Publications by authors named "Philippe Darriet"

52 Publications

Sensorial Impact and Distribution of 3-Methyl-2,4-nonanedione in Cognacs and Spirits.

J Agric Food Chem 2021 Apr 8;69(15):4509-4517. Epub 2021 Apr 8.

Unité de recherche OEnologie, EA 4577, USC 1366 INRAE, ISVV, Univ. Bordeaux, 33882 Villenave d'Ornon cedex, France.

The aim of this study was to improve our knowledge on the chemical markers of Cognac aromas. We report results concerning the distribution and sensorial impact of 3-methyl-2,4-nonanedione (MND), a well-known compound in aged red wine, reminiscent of anise or "dried fruit", according to its concentration. We assayed first this diketone (solid-phase microextraction (SPME)-gas chromatography (GC)/mass spectrometry (MS), chemical ionization (CI)) in many Cognac samples followed by grappa, brandy, rum, whisky, vodka, and fruit spirits, and concentrations ranged from traces to 11.2 μg/L. Highest concentrations were obtained in grappa and freshly distilled eaux-de-vie of Cognac samples. Exceeding its detection threshold (100 ng/L, 70 vol %), MND contributes to the anise descriptor of these spirits. Its concentration decreased over aging while being highly correlated with the total amount of fatty acid ethyl ester. In addition, we showed that MND was produced during distillation according to the oxidation state of the white wine as well as the amount of lees used.
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http://dx.doi.org/10.1021/acs.jafc.1c00643DOI Listing
April 2021

Grape Berry Secondary Metabolites and Their Modulation by Abiotic Factors in a Climate Change Scenario-A Review.

Front Plant Sci 2021 22;12:643258. Epub 2021 Mar 22.

Faculty of Land and Food Systems, Wine Research Centre, The University of British Columbia, Vancouver, BC, Canada.

Temperature, water, solar radiation, and atmospheric CO concentration are the main abiotic factors that are changing in the course of global warming. These abiotic factors govern the synthesis and degradation of primary (sugars, amino acids, organic acids, etc.) and secondary (phenolic and volatile flavor compounds and their precursors) metabolites directly, via the regulation of their biosynthetic pathways, or indirectly, via their effects on vine physiology and phenology. Several hundred secondary metabolites have been identified in the grape berry. Their biosynthesis and degradation have been characterized and have been shown to occur during different developmental stages of the berry. The understanding of how the different abiotic factors modulate secondary metabolism and thus berry quality is of crucial importance for breeders and growers to develop plant material and viticultural practices to maintain high-quality fruit and wine production in the context of global warming. Here, we review the main secondary metabolites of the grape berry, their biosynthesis, and how their accumulation and degradation is influenced by abiotic factors. The first part of the review provides an update on structure, biosynthesis, and degradation of phenolic compounds (flavonoids and non-flavonoids) and major aroma compounds (terpenes, thiols, methoxypyrazines, and C13 norisoprenoids). The second part gives an update on the influence of abiotic factors, such as water availability, temperature, radiation, and CO concentration, on berry secondary metabolism. At the end of the paper, we raise some critical questions regarding intracluster berry heterogeneity and dilution effects and how the sampling strategy can impact the outcome of studies on the grapevine berry response to abiotic factors.
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http://dx.doi.org/10.3389/fpls.2021.643258DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8020818PMC
March 2021

Biosynthesis and Cellular Functions of Tartaric Acid in Grapevines.

Front Plant Sci 2021 4;12:643024. Epub 2021 Mar 4.

College of Science and Engineering, Flinders University, Bedford Park, SA, Australia.

Tartaric acid (TA) is an obscure end point to the catabolism of ascorbic acid (Asc). Here, it is proposed as a "specialized primary metabolite", originating from carbohydrate metabolism but with restricted distribution within the plant kingdom and lack of known function in primary metabolic pathways. Grapes fall into the list of high TA-accumulators, with biosynthesis occurring in both leaf and berry. Very little is known of the TA biosynthetic pathway enzymes in any plant species, although recently some progress has been made in this space. New technologies in grapevine research such as the development of global co-expression network analysis tools and genome-wide association studies, should enable more rapid progress. There is also a lack of information regarding roles for this organic acid in plant metabolism. Therefore this review aims to briefly summarize current knowledge about the key intermediates and enzymes of TA biosynthesis in grapes and the regulation of its precursor, ascorbate, followed by speculative discussion around the potential roles of TA based on current knowledge of Asc metabolism, TA biosynthetic enzymes and other aspects of fruit metabolism.
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http://dx.doi.org/10.3389/fpls.2021.643024DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7970118PMC
March 2021

Sensory-directed characterisation of distinctive aromas of Sauternes and Viognier wines through semi-preparative liquid chromatography and gas chromatography approaches.

J Chromatogr A 2021 Jan 16;1637:461803. Epub 2020 Dec 16.

University of Bordeaux, Unité de recherche Œnologie, EA 4577, USC 1366 INRAE, F-33140 Villenave d'Ornon, France.

