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International audience; BACKGROUND Today, many agricultural products claiming a link to their origin and typicity receive a warm welcome on the market. Nevertheless, the notion of typicity is blurred for consumers and needs to be objectified for communication purposes. This study aims at formalizing a methodology for studying typicity of terroirs, with PDO wines as an example, using a participatory approach with professionals of the wine sector from terroirs, using focus group and tasting. The vision of typicity of terroirs by professionals outside of these terroirs has been studied by a free word association task.RESULTS This study allowed a clear distinguishing of the typicity of the studied terroirs. Professionals from terroirs identified the global conceptual typicity of their terroirs using various factors, mainly soil, geography and grape variety, whereas professionals outside terroirs expressed their visions of terroirs by reputation or sensory characteristics of wines. Tasting results showed a discrimination of wines based on their typicity and highlighted descriptors involved in sensory perceptual typicity for each studied terroir.CONCLUSIONS Professionals from terroirs share a common vision of their typicity and identify more typicity factors than professionals outside terroirs. Sensory typicity has been highlighted for five of the six terroirs studied, according to the various descriptors. The study of two populations, from and outside terroirs, shows the gap between the typicities identified by professionals from terroirs and those perceived by professionals outside terroirs. (c) 2020 Society of Chemical Industry

A strong blackcurrant aroma was recently perceived in some red wines originating from the same appellation. Varietal thiols such as 4-mercapto-4-methyl-2-pentanone (4MMP), 3-(mercapto)hexyl acetate (3MHA) and 3-mercapto-1-hexanol (3MH) are compounds potentially responsible for the development of this aroma. In order to demonstrate the correlation between thiols concentrations in red wines and blackcurrant aroma intensity, a multiple variable analysis was realised with thiols concentrations obtained by chemical analysis and blackcurrant aroma intensities obtained by descriptive sensory analysis. The 4MMP concentration was very well correlated to the blackcurrant aroma, and 3MHA and 3MH present at high concentrations act as enhancers of the perception of this aroma. This correlation was further supported after performing a sensory comparison by classification test. The different factors that could impact on the development of blackcurrant aroma in red wine were discussed.

Varietal Thiols in Wine: Discovery, Analysis and Applications Aur elie Roland, R emi Schneider,* Alain Razungles, and Florine Cavelier* Interloire, 12 rue Etienne Pallu, BP 1921, 37019 Tours Cedex 01, France UMR 1083 Sciences pour l’!nologie, INRA, SupAgro, Universit e Montpellier I, 34060 Montpellier Cedex 01, France Institut Franc ) ais de la Vigne et du Vin, at UMR 1083 Sciences pour l’!nologie, INRA, 34060 Montpellier Cedex 01, France IBMM, UMR-CNRS 5247, Universit es Montpellier I et II, Place Eug ene Bataillon, 34095 Montpellier, France

The isotopically labelled S-3-(hexan-1-ol)-glutathione d 2 /d 3 (G3MHd 2 /d 3 ) was synthesized with a strategy based on acid-labile protecting groups. The natural analogue of this compound could be a precursor of 3-mercaptohexanol, a varietal thiol reminiscent of grape fruit, released during alcoholic fermentation. In a first time, deuterated glutathione conjugate was used to perform identification and quantification by stable isotope dilution assay of G3MH in musts from several varieties: Sauvignon, Riesling and Gewurztraminer. In a second time, synthetic and natural musts (Sauvignon Blanc) were spiked by G3MHd 2 /d 3 at different levels from 12 to 150 μg L −1 to demonstrate the relationship between 3-mercaptohexan-1-ol (3MH) and G3MH. GC–ITMS/MS analysis of the resulting wines clearly showed the formation of the corresponding deuterated 3MH, that proves the direct connection with G3MH under enological conditions. In Sauvignon Blanc grape juice, a conversion yield of 4.4% was found in duplicate for an initial spiking of G3MH d 2 /d 3 equivalent to 12 μg L −1 .

International audience; Thiol precursor content in Melon B. and Sauvignon blanc grape juices obtained under vacuum was determined by quantifying cysteinylated and glutathionylated conjugates of 3-mercaptohexan-1-ol (3MH) and 4-methyl-4-mercaptopentan-2-one (4MMP). This characterization allowed the study of thiol precursor evolution during ripening of Sauvignon blanc grapes in several viticultural situations together with grape reaction product (GRP) and the main substrate of polyphenoloxidase, that is, caftaric acid. Concentration of precursors greatly increased during ripening except for the cysteinylated conjugate of 4MMP. Precursor evolution was also monitored during the oxidation of grape juice. Addition of oxygen to a grape juice set off the enzymatic oxidation of hydroxycinnamic acids but did not negatively affect precursor concentrations. Part of the glutathionylated precursor of the 3MH was produced during prefermentative operations (up to 140% in Sauvignon blanc). Consequently, this precursor naturally occurring in grapes was also formed during prefermentative operations. The proportion of biogenetic and prefermentary formation of the glutathionylated precursor of 3MH was different under industrial conditions depending on the grape variety considered. Addition of glutathione and hexenal in grape juices of Melon B. and Sauvignon induced an increase of the production of 3MH and consequently of its acetate in the resulting wines. Residual glutathione in must has to be preserved to enhance the aromatic potential of grapes

