OENO One Aromatic complexity in Verdicchio wines:a case study 1 Department of Food Quality and Nutrition, Research and Innovation Centre, Fondazione Edmund Mach (FEM), Via E. Mach, 1 38010 S. Michele all’Adige, TN, Italy 2 Department of Agricultural, Food, Environmental and Animal Sciences, University of Udine, Via delle Scienze 208, 33100 Udine, Italy 3 Fazi Battaglia Winery, Via Roma 117, Castelplanio Ancona, Italy 4 University of Trento, Department of Physics, Via Sommarive 14, 38123 Povo, TN, Italy Carlin Silvia 1 2 Lonardi UrskaVrhovsek1andrea 3 Mattivi LorenzoLandi3andFulvio 1 4 * Key words: Verdicchio, solid phase extraction, solid-phase-microextraction, aroma Introduction

The aroma of a wine is influenced by the action of several different compounds on the sensory organs. These compounds are produced through metabolic pathways during the ripening and harvesting of grapes and during the fermentation and storage of wine (Rapp and Mandery, 1986; Rapp and Versini, 1995). Of these factors, it is well known that the grape varieties gives characteristic aromas. This varietal aroma allows the classification and even the labelling of wines, so it is important to know the typical aromatic pattern of a wine variety in order to ensure its quality (Marais, 1983).

Verdicchio is a white grape variety grown almost exclusively in the Marche region in central Italy. Genetic analysis has shown a very close relationship between Verdicchio, “Trebbiano di Soave” and “Trebbiano di Lugana or Turbiana” (Costacurta et al., 2003). The genetic origin of Verdicchio and therefore of Trebbiano di Soave, is however still being debated. One hypothesis, based on the documented 15th century migration of farmers from the province of Verona in northern Italy to the Marche, partially depopulated by the plague, is now the most accredited. The settlers are thought to have brought their vines with them and thus it is surmised that they originally came from the Veneto region. In a recent work (Ghidoni et al., 2010) it was reported that the three varieties are genetically identical, at least as far as the analysed part of the genome is concerned, but they could be traced to three different biotypes of the same variety, in relation to phenotypical traits related to the environment. Indeed, the length of the separation would appear to justify some olfactory differences between Trebbiano di Soave and Verdicchio, over and beyond the demonstrated genetic identity (Vantini et al., 2003). Verdicchio is not characterised by a large quantity of terpenes. Indeed, in analysis carried out in the past, a very low content of the main monoterpenes was observed. The floral terpene note could derive from the Ho-terpendiol I (about 20 μg L-1), also present in bound forms, which could then be released over time (Nicolini et al., 2003). What was instead observed was the presence of a characterising compound, methyl salicylate, which in this variety can reach 45 μg L-1 in free forms and more than 500 μg L-1 in bound forms, as reported for Trebbiano di Soave and Verdicchio (Versini et al., 2005). When added to wine, it is described as providing a floral note, slightly balsamic, tending to cinnamon-chestnut honey (Bauer et al., 2008). A study involving Trebbiano di Lugana wines (genetically similar to Trebbiano di Soave and Verdicchio) highlighted that the grapes also contain the precursors of sulphured aromatic compounds, in particular 3-mercaptohexanol and 3-mercapto hexyl acetate, which could impart tropical and citrus fruit scents to the wines (Mattivi et al., 2012). During the tasting of this wine, notes of anise/fennel are sometimes perceived and even balsamic scents in aged wines. One of the objectives of this work was to understand which compounds could contribute to these descriptors. For this reason we used gas chromatography–olfactometry (GC-O), a powerful tool for the study of chemical compounds responsible for wine aroma (van Ruth, 2001).

Materials and methods 1. Wine samples 1.1. Sample set 1 (vertical collection)

For the preliminary survey, four types of wines were obtained using Verdicchio grapes grown in different areas but in the same Italian region (Marche) and produced by Fazi Battaglia winery. A sample of 24 Verdicchio wines from different vintages – 11 Massaccio (2002–2015), eight San Sisto (2001–2015), three Titulus (2013–2015) and three Le Moie (2008–2015) – were analysed with SPME and GC×GC-ToF-MS. Massaccio is obtained from the highest and most south-facing areas, San Sisto derives from colder areas with clayish soil, Le Moie is obtained in vineyards closer to the sea on sandy soils and Titulus is produced with grapes grown in the 300 hectares of estate-vineyards, subdivided into 12 distinct vineyards with different exposure.

1.2. Sample set 2 (horizontal collection, 2016 harvest)

Wines from each of the three different areas (Massaccio, San Sisto and Le Moie) were analysed. In addition, in the case of San Sisto, wines produced from three different harvesting data were produced: early harvest (H1) on 23 September, normal harvest (H2) after 1 week and late harvest on 5 October (H3). Furthermore, for Massaccio, five experimental wines were produced with three different clones (VCR-3, VL-50, R-2) and from separate harvest of vines of high and low vigour. All the wines were obtained following a strictly controlled protocol. The grapes were harvested manually and subjected to cold maceration at 10°C for 3 h in reductive conditions, then pressed at 0.2 bar. The obtained juices were inoculated with selected yeasts Saccharomyces cerevisiae (Zymaflore X5 Laffort). Fermentation was performed under a controlled temperature gradient, starting at 12 °C and gradually increasing up to 19°C at the end of fermentation. After fermentation, two “batonnages” per week were performed. The wines stayed 7 months on the lees and no malolactic fermentation was done.

Two additional wines were produced with modified winemaking techniques: one with skin contact and the other, known as “Arkezia”, was designed produce a sweet wine using grapes infected with noble rot.

The volume of the experimental wines was 6 hl for the three clones and 2.3 hl for Arkezia. All other thesis were produced at real scale, i.e. ≥ 40 hl.

Three different bottles of each of the 2016 wines were extracted with the solid phase extraction (SPE) technique and both free and bound (after enzymatic hydrolysis) forms were analysed. The most volatile compounds were analysed with the SPME technique, 3-methyl-2,4-nonanedione (3-MND) was quantified with SPME after derivatisation and the SPE extract was used for GC-O analysis.

2. Solid phase extraction (SPE ENV+) procedure

50 mL of wine were extracted with SPE using ENV+ cartridges, 1 g (Biotage, Sweden). The cartridge was pre-conditioned with 15 mL of methanol followed by 20 mL of water. The aqueous extract was loaded onto the cartridge, which was then washed with 15 mL of water. The free aromatic compounds were eluted from the cartridge with 30 mL of dichloromethane and the bound aromatic compounds (i.e. glycosides) with 30 mL of methanol. The free volatiles were collected in a 100-mL flask and 60 mL of pentane was added, followed by the addition of anhydrous Na2SO4 to remove water. Subsequently, prior to analysis the whole fraction was carefully concentrated up to 200 μL using a Vigreux column. Methanol was eliminated under vacuum and the residue solubilised in 5 mL of a citrate buffer pH 5, while the glycosidically bound fraction was hydrolysed with 400 L of a commercial glycosidase rich enzyme (70 mg mL−1 Rapidase AR 2000 DSM) at 40°C for 12 h. The mixture with the aglycons was eluted through an ENV+ 1 g cartridge previously activated with 5 mL of methanol and 10 mL of milliQ water and the free compounds were collected with 10 mL of dichloromethane. The relative amount of each volatile was expressed as g/L of n-heptanol.

 3. Solid phase microextraction (SPME) for 3-methyl-2,4-nonanedione (3-MND) determination after PFBHA (O-(2,3,4,5,6-Pentafluorobenzyl)hydroxylamine) derivatisation

5 mL of wine were put in a 20 mL headspace vial with 20 L of IS (4-methyl-3-penten-2one d11 10 g L-1) and 400 uL of a o-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine (PFBHA) water solution (20 g L−1) was added to the vial. The method was adapted from Moreira et al. (2013) and Saison et al. (2009) The PFBHA solution was prepared daily in ultrapure water at 20 g L−1. The IS was prepared in ethanol at 1 g L−1 and further diluted at 10 µg L−1 The vials were equilibrated for 20 min at room temperature, after that a 65m PDMS/DVB was inserted into the headspace for 40 min at 50°C. Standard solutions were prepared in ethanol at 1 g L−1 and stored at 4°C. For the calibration curves, seven different concentrations of 3-MND, from 10 ng L−1 to 400 ng L−1, were spiked in a white wine.