Gas chromatography-olfactometry-mass spectrometry (GC-O-MS) has been very useful in identifying aroma compounds from within the complex matrix of wine. Supplementary separation can be required to overcome co-elution of volatiles or other sensory-directed chromatographic strategies are needed, including multidimensional chromatography and preparative fraction collection coupled to GC. Studies investigating 'overripe orange' aroma in sweet Sauternes wine and the similar 'apricot' aroma in Viognier wine were conducted. Wines with the targeted aroma attributes were selected and concentrated wine extracts prepared. GC-O found no individual aroma compounds with the targeted aroma attribute. Semi-preparative HPLC was used to obtain less complex fractions of the wine extracts. The fractions were eluted in water/ethanol and, therefore, could be smelled directly. Fractions with the targeted aroma character were further resolved by GC-preparative fraction collection (GC-PFC). Recombinational GC-PFC demonstrated the importance of the components within a 4 min preparative GC fraction to the 'overripe orange' aroma of typical Bordeaux dessert wine. In Viognier wine, monoterpenes linalool, α-terpineol and geraniol as well as benzaldehyde were found to be associated with the 'apricot' character. Thus, several wine aroma compounds interact for these specific aromas to be perceived. This sensory-led combination of separation techniques is a powerful tool for the identification of key compounds responsible for specific aromas across the wine and beverage industries.
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http://dx.doi.org/10.1016/j.chroma.2020.461803DOI Listing
January 2021

Symposium Introduction: Recent Progress and Current Challenges in Wine Analytical Sciences.

J Agric Food Chem 2020 Nov;68(47):13291-13293

University of Trento, Centre Agriculture Food Environment (C3A), and Fondazione Edmund Mach, Research and Innovation Centre, Via Edmund Mach 1, 38010 San Michele all'Adige, Italy.

Œnology in its scientific dimension makes it possible to bring together a large community of researchers from various fields of expertise to share their knowledge and experience around wine. Two international meetings, the 11th International Œnology Symposium and In Vino Analytica Scientia 2019, were exceptionally held in the context of a joint organization under a common title ŒnoIVAS 2019, in Bordeaux, France, in June 2019. The conferences were attended by 350 delegates, from 24 countries, who shared different aspects of wine and spirits research, with 7 invited lectures, 71 oral communications, and over 200 posters. This special issue is a collection of full papers from a selection of contributed oral presentations and posters presented at the conference.
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http://dx.doi.org/10.1021/acs.jafc.0c05905DOI Listing
November 2020

Aromatic Potential of Bordeaux Grape Cultivars: Identification and Assays on 4-Oxononanoic Acid, a γ-Nonalactone Precursor.

J Agric Food Chem 2020 Nov 9;68(47):13344-13352. Epub 2020 Nov 9.

Université de Bordeaux, INRAE, Unite de Recherche Œnologie, EA 4577, USC 1366 INRAE, ISVV, 33882 Villenave d'Ornon Cedex, France.

γ-Nonalactone has been demonstrated to be a chemical marker of dried/cooked fruit nuances detected in must and wine, but little is known about its formation pathways. Therefore, on the basis of the literature, we hypothesized 4-oxononanoic acid as a potential precursor. Using dichloromethane extraction followed by gas chromatography coupled to negative chemical ionization mass spectrometry, this keto acid was identified and quantified in Merlot and Cabernet Sauvignon musts. Its concentration ranged from traces to 60 μg/L. The biotransformation of 4-oxononanoic acid into γ-nonalactone by during alcoholic fermentation was demonstrated using labeled -4-oxononanoic acid. Additional experiments shed light on the 4-oxononanoic acid role as a γ-nonalactone precursor and revealed that this biotransformation was ()-enantioselective. Sensory and distribution studies of the enantiomers revealed that the detection threshold of and forms were 66 and 35 μg/L and the average ratio of / in grape and wine was 94:6 and 65:35.
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http://dx.doi.org/10.1021/acs.jafc.0c04171DOI Listing
November 2020

Exploration of space to achieve scientific breakthroughs.

Biotechnol Adv 2020 11 12;43:107572. Epub 2020 Jun 12.

Department of Biology, Friedrich-Alexander-University Erlangen-Nuremberg, Erlangen, Germany; Space Biology Unlimited SAS, Bordeaux, France. Electronic address:

Living organisms adapt to changing environments using their amazing flexibility to remodel themselves by a process called evolution. Environmental stress causes selective pressure and is associated with genetic and phenotypic shifts for better modifications, maintenance, and functioning of organismal systems. The natural evolution process can be used in complement to rational strain engineering for the development of desired traits or phenotypes as well as for the production of novel biomaterials through the imposition of one or more selective pressures. Space provides a unique environment of stressors (e.g., weightlessness and high radiation) that organisms have never experienced on Earth. Cells in the outer space reorganize and develop or activate a range of molecular responses that lead to changes in cellular properties. Exposure of cells to the outer space will lead to the development of novel variants more efficiently than on Earth. For instance, natural crop varieties can be generated with higher nutrition value, yield, and improved features, such as resistance against high and low temperatures, salt stress, and microbial and pest attacks. The review summarizes the literature on the parameters of outer space that affect the growth and behavior of cells and organisms as well as complex colloidal systems. We illustrate an understanding of gravity-related basic biological mechanisms and enlighten the possibility to explore the outer space environment for application-oriented aspects. This will stimulate biological research in the pursuit of innovative approaches for the future of agriculture and health on Earth.
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http://dx.doi.org/10.1016/j.biotechadv.2020.107572DOI Listing
November 2020

Contribution of Volatile Odorous Terpenoid Compounds to Aged Cognac Spirits Aroma in a Context of Multicomponent Odor Mixtures.

J Agric Food Chem 2020 Nov 21;68(47):13310-13318. Epub 2020 Feb 21.

Université de Bordeaux, Unité de Recherche Œnologie, EA 4577, USC 1366 INRA, ISVV, 33882 Villenave d'Ornon Cedex, France.