International audience; The contribution of dimethyl sulfide (DMS) to the aroma of Syrah and Grenache Noir wines from the Rhone Valley of France was investigated by sensory analysis, and its levels in these wines were measured. The potential DMS in the corresponding grapes and wines, susceptible to release during wine aging, was evaluated. Free DMS and potential DMS assessed by a heat-alkaline treatment were measured in grape juices and wines by SPME-GC-MS using methods previously reported and slightly modified. A relationship between potential DMS from grapes and the total DMS levels in wine was demonstrated. Furthermore, a linear regression between the ratio of free DMS levels to these total DMS levels in wine and time of storage was found. Free and potential DMS levels in grapes and wines depended on grape variety, vintage, and vine location. DMS imparted a noticeable and complex contribution to the aroma of the wines investigated, depending on the mode of sensory perception used, either before or after glass swirling. It significantly enhanced the fruity notes of the wines, and additional truffle and black olive notes

The aromas of six Merlot and three Cabernet Sauvignon wines of the 1996 vintage from the Bordeaux region were evaluated by sensory analysis. A panel of selected enology students was trained to assess 20 attributes previously generated for these wines by enologists of Bordeaux. Using statistical methods, this 20-attribute list was reduced to a 12-attribute list. The aroma profiles of the wines of Merlot and Cabernet Sauvignon were very close. Differentiation of the wines of these two varieties was significant only for the caramel descriptor, which was rated higher in the Merlot wines. Gas chromatography/olfactometry (GC/O) and GC/MS analyses were used to detect and identify the potent odorants with the caramel odor in the two most differentiated samples for this attribute, a Merlot wine and a Cabernet Sauvignon wine. Two odorant zones with this odor resulted in identification of 4-hydroxy-2,5-dimethylfuran-3(2H)-one (HDMF) and 4-hydroxy-2(or 5)-ethyl-5(or 2)-methylfuran-3(2H)-one (HEMF). Aroma extract dilution analysis (AEDA) method showed a higher dilution factor (FD) for HDMF in the Merlot wine extract than in the Cabernet Sauvignon extract. The HDMF levels determined in the wines studied using a stable isotope dilution assay (SIDA) method were consistent with the results found by sensory analysis and GC/O; i.e., higher HDMF levels were present in the Merlot wines than in the Cabernet Sauvignon wines.

The presence of β-carotene and a precursor of lutein is described in wood for the first time. These compounds were found in the wood of sessile oak, pedunculate oak, American white oak, chestnut, and beech. The levels were generally low and varied considerably from one tree to another. Among the European oaks, sessile oak was significantly richer in lutein than pedunculate oak. Sessile oaks from Jupilles forest contained the highest β-carotene levels. The position of the wood sample in the trunk affected the carotenoid content, and barrel wood is taken from a zone that is fairly rich in these compounds. Keywords: Carotenoids; oak wood; age of wood; European oak; American oak

International audience; In order to examine varietal thiol precursors in both the skin and the pulp of grapes, two grape varieties, Melon B. and Sauvignon Blanc, were considered. We found that cysteinylated and glutathionylated pre- cursors of 3-mercapto-1-hexanol and 4-methyl-4-mercapto-2-pentanone were preferentially in skin. In the Sauvignon Blanc variety, precursors were detected both in the skin and the pulp, while in Melon B., only S-3-(1-hexanol)glutathione was detected in pulp, any other precursors being exclusively found in skin. During an industrial pressing cycle, extraction of thiol precursors was enhanced at the end of the cycle (highest pressures), thus producing more varietal thiols in the resulting wines. Cold prefermen- tation skin contact did not influence the concentration of the measured precursors in Sauvignon Blanc must. Nevertheless, the release of thiol in resulting wines increased significantly between 1 and 7 days of cold prefermentation skin contact. This increase could be due to the formation of other thiol precur- sors, such as S-3-(1-hexanal)glutathione or S-3-(1-hexanal)cysteine, during prefermentative operations.