 4. Solid phase microextraction (SPME) and GC-MS-MS method for 3-MND quantification

GC analysis was performed on a Trace GC Ultra gas chromatograph coupled with an XLS Tandem mass spectrometer. The system was equipped with a Pal autosampler (CTC Analytics AG, Zwingen, Switzerland). GC separation was performed on a 30 m VF Wax column with an internal diameter of 0.25 mm and a film thickness of 0.25 m (Agilent). Supelco (Bellafonte, USA) PDMS/DVB 65 m fibre was exposed in the sample for 40 min at 50°C and then desorbed into the GC liner, set at 250°C in splitless/surge mode for 3 min. The temperature programme was 80°C held for 4 min after injection, 8°C/min up to 220°C, held for 1 min and 15°C/min up to 270°C, held for 5 min. Helium was used as the carrier gas at a constant flow rate of 1.2 mL min−1. The mass spectrometer was operated in electron impact (EI) ionisation mode at 70 eV. The filament current was 50 A. The temperature of the transfer line was 250°C and argon (99.9998% purity) was used as the collision gas, with collision cell pressure of 1.5 mTorr. Data acquisition and analysis were performed using the Xcalibur Workstation software supplied by the manufacturer. In order to determine the retention time and the characteristic mass fragments of 3-MND, full scan analysis (m/z 40–300) was performed. The retention times were 29.62 and 29.91 min for monosubstituted 3-MND and RT 35.83 and 36.39 and 36.81 for disubstituted 3-MND. For quantitative analysis, we selected the transitions m/z 168>71 (10 eV) for monosubstituded 3-MND and m/z 363>181 (10 eV) for disubstituted 3-MND. In addition, the transitions m/z 267>86 (10 eV) and 307>181 (10 eV) were also used as qualifiers for mono and disubstituted 3-MND, respectively. For the internal standard the transition m/z 122>74 and m/z 122> 78 (10 eV) were used. For quantification, the chosen transitions were monitored in multiple reaction monitoring (MRM) mode and the peak area ratios of 3-MND to 4-methyl-3-penten-2one d11 (internal standard) were calculated on the basis of the compound concentration.

Quantification was performed using the internal standard (IS) method. For the calibration curves, seven different concentrations of 3-MND from 10 ng L−1 to 400 ng L−1 were spiked in a white wine. The repeatability of the method was checked by running 10 samples spiked with two different concentrations (20 ng L−1 and 100 ng L−1) and the cv% was <13%.

 5. Solid phase microextraction (SPME) and two-dimensional (GC×GC) gas chromatography with time-of-flight mass spectrometry (TOF-MS)

1.5 g of sodium chloride was added to a 20 mL headspace vial, followed by 1 mL of wine spiked with 50 µL of 2-octanol as internal standards (1 mg L−1). Quality control (QC) samples consisting of equal proportions of each sample were taken at the beginning of the run (n=5) and then after every tenth sample. GC×GC-TOF-MS analysis of wines was performed using a gas chromatograph (GC) Agilent 6890N (Agilent Technologies), coupled with a LECO Pegasus IV time-of-flight mass spectrometer (TOF-MS) (Leco Corporation, St. Joseph, MI, USA) equipped with a Gerstel MPS autosampler (Gerstel GmbH & Co. KG). Samples were incubated for 5 min at 35°C and volatiles were extracted with a DVB/CAR/PDMS coating of 50/30 μm and 2-cm long SPME fibre (Supelco Sigma-Aldrich, Milan, Italy) for 20 min, desorbed for 3 min at 250°C in splitless mode. The fibre was reconditioned between each sample for 7 min at 270°C. Helium was used as a carrier gas at a flow of 1.2 mL min−1. The GC oven was equipped with a VF Wax ms 30 m × 0.25 mm column with 0.25 μm film thickness (Agilent Technologies) for the first dimension (1D) and a Rxi 17 Sil MS 1.5 m × 0.15 mm column with 0.15 μm film thickness (Restek, Bellefonte, PA, USA) for the second dimension (2D). Oven temperature was held at 40°C for 3 min and ramped at the rate of 6°C/min to 250°C, where it was held for 5 min before returning to the initial conditions. The secondary oven temperature was held at 5°C above the temperature of the primary oven throughout the chromatographic run. The modulator was offset by +15°C in relation to the secondary oven and modulation time was 7 s. The ion source temperature was set at 230°C and electron ionisation at 70 eV. Spectra were collected in a mass range of m/z 40–350 with an acquisition rate of 200 spectra/s and acquisition delay of 120 s.

 6. Gaschromatograpy-olfactometry and mass spectrometry (GC-O-MS)

1 L of SPE extract was analysed with a Trace GC Ultra chromatograph, coupled with a ISQ QD single quad mass spectrometer (Thermo Scientific, Milan, Italy), equipped with a splitless injector maintained at 250°C; the split vent was opened 0.5 min post injection. Compounds were analysed with a VF Wax (Agilent J&W, Folsom, CA, USA) column (30 m × 0.25 mm i.d., 0.25 μm film thickness) in scan mode. The carrier gas was helium. The oven temperature was programmed to rise from 50°C to 250°C at 2.5°C/min and then be kept at 250°C for 10 min. To assess the olfactory potential of the extracts, the column was connected to a GC-O port Olfactory Port (GL Sciences Tokyo, Japan) maintained at 220°C. The effluent was diluted with a large volume of air (20 mL min−1) prehumidified with an aqueous solution. For aroma extract dilution analysis (AEDA), the concentrated fraction was diluted stepwise (1:3) with pentane:dichloromethane (2:1) to obtain dilutions 1:9, 1:27, 1:81, 1:243. Complete aroma extract dilution analysis (AEDA) was performed by five trained panellists. Sniffing of dilutions was continued until no odorant could be detected by GC-MS-O. Each odorant was thus assigned a flavour dilution factor (FD factor) representing the last dilution in which the odorant was still detectable. The analysis was repeated in duplicate by each assessor.

 7. Volatile compounds identification

Volatile compounds identification was achieved by comparing retention times and mass spectra with those of pure standards when available and with mass spectra from NIST05 and Wiley libraries. Linear retention indices (relative to n-alkanes C10 to C28) were calculated and compared to those from literature.

 8. Statistical data elaboration

Data from 1D-GC-MS and GC×GC-TOF-MS analyses were processed using multivariate techniques. PLS-DA and heatmaps were generated using MetaboAnalyst v. 3.0 (http://www.metaboanalyst.ca), created at the University of Alberta, Canada (Xia et al., 2015).

 9. Sensory test

In order to understand the contribution of 3-MND to the Verdicchio aroma, the standard was added to a “neutral” Verdicchio (3-MND not detectable). The concentrations tested were 10 ng L−1, 25 ng L−1, 50 ng L−1, 100 ng L−1 and 500 ng L−1. A blank wine, without additions, was also included in the tasting.

 Results and discussion

The initial exploration was carried out using four different types of Verdicchio wines (Massaccio, San Sisto, Le Moie and Titulus) by analysing a series of vintages and using SPME with GC×GC-ToF-MS. Two-dimensional analysis made it possible to find many compounds characterising the different types of Verdicchio. Indeed, it is possible to notice clear separation in the PLS-DA (partial least squares discriminant analysis) plot (Figure 1). As shown in the graph, the first component can separate types of Titulus, especially old vintages, from other wines and San Sisto, Massaccio and Le Moie are separated by the second component.

Figure 1. Partial least squares discriminant analysis (PLS-DA) scatterplot of Verdicchio wines from grapes grown in different areas. Eleven vintages of Massaccio (2002–2015), eight vintages of San Sisto (2001–2015), three vintages of Titulus (2013–2015) and three vintages of Le Moie (2008–2015).

The score scatter each point represents the vintages (each vintage with three technical replicates).

