Effect of Vine Water and Nitrogen Status, as Well as Temperature, on Some Aroma Compounds of Aged Red Bordeaux Wines.

Wine aging bouquet is defined as a positive, complex evolution of aromas during bottle aging. The aim of this study was to look for the link between some of the vine status parameters and the development, during wine aging, of volatile compounds such as DMS, tabanones, and some wine aromatic heterocycles. The potential influence of air temperature was investigated as well as vine nitrogen and water status. Wines were obtained by microvinification from plots of Vitis vinifera L. cv. Merlot, Cabernet-Sauvignon, and Cabernet franc, over vintages from 1996 to 2007, and cellar-aged until 2014. Wine aging aromas were quantified using gas chromotography-mass spectrometry. The effects of the vintage and vine water and nitrogen status were greater than the varietal effects. The nine aroma compounds measured showed very high levels in the 2003 vintage. The results revealed a positive link between vine nitrogen status and dimethyl-sulfide and N, S, O-heterocycle levels measured in the aged wines. Levels of 4-[2-butylidene]-3,5,5-trimethyl-2-cyclohexen-1-one and 4-[( 3E)-1-butylidene]-3,5,5-trimethyl-2-cyclohexen-1-one (megastigmatrienones; tabanone) isomers increased when the vines were affected by a water deficit.

N,S,O-Heterocycles in Aged Champagne Reserve Wines and Correlation with Free Amino Acid Concentrations.

Champagne regulations allow winegrowers to stock still wines to compensate for quality shifts in vintages, mainly due to climate variations. According to their technical requirements and house style, Champagne producers use these stored wines in their blends to enhance complexity. The presence of lees and aging at low pH (2.95-3.15), as in Champagne wines, lead to several modifications in wine composition. These conditions, combined with extended aging, result in the required environment for the Maillard chemical reaction, involving aromatic molecules, including sulfur, oxygen, and nitrogen heterocycles (such as thiazole, furan, and pyrazine derivatives), which may have a sensory impact on wine. Some aromatic heterocycles in 50 monovarietal wines aged from 1 to 27 years provided by Veuve Clicquot Ponsardin Champagne house were determined by the SPME-GC-MS method. The most interesting result highlighted a strong correlation between certain heterocycle concentrations and wine age. The second revealed a correlation between heterocyclic compound and free amino acid concentrations measured in the wines, suggesting that these compounds are potential aromatic precursors when wine is aged on lees and, thus, potential key compounds in the bouquet of aged Champagnes. The principal outcome of these assays was to reveal, for the first time, that aromatic heterocycle concentrations in Champagne base wines are correlated with wine age.