Cognac spirit aromas result from the presence of a wide variety of volatile odorous compounds associated with the modalities of spirit distillation and aging. However, very few studies have been carried out on aging notes of Cognac spirits. An HPLC fractionation approach was used in order to evidence fractions of interest recalling the specific aromatic nuances of aged Cognac. Then, a GC-O/MS analysis of the selected fractions allowed one to detect odorous zones and identify several volatile compounds. Among them, various well-known volatile compounds representative of the terpenoid family were highlighted, such as geraniol, α-terpinene, nerol, α-terpineol, 1,8-cineole (eucalyptol) and, particularly, piperitone, santalol, and α-campholenal, which have not previously been cited in Cognac. These compounds were quantitated and their detection thresholds were determined. Geraniol, α-terpinene, α-terpineol, and 1,8-cineole concentrations increased while spirits were more aged, while nerol tends to decrease. A sensory contribution of terpenes was observed through perceptual synergic effects, along with β-damascenone and whisky lactone.
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http://dx.doi.org/10.1021/acs.jafc.9b06656DOI Listing
November 2020

Identification and analysis of new α- and β-hydroxy ketones related to the formation of 3-methyl-2,4-nonanedione in musts and red wines.

Food Chem 2020 Feb 5;305:125486. Epub 2019 Sep 5.

Université de Bordeaux, Unité de recherche OEnologie, EA 4577, USC 1366 INRA, ISVV, 33882 Villenave d'Ornon cedex, France; Seguin Moreau Cooperage, ZI Merpins, 16103 Cognac, France.

The formation of 3-methyl-2,4-nonanedione (MND) during red wine aging can contribute to the premature evolution of aroma, characterized by the loss of fresh fruit and development of dried fruit flavors. The identification of two new hydroxy ketones, 2-hydroxy-3-methylnonan-4-one (syn- and anti-ketol diastereoisomers) and 3-hydroxy-3-methyl-2,4-nonanedione (HMND), prompted the investigation of the precursors and pathways through which MND is produced and evolves. An HS-SPME-GC-MS method was optimized for their quantitation in numerous must and wine samples, providing insight into the evolution of MND, HMND, and ketols through alcoholic fermentation and wine aging. Alcoholic fermentation resulted in a significant decrease in MND and HMND and the simultaneous appearance of ketol diastereoisomers. The analysis of 167 dry red wines revealed significant increases in MND and anti-ketol contents through aging and a significant positive correlation between MND and anti-ketols. Additional experiments demonstrated that ketols are precursors to MND during red wine oxidation.
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http://dx.doi.org/10.1016/j.foodchem.2019.125486DOI Listing
February 2020

Identification of Dialkylpyrazines Off-Flavors in Oak Wood.

J Agric Food Chem 2019 Sep 29;67(36):10137-10144. Epub 2019 Aug 29.

Univ. Bordeaux, Unité de recherche Œnologie, EA 4577, USC 1366 INRA, ISVV , 33882 Villenave d'Ornon cedex , France.

Volatile extractive compounds from high-quality oak wood ( sp.) are responsible for important pleasant olfactory notes, such as coconut, wood, vanilla, caramel, and spice. Recently, a new off-flavor reminiscent of rancid butter has been detected in oak wood. Using gas chromatography-olfactometry (GC-O) coupled to several detection modes, such as nitrogen-phosphorus detection (GC-O-NPD) or mass spectrometry (GC-O-MS) and multidimensional GC-O coupled to time-of-flight mass spectrometry, six compounds containing nitrogen atoms were identified. The volatiles were suggested to belong to 2,5-disubstituted pyrazines family, which was confirmed by comparison with synthetic reference compounds. For this purpose, symmetric and dissymmetric 2,5-dialkylpyrazines were prepared from methyl esters of corresponding aliphatic amino acids (Val, Leu, and Ile) by a three-step, one-pot reaction under mild reducing conditions. Organoleptic descriptors and odor detection thresholds were also determined, whereas a bacterial origin explaining these off-flavors was hypothesized.
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http://dx.doi.org/10.1021/acs.jafc.9b03185DOI Listing
September 2019

Quantitation, Organoleptic Contribution, and Potential Origin of Diethyl Acetals Formed from Various Aldehydes in Cognac.

J Agric Food Chem 2019 Mar 25;67(9):2617-2625. Epub 2019 Feb 25.

Université de Bordeaux, Unité de recherche CEnologie, EA 4577, USC 1366 INRA, ISVV , 33882 Villenave d'Ornon cedex , France.

Cognac wine distillate (WD), especially that produced during aging, is marked by complex and elegant aroma. This work aimed at expanding the knowledge on the Cognac WD aroma by a sensory-guided approach, involving a fractional-distillation technique and gas chromatography coupled to olfactometry and mass spectrometry (GC-O-MS). In doing so, a fruity-odor zone was highlighted in WD extracts that was attributed to the diethyl acetal family. Ten additional diethyl acetals were detected by GC-MS. Next, an assay method was developed and validated for seven of these diethyl acetals. Their detection thresholds were evaluated in a model solution of water/ethanol (60:40, v/v). 1,1-Diethoxy-3-methylbutane was shown to present a significant organoleptic impact because its olfactory-detection threshold (323 μg/L) is lower than its range of concentrations in WD (461 to 3337 μg/L). Given that diethyl acetals result from reactions between ethanol and aldehydes, quantitative correlations between diethyl acetals and corresponding aldehydes were considered.
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http://dx.doi.org/10.1021/acs.jafc.9b01084DOI Listing
March 2019

Molecular interpretation of dried-fruit aromas in Merlot and Cabernet Sauvignon musts and young wines: Impact of over-ripening.