Figure 1. Partial least squares discriminant analysis (PLS-DA) scatterplot of Verdicchio wines from grapes grown in different areas. Eleven vintages of Massaccio (2002–2015), eight vintages of San Sisto (2001–2015), three vintages of Titulus (2013–2015) and three vintages of Le Moie (2008–2015).

The score scatter each point represents the vintages (each vintage with three technical replicates).

The volatile compounds determining this separation were whisky lactone, 5-methylfurfural, 2-furancarboxaldehyde, 2,4,5-trimethyl-1,3-dioxolane, benzofuran and 2-methylthiophene for the San Sisto samples. The first three compounds derive from the use of wood, while dioxolane is a compound correlated with ageing. Le Moie wines were characterised by a higher content of norisorenoids such as -damascenone and safranal. Titulus wines were richer in other norisoprenoids, such as TDN and also in some sesquiterpenes such as alpha calacorene and monoterpenes such as alpha-terpineol and alpha terpinolene. Wines from the Massaccio areas were the richest in benzenacetaldehyde and linalool. San Sisto and Massaccio were also the richest in 4-methyl 1-pentanol and 2-acetyl furanone. It is also possible to observe that the typical trend of TDN increases over the years in Massaccio wines (Figure 2). This compound can derive from different precursors linked to sugar molecules and is formed by hydrolysis during ageing (Versini et al., 2001; Winterhalter and Schreier, 1994; Winterhalter, 1991); pH, temperature and presence of oxygen are important parameters in the formation and degradation of TND (Silva Ferreira et al., 2004).

Figure 2. Increase of TDN (g/L) content during ageing in 11 vintages of Verdicchio wines produced in the Massaccio area, 2002–2015.

Figure 2. Increase of TDN (g/L) content during ageing in 11 vintages of Verdicchio wines produced in the Massaccio area, 2002–2015.

After analysing the vertical collection of old vintages as a survey study, a horizontal collection of Verdicchio wines produced in 2016 were analysed in depth. In this case, several different tests were carried out in order to understand the volatile profile of this variety. Results from SPE and SPME analyses are shown in Tables 1 and 2. As the data refer to a single vintage, no definitive conclusions can be drawn, although the wines from Massaccio, San Sisto and Le Moie areas were again distinguishable (Figure 3, heatmap free). Le Moie wine was distinguished by a higher content of hexyl acetate, octanoic and decanoic ethyl ester and the corresponding acids, by the highest amount of Ho-terpendiol I and of 3-methyl-2,4-nonanedione. Le Moie was also the area richest in the bound form. Massaccio was higher in norisoprenoids such as TDN and its precursor riesling acetale, methyl salicylate, homofuraneol and 2-(H)-pyran-2,6(3H)-dione. Some of these compounds will be also discussed in the GC-O section. Samples from San Sisto H1 were the richest in benzyl alcohol, methionol, 2-methyltetrahydrothiophen-3-one and 4-vinylguaiacol. It was also clear that the amount of terpenes increased from San Sisto H1 to San Sisto H3. The latter was indeed the richest in terpenoids such as linalool, citronellol, limonene and alpha-terpineol, both in the free and in the bound forms (Figure 4) and in -damascenone. TDN, vitispirane and riesling acetale reached their maximum in the H2 harvest data and then decreased slightly in H3; the same trend was reported in previous studies (Coelho et al., 2007).

The most vigorous vines resulted in a wine with a higher content of C6 compounds such as 1-hexanol, trans and cis 3-hexenol, trans 2-hexenol and hexyl acetate, while C13 norisoprenoids, especially TDN, were higher in the wine from less vigorous vines. This is in accordance with the literature (Kwasniewski et al., 2010), where an increase in solar radiation leads to an increase of its precursor carotenoids.

The wines from different clones differed in the content of thiols (data not reported in this paper) and also in the content of methyl salicylate. Late harvested Arkezia, obtained from grapes with noble rot and a withering stage, was characterised by the presence of marker compounds for Botrytis infection, such as benzaldehyde, acetic acid, furfural and terpinen-4-ol. (Fedrizzi et al., 2011)

However, it will be necessary to confirm these preliminary observations made for the 2016 vintage by considering other vintages.

To better understand the sensorial impact of some compounds in Verdicchio aroma, SPE extracts from the three different areas were injected into GC-O and sniffed by six expert panellists: 48 main odorants were found in the SPE extract (Table 3). What is perceived in the glass is a mixture of odour and taste molecules, which may combine to act in a suppressive or additive manner, or synergistically (Frijters and Schifferstein, 1994). In GC-O, by contrast, the odorants are delivered to the olfactory epithelia as single entities, which simplifies the recognition task. Aroma extract dilution analysis (AEDA) was used to determine the relative odour potency of compounds present in the sample extract.

Figure 3. Hierarchical clustering analysis performed using volatile aroma compound profiles of 2016 wines produced from grapes from three areas (Le Moie, Massaccio, San Sisto) and three harvest data (San Sisto) (Ward algorithm and Euclidean distance analysis using MetaboAnalyst v. 3.0).

The heatmap was generated using 70 compounds. The rows in the heatmap represent compounds and the columns indicate samples. The colours of the heatmap cells indicate the abundance of compounds across different samples. The colour gradient, ranging from dark blue through white to dark red, represents low, middle and high abundance of a compound.

Figure 3. Hierarchical clustering analysis performed using volatile aroma compound profiles of 2016 wines produced from grapes from three areas (Le Moie, Massaccio, San Sisto) and three harvest data (San Sisto) (Ward algorithm and Euclidean distance analysis using MetaboAnalyst v. 3.0).

The heatmap was generated using 70 compounds. The rows in the heatmap represent compounds and the columns indicate samples. The colours of the heatmap cells indicate the abundance of compounds across different samples. The colour gradient, ranging from dark blue through white to dark red, represents low, middle and high abundance of a compound.

Figure 4. Hierarchical clustering analysis performed using volatile aroma compound profiles of 2016 wines produced from grapes from three areas (Le Moie, Massaccio, San Sisto) and three harvest data (San Sisto) (Ward algorithm and Euclidean distance analysis using MetaboAnalyst v. 3.0).

The heatmap was generated using 30 most significant bound compounds after enzymatic hydrolysis (the highest Fisher ratios). The rows in the heatmap represent compounds and the columns indicate samples. The colours of the heatmap cells indicate the abundance of compounds across different samples. The colour gradient, ranging from dark blue through white to dark red, represents low, middle and high abundance of a compound.

Figure 4. Hierarchical clustering analysis performed using volatile aroma compound profiles of 2016 wines produced from grapes from three areas (Le Moie, Massaccio, San Sisto) and three harvest data (San Sisto) (Ward algorithm and Euclidean distance analysis using MetaboAnalyst v. 3.0).

The heatmap was generated using 30 most significant bound compounds after enzymatic hydrolysis (the highest Fisher ratios). The rows in the heatmap represent compounds and the columns indicate samples. The colours of the heatmap cells indicate the abundance of compounds across different samples. The colour gradient, ranging from dark blue through white to dark red, represents low, middle and high abundance of a compound.

