2,4,6-Trichloroanisole
Chemical primarily responsible for cork taint in wines (TCA)
From Wikipedia, the free encyclopedia
2,4,6-Trichloroanisole (TCA) is an organic compound with the formula CH3OC6H2Cl3. It is one of several isomers of trichloroanisole. It is a colorless solid.
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| Names | |
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| Preferred IUPAC name
1,3,5-Trichloro-2-methoxybenzene | |
| Other names
2,4,6-Trichloroanisole TCA 2,4,6-Trichloromethoxybenzene | |
| Identifiers | |
3D model (JSmol) |
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| ChEBI | |
| ChemSpider | |
| ECHA InfoCard | 100.001.585 |
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| KEGG | |
PubChem CID |
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| UNII | |
CompTox Dashboard (EPA) |
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| Properties | |
| C7H5Cl3O | |
| Molar mass | 211.47 g·mol−1 |
| Melting point | 60 to 62 °C (140 to 144 °F; 333 to 335 K) |
| Boiling point | 140 °C (284 °F; 413 K) at 28 Torr |
| Hazards | |
| GHS labelling: | |
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| Warning | |
| H302, H319, H413 | |
| P264, P270, P273, P280, P301+P312, P305+P351+P338, P330, P337+P313, P501 | |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Occurrence
2,4,6-Trichloroanisole represents one of the strongest of off-flavors, substances "generated naturally in foods/beverages [that considerably] deteriorate the quality" of such products.[1][2] It is also a component of some drinking waters.[3] It has also been detected in blood samples.[4]
Wine
As of 2000, TCA was considered the primary chemical compound responsible for the phenomenon of cork taint in wines,[1][5] and it has an unpleasant earthy, musty and moldy smell.[2]
Coffee
TCA has also been suggested as cause of the "Rio defect" in coffees from Brazil and other parts of the world,[6] which refers to a taste described as "medicinal, phenolic, or iodine-like".[7] In investigation of the mechanism of its role in producing off-flavor effects, it was found to "attenuate olfactory transduction by suppressing cyclic nucleotide-gated channels, without evoking odorant responses."[1]
Formation
TCA is formed by the methylation of 2,4,6-trichlorophenol.[7][8] More generally, it may be produced when naturally occurring airborne fungi and bacteria are presented with chlorinated phenolic compounds, which they then convert into chlorinated anisole derivatives.[9] Species implicated include those of the genera Aspergillus, Penicillium, Actinomycetes, Botrytis (e.g. Botrytis cinerea), Rhizobium, or Streptomyces.[9][10][11]
The chlorophenol precursor, 2,4,6-trichlorophenol, is used as a fungicide; more generally, related compounds can originate as contaminants found in some pesticides and wood preservatives, or as by-products of the chlorine bleaching process used to sterilize or bleach wood, paper, and other materials.[12]
Further reading
- Marsili, R. (2000). "Solid-Phase Microextraction: Food Technology Applications". In Wilson, Ian D. (ed.). Encyclopedia of Separation Science. New York, NY: Academic Press. pp. 4178–4190. doi:10.1016/B0-12-226770-2/06791-0. ISBN 9780122267703.
Over the last two decades, the incidence of mouldy and musty off-flavours in cork-sealed wines has increased significantly. 2,4,6-Trichloroanisole (TCA) has been identified as the primary chemical responsible for cork taint. The human olfactometry threshold for TCA is 4–10 ng L−1 in white wine and 50 ng L−1 in red wine. In the case of wine, a worldwide loss of roughly US$1 billion per year is attributed to cork taint.
- Science Direct Staff (June 2023). "2-4-6-Trichloroanisole" (Science Direct citation sample/listing). Retrieved June 26, 2023.
- Buser, H.R.; Zanier, C. & Tanner, H. (1982). "Identification of 2,4,6-Trichloroanisole as a Potent Compound Causing Cork Taint in Wine". Journal of Agricultural and Food Chemistry. 30 (2): 359–362. doi:10.1021/jf00110a037.
{{cite journal}}: CS1 maint: multiple names: authors list (link) An early primary research report on the role of TCA in cork taint.