4-vinylcatechol oligomers
compound class / compound-class-vinylcatechol-oligomers
4-ビニルカテコールオリゴマー
Oligomer group with harsh (stinging) bitterness generated alongside the decomposition of quinides under heavy-roast conditions.
On this page (7 sections)
Reading the bitterness
When caffeoyl quinides decompose, they pass through a common intermediate, 4-vinylcatechol, whose oligomerization produces a group of bitter compounds. In a study examining model reactions of caffeic acid subjected to high-temperature treatment by taste dilution analysis, a total of 10 compounds—including 1,3-bis(3',4'-dihydroxyphenyl)butane, its butene analogue, and multiple hydroxylated phenylindanes—were identified as bitter compounds. This confirmation is within the scope of the abstract.
The recognition thresholds of these 10 compounds ranged from 23 to 178 µmol/L, and each was confirmed in coffee beverages by liquid chromatography–tandem mass spectrometry. The bitterness produced by this heat-treatment model is described as reminiscent of strongly roasted espresso-type coffee bitterness. In another study of extracts made by systematically varying roast conditions, quinides decomposed at heavy roasting to generate 4-vinylcatechol oligomers (compounds 12–20) with harsh (stinging) bitterness; this change matched the change in bitterness quality observed in sensory evaluation. Both confirmations are within the scope of the abstract.
In another study without bitterness measurement, it was confirmed by structure determination that the compounds generated in model reactions of caffeic acid subjected to high-temperature treatment are oligomers produced via the intermediate 4-vinylcatechol. Coupling products of caffeic acid and 4-vinylcatechol formed mainly at 140–170 °C, while at 200 °C further reaction products formed via addition and elimination of catechol units are described as predominating; an independent research group confirmed the formation pathway and temperature dependence. This research was conducted for a different purpose and did not measure bitterness itself.
In the background section of one paper, it is described that 4-vinylcatechol produced from the decomposition of quinides in the later stages of roasting oligomerizes to form a group of compounds called phenylindanes, which have harsh and lingering bitterness; however, this description is based on prior research cited by the same paper. This paper states that one compound obtained in a model of non-enzymatic browning reaction from heating caffeic acid alone has the same carbon skeleton as a diastereomer of bitter-tasting 4-vinylcatechol oligomers isolated and structure-determined in prior research, and that its formation during actual coffee roasting has been confirmed in another prior study; however, bitterness measurement itself was not conducted in this paper.
Sources for this overview
Checked for this overview: Used taste dilution analysis for narrowing down bitter compounds. / Used the recognition threshold range of 10 compounds and confirmation in beverages.
Checked for this overview: Used the correspondence of quinide decomposition and oligomer generation under heavy roasting.
Checked for this overview: Used confirmation of formation pathway and temperature dependence by an independent group.
Impact of Interactions between Melanoidins and Caffeine on the Bitter Taste of Coffee Beverages
Checked for this overview: Used the background description of formation pathway to phenylindanes.
Checked for this overview: Used structure confirmation of the same carbon skeleton in non-enzymatic browning model.
Follow the connections
4-vinylcatechol oligomers →contributes to→ bitterness →can be measured separately …→ astringency
Structured claims — open a section to read each claim's confidence, evidence and limits
Composition and content (1)
Scope: Layer: Solution. Structure determination of browning products in a non-enzymatic browning model reaction system in which caffeic acid (4-vinylcatechol precursor) was heated alone.
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compound-class-vinylcatechol-oligomers —is_documented_as_having→ "Compound 3 ((E)-4,4′-(but-1-ene-1,3-diyl)bis(benzene-1,2-diol)) generated in a non-enzymatic browning model reaction of caffeic acid has the same carbon skeleton as a diastereomer of bitter-tasting 4-vinylcatechol oligomers isolated and structure-determined in prior research, and its formation during actual coffee roasting has been confirmed in another prior study."How processing and cooking change it (2)
Scope: Formed under heavy-roast conditions alongside the decomposition of quinides, producing a harsh bitterness quality
Note: The chemical substance behind how the “quality” of bitterness changes with roast degree.
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compound-class-vinylcatechol-oligomers —contributes_to→ sensation-bitterScope: Layer: Literature. Background description of the formation pathway from quinides to 4-vinylcatechol oligomers (phenylindanes) in roasted coffee.
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compound-class-vinylcatechol-oligomers —contributes_to→ sensation-bitter