Table 1. Concentration (means ± standard deviations) in g/L except * in mg/L as equivalent of n-heptanol of free volatile compounds in 2016 Verdicchio wines.
titre du tableau
Free aroma compounds OPT° RI exp RI lit     Harvest date     Vigour Clones Vinification
Areas
le Moie Massaccio San Sisto H1 San Sisto H2 San Sisto H3 Low vigour High vigour VCR3 VL50 R2 Late harvest Skin maceration
ethyl butanoate* 0,02 1030 1030 0.32 ± 0.02 0.37 ± 0.02 0.35 ± 0.02 0.5 ± 0.02 0.31 ± 0.01 0.3 ± 0.01 0.3 ± 0.01 0.33 ± 0.02 0.35 ± 0.02 0.29 ± 0.01 0.19 ± 0.01 0.35 ± 0.02
1-propanol, 2-methyl* 40 1087 1060 2.95 ± 0.1 3.56 ± 0.12 5.03 ± 0.18 2.79 ± 0.1 3.12 ± 0.11 3.02 ± 0.11 2.38 ± 0.08 3.86 ± 0.14 3.48 ± 0.12 5.19 ± 0.18 8.1 ± 0.28 4.97 ± 0.17
1-butanol, 3-methyl-, acetate* 0,03 1122 1120 1.81 ± 0.07 1.64 ± 0.06 1.1 ± 0.04 2.63 ± 0.1 1.88 ± 0.07 2.79 ± 0.11 3.54 ± 0.13 2.31 ± 0.09 2.64 ± 0.1 2.55 ± 0.1 0.82 ± 0.03 1.41 ± 0.05
1-butanol* 150 1135 1130 0.25 ± 0.01 0.21 ± 0.01 0.64 ± 0.02 0.72 ± 0.03 0.59 ± 0.02 0.59 ± 0.02 0.49 ± 0.02 0.21 ± 0.01 0.19 ± 0.01 0.2 ± 0.01 0.16 ± 0.01 0.65 ± 0.02
limonene 10 1197 1199 16.9 ± 0.59 3.75 ± 0.13 2.74 ± 0.1 2.3 ± 0.08 2.09 ± 0.07 0.97 ± 0.03 1.58 ± 0.06 31.79 ± 1.11 22.26 ± 0.78 3.65 ± 0.13 4.51 ± 0.16 1.7 ± 0.06
1-butanol, 3-methyl-* 30 1205 1221 77.4 ± 3.48 92.9 ± 4.18 80.6 ± 3.63 66.6 ± 2.99 88.1 ± 3.97 94.7 ± 4.26 86.6 ± 3.9 95.5 ± 4.3 103.9 ± 4.68 110.1 ± 4.95 97.1 ± 4.37 92.6 ± 4.17
ethyl hexanoate* 0,014 1234 1236 1.14 ± 0.05 1.31 ± 0.05 1.25 ± 0.05 1.84 ± 0.08 1.08 ± 0.04 0.9 ± 0.04 0.96 ± 0.04 1.09 ± 0.04 1.23 ± 0.05 1.08 ± 0.04 0.55 ± 0.02 1.01 ± 0.04
hexyl acetate* 1,5 1270 1272 0.14 ± 0.004 0.12 ± 0.004 0.08 ± 0.003 0.21 ± 0.01 0.16 ± 0.01 0.18 ± 0.01 0.25 ± 0.01 0.14 ± 0.005 0.18 ± 0.01 0.21 ± 0.01 0.01 ± 0.001 0.08 ± 0.003
acetoin 150000 1279 1268 9.81 ± 0.38 27.21 ± 1.06 10.41 ± 0.41 24.73 ± 0.96 29.35 ± 1.14 70.82 ± 2.76 88.28 ± 3.44 39.15 ± 1.53 19.97 ± 0.78 9.23 ± 0.36 16.28 ± 0.63 7.65 ± 0.3
4-methyl-1-pentanol   1312 1328 20.9 ± 0.75 37.21 ± 1.34 31.34 ± 1.13 26.65 ± 0.96 44.37 ± 1.6 43.98 ± 1.58 42.79 ± 1.54 35.48 ± 1.28 49.38 ± 1.78 37.4 ± 1.35 24.57 ± 0.88 29.65 ± 1.07
3-methyl-1-pentanol 830 1324 1341 53.1 ± 1.91 97.37 ± 3.51 85.02 ± 3.06 92.07 ± 3.31 104.69 ± 3.77 94.98 ± 3.42 87.87 ± 3.16 99.05 ± 3.57 111.71 ± 4.02 85.21 ± 3.07 61.59 ± 2.22 79.1 ± 2.85
ethyl lactate* 154 1340 1326 3.98 ± 0.16 3.03 ± 0.12 4.18 ± 0.17 3.21 ± 0.13 1.6 ± 0.07 1.02 ± 0.04 0.95 ± 0.04 2.32 ± 0.1 2.87 ± 0.12 3.04 ± 0.12 1.98 ± 0.08 3.36 ± 0.14
n-hexanol* 8 1354 1356 1.36 ± 0.05 1.28 ± 0.05 1.45 ± 0.06 1.24 ± 0.05 1.58 ± 0.06 1.05 ± 0.04 1.16 ± 0.05 1.51 ± 0.06 1.57 ± 0.06 1.86 ± 0.07 0.45 ± 0.02 1.75 ± 0.07
trans-3-hexenol 400 1363 1361 50.7 ± 1.87 67.3 ± 2.49 103.2 ± 3.82 97.1 ± 3.59 80.8 ± 2.99 63.1 ± 2.34 65.5 ± 2.42 71.1 ± 2.63 67.1 ± 2.48 67.3 ± 2.49 14.3 ± 0.53 73.0 ± 2.7
3-ethoxy-1-propanol* 0,1 1371 1389 0.57 ± 0.02 0.56 ± 0.02 0.48 ± 0.01 0.61 ± 0.02 0.25 ± 0.01 0.17 ± 0.01 0.16 ± 0 0.55 ± 0.02 0.45 ± 0.01 0.58 ± 0.02 0.09 ± 0 0.74 ± 0.02
cis-3-hexenol   1386 1379 45.5 ± 1.64 31.93 ± 1.15 35.62 ± 1.28 33.69 ± 1.21 23.39 ± 0.84 39.95 ± 1.44 53.19 ± 1.91 58.71 ± 2.11 53.03 ± 1.91 86.18 ± 3.1 12.41 ± 0.45 116.1 ± 4.18
trans-2-hexen-1-ol   1407 1410 8.98 ± 0.31 10.55 ± 0.37 22.0 ± 0.77 10.37 ± 0.36 9.29 ± 0.33 6.56 ± 0.23 10.05 ± 0.35 11.12 ± 0.39 12.58 ± 0.44 12.58 ± 0.44 12.5 ± 0.44 10.27 ± 0.36
ethyl octanoate* 0,02 1437 1435 1.87 ± 0.08 1.67 ± 0.08 1.55 ± 0.07 2.29 ± 0.1 1.59 ± 0.07 1.32 ± 0.06 1.32 ± 0.06 1.41 ± 0.06 1.54 ± 0.07 1.47 ± 0.07 0.63 ± 0.03 1.18 ± 0.05
acetic acid* 200 1453 1430 0.25 ± 0.01 0.4 ± 0.02 0.29 ± 0.01 0.33 ± 0.01 0.55 ± 0.02 0.21 ± 0.01 0.13 ± 0.01 0.67 ± 0.03 0.61 ± 0.02 0.81 ± 0.03 1.14 ± 0.04 0.39 ± 0.02
2-ethyl-1-hexanol   1491 1485 38.2 ± 1.14 39.59 ± 1.19 41.95 ± 1.26 57.28 ± 1.72 63.66 ± 1.91 58.8 ± 1.76 51.53 ± 1.55 43.47 ± 1.3 31.08 ± 0.93 33.26 ± 1 36.65 ± 1.1 67.01 ± 2.01
benzaldehyde 1508 1506 1508 15.9 ± 0.51 9.7 ± 0.31 29.18 ± 0.93 25.47 ± 0.82 19.06 ± 0.61 9.6 ± 0.31 9.63 ± 0.31 14.73 ± 0.47 11.13 ± 0.36 11.31 ± 0.36 40.56 ± 1.3 13.28 ± 0.42
ethyl 3-hydroxybutanoate*   1511 1499 0.22 ± 0.01 0.31 ± 0.01 0.42 ± 0.02 0.47 ± 0.02 0.46 ± 0.02 0.43 ± 0.02 0.41 ± 0.02 0.28 ± 0.01 0.31 ± 0.01 0.3 ± 0.01 0.18 ± 0.01 0.53 ± 0.02
2-methyltetrahydrothiophen-3-one   1514 1538 16.1 ± 0.52 18.06 ± 0.58 27.74 ± 0.89 27.26 ± 0.87 23.75 ± 0.76 35.48 ± 1.14 38.48 ± 1.23 13.96 ± 0.45 18.33 ± 0.59 17.67 ± 0.57 11.9 ± 0.38 11.73 ± 0.38