Food Chem 2018 11 5;266:245-253. Epub 2018 Jun 5.

Université Bordeaux, ISVV, EA 4577, Unité de recherche OENOLOGIE, F-33882 Villenave d'Ornon, France; INRA, ISVV, USC1366, Unité de recherche Œnologie, F-33882 Villenave d'Ornon, France; Seguin Moreau Cooperage, ZI Merpins, 16103 Cognac, France. Electronic address:

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http://dx.doi.org/10.1016/j.foodchem.2018.06.022DOI Listing
November 2018

Volatile Compounds Related to 'Stone Fruit' Aroma Attributes in Viognier and Chardonnay Wines.

J Agric Food Chem 2018 Mar 27;66(11):2838-2850. Epub 2018 Feb 27.

The Australian Wine Research Institute , P.O. Box 197, Glen Osmond (Adelaide) SA 5064 , Australia.

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.
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http://dx.doi.org/10.1021/acs.jafc.7b05343DOI Listing
March 2018

Impact of Plasmopara viticola infection of Merlot and Cabernet Sauvignon grapes on wine composition and flavor.

Food Chem 2018 Jan 15;239:102-110. Epub 2017 Jun 15.

Université Bordeaux, ISVV, EA 4577, Unité de recherche Œnologie, F-33882 Villenave d'Ornon, France; INRA, ISVV, USC1366, Unité de recherche Œnologie, F-33882 Villenave d'Ornon, France.

This work reports the identification of volatile compounds involved in the particular and atypical flavor detected in Vitis vinifera red Merlot and Cabernet Sauvignon wines made with grapes infected and wilted by brown rot (Plasmopara viticola). Must made from withered grapes had green aromas while red wines were marked by intense odor reminiscent of green, herbaceous notes but also figs and cooked fruit. Thanks to GC-O and GC-MS analysis, cooked fruit notes were identified as 3-methyl-2,4-nonanedione, γ-nonalactone and γ-decalactone, whereas herbaceous and green aromas were identified as (Z)-1,5-octadien-3-one and 3-isobutyl-2-methoxypyrazine. We show that the organoleptic impact of P. viticola is more pronounced in Merlot wines compared to Cabernet Sauvignon ones. The highest levels of 3-methyl-2,4-nonanedione (75.3ng/L) were found in old Merlot wines made with 20% infected berries, suggesting the incidence of berry quality on the ability of a wine to age.
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http://dx.doi.org/10.1016/j.foodchem.2017.06.087DOI Listing
January 2018

Study of the contribution of massoia lactone to the aroma of Merlot and Cabernet Sauvignon musts and wines.

Food Chem 2017 Oct 30;232:229-236. Epub 2017 Mar 30.

Univ. de Bordeaux, ISVV, EA4577 Œnologie, F-33140 Villenave d'Ornon, France; INRA, ISVV, USC 1366 Œnologie, F-33140 Villenave d'Ornon, France.

Organic extracts of musts and red wines marked by dried fruit and cooked fruit aromas were analyzed by gas chromatography coupled to olfactometry and mass spectrometry. Thanks to this analytical approach we identified a fragrant lactone corresponding to an odorant zone reminiscent of coconut and dried figs as 5,6-dihydro-6-pentyl-2H-pyran-2-one (C10 massoia lactone). Using chiral GC-GC-MS, we show that only the (R)-C10 massoia lactone is found in musts and wines. Its detection thresholds were 10µg/L and 11µg/L in must and wine model solution, respectively. In Merlot and Cabernet Sauvignon musts marked by dried fruit flavors from overripe grapes, its concentration reached 68µg/L. In contrast, in wines marked by these flavors, it never exceeded 20µg/L. We show that (R)-C10 massoia lactone is reduced to (R)-δ-decalactone during alcoholic fermentation. In addition, we underline the contribution of temperature during the growing season on its level in old red wines.
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http://dx.doi.org/10.1016/j.foodchem.2017.03.151DOI Listing
October 2017

Identification and Organoleptic Contribution of (Z)-1,5-Octadien-3-one to the Flavor of Vitis vinifera cv. Merlot and Cabernet Sauvignon Musts.

J Agric Food Chem 2017 Mar 23;65(9):1915-1923. Epub 2017 Feb 23.

Université de Bordeaux, ISVV, EA4577 Œnologie , F-33140 Villenave d'Ornon, France.

The main goal of this research was to identify key aroma compounds involved in the dried fruits (prune and dried fig) aroma of musts. An odoriferous zone (OZ) was detected by gas chromatography coupled with olfactometry (GC-O) and identified as (Z)-1,5-octadien-3-one (geranium). A quantitation method by SPME-GC-MS (CI, MeOH) was developed and validated for assaying this very fragrant ketone in musts for the first time (LOD, 0.15 ng/L; LOQ, 0.5 ng/L). Concentrations of (Z)-1,5-octadien-3-one in musts marked by dried fruits flavors reached 90 ng/L, thus exceeding its detection threshold (D = 9 ng/L). Moreover, sensory experiments showed that this compound contributes to the dried fig nuance at concentrations ranging from 64 to 96 ng/L. Above that level, it contributes to the geranium nuance of the must. Its affinity with sulfur dioxide was also established; 30 mg/L of sulfur dioxide causes a decrease of concentration of 60%.
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http://dx.doi.org/10.1021/acs.jafc.6b05293DOI Listing
March 2017

Toward a Molecular Understanding of the Typicality of Chardonnay Wines: Identification of Powerful Aromatic Compounds Reminiscent of Hazelnut.

