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Sweet fortified wines, traditionally aged under strong oxidation conditions, have a characteristic aroma. An experimental study investigated the aging of white sweet fortified wines under various conditions. The development of various molecules, previously identified as characteristic of the aroma of this type of wine, was monitored by analysis. The development of these compounds during accelerated aging was affected by oxidation and the color of the wine. Aging in oak containers, variable storage temperatures, and variable modes of oxidation affect the formation of many of the volatile compounds responsible for the aging aroma of vins doux naturels (fortified wines). Furfural (1), 5-ethoxymethylfurfural (2), and sotolon (3) always reach concentrations above their perception thresholds in wood-aged wines, especially when new oak is used. The isomers of methyl-gamma-octalactone (4 and 5) are reliable indicators of aging in oak. Among the many identifiable volatile phenols, only the vanillin (7) content increases with aging, particularly if the container is made of wood and there is a high degree of oxidation. This molecule frequently reaches and even exceeds its perception threshold. We show here that vanillin and isomers of methyl-gamma-octalactone have a major impact on the aromas of fortified wines.

Toasting changes both the quantity and the quality of the extractable substances in the oak wood of barrels used for the aging of fine wines and spirits. Mastery and repeatability of toasting are vital in the production of quality barrels to be used for the aging of wines and spirits. In this study, we show that it is possible for a given cooperage to differentiate barrel toasting levels by analyzing a certain number of volatile and semivolatile compounds resulting from the thermal degradation of oak. Toasted wood components, which can be extracted by the wines or spirits during the aging process, are normally analyzed after the wood has soaked in standard alcoholic solutions and can be used to control the intensity of the wood toasting. The results of the comparative analysis presented in this work show that headspace analysis with a microextractive method using a stationary polydimethylsiloxane type phase is a promising technique for analyzing toasted oak wood from barrels. It is easier to use than the traditional maceration and extraction method and provides similar information.

This study is dedicated to quantification, by gas chromatography combined with mass spectrometry, of some volatile compounds founded during ageing of sweet natural wines. Besides determination of the thresholds olfactory perception enable us knowing better the more active compound in sweet natural wines aroma.The results enable to know better volatile compounds which are able to produce ageing aromas characteristic of sweet natural wines. These products are always rich in sugar and grown up in a more or less oxidising environment. Logically, many of the compounds identified in this work (derived furanic compounds and many others) are Iinked with chemical like Maillard reactions between sugars and amino-acids. Others compounds as a sotolon need oxidising phenomena to increase in the environment.Comparatively, oldest Port wines have been analysed. The compounds measured in these Port wines also exist in French sweet natural wines of type Banyuls and Rivesaltes, keeped under oxidising environment. But the dillerences of concentrations in some compounds discriminate them from the Port wines.

Toasting wood to be used in barrels for aging wine and brandy produces a great number of volatile and odiferous compounds. Some of these have a "toasty caramel" aroma. Analysis by high-performance gas chromatography of toasted oak extracts, combined with olfactory detection, enabled various Chromatographic peaks with these specific aromas to be isolated. These same odors were simultaneously studied by heating glucose both with and without proline. Aromatic compounds of interest were identified thanks to a combination of gas chromatography and both mass and infrared spectrometry. In addition to already-known substances such as 2-hydroxy-3-methyl-2-cyclopenten-1-one (cyclotene) (1) and 3-hydroxy-2-methyl-4H-pyran-4-one (maltol) (2), we identified, for the first time, 2,3-dihydro-3,5-dihydroxy-6-methyl-4H-pyran-4-one (DDMP) (3), 4-hydroxy-2,5-dimethyl-3(2H)-furan-3-one (furaneol) (4), and 2,3-dihydro-5-hydroxy-6-methyl-4H-pyran-4-one (dihydromaltol) (5) as compounds which actively contribute to the "toasty caramel" aroma of heated oak. Their role in the aroma of wines and spirits is thus well worth studying. These molecules were absent from the glucose pyrolysis but were relatively plentiful after heating in the presence of proline. Therefore, Maillard reactions were seen to be the cause of these substances in the heated oak wood.

Sweet fortified wines, traditionally aged under strong oxidation conditions, have a characteristic aroma. An experimental laboratory study investigated the aging of red and white sweet fortified wines under various conditions. The formation of various molecules, previously identified as characteristic of the aroma of this type of wine, was monitored by analysis. The development of these compounds during accelerated aging was affected by oxidation and the color of the wine. Among the molecules studied, sotolon [3-hydroxy-4, 5-dimethyl-2(5H)-furanone] was one of the few molecules present in concentrations above the perception threshold, in both red and white wines. Buildup was strongly affected by the presence of oxygen in white wine subjected to accelerated aging. (Ethoxymethyl)furfural, formed from 5-(hydroxymethyl)furfural, and furfural, derived from sugars, are also involved in the aroma of sweet fortified white wines aged in oxygen-free conditions. The substances most characteristic of accelerated aging of sweet fortified red wines were 5-(hydroxymethyl)furfural, acetylformoin, and hydroxymaltol, the formation of which is affected by oxidation, and dihydromaltol, formed in the absence of oxidation.

Toasting wood to be used in barrels for aging wine produces a great number of volatile and odiferous compounds. Three new volatile odorous compounds in toasted oak were identified. Analysis by high-performance gas chromatography of toasted oak extracts, combined with olfactory detection, enabled various chromatographic peaks with these specific aromas to be isolated. These same odors were simultaneously studied by heating glucose both with and without proline and phenylalanine. Aromatic compounds of interest were identified thanks to a combination of gas chromatography and both mass and infrared spectrometry. An analysis RMN was also used. Hydroxymaltol, 2,5-furanedicarbaldehyde, and furylhydroxymethyl ketone have been detected in extract of toasted oak wood. These molecules may be formed by direct pyrolysis of sugar or Maillard reactions. The acetylformoine was not detected in extract of toasted oak wood, whereas it was detected in heated extracts of various sugars and sugars mixtures with amino acids.