2,3-butanediol meso* 100 1530 1525 1.39 ± 0.04 2.46 ± 0.07 1.37 ± 0.04 1.76 ± 0.05 2.54 ± 0.08 1.51 ± 0.05 2.01 ± 0.06 2.57 ± 0.08 2.49 ± 0.07 2.81 ± 0.08 3.05 ± 0.09 1.41 ± 0.04
propanoic acid   1540 1546 56.1 ± 2.58 63.79 ± 2.93 70.63 ± 3.25 71.68 ± 3.3 75.6 ± 3.48 82.79 ± 3.81 64.79 ± 2.98 95.41 ± 4.39 73.97 ± 3.4 78.33 ± 3.6 88.64 ± 4.08 69.07 ± 3.18
linalool 25 1551 1542 11.8 ± 0.59 7.37 ± 0.37 10.7 ± 0.53 12.09 ± 0.6 56.37 ± 2.81 14.37 ± 0.72 16.19 ± 0.81 7.29 ± 0.36 7.65 ± 0.38 8.17 ± 0.41 5.1 ± 0.25 33.14 ± 1.65
1-octanol   1554 1552 17.5 ± 0.53 20.03 ± 0.6 25.93 ± 0.78 13 ± 0.39 13.58 ± 0.41 10.62 ± 0.32 9.54 ± 0.29 17.2 ± 0.52 11.35 ± 0.34 13.61 ± 0.41 15.14 ± 0.45 23.56 ± 0.71
propanoic acid 2-methyl- *   1567 1583 0.36 ± 0.01 0.46 ± 0.02 0.51 ± 0.02 0.44 ± 0.02 0.71 ± 0.03 0.44 ± 0.02 0.37 ± 0.01 0.94 ± 0.03 0.52 ± 0.02 0.62 ± 0.02 1.53 ± 0.06 0.49 ± 0.02
cis-4-hydroxymethyl-2-methyl-1,3-dioxolane   1602 1623 2.14 ± 0.07 4.75 ± 0.15 1.91 ± 0.06 3.14 ± 0.1 8.31 ± 0.27 10.17 ± 0.33 8.5 ± 0.27 12.15 ± 0.39 3.62 ± 0.12 3.3 ± 0.11 24.85 ± 0.8 2.59 ± 0.08
butirrolattone* 35 1611 1650 0.33 ± 0.01 0.4 ± 0.02 0.43 ± 0.02 0.27 ± 0.01 0.29 ± 0.01 0.16 ± 0.01 0.14 ± 0.01 0.44 ± 0.02 0.48 ± 0.02 0.32 ± 0.01 0.56 ± 0.02 0.39 ± 0.02
butyric acid* 0,17 1623 1600 0.97 ± 0.04 1.11 ± 0.04 1.11 ± 0.04 1.34 ± 0.05 1.03 ± 0.04 0.76 ± 0.03 0.83 ± 0.03 1.13 ± 0.04 1.01 ± 0.04 0.9 ± 0.04 0.66 ± 0.03 1.03 ± 0.04
phenylacetaldehyde   1626 1612 4.72 ± 0.15 3.58 ± 0.11 3.66 ± 0.12 3.16 ± 0.1 4.27 ± 0.14 3.43 ± 0.11 3.96 ± 0.13 4.65 ± 0.15 4.55 ± 0.15 4.8 ± 0.15 44.69 ± 1.43 4 ± 0.13
ethyl decanoate*   1641 1637 1.39 ± 0.05 1.23 ± 0.04 0.87 ± 0.03 1.81 ± 0.06 1.26 ± 0.04 1.45 ± 0.05 1.17 ± 0.04 1.28 ± 0.04 1.33 ± 0.04 1.16 ± 0.04 0.64 ± 0.02 0.96 ± 0.03
butanoic acid, 3-methyl- * 0,03 1667 1642 0.54 ± 0.03 0.69 ± 0.04 0.74 ± 0.04 0.58 ± 0.03 0.75 ± 0.04 0.73 ± 0.04 0.69 ± 0.04 0.85 ± 0.05 0.64 ± 0.04 0.78 ± 0.04 1.08 ± 0.06 0.95 ± 0.05
diethyl succinate* 6 1672 1667 1.96 ± 0.06 4.37 ± 0.14 3.29 ± 0.11 3.16 ± 0.1 4.06 ± 0.13 3.47 ± 0.11 3.46 ± 0.11 3.2 ± 0.1 2.87 ± 0.09 2.37 ± 0.08 3.21 ± 0.1 2.5 ± 0.08
-terpineol   1686 1684 10.3 ± 0.36 7.92 ± 0.28 6.36 ± 0.22 5.07 ± 0.18 19.9 ± 0.7 6.62 ± 0.23 6.72 ± 0.24 9.13 ± 0.32 8.47 ± 0.3 10.44 ± 0.37 4.47 ± 0.16 18.62 ± 0.65
3-methylthiopropanol* 1 1705 1725 0.45 ± 0.01 0.68 ± 0.02 0.86 ± 0.03 0.47 ± 0.01 0.92 ± 0.03 1.16 ± 0.03 1.11 ± 0.03 0.51 ± 0.02 0.56 ± 0.02 0.66 ± 0.02 1.31 ± 0.04 1.04 ± 0.03
naphtalene   1715 1728 9 ± 0.23 29.52 ± 0.74 4.65 ± 0.12 4.63 ± 0.12 4.94 ± 0.12 3.94 ± 0.1 4.65 ± 0.12 29.36 ± 0.73 24.88 ± 0.62 28.48 ± 0.71 24.69 ± 0.62 5.25 ± 0.13
1,3-propylene diacetate (t.i.)*   1730 - 0.61 ± 0.02 0.74 ± 0.02 0.6 ± 0.02 0.77 ± 0.02 0.92 ± 0.03 0.98 ± 0.03 1.11 ± 0.03 0.68 ± 0.02 0.52 ± 0.02 0.77 ± 0.02 0.76 ± 0.02 0.89 ± 0.03
α-cumyl alcohol   1750 1779 24.2 ± 0.7 24.36 ± 0.71 66.48 ± 1.93 76.54 ± 2.22 75.76 ± 2.2 71.3 ± 2.07 74.63 ± 2.16 26.82 ± 0.78 25.47 ± 0.74 24.24 ± 0.7 25.48 ± 0.74 71.83 ± 2.08
methyl salicylate 50 1754 1759 30.5 ± 1.13 44.79 ± 1.66 41.73 ± 1.54 35.28 ± 1.31 33.51 ± 1.24 26.51 ± 0.98 25.34 ± 0.94 37.91 ± 1.4 24.9 ± 0.92 21.12 ± 0.78 19.16 ± 0.71 23.21 ± 0.86
methyl-4-hydroxybutanoate   1758 - 3.14 ± 0.08 5.44 ± 0.14 3.33 ± 0.08 4.44 ± 0.11 6.04 ± 0.15 4.33 ± 0.11 3.85 ± 0.1 11 ± 0.28 6.36 ± 0.16 6.35 ± 0.16 42.69 ± 1.07 15.37 ± 0.38
ethyl 4-hydroxybutanoate*   1799 1827 1.16 ± 0.03 2.88 ± 0.08 1.75 ± 0.05 2 ± 0.06 2.9 ± 0.08 1.66 ± 0.05 1.3 ± 0.04 7.07 ± 0.21 4.03 ± 0.12 3.25 ± 0.09 10.53 ± 0.31 3.77 ± 0.11
2-phenylethyl acetate* 0,25 1802 1803 0.2 ± 0.01 0.25 ± 0.01 0.12 ± 0.01 0.37 ± 0.01 0.32 ± 0.01 0.71 ± 0.02 0.83 ± 0.02 0.39 ± 0.01 0.43 ± 0.01 0.43 ± 0.01 0.18 ± 0.01 0.14 ± 0
4-(methylthio)-1-butanol   1833 1812 8.21 ± 0.26 7.93 ± 0.25 11.87 ± 0.38 12.16 ± 0.39 11.98 ± 0.38 8.97 ± 0.29 8.62 ± 0.28 6.81 ± 0.22 6.41 ± 0.21 6.69 ± 0.21 4.47 ± 0.14 12.51 ± 0.4
hexanoic acid* 0,42 1840 1830 4.41 ± 0.2 4.64 ± 0.21 2.82 ± 0.13 3.16 ± 0.15 2.55 ± 0.12 1.95 ± 0.09 2.48 ± 0.11 3.02 ± 0.14 3.59 ± 0.17 3.98 ± 0.18 1.87 ± 0.09 2.27 ± 0.1
N-(3-methylbutyl)acetamide*   1855 1855 0.12 ± 0.004 0.02 ± 0.001 0.04 ± 0.001 0.03 ± 0.001 0.29 ± 0.01 0.01 ± 0.001 0.01 ± 0.001 0.04 ± 0.002 0.03 ± 0.001 0.04 ± 0.001 2.11 ± 0.07 0.35 ± 0.01
benzyl alcohol*   1863 1876 0.16 ± 0.01 0.31 ± 0.02 0.4 ± 0.02 0.19 ± 0.01 0.25 ± 0.01 0.28 ± 0.02 0.28 ± 0.02 0.23 ± 0.01 0.15 ± 0.01 0.16 ± 0.01 0.04 ± 0 0.48 ± 0.03