J Agric Food Chem 2017 Feb 26;65(5):1058-1069. Epub 2017 Jan 26.

Université de Bordeaux, ISVV , EA 4577, Unité de recherche ŒNOLOGIE, F-33882 Villenave d'Ornon, France.

Chardonnay wines impart a unique complex aroma characterized by its buttery, yellow stone fruit, melon, bready, and woody notes. Among the terms used in the sensory analysis of these wines, this study investigated hazelnut-like attributes. Multidimensional gas chromatography coupled to olfactometry identified five pyrroles reminiscent of hazelnut: 1-ethylpyrrole-2-carboxaldehyde, 1H-pyrrole, 2-acetyl-1H-pyrrole (first identification in wine), 1-methylpyrrole-2-carboxaldehyde, and 1H-pyrrole-2-carboxaldehyde. Quantitative analyses demonstrated their significantly higher abundance in Chardonnay wines. However, they proved irrelevant in sensory terms, given the low amounts measured in wine compared to their olfactory detection threshold. Nevertheless, the presence of methanethiol derivatives from these pyrroles was investigated in wine. 1-Methylpyrrole-2-methanethiol and 1-ethylpyrrole-2-methanethiol were identified and exhibited hazelnut-like aroma. These compounds, which have not been observed in natural products to date, are potent volatile compounds with detection thresholds of 0.7 and 1.4 ng/L, respectively, in model wine. These findings open up promising perspectives concerning the interpretation of the typical aromatic nuances of some Chardonnay wines.
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http://dx.doi.org/10.1021/acs.jafc.6b04516DOI Listing
February 2017

1,8-Cineole in French Red Wines: Evidence for a Contribution Related to Its Various Origins.

J Agric Food Chem 2017 Jan 6;65(2):383-393. Epub 2017 Jan 6.

Univ. Bordeaux , ISVV, EA 4577 Œnologie, F-33140 Villenave d'Ornon, France.

The aromatic descriptor "green", reflecting grape unripeness in French red wines, is frequently associated with the levels of 3-alkyl-2-methoxypyrazines, particularly 3-isobutyl-2-methoxypyrazine (IBMP), which has bell pepper nuances. Nevertheless, not all green aromatic expressions in red wines correlate with 3-alkyl-2-methoxypyrazine concentrations. This study considered sensory and chemical approaches using Cabernet Sauvignon wines obtained from grapes harvested at one-month intervals during the 2014 and 2015 vintages to investigate other volatile odoriferous compounds. Semipreparative HPLC fractionation of wine extracts revealed a fraction with specific green aromas in the early harvest wines. Its sensory impact was confirmed by omission and reconstitution tests. Then, multidimensional gas chromatography coupled with olfactometry and mass spectrometry (MDGC-O-MS/TOF) was used for molecular characterization of the aroma compounds associated with the green aromas. Surprisingly, eucalyptol (1,8-cineole), with menthol odor was highlighted and assayed at concentrations sometimes above its olfactory detection threshold in Cabernet Sauvignon and Fer Servadou wines. Sensory tests confirmed its impact at several concentrations detected in French red wines (up to 2.61 ± 0.03 μg/L) on the menthol nuance and overall green perception, particularly via an additive effect with IBMP. Quantitation of 1,8-cineole in Cabernet Sauvignon and Merlot grapes during berry development in 2015 revealed its varietal origin with abundant concentrations in unripe berries and decrease during grape maturation. Moreover, the implication of an invasive plant (Artemisia verlotiorum) growing in certain vineyards was shown to be responsible for increased 1,8-cineole concentrations in some wines.
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http://dx.doi.org/10.1021/acs.jafc.6b03042DOI Listing
January 2017

Unexpected impact of 2-methylisoborneol as off-odour substance in aged wines.

Food Chem 2017 Apr 5;220:498-504. Epub 2016 Oct 5.

Department of Chemistry and Pharmacy, Emil Fischer Center, Friedrich-Alexander-Universität Erlangen-Nürnberg, Henkestrasse 9, 91054 Erlangen, Germany; Fraunhofer Institute for Process Engineering and Packaging IVV, Giggenhauser Strasse 35, 85354 Freising, Germany. Electronic address:

Four Pinot noir wines from Burgundy were investigated by gas chromatography-olfactometry, with regard to the presence of earthy-smelling compounds. 2-Methylisoborneol (2-MIB) was detected in two of these wines, although the samples were seven years old, contradicting previous reports that this substance is unstable in wine and must. In order to investigate this seemingly paradoxical situation, 2-MIB stability was reinvestigated in wine and in model solution starting with an elevated initial concentration. Although 2-MIB concentration greatly decreased during the 90days of storage, the final concentration measured in both media was well above the odour threshold of the substance. Based on the observation of a decelerating decrease of 2-MIB with time, it was concluded that this substance can still be detected in wine and can induce, in this case, an earthy off-odour on condition that the start concentration is high enough.
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http://dx.doi.org/10.1016/j.foodchem.2016.10.021DOI Listing
April 2017

Influence of Chirality of Lactones on the Perception of Some Typical Fruity Notes through Perceptual Interaction Phenomena in Bordeaux Dessert Wines.

J Agric Food Chem 2016 Nov 21;64(43):8160-8167. Epub 2016 Oct 21.

Univ. de Bordeaux, ISVV , EA4577 Œnologie, F-33140 Villenave d'Ornon, France.

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 Botrytis cinerea development under the form of noble rot (2-nonen-4-olide and γ-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 γ-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 γ-nonalactone isomers was observed.
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http://dx.doi.org/10.1021/acs.jafc.6b03117DOI Listing
November 2016

Perceived minerality in sauvignon blanc wine: Chemical reality or cultural construct?