Correspondance auteur: Roland A. E-mail: roland@supagro.inra.fr Publication Inra prise en compte dans l'analyse bibliométrique des publications scientifiques mondiales sur les Fruits, les Légumes et la Pomme de terre. Période 2000-2012. http://prodinra.inra.fr/record/256699; International audience; A rapid nanoLc-MS/MS method was developed and validated for the simultaneous determination of glutathionylated and cysteinylated precursors of 3-mercapto-hexan-1-ol (3MH) and 4-methyl-4-mercaptopentan-2-one in grape juice using stable isotope dilution assay (SIDA). The analytes were extracted from must using a cation exchange resin and purified on C18 cartridges. They were chromatographically separated on a reverse phase column and finally analyzed by tandem mass spectrometry in selected reaction monitoring mode (SRM) using deuterated analogues as standards except for glutathionylated Conjugate of 4MMP which was analyzed by external calibration. The method was validated according to the International Conference on Harmonization recommendations by determining linearity, accuracy, precision, recovery, matrix effect, repeatability, intermediate reproducibility, LODs and LOQs. Calibration for each precursor was determined by performing Lack-of-Fit test and the best fitting for 3MH precursors was a quadratic model whereas a linear model was better adapted for 4MMP Precursors. All calibration curves showed (quite satisfactory Correlation coefficients (R-2 > 0.995 for SIDA quantification and R-2 > 0.985 for external calibration). Quantification by SIDA and external calibration allowed a high level of accuracy since the averaged value ranged from 80 to 108%. Quantification of aroma precursors was accurate and reproducible Over five clays since intermediate precision (same analyst, same sample and same apparatus), which was evaluated by the calculation of RSD was inferior to 16%. Limits Of quantification for G3MH and G4MMP were closed to 0.50 and 0.07 nmol/L and as 4.75 and 1.90 nmol/L for Cys3MH and Cys4MMP respectively. This method was applied to the quantification of precursors into several types of grape juices: Melon B., Sauvignon, Riesling and Gewurztraminer

International audience; Straightforward synthesis of labeled S-3-(hexan-1-ol)-glutathione and S-4-(4-methylpentan-2-one)- glutathione has been developed through a conjugate addition optimization study. Sauvignon blanc fermentation experiments with the [2H10] S-4-(4-methylpentan-2-one)-glutathione used as a tracer released the corresponding deuterated thiol, thus proving the direct relationship with the 4-mercapto-4- methylpentan-2-one under enological conditions. The conversion yield of such transformation was estimated to be close to 0.3%, opening an avenue for additional study on varietal thiol biogenesis.

Aims: Grenache noir and Syrah are the predominant grape varieties in the French Rhone valley vineyard. This study aimed at identifying the odorants generated from glycoconjugates extracted from wines made with Grenache noir and Syrah.Methods and results: Synthetic model wines enriched with glycoconjugates, treated or not with enzymes, were stored at 45 °C for 3 weeks, or at 13 °C for 18 months. Aromas generated were extracted and analyzed by GC-Olfactometry (only samples from accelerated aging) and were further quantitatively determined by GC-MS. Analysis of the extracts allowed to identify 49 odorants, including 27 that could be aglycons, or related compounds, of glycoconjugates from the grapes. In addition, the active compounds were quantified in similar experiments led in conditions of natural aging for 18 months.Conclusion: The two varieties, Grenache noir and Syrah, were distinguishable by 14 odorant zones. Multivariate analyses (PCA) performed with the amounts of aroma compounds formed during both model and natural aging confirmed the effect of the glycosidase treatment on the acceleration of the aroma compounds formation and on the increase of the varietal differences of the wines.Significance and impact of study: GC-Olfactometry coupled with GCMS were good techniques to indentify and apreciate the odorants generated from glycoconjugates in the wines of Syrah and Grenache Noir, but in the context of a blend of odors, these techniques showed their limits and did not permit to determine the real impact of a molecule in the global aroma of the wine perceived by the taster. Other methods as additive techniques should be used to complete this study.

The origin of dimethyl sulfide (DMS) produced during wine aging was examined through different assays. The production of DMS during the model aging of a wine and the concomitant decrease of residual potential DMS (PDMS), as DMS released by heat-alkaline treatment in 0.5 M sodium hydroxide at 100 °C for 1 h, were demonstrated. Then, dimethyl sulfoxide (DMSO), methionine sulfoxide (MSO), S-methylmethionine (SMM), and dimethylsulfonium propanoic acid (DMSPA), reported previously as possible DMS precursors, were investigated for their ability to be DMS precursors in wine in the conditions of this model aging and of the heat-alkaline treatment. The results showed that DMSO, MSO, and DMSPA could hardly be DMS precursors in the conditions used, whereas SMM appeared to be a good candidate. Finally, the use of [2H6]-DMSPA as an internal standard for PDMS determination was proposed, because it provided better reproducibility than [2H6]-DMS used as an external standard. Keywords: Aroma; wine; aging; dimethyl sulfide...

Carotenoid composition of fruits of two Rosa species (Rosa canina and Rosa rugosa) and of chokeberry (Aronia melanocarpa) was studied by high performance liquid chromatography. Nine carotenoids were determined: three carotenes (lycopene, ζ-carotene, β-carotene) and six xanthophylls (neoxanthin, trans-violaxanthin, cis-violaxan-thin, 5,6-epoxylutein, lutein, β-cryptoxanthin). This high number of compounds classified these fruits among those with the greatest variety of carotenoid pigments. Quantitatively large differences occurred in the carotenoid composition of the three fruits. Rosa hips contained the highest concentrations of total carotenoids, which were mainly comprised of lycopene and βcarotene. Conversely, total xanthophylls were low. In contrast to Rosa, fruits of Aronia were lower in total carotenoids while xanthophylls composed a higher proportion.

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