2-phenylethanol* 50 1895 1893 24.1 ± 0.92 33.26 ± 1.26 24.15 ± 0.92 19.31 ± 0.73 34.58 ± 1.31 35.05 ± 1.33 38.9 ± 1.48 37.03 ± 1.41 39.96 ± 1.52 43.35 ± 1.65 52.9 ± 2.01 28.07 ± 1.07
Ho-terpendiol 1   1943 1957 27.61 ± 0.97 8.61 ± 0.3 10.86 ± 0.38 13.4 ± 0.47 152.14 ± 5.32 11.22 ± 0.39 11.03 ± 0.39 10.82 ± 0.38 9.57 ± 0.33 7.03 ± 0.25 18.84 ± 0.66 49.57 ± 1.73
trans-2-hexenoic_acid   1960 1971 29.39 ± 0.65 38.16 ± 0.84 33.5 ± 0.74 28.51 ± 0.63 42.92 ± 0.94 45.43 ± 1 46.45 ± 1.02 80.17 ± 1.76 53.91 ± 1.19 78.05 ± 1.72 10 ± 0.22 105.09 ± 2.31
2-(H)-pyran-2,6(3H)-dione (t.i.) *   1979 - 0.56 ± 0.02 0.92 ± 0.03 0.89 ± 0.03 0.97 ± 0.03 1.12 ± 0.04 1 ± 0.04 0.93 ± 0.03 1 ± 0.04 0.81 ± 0.03 0.85 ± 0.03 0.36 ± 0.01 0.77 ± 0.03
pantolactone   2013 2033 56.6 ± 1.87 45.61 ± 1.51 78.56 ± 2.59 55.41 ± 1.83 53.02 ± 1.75 40.41 ± 1.33 45.76 ± 1.51 77.44 ± 2.56 55.93 ± 1.85 79.05 ± 2.61 88.98 ± 2.94 85.13 ± 2.81
diethyl malate*   2029 2070 2.02 ± 0.07 2.51 ± 0.09 3.14 ± 0.11 2.19 ± 0.07 1.13 ± 0.04 1.08 ± 0.04 1.12 ± 0.04 1.37 ± 0.05 1.8 ± 0.06 1.69 ± 0.06 1.19 ± 0.04 1.82 ± 0.06
octanoic acid* 0,5 2053 2043 7.78 ± 0.3 6.84 ± 0.27 6.29 ± 0.25 8.07 ± 0.31 5.01 ± 0.2 4.57 ± 0.18 5.25 ± 0.2 4.9 ± 0.19 6.33 ± 0.25 6.07 ± 0.24 2.12 ± 0.08 4.5 ± 0.18
homofuraneol 40 2075 2090 11.7 ± 0.42 14.6 ± 0.53 7.23 ± 0.26 20.24 ± 0.73 48.22 ± 1.74 76.67 ± 2.76 28.96 ± 1.04 92.52 ± 3.33 40.59 ± 1.46 21.94 ± 0.79 33.86 ± 1.22 8.69 ± 0.31
unknown m/z 114 *   2094 - 0.26 ± 0.01 0.26 ± 0.01 0.27 ± 0.01 0.23 ± 0.01 0.32 ± 0.01 0.3 ± 0.01 0.29 ± 0.01 0.44 ± 0.01 0.33 ± 0.01 0.44 ± 0.01 0.23 ± 0.01 0.28 ± 0.01
diethyl 2-hydroxy-3-methylsuccinate   2137 - 49.6 ± 1.49 83.9 ± 2.52 128 ± 3.84 63.8 ± 1.91 114.4 ± 3.43 83.1 ± 2.49 129.7 ± 3.89 97.3 ± 2.92 69 ± 2.07 89.2 ± 2.68 92.7 ± 2.78 250.3 ± 7.51
4-vinylguaiacol   2175 2175 66.4 ± 2.12 78.5 ± 2.51 108 ± 3.46 160.6 ± 5.14 278.4 ± 8.91 162.8 ± 5.21 148.9 ± 4.76 95.2 ± 3.05 140.5 ± 4.5 95.9 ± 3.07 142.5 ± 4.56 113.7 ± 3.64
carboethoxy-γ-butyrolactone*   2211 2241 0.67 ± 0.04 0.99 ± 0.06 1.36 ± 0.08 1 ± 0.06 1.11 ± 0.07 0.88 ± 0.05 1.02 ± 0.06 0.58 ± 0.04 0.74 ± 0.05 0.77 ± 0.05 0.51 ± 0.03 1.1 ± 0.07
decanoic acid* 1 2269 2257 3.88 ± 0.12 3 ± 0.09 2.36 ± 0.07 3.72 ± 0.11 2.18 ± 0.07 2.71 ± 0.08 3.03 ± 0.09 2.45 ± 0.07 2.95 ± 0.09 2.74 ± 0.08 1.21 ± 0.04 2.11 ± 0.06
succinic acid monoethylester   2267 2256 50.5 ± 1.52 35.38 ± 1.06 32.39 ± 0.97 48.41 ± 1.45 30.81 ± 0.92 40 ± 1.2 39.82 ± 1.19 31.51 ± 0.95 38.94 ± 1.17 33.58 ± 1.01 15.68 ± 0.47 29.9 ± 0.9
4-methyl-5-(β-hydroxyethyl)thiazole *   2285 2300 0.2 ± 0.001 0.16 ± 0.001 0.21 ± 0.001 0.22 ± 0.01 0.28 ± 0.01 0.15 ± 0 0.22 ± 0.01 0.54 ± 0.01 0.13 ± 0 0.38 ± 0.01 0.09 ± 0.001 0.06 ± 0.001
ethyl hydrogen succinate*   2373 2367 18.9 ± 0.57 41.36 ± 1.24 37.52 ± 1.13 27.02 ± 0.81 37.68 ± 1.13 34.26 ± 1.03 33.73 ± 1.01 41.64 ± 1.25 41.62 ± 1.25 31.7 ± 0.95 40.16 ± 1.2 26.66 ± 0.8
dodecanoic acid*   2472 2465 0.31 ± 0.01 0.35 ± 0.01 0.25 ± 0.01 0.5 ± 0.02 0.33 ± 0.01 0.5 ± 0.02 0.5 ± 0.02 0.27 ± 0.01 0.24 ± 0.01 0.27 ± 0.01 0.15 ± 0.01 0.23 ± 0.01
benzeneacetic acid 2500 2539 2534 41.5 ± 0.95 30.62 ± 0.7 36.48 ± 0.84 30.58 ± 0.7 100.1 ± 2.3 30.84 ± 0.71 32.97 ± 0.76 36.72 ± 0.84 31.34 ± 0.72 57.85 ± 1.33 233.01 ± 5.36 112.17 ± 2.58
acetovanillon*   2607 2626 0.11 ± 0.001 0.09 ± 0.001 0.11 ± 0.001 0.12 ± 0.001 0.13 ± 0.001 0.14 ± 0.001 0.14 ± 0.001 0.12 ± 0.001 0.1 ± 0.001 0.1 ± 0.001 0.19 ± 0.001 0.22 ± 0.01
tyrosol*   2990 2985 2.92 ± 0.07 4.89 ± 0.12 4.26 ± 0.11 4.56 ± 0.11 8.8 ± 0.22 9.98 ± 0.25 9.65 ± 0.24 6.33 ± 0.16 5.07 ± 0.13 6.66 ± 0.17 6.96 ± 0.17 4.62 ± 0.12
C13-norisoprenoids SPME                              
-damascenone 0,05 1801 1820 4.86 ± 0.002 3.08 ± 0.003 1.57 ± 0.001 2.8 ± 0.003 3.3 ± 0.001 5.24 ± 0.002 5.28 ± 0.003 3.37 ± 0.001 3.18 ± 0.002 3.57 ± 0.001 3.32 ± 0.003 2.62 ± 0.001
VTP (sum of isomers) 800 1524 1514 2.45 ± 0.1 2.93 ± 0.11 3.93 ± 0.15 2.87 ± 0.11 0.5 ± 0.02 2.82 ± 0.11 2.5 ± 0.1 2.26 ± 0.09 2.37 ± 0.09 1.82 ± 0.07 3.74 ± 0.15 3.6 ± 0.14
riesling acetale   1656 1638 2.5 ± 0.11 2.68 ± 0.11 2.51 ± 0.11 2.51 ± 0.11 2.56 ± 0.11 2.96 ± 0.12 2.87 ± 0.12 2.66 ± 0.11 2.6 ± 0.11 2.74 ± 0.12 2.3 ± 0.1 2.46 ± 0.1
TDN 2 1739 1743 1.06 ± 0.04 3.3 ± 0.13 1.45 ± 0.06 2.15 ± 0.09 1.52 ± 0.06 3.98 ± 0.16 3.1 ± 0.12 3.37 ± 0.13 1.82 ± 0.07 2.63 ± 0.11 1.33 ± 0.05 3.14 ± 0.13
SPME with derivatization                              
3-methyl-2,4-nonanedione (ng/L) 0,016 1732 1723 77 ± 10.01 16 ± 2.08 67 ± 8.71 35 ± 4.55 68 ± 8.84 24 ± 3.12 28 ± 3.64 30 ± 3.9 29 ± 3.77 38 ± 4.94 60 ± 7.8 54 ± 7.02

