Quantification of Several 4-Alkyl Substituted gamma-Lactones in Australian Wines
Date
2009
Authors
Cooke, R.
Capone, D.
van Leeuwen, K.
Elsey, G.
Sefton, M.
Editors
Advisors
Journal Title
Journal ISSN
Volume Title
Type:
Journal article
Citation
Journal of Agricultural and Food Chemistry, 2009; 57(2):348-352
Statement of Responsibility
Rachel C. Cooke, Dimitra L. Capone, Katryna A. van Leeuwen, Gordon M. Elsey and Mark A. Sefton
Conference Name
Abstract
Stable isotope dilution assays have been developed for gamma-octalactone (1), gamma-nonalactone (2), gamma-decalactone (3) and gamma-dodecalactone (4) in both white and red wines for the first time. (2)H(7)-analogues of each lactone were prepared for use as internal standards via a strategy employing ring-opening, esterification and oxidation of the respective starting lactones. The methods were shown to be highly accurate and reproducible (R(2) > or = 0.999; SD < or = 1%). A large selection of Australian wines (n = 178) were analyzed for the presence of lactones 1-4. Fifty-eight white wines covering the varieties Chardonnay, Riesling, Sauvignon Blanc, Semillon and Viognier, as well as Botrytis style wines, were analyzed and showed broadly that gamma-octalactone (1) was the most common lactone, being observed above its limit of detection in 28 of the wines, followed by gamma-nonalactone (2) in 23 wines. The Botrytis style white wines had the highest concentrations of 1 and 2 (maximum concentrations 8.5 and 59 microg/L respectively). A total of 120 red wines covering the varieties Cabernet Sauvignon, Durif, Merlot, Pinot Noir and Shiraz were also studied and showed gamma-octalactone (1) and gamma-nonalactone (2) to be the most common lactones present, in 56 and 57 of the wines, respectively. gamma-Decalactone (3) was observed in only a small number (13) of red wine samples and not at all in the white varieties. gamma-Dodecalactone (4) was absent from all 178 samples studied. The highest concentrations of lactones 1, 2 and 3 in the red wines were 4.2, 39.7 and 4.0 microg/L respectively.