Odor detection thresholds and enantiomeric distributions of several 4-alkyl substituted γ-lactones in Australian red wine

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dc.contributor.authorCooke, R.
dc.contributor.authorvan Leeuwen, K.
dc.contributor.authorCapone, D.
dc.contributor.authorGawel, R.
dc.contributor.authorElsey, G.
dc.contributor.authorSefton, M.
dc.date.issued2009
dc.description.abstractThe individual enantiomers of γ-octalactone (1), γ-nonalactone (2), γ-decalactone (3) and γ-dodecalactone (4) have been synthesized. The (R) series of enantiomers was prepared from l-glutamic acid by a strategy involving deamination and reduction to (S)-5-oxo-2-tetrahydrofurancarboxaldehyde (S)-7. The different length side chains were introduced by a series of Wittig reactions, varying in the choice of phosphorane used. Hydrogenation then gave the final γ-lactones 1−4. The (S) series of enantiomers was prepared in an analogous fashion beginning with d-glutamic acid. Aroma detection thresholds for all eight enantiomers were determined in a “bag in a box” dry red wine by the application of ASTM method E 679, employing a panel of 25 members. The lowest threshold determined was 8 μg/L for (R)-dodecalactone (4) while the highest threshold was 285 μg/L for (R)-nonalactone (2). With the exception of γ-decalactone (3) there were statistically significant differences (at the 5% level) in aroma detection thresholds between the two enantiomers of the same lactone. A stable isotope method developed for quantification of the lactones 1−4 has been extended for use with chiral phase GC (Rt-βDEXcst capillary column) allowing quantification of the individual enantiomers. The enantiomeric distribution of γ-octalactone (1) and γ-nonalactone (2) in seven botrytized wines and of 2 in a total of 34 red wines were thus determined; with few exceptions, the (R) enantiomer of γ-nonalactone (2) was found to be more prevalent than its (S) counterpart in the dry red and botrytized white wines analyzed. The same was true for γ-octalactone (1) in the botrytized white wines.
dc.description.statementofresponsibilityRachel C. Cooke, Katryna A. van Leeuwen, Dimitra L. Capone, Richard Gawel, Gordon M. Elsey and Mark A. Sefton
dc.identifier.citationJournal of Agricultural and Food Chemistry, 2009; 57(6):2462-2467
dc.identifier.doi10.1021/jf802866f
dc.identifier.issn0021-8561
dc.identifier.issn1520-5118
dc.identifier.orcidCapone, D. [0000-0003-4424-0746]
dc.identifier.urihttp://hdl.handle.net/2440/55038
dc.language.isoen
dc.publisherAmer Chemical Soc
dc.source.urihttps://doi.org/10.1021/jf802866f
dc.subjectLactones
dc.subjectAlkylation
dc.subjectStereoisomerism
dc.subjectWine
dc.subjectAustralia
dc.subjectOdorants
dc.titleOdor detection thresholds and enantiomeric distributions of several 4-alkyl substituted γ-lactones in Australian red wine
dc.title.alternativeOdor detection thresholds and enantiomeric distributions of several 4-alkyl substituted gamma-lactones in Australian red wine
dc.typeJournal article
pubs.publication-statusPublished

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