Three different areas (Le Moie, Massaccio, San Sisto), three harvest times (San Sisto H1, H2, H3), low and high vigour, three different clones and two different vinifications (late harvest and whitering process, skin maceration) RI exp and lit on polar column.

Table 2. Concentration (means ± standard deviations) and odour thresholds (OPT) in g/L except * in mg/L as equivalent of n-heptanol of bound compounds in 2016 Verdicchio wines.
titre du tableau
Bound aroma compounds RI exp RI lit le Moie Harvest date Vigour Clones Vinification
Areas
Massaccio San Sisto H1 San Sisto H2 San Sisto H3 Low vigour High vigour VCR3 VL50 R2 Late harvest Skin maceration
n-hexanol 1354 1356 54.7 ± 9.4 44 ± 7.5 39.3 ± 6.7 44.7 ± 7.6 59.5 ± 10.2 34.2 ± 5.8 30.9 ± 5.3 33.2 ± 5.7 38.5 ± 6.6 28.3 ± 4.8 285.5 ± 48.8 73.2 ± 12.5
n-octanol* 1554 1552 0.47 ± 0.03 0.56 ± 0.03 0.27 ± 0.02 0.49 ± 0.03 0.4 ± 0.02 0.41 ± 0.02 0.43 ± 0.03 0.49 ± 0.03 0.53 ± 0.03 0.65 ± 0.04 0.45 ± 0.03 0.24 ± 0.01
trans-linalool oxide furan 1444 1429 3.13 ± 0.38 1.8 ± 0.22 1.85 ± 0.22 2.02 ± 0.24 8.4 ± 1.01 2.34 ± 0.28 2.38 ± 0.29 2.46 ± 0.3 2.39 ± 0.29 2.3 ± 0.28 3.83 ± 0.46 6.85 ± 0.82
cis-linalool oxide furan 1463 1454 3.97 ± 0.46 3.04 ± 0.35 3.02 ± 0.35 3.33 ± 0.39 4.33 ± 0.5 3.85 ± 0.45 3.95 ± 0.46 3.94 ± 0.46 4.35 ± 0.5 3.93 ± 0.46 4.28 ± 0.5 5.74 ± 0.67
linalool 1546 1545 1.11 ± 0.16 0.46 ± 0.06 0.31 ± 0.04 0.67 ± 0.09 7.62 ± 1.07 0.76 ± 0.11 0.84 ± 0.12 0.6 ± 0.08 0.47 ± 0.07 0.45 ± 0.06 0.74 ± 0.1 4.26 ± 0.6
tricyclo octane (t.i.) 1679 - 0.54 ± 0.04 0.32 ± 0.02 0.25 ± 0.02 0.41 ± 0.03 0.61 ± 0.04 0.6 ± 0.04 0.51 ± 0.04 0.7 ± 0.05 0.57 ± 0.04 0.5 ± 0.04 1.53 ± 0.11 1.36 ± 0.1
-terpineol 1686 1698 6.04 ± 0.79 5.48 ± 0.71 6.07 ± 0.79 6.38 ± 0.83 8.38 ± 1.09 7.41 ± 0.96 8.23 ± 1.07 8.7 ± 1.13 7.34 ± 0.95 8.82 ± 1.15 7.48 ± 0.97 21.85 ± 2.84
trans-linalool oxide pyran 1727 1716 7.31 ± 1.02 6.01 ± 0.84 6.11 ± 0.86 8.41 ± 1.18 12.72 ± 1.78 8.18 ± 1.15 9.22 ± 1.29 6.83 ± 0.96 7.9 ± 1.11 7.31 ± 1.02 10.57 ± 1.48 11.84 ± 1.66
cis-linalool oxide pyran 1755 1781 5.04 ± 0.66 3.93 ± 0.51 3.98 ± 0.52 5.15 ± 0.67 4.97 ± 0.65 2.87 ± 0.37 3.6 ± 0.47 3.62 ± 0.47 4.12 ± 0.54 4.16 ± 0.54 3.69 ± 0.48 3.43 ± 0.45
citronellol 1762 1772 1.89 ± 0.17 1.68 ± 0.15 2.87 ± 0.26 3.75 ± 0.34 2.6 ± 0.23 2.3 ± 0.21 4.99 ± 0.45 1.28 ± 0.12 0.89 ± 0.08 2.71 ± 0.24 1.89 ± 0.17 2.82 ± 0.25
nerol 1790 1819 4.5 ± 0.5 4.37 ± 0.48 4.58 ± 0.5 4.91 ± 0.54 17.82 ± 1.96 5.96 ± 0.66 5.56 ± 0.61 5.38 ± 0.59 4.47 ± 0.49 4.74 ± 0.52 4.42 ± 0.49 10.63 ± 1.17
geraniol 1847 1831 12.97 ± 1.56 9.75 ± 1.17 10.31 ± 1.24 12.05 ± 1.45 37.13 ± 4.46 11.88 ± 1.43 12.39 ± 1.49 10.57 ± 1.27 10.46 ± 1.26 10.75 ± 1.29 8.8 ± 1.06 25.07 ± 3.01
exo-2-hydroxycineole 1849 1861 19.66 ± 2.56 19.3 ± 2.51 21.39 ± 2.78 24.8 ± 3.22 21.07 ± 2.74 23.03 ± 2.99 25.52 ± 3.32 22.2 ± 2.89 22.85 ± 2.97 24.43 ± 3.18 37.87 ± 4.92 50.07 ± 6.51
HO-terpendiol I 1943 1957 7.66 ± 0.46 8.51 ± 0.51 6.47 ± 0.39 8.92 ± 0.54 7.81 ± 0.47 8.14 ± 0.49 8.52 ± 0.51 8.26 ± 0.5 8.86 ± 0.53 10.06 ± 0.6 7.02 ± 0.42 5.02 ± 0.3
trans-8-hydroxylinalool 2264 2277 35.95 ± 3.24 36.16 ± 3.25 39.18 ± 3.53 49.07 ± 4.42 81.57 ± 7.34 57.1 ± 5.14 65.36 ± 5.88 41.81 ± 3.76 50.07 ± 4.51 46.42 ± 4.18 62.85 ± 5.66 82.47 ± 7.42
7-OH geraniol (t.i.) 2299 - 18.86 ± 1.32 16.15 ± 1.13 63.77 ± 4.46 68.83 ± 4.82 78.97 ± 5.53 71.89 ± 5.03 61.96 ± 4.34 15.75 ± 1.1 16.83 ± 1.18 17.45 ± 1.22 17.18 ± 1.2 81.43 ± 5.7
cis-8-hydroxylinalool 2302 2315 51.37 ± 4.11 14.53 ± 1.16 12.99 ± 1.04 15.75 ± 1.26 26.09 ± 2.09 12.88 ± 1.03 14.68 ± 1.17 16.5 ± 1.32 18.93 ± 1.51 15.41 ± 1.23 28.54 ± 2.28 30.12 ± 2.41
trans-geranic acid 2301 2289 6.77 ± 0.81 6.35 ± 0.76 8.42 ± 1.01 7.32 ± 0.88 26.25 ± 3.15 10.48 ± 1.26 8.69 ± 1.04 7.38 ± 0.89 8.72 ± 1.05 8.4 ± 1.01 5.97 ± 0.72 31.12 ± 3.73
myrtenol (t.i.) 2500 - 171.4 ± 11.31 136.6 ± 9.02 173.1 ± 11.42 197 ± 13 176.1 ± 11.62 161.1 ± 10.63 170.3 ± 11.24 142.7 ± 9.42 159.2 ± 10.51 187.5 ± 12.38 272.5 ± 17.99 353.1 ± 23.3
3-hydroxy--damascone 2512 2558 32.26 ± 3.87 31.77 ± 3.81 21.97 ± 2.64 27.24 ± 3.27 31.75 ± 3.81 33.84 ± 4.06 35.37 ± 4.24 23.08 ± 2.77 24.44 ± 2.93 28.36 ± 3.4 26.25 ± 3.15 38.76 ± 4.65
3-oxo--ionone 2603 2582 67 ± 7.37 52.56 ± 5.78 55.31 ± 6.08 62.52 ± 6.88 79.17 ± 8.71 102.37 ± 11.26 90.43 ± 9.95 85.87 ± 9.45 73.09 ± 8.04 91.79 ± 10.1 116.1 ± 12.77 150.4 ± 16.54
dihydro--ionone (t.i.) 2642 - 17.69 ± 1.77 11.89 ± 1.19 13.64 ± 1.36 13.17 ± 1.32 17.43 ± 1.74 19.75 ± 1.98 16.59 ± 1.66 16.29 ± 1.63 15.19 ± 1.52 16.67 ± 1.67 22.35 ± 2.24 45.4 ± 4.54
3-hydroxy-5,6-epoxy--ionone (t.i.) 2696 - 6.26 ± 0.43 5.64 ± 0.39 3.21 ± 0.22 4.31 ± 0.3 11.31 ± 0.78 29.28 ± 2.02 26.15 ± 1.8 44.99 ± 3.1 13.17 ± 0.91 25.59 ± 1.77 11.17 ± 0.77 141.1 ± 9.74
3-hydroxy-7,8-dihydro--ionol 2739 2722 23.52 ± 2.12 21.18 ± 1.91 22.26 ± 2 24.2 ± 2.18 27.05 ± 2.43 27.76 ± 2.5 25.49 ± 2.29 21.46 ± 1.93 24.45 ± 2.2 27.93 ± 2.51 38.65 ± 3.48 40.4 ± 3.64
4-oxo--isodamascol (t.i.) 2856 - 13.87 ± 0.94 11.42 ± 0.78 10.96 ± 0.75 12.93 ± 0.88 14.77 ± 1 13.25 ± 0.9 12.18 ± 0.83 9.01 ± 0.61 12.04 ± 0.82 16.24 ± 1.1 29.86 ± 2.03 20.89 ± 1.42
benzenoids                            
benzyl alcohol* 1863 1876 1.29 ± 0.11 0.98 ± 0.09 0.88 ± 0.08 2.15 ± 0.19 1.33 ± 0.12 1.3 ± 0.12 0.85 ± 0.08 1.34 ± 0.12 1.18 ± 0.11 1.1 ± 0.1 1.08 ± 0.1 1.19 ± 0.11
phenylethanol* 1895 1893 0.24 ± 0.02 0.22 ± 0.02 0.21 ± 0.02 0.25 ± 0.02 0.32 ± 0.03 0.29 ± 0.03 0.3 ± 0.03 0.25 ± 0.02 0.26 ± 0.02 0.3 ± 0.03 0.49 ± 0.04 0.43 ± 0.04
2-methoxy benzyl alcohol 2138 2082 7.65 ± 0.92 6.62 ± 0.79 7.95 ± 0.95 8.87 ± 1.06 7.96 ± 0.96 9.61 ± 1.15 9.9 ± 1.19 6.63 ± 0.8 7.53 ± 0.9 8.7 ± 1.04 9.66 ± 1.16 10.37 ± 1.24
α-cumyl alcohol 1750 1779 4.96 ± 0.3 5.11 ± 0.31 15.94 ± 0.96 15.58 ± 0.93 12.86 ± 0.77 17.47 ± 1.05 18.03 ± 1.08 4.35 ± 0.26 5.6 ± 0.34 5.6 ± 0.34 4.38 ± 0.26 15.2 ± 0.91
vanillic alcohol 2778 2787 16.05 ± 1.28 9.29 ± 0.74 10.88 ± 0.87 7.97 ± 0.64 8.65 ± 0.69 11.12 ± 0.89 10.4 ± 0.83 8.94 ± 0.72 14.71 ± 1.18 15.64 ± 1.25 21.32 ± 1.71 17.93 ± 1.43
methyl salicylate* 1754 1759 0.47 ± 0.04 0.33 ± 0.03 0.34 ± 0.03 0.49 ± 0.04 0.41 ± 0.04 0.27 ± 0.02 0.24 ± 0.02 0.29 ± 0.03 0.39 ± 0.04 0.35 ± 0.03 0.25 ± 0.02 0.21 ± 0.02