Food Res Int 2016 Sep 1;87:168-179. Epub 2016 Jul 1.

Lincoln University, Christchurch, New Zealand.

The study aimed to determine the relationship between perceived mineral character in wine and wine chemical composition. We investigated the sensory properties and chemical composition of sauvignon blanc wines from two major sauvignon-producing countries, New Zealand and France. Sensory experiments employing 16 wines (8 French, 8 New Zealand) were conducted in Marlborough, New Zealand and in three regions of France, namely Bordeaux, Burgundy, and the Sancerre/Loire region. Wine professionals (31 New Zealanders and 32 French professionals) sensorially characterised the 16 wines under three conditions, bouquet only (ortho-nasal olfaction), palate only (nose clip condition), and full tasting (global condition: ortho-nasal olfaction, retronasal olfaction, taste, trigeminal stimulation). Sensory data from the global condition only are reported in this article. Physical and chemical analyses conducted on all wines included wine standard parameters, elemental composition, volatile aroma composition, and measures of organic acids. Major results demonstrate that (i) on average French and New Zealand wines were perceived similarly in intensity of mineral character, although judgments to individual wines differed as a function of participant culture; (ii) French and NZ participants drew on different information to make their sensory judgments; and (iii) several aspects of wine composition associated positively with perception of mineral character while others associated negatively, the significant associations differing as a function of participant culture.
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http://dx.doi.org/10.1016/j.foodres.2016.06.026DOI Listing
September 2016

Vine nitrogen status and volatile thiols and their precursors from plot to transcriptome level.

BMC Plant Biol 2016 08 8;16(1):173. Epub 2016 Aug 8.

Bordeaux Sciences Agro, Institut des Sciences de la Vigne et du Vin (ISVV), Ecophysiologie et Génomique Fonctionnelle de la Vigne (EGFV), UMR 1287, 33140, Villenave d'Ornon, France.

Background: Volatile thiols largely contribute to the organoleptic characteristics and typicity of Sauvignon blanc wines. Among this family of odorous compounds, 3-sulfanylhexan-1-ol (3SH) and 4-methyl-4-sulfanylpentan-2-one (4MSP) have a major impact on wine flavor. These thiols are formed during alcoholic fermentation by the yeast from odorless, non-volatile precursors found in the berries and the must. The present study investigates the effects of vine nitrogen (N) status on 3SH and 4MSP content in Sauvignon blanc wine and on the glutathionylated and cysteinylated precursors of 3SH (Glut-3SH and Cys-3SH) in the berries and the must. This is paralleled by a RNA-seq analysis of gene expression in the berries. The impact of N supply on the expression of the glutathione-S-transferase 3 and 4 (VviGST3 and VviGST4) and the γ-glutamyltranspeptidase (VviGGT), considered as key genes in their biosynthesis, was also evaluated.

Results: N supply (N100 treatment) increased the 3SH content in wine while no effect was noticed on 4MSP level. Furthermore, N supply increased Glut-3SH levels in grape berries at late berry ripening stages, and this effect was highly significant in must at harvest. No significant effect of N addition was noticed on Cys-3SH concentration. The transcript abundance of the glutathione-S-transferases VviGST3 and VviGST4 and the γ-glutamyltranspeptidase (VviGGT), were similar between the control and the N100 treatment. New candidate genes which might be implicated in the biosynthetic pathway of 3SH precursors were identified by whole transcriptome shotgun sequencing (RNA-seq).

Conclusions: High vine N status has a positive effect on 3SH content in wine through an increase of Glut-3SH levels in grape berries and must. Candidate GSTs and glutathione-S-conjugates type transporters involved in this stimulation were identified by RNA-seq analysis.
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http://dx.doi.org/10.1186/s12870-016-0836-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4976470PMC
August 2016

Nebulized water cooling of the canopy affects leaf temperature, berry composition and wine quality of Sauvignon blanc.

J Sci Food Agric 2017 Mar 19;97(4):1267-1275. Epub 2016 Jul 19.

Department for Innovation in Biological, Agro-Food and Forest systems (DIBAF), University of Tuscia, 01100 Viterbo, Italy.

Background: The present paper details a new technique based on spraying nebulized water on vine canopy to counteract the negative impact of the current wave of hot summers with temperatures above 30 °C, which usually determine negative effects on vine yield, grape composition and wine quality.

Results: The automatized spraying system was able to maintain air temperature at below 30 °C (the threshold temperature to start spraying) for all of August 2013, when in the canopy of uncooled vines the temperature was as high as 36 °C. The maintenance of temperature below 30 °C reduced leaf stress linked to high temperature and irradiance regimes as highlighted by the decrease of H O content and catalase activity in the leaves. A higher amount of total polyphenols and organic acids and lower sugars characterized the grapes of cooled vines. Wine from these grapes had a higher content of some volatile thiols like 3-sulfanylhexanol (3SH) and 3-sulfanylhexylacetate (3SHA), and lower content of 4-methyl-4-sulfanylpentan-2-one (4MSP).

Conclusion: Under conditions of high temperature and irradiance regimes, water nebulization on the vine canopy can represent a valid solution to reduce and/or avoid oxidative stress and associated effects in the leaves, ensure a regular berry ripening and maintain high wine quality. The consumption of water during nebulization was acceptable, being 180 L ha min , which lasted an average of about 1 min to reduce the temperature below the threshold value of 30 °C. A total of 85-90 hL (from 0.8 to 0.9 mm) of water per hectare per day was required. © 2016 Society of Chemical Industry.
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http://dx.doi.org/10.1002/jsfa.7860DOI Listing
March 2017

Identification and analysis of piperitone in red wines.

