- Quantitation, Organoleptic Contribution, and Potential Origin of Diethyl Acetals Formed from Various Aldehydes in Cognac
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Cognac wine distillate (WD), especially that produced during aging, is marked by complex and elegant aroma. This work aimed at expanding the knowledge on the Cognac WD aroma by a sensory-guided approach, involving a fractional-distillation technique and gas chromatography coupled to olfactometry and mass spectrometry (GC-O-MS). In doing so, a fruity-odor zone was highlighted in WD extracts that was attributed to the diethyl acetal family. Ten additional diethyl acetals were detected by GC-MS. Next, an assay method was developed and validated for seven of these diethyl acetals. Their detection thresholds were evaluated in a model solution of water/ethanol (60:40, v/v). 1,1-Diethoxy-3-methylbutane was shown to present a significant organoleptic impact because its olfactory-detection threshold (323 μg/L) is lower than its range of concentrations in WD (461 to 3337 μg/L). Given that diethyl acetals result from reactions between ethanol and aldehydes, quantitative correlations between diethyl acetals and corresponding aldehydes were considered.
- Thibaud, Fannie,Shinkaruk, Svitlana,Darriet, Philippe
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- Living and Alternating Cationic Copolymerization of o-Phthalaldehyde and Various Bulky Enol Ethers: Elucidation of the "Limit" of Polymerizable Monomers
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Cationic copolymerization of various bulky enol ethers, which have been difficult to homopolymerize and/or copolymerize, was shown to proceed when o-phthalaldehyde (OPA) was used as a comonomer. A series of enol ethers with various substituents on the β-carbon was synthesized from aliphatic aldehydes and alcohols. The relationships between the structures of the enol ethers and the copolymerization behavior were systematically investigated. As a result, monomers with one or two methyl and/or primary alkyl groups on the β-carbon were found to undergo alternating copolymerization with OPA. Moreover, living cationic copolymerization of enol ethers and OPA yielded alternating copolymers under appropriate polymerization conditions. To elucidate the limit of polymerizable monomers, the copolymerization of very bulky enol ethers such as β-t-butyl- or norbornenylidene-type monomers with OPA was also examined. OPA was found to be copolymerizable even with such very bulky monomers, indicating that the unique reactivity of the OPA-derived propagating carbocation with small steric hindrance is the key factor for successful copolymerization.
- Hayashi, Keisuke,Kanazawa, Arihiro,Aoshima, Sadahito
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p. 1365 - 1375
(2022/02/23)
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- Characterization of aroma compounds of Chinese "Wuliangye" and "Jiannanchun" liquors by aroma extract dilution analysis
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Aroma compounds in Chinese "Wuliangye" liquor were identified by gas chromatography-olfactometry (GC-O) after fractionation. A total of 132 odorants were detected by GC-O in Wuliangye liquor on DB-wax and DB-5 columns. Of these, 126 aromas were identified by GC-mass spectrometry (MS). Aroma extract dilution analysis (AEDA) was further employed to identify the most important aroma compounds in "Wuliangye" and "Jiannanchun" liquors. The results showed that esters could be the most important class, especially ethyl esters. Various alcohols, aldehydes, acetals, alkylpyrazines, furan derivatives, lactones, and sulfur-containing and phenolic compounds were also found to be important. On the basis of flavor dilution (FD) values, the most important aroma compounds in Wuliangye and Jiannanchun liquors could be ethyl butanoate, ethyl pentanoate, ethyl hexanoate, ethyl octanoate, butyl hexanoate, ethyl 3-methylbutanoate, hexanoic acid, and 1,1-diethoxy-3-methylbutane (FD ≥ 1024). These compounds contributed to fruity, floral, and apple- and pineapple-like aromas with the exception of hexanoic acid, which imparts a sweaty note. Several pyrazines, including 2,5-dimethyl-3-ethylpyrazine, 2-ethyl-6-methylpyrazine, 2,6-dimethylpyrazine, 2,3,5-tri-methylpyrazine, and 3,5-dimethyl-2-pentylpyrazine, were identified in these two liquors. Although further quantitative analysis is required, it seems that most of these pyrazine compounds had higher FD values in Wuliangye than in Jiannanchun liquor, thus imparting stronger nutty, baked, and roasted notes in Wuliangye liquor.
- Fan, Wenlai,Qian, Michael C.
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p. 2695 - 2704
(2007/10/03)
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- Reactions of Co-ordinated Ligands. Part 8. Reaction of Grignard Reagents with 2-Alkoxy-1,3-dioxolans; an Improved Route to Aldehydes
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The yields of 2-phenyl-1,3-dioxolan obtained from phenylmagnesium bromide and 2-alkoxy-1,3-dioxolans in which the type Men-O increase as the value of n proceeds along the series 4,3,1,2.Several Grignard reagents(including phenylmagnesium bromide) react with the 2-alkoxy-1,3-dioxolan in which n=2 to give the expected 2-substituted-1,3-dioxolans, whose yields are considerably higher than those of the diethyl acetals obtained from the corresponding reation with ethyl ortoformate.
- Houghton, Roy P.,Morgan, Alan D.
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p. 756 - 758
(2007/10/02)
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