Date of Award
Doctor of Philosophy (PhD)
Professor R.H. Tomlinson
A new analytical method has been developed for examining flavor compounds in wine that detracts from the traditional method; the isolation-concentration process takes 5½ hours, using only 95 ml of wine. The heart of this method is a new design of a low-temperature, high-vacuum concentrator, which is more efficient than any previously described design of its kind. It was used together with a previously designed solvent extractor to isolate and enrich the volatile fraction of the wine. Capillary GC/MS techniques were used to separate and identify components of the flavor extract.
The method was used to confirm the presence of 2-methoxy-3-isobutylpyrazine, a twice compound previously identified in the grapes but not in the wine, for the first time in Cabernet Sauvignon wine. Ethyl 4-acetyloxybutyrate and 2-hydroxybenzothiazole were also identified for the first time in this wine.
This method was used to analyse the volatile flavor composition of White Riesling, whose vines have recently been successfully cultivated locally. The results of the qualitative and quantitative analyses of the musts and wines of local White Riesling compared quite favorably with results obtained on the same grape variety cultivated in the temperate climate. These results, it is hoped, would enable vintners and viticulturalists anticipate the potentialities of the locally cuItivated vinifera vines.
It was discovered that the method used to examine the flavor composition of vinifera varieties had to be modified for the labrusca varieties and, only under inert conditions could the compound tentatively identified as N-(N-methyl,N-hydroxy-ϒ-aminobutyryl)glycine be detected in all the varieties examined. For the first time, it is being suggested that this compound, rather than methyl anthranilate, may be responsible for the typical labrusca flavor. 3-Methyltetrahydrothiophene, 3-methylthiopropanol, phthalide, 2,5-dimethyl-4-hydroxy-3(2H) furanone, dihydrobenzofuran, 2-hydroxybenzothiazole and α-naphthol were identified for the first time in Moulin Rouge and Concord.
Boison, Joe Oslo King, "Capillary GC/MS Analysis of the Volatile Flavor Components in Wines" (1985). Open Access Dissertations and Theses. Paper 1143.