Food Chem 2016 Sep 19;206:191-6. Epub 2016 Mar 19.

Univ. Bordeaux, ISVV, EA 4577, Unité de recherche OENOLOGIE, F-33882 Villenave d'Ornon, France; INRA, ISVV, USC 1366 Œnologie, F-33140 Villenave d'Ornon, France.

The present study concerns the search for new aroma compounds associated with the flavor of aged and prematurely aged red wines. Sensory descriptive analysis associated with gas chromatography-olfactometry was first performed to find specific odoriferous zones. One of the zones, reminiscent of mint, was found in red wines with a prune flavor. Thanks to several analytical approaches including preparative gas chromatography, p-menth-1-en-3-one (piperitone), has been identified in red wines. The olfactory detection threshold of this terpene reminiscent of mint was 0.9μg/L in model hydroalcoholic solution and 70μg/L in red wines. Chiral multidimensional GC-MS was used to show that piperitone was present mainly in the (R) form in red wines. The concentration of piperitone in aged red wines ranged from a few ng/L to 435ng/L, but the level was not linked to the age of the wine nor to its premature evolution.
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http://dx.doi.org/10.1016/j.foodchem.2016.03.064DOI Listing
September 2016

Identification and Organoleptic Contribution of Vanillylthiol in Wines.

J Agric Food Chem 2016 Feb 3;64(6):1318-25. Epub 2016 Feb 3.

Univ. Bordeaux, ISVV, EA 4577, Unité de recherche Oenologie, F-33882 Villenave d'Ornon, France.

Vanillylthiol, a chemical compound reminiscent of clove and smoke, has been identified for the first time in young red and dry white wines. The chemical structure of this new aroma was confirmed by original chemical synthesis. Vanillylthiol was prepared by a two-step procedure from vanillin. The conversion of vanillin to divanillyl disulfide was easily achieved by treatment with an inorganic sulfur-donor reagent. Reduction of the disulfide gave the target thiol in good yield. The quantification of vanillylthiol in wine was performed by nonspecific liquid/liquid extraction (CH2Cl2), separation of the volatile compounds using gas chromatography, and specific detection using tandem mass spectrometry (triple quadrupole). Vanillylthiol was found particularly in young wines aged in new oak barrels. These wines contained between a few 50 ng/L to more than 8300 ng/L. The highest levels were found in red wines aged 12 months in new oak barrels. Given its perception threshold in a wine model solution (3.8 μg/L), vanillylthiol may contribute to the spicy, clove-like flavor of red wines aged in oak barrels.
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http://dx.doi.org/10.1021/acs.jafc.5b05733DOI Listing
February 2016

Identification of S-3-(hexanal)-glutathione and its bisulfite adduct in grape juice from Vitis vinifera L. cv. Sauvignon blanc as new potential precursors of 3SH.

Food Chem 2016 May 17;199:711-9. Epub 2015 Dec 17.

Univ. de Bordeaux, ISVV, EA4577 Œnologie, FR-33140 Villenave d'Ornon, France.

Two main precursors (S-3-(hexan-1-ol)-l-cysteine and S-3-(hexan-1-ol)-l-glutathione) of 3-sulfanylhexanol (3SH, formerly named 3-mercaptohexanol) have been identified so far in grape juice but a correlation between precursor concentrations in grape juices and 3SH concentrations in wines is not always observed. This suggests that there may be other compounds associated with the aromatic potential. In this work, S-3-(hexanal)-glutathione (Glut-3SH-Al) and its bisulfite (Glut-3SH-SO3) adduct were identified in Sauvignon blanc grape juice by liquid chromatography coupled to Fourier transform mass spectrometry experiments. A partial purification of the compounds was carried out by Medium Pressure Liquid Chromatography (MPLC) on the reverse phase using 5L of grape juice. The addition of synthetized Glut-3SH-Al and Glut-3SH-SO3 in the synthetic medium induced a significant release of 3SH after fermentation. Moreover, we demonstrate that Glut-3SH-Al and its bisulfite adduct are present in grape juice and could be considered as new direct 3SH precursors with molar conversion yields close to 0.4%.
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http://dx.doi.org/10.1016/j.foodchem.2015.12.069DOI Listing
May 2016

Vine Nitrogen Status Does Not Have a Direct Impact on 2-Methoxy-3-isobutylpyrazine in Grape Berries and Wines.

J Agric Food Chem 2015 Nov 3;63(44):9789-802. Epub 2015 Nov 3.

Ecophysiology and Functional Genomics of the Vine (EGFV), UMR 1287, Bordeaux Sciences Agro, Institut des Sciences de la Vigne et du Vin (ISVV) , 33140 Villenave d'Ornon, France.

Methoxypyrazines (MP) constitute a large family of compounds that contribute to the vegetative varietal aroma of many grapevine varieties and wines. The berry content in 2-methoxy-3-isobutylpyrazine (IBMP), a major MP reminiscent of green-pepper aroma, can be influenced by environmental factors or cultural practices such as water status or mineral nutrition. To date, no study has investigated a possible direct effect of nitrogen (N) on IBMP synthesis without possible interference from water status and vigor variations. In this study, only vine nitrogen status was significantly different among treatments. Water status was controlled during the season, and vine vigor was similar among treatments. IBMP level was maximal at bunch closure and decreased during the season. There was no significant effect of nitrogen nutrition on this metabolite. Moreover, the expression profiles of VvOMT3 and VvOMT4, key genes in the IBMP biosynthetic pathway, were similar between treatments. This result indicates that when an effect of N on IBMP was found in previous studies, it was likely mediated through the modification of bunch-zone microclimate, induced by the higher vigor of high N-status vines.
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http://dx.doi.org/10.1021/acs.jafc.5b03838DOI Listing
November 2015

Involvement of Dimethyl Sulfide and Several Polyfunctional Thiols in the Aromatic Expression of the Aging Bouquet of Red Bordeaux Wines.

