sellingskin moisturizersfound 45% of those marketed as "fragrance-free" contained fragrance.[17]
List of chemicals used as fragrances
[edit]In 2010, theInternational Fragrance Associationpublished a list of 3,059 chemicals used in 2011 based on a voluntary survey of its members, identifying about 90% of the world's production volume of fragrances.[18]
See also
[edit]- Aroma of wine
- Eau de toilette
- Flavour and Fragrance Journal
- Fragrances of the World
- Foodpairing
- Odor
- Odor detection threshold
- Odorizer,a device for adding an odorant to gas flowing through a pipe
- Olfaction
- Olfactory receptor
- Olfactory system
- Pheromone
- vabbing
References
[edit]- ^abcdEl Hadi, Muna; Zhang, Feng-Jie; Wu, Fei-Fei; Zhou, Chun-Hua; Tao, Jun (July 11, 2013)."Advances in fruit aroma volatile research".Molecules.18(7): 8200–8229.doi:10.3390/molecules18078200.ISSN1420-3049.PMC6270112.PMID23852166.
- ^Ulrich, Detlef; Kecke, Steffen; Olbricht, Klaus (March 13, 2018). "What do we know about the chemistry of strawberry aroma?".Journal of Agricultural and Food Chemistry.66(13): 3291–3301.doi:10.1021/acs.jafc.8b01115.ISSN0021-8561.PMID29533612.
- ^Rothe, M; Specht, M (1976)."[Notes about molecular weights of aroma compounds]".Nahrung.20(3): 281–6.doi:10.1002/food.19760200308.PMID958345.RetrievedSeptember 29,2020.
- ^Fahlbusch, Karl-Georg; Hammerschmidt, Franz-Josef; Panten, Johannes; Pickenhagen, Wilhelm; Schatkowski, Dietmar; Bauer, Kurt; Garbe, Dorothea; Surburg, Horst. "Flavors and fragrances".Ullmann's Encyclopedia of Industrial Chemistry.Weinheim: Wiley-VCH.doi:10.1002/14356007.a11_141.ISBN978-3527306732.
- ^abHaugeneder, Annika; Trinkl, Johanna; Härtl, Katja; Hoffmann, Thomas; Allwood, James William; Schwab, Wilfried (October 26, 2018)."Answering biological questions by analysis of the strawberry metabolome".Metabolomics.14(11): 145.doi:10.1007/s11306-018-1441-x.ISSN1573-3882.PMC6394451.PMID30830391.
- ^Ilc, Tina; Werck-Reichhart, Danièle; Navrot, Nicolas (September 30, 2016)."Meta-analysis of the core aroma components of grape and wine aroma".Frontiers in Plant Science.7:1472.doi:10.3389/fpls.2016.01472.ISSN1664-462X.PMC5042961.PMID27746799.
- ^Gane, S; Georganakis, D; Maniati, K; Vamvakias, M; Ragoussis, N; Skoulakis, EMC; Turin, L (2013)."Molecular-vibration-sensing component in human olfaction".PLOS ONE.8(1): e55780.Bibcode:2013PLoSO...855780G.doi:10.1371/journal.pone.0055780.PMC3555824.PMID23372854.
- ^abGlindemann, D.; Dietrich, A.; Staerk, H.; Kuschk, P. (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.PMID17009284.
- ^Block, E. (2010).Garlic and Other Alliums: The Lore and the Science.Royal Society of Chemistry.ISBN978-0-85404-190-9.
- ^Lin, D.Y.; Zhang, S.Z.; Block, E.; Katz, L.C. (2005). "Encoding social signals in the mouse main olfactory bulb".Nature.434(7032): 470–477.Bibcode:2005Natur.434..470L.doi:10.1038/nature03414.PMID15724148.S2CID162036.
- ^Brattoli, M; Cisternino, E; Dambruoso, PR; de Gennaro, G; Giungato, P; Mazzone, A; Palmisani, J; Tutino, M (December 5, 2013)."Gas chromatography analysis with olfactometric detection (GC-O) as a useful methodology for chemical characterization of odorous compounds".Sensors (Basel, Switzerland).13(12): 16759–800.Bibcode:2013Senso..1316759B.doi:10.3390/s131216759.PMC3892869.PMID24316571.
- ^Zug, Kathryn A.; Warshaw, Erin M.; Fowler, Joseph F.; Maibach, Howard I.; Belsito, Donald L.; Pratt, Melanie D.; Sasseville, Denis; Storrs, Frances J.; Taylor, James S.; Mathias, C. G. Toby; Deleo, Vincent A.; Rietschel, Robert L.; Marks, James (2009)."Patch-test results of the North American Contact Dermatitis Group 2005-2006".Dermatitis: Contact, Atopic, Occupational, Drug.20(3): 149–160.ISSN2162-5220.PMID19470301.
- ^Anne Steinemann,"Fragranced consumer products: exposures and effects from emissions",Air Quality, Atmosphere & Health,December 2016, Volume 9, Issue 8, pp 861–866.
- ^Anne C. Steinemann et al.,"Fragranced Consumer Products: Chemicals Emitted, Ingredients Unlisted",Environmental Impact Assessment Review,Vol. 31, Issue 3, April 2011, pp. 328-333.
- ^abFragrances in Cosmetics
- ^Randall Fitzgerald(2006).The Hundred Year Lie.Dutton,2006. p.23.ISBN978-0-525-94951-0.
- ^Patti Neighmond (October 2, 2017)."'Hypoallergenic' And 'Fragrance-Free' Moisturizer Claims Are Often False ".NPR.
- ^"IFRA Survey:Transparency List".IFRA.RetrievedDecember 3,2014.