Search

International audience; A 'stone fruit' aroma is important in many white wine varieties and styles, but little is known about the chemical basis of this wine aroma attribute. A set of Viognier and Chardonnay wines that featured 'stone fruit' aroma attributes were selected by a panel of wine experts. The selected wines were characterized by sensory descriptive analysis and detailed volatile chemical composition analyses. This comprehensive data also allowed Viognier wine to be profiled for the first time. By partial least-squares regression, several esters and fatty acids and benzaldehyde were indicated as contributing to the 'peach' attribute; however, a reconstitution sensory study was unsuccessful in mimicking this attribute. A mixture of γ-lactones, monoterpenes, and aldehydes were positively correlated to the 'apricot' aroma, which were generally higher in the Viognier wines. Reconstitution studies confirmed that the monoterpenes linalool, geraniol, and nerol were the most important compounds for the mixture being perceived as having an 'apricot' aroma.

International audience; Recent studies concerning the aroma of noble rot dessert wines revealed the importance of a well-known phenomenon in perfumery, the perceptual blending, to create the perception of "overripe orange" nuances. Thus, compounds associated with both oak wood aging (3-methyl-4-octanolide and eugenol) and Botiytis cinerea development under the form of noble rot (2-nonen-4-olide and gamma-nonalactone) contribute to a specific aroma of great noble rot dessert wines through perceptual interaction phenomena. This synthetic perception phenomenon was established from reconstitution, addition, and omission sensory experiments, using wine extract fractions supplemented with the volatile compounds previously mentioned. To better understand the sensory impact of these compounds, the goal of this research was to study the contributions of enantiomeric forms of 2-nonen-4-olide and gamma-nonalactone and the diastereoisomers of 3-methyl-4-octanolide. After multidimensional chiral chromatography-analysis, the relative proportions of enantiomers or diastereomeric forms were first established and then sensory experiments were carried out using the reference compounds with isolated fractions from dessert wines. A dominance of the R form was established for 2-nonen-4-olide, which was correlated with wine aging, while the S form is more dominant in young dessert wines. Furthermore, the reconstitution experiments confirmed perceptual interaction phenomena and revealed the sensory contribution of (R)-2-nonen-4-olide and cis-3-methyl-4-octanolide concerning the "overripe orange" nuances, whereas no sensory impact for the gamma-nonalactone isomers was observed.

The flavour of wine is derived, in part, from the flavour compounds present in the grape, which change as the grapes accumulate sugar and ripen. Grape berry terpene concentrations may vary at different stages of berry development. This study aimed to investigate terpene evolution in grape berries from four weeks post-flowering to maturity. Grape bunches were sampled at fortnightly intervals over two vintages (2012-13 and 2013-14). In total, five monoterpenoids, 24 sesquiterpenes, and four norisoprenoids were detected in grape samples. The highest concentrations of total monoterpenoids, total sesquiterpenes, and total norisoprenoids in grapes were all observed at pre-veraison. Terpenes derived from the same biosynthetic pathway had a similar production pattern during berry development. Terpenes in grapes at harvest might not necessarily be synthesised at post-veraison, since the compounds or their precursors may already exist in grapes at pre-veraison, with the veraison to harvest period functioning to convert these precursors into final products.

Terpenoids were extracted from grape vine bunches during plant development and analysed by GC-MSD. The grapevines analysed were from a commercial harvest of Vitis vinifera cv. Shiraz. The terpenoids were analysed from 4 weeks post flowering (wpf) to harvest in one season. The data are presented with the structure of the compound and aroma profile and semi-quantified. The sub-class of sesquiterpenes was given special attention, and this data set describes the first analysis of these compounds during ripening of this important economic crop. Sesquiterpenes may have a hitherto described contribution to wine aroma. This data set may provide insight into biosynthetic pathways and aroma chemistry. Interpretation of our data and further discussion can be found in “Terpene evolution during the development of Vitis vinifera L. cv. Shiraz grapes” (Zhang et al., 2016) [1]. Keywords: Rotundone, Terpene, Sesquiterpene, Grape ripening