J Agric Food Chem 2015 Oct 30;63(40):8879-89. Epub 2015 Sep 30.

Univ. Bordeaux, ISVV, EA 4577 Œnologie, F-33140 Villenave d'Ornon, France.

The development of an aromatic bouquet during fine wine aging depends on complex transformations occurring in a reductive atmosphere, favorable to the formation and preservation of sulfur odorants, such as dimethyl sulfide (DMS) and polyfunctional thiols. The aim of this study was to address their role in the occurrence, evolution, and perceived sensory nuances of the aging bouquet of red Bordeaux wines. These compounds were quantified in 24 wines and scored by a professional wine panel for the degree to which they reflected the aging bouquet olfactory concept. Partial least square (PLS) analysis, combining sensory and quantitative chemical data, predicted that DMS, 2-furanmethanethiol, and 3-sulfanylhexanol concentrations correlated with the typicality score, discriminating highly-typical wines from less-typical ones. Several vintages from three vineyards were then subjected to sensory and chemical analysis to determine how aging bouquet typicality and the intensity of five key aromatic notes (undergrowth, truffle, fresh fruit, toasted, and empyreumatic) evolved during bottle storage in relation to these three sulfur odorants. PCA analysis emphasized their combined impact on aging bouquet typicality and their contribution to undergrowth, truffle, and empyreumatic attributes.
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http://dx.doi.org/10.1021/acs.jafc.5b03977DOI Listing
October 2015

Comparison of electron and chemical ionization modes for the quantification of thiols and oxidative compounds in white wines by gas chromatography-tandem mass spectrometry.

J Chromatogr A 2015 Oct 21;1415:123-33. Epub 2015 Aug 21.

INRA, ISVV, USC 1366 Œnologie, FR-33140 Villenave d'Ornon, France; Univ. de Bordeaux, ISVV, EA 4577 Œnologie, F-33140 Villenave d'Ornon, France.

A rapid, sensitive method for assaying volatile impact compounds in white wine was developed using gas chromatography-tandem mass spectrometry (GC-MS/MS) technology, with a triple quadrupole analyzer operating in chemical ionization and electron impact mode. This GC-MS/MS method made it possible to assay volatile thiols (3SH: 3-sulfanylhexanol, formerly 3MH; 3SHA: 3-sulfanylhexyl acetate, formerly 3MHA; 4MSP: 4-methyl-4-sulfanylpentan-2-one, formerly 4MMP; BM: benzenemethanethiol; E2SA: ethyl 2-sulfanylacetate; and 2FM: 2-furanmethanethiol) and odoriferous oxidation markers (Sotolon: 4,5-dimethyl-3-hydroxy-2(5)H-furanone, methional, and phenylacetaldehyde) simultaneously in dry white wines, comparing electron impact (EI) and chemical ionization (CI) modes. More molecular ions were produced by CI than protonated molecules, despite the greater fragmentation caused by EI. So, even using the best reactant gas giving the highest signal for thiols, EI was the best ionization mode, with the lowest detection limits. For all compounds of interest, the limits of quantification (LOQ) obtained were well below their detection thresholds (ranging from 0.5 to 8.5ng/L for volatile thiols and 65-260ng/L for oxidation markers). Recovery rates ranged from 86% to 111%, reproducibility (in terms of relative standard deviation; RSD) was below 18% in all cases, with correlation coefficients above 0.991 for all analytes. The method was successfully applied to the analysis of compounds of interest in Sauvignon Blanc wines from a single estate and ten different vintages.
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http://dx.doi.org/10.1016/j.chroma.2015.08.027DOI Listing
October 2015

Identification of a new lactone contributing to overripe orange aroma in Bordeaux dessert wines via perceptual interaction phenomena.

J Agric Food Chem 2014 Mar 17;62(12):2469-78. Epub 2014 Mar 17.

Univ. Bordeaux, ISVV, EA 4577 Œnologie , F-33140 Villenave d'Ornon, France.

Recent studies have demonstrated the existence of a typical sensory concept for Bordeaux dessert wines, including the world famous wines of Sauternes. Volatile compounds from several chemical families (thiols, aldehydes, and lactones) were identified and correlated with aromatic typicality in these wines. However, these studies were unable to indicate "key" aromas of overripe fruits, especially overripe orange. The alternative strategy developed in this research combined both analytical and sensory studies of fractions of dessert wine extracts obtained by semipreparative high-performance liquid chromatography (HPLC). Multidimensional gas chromatography coupled to olfactometry and mass spectrometry (MDGC-O/MS) was applied to some of the HPLC fractions recalling "overripe fruit", and a new lactone, 2-nonen-4-olide, was identified. Reconstitution and omission tests using the HPLC fractions highlighted the importance of specific compounds, particularly 2-nonen-4-olide, in the expression of overripe orange notes. Although this lactone presents minty and fruity odors, its key contribution to the typical aroma of orange in Bordeaux dessert wines was revealed through perceptual blending.
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http://dx.doi.org/10.1021/jf405397cDOI Listing
March 2014