Three different areas (Le Moie, Massaccio, San Sisto), three harvest time (San Sisto H1, H2, H3), low and high vigour, three different clones and two different vinifications (late harvest and whitering process, skin maceration) volatile compounds in 2016 Verdicchio wines

Aroma compounds with a higher FD value (>3) likely contributed considerably to overall Verdicchio wine aroma. In particular, we observed that the most important compounds in terms of sensorial impact were ethyl 2-methylpropanoate, with notes of apple fruit, ethyl hexanoate with a bilberry-fruity note, -damascenone with a baked apple note, furaneol and homofuraneol with a cotton candy scent, vanillin with a characteristic sweet pastry note, phenylacetic acid associated with honey-withered flower, one unknown compound with a toasted almond smell, isovaleric acid with a cheese odour, -ionone with a violet note and methional and methionol with a boiled potato odour. In some wines, a passion fruit/tropical note was also found at the retention index very close to 3-mercapto-hexanol. Moreover, in all samples a liquorice note was present, probably associated with the compound pantolactone, together with a clove/spice note given by 4-vinylguaiacol and a clear celery/vegetal scent, probably due to sotolone.

Furthermore, we focused our attention on the anise note noticeable in some vintages of Verdicchio. GC-O analysis made it possible to find the area where the six expert panellists sensed this note. In the literature, the compounds that can contribute to this note are trans and cis anethole, estragol (Zeller and Rychlik, 2007), ethyl hexanoate (San-Juan et al., 2010), R carvone (Pinar et al., 2017) and 3-methyl-2,4 nonanedione (Pons et al., 2008). Except for ethyl hexanoate, which is eluted early, all the other compounds showed an RI on a polar column between 1687 and 1800. Analysis of the pure standards led to identification of the 3-methyl-2,4 nonanedione (3-MND) compound responsible for the anise note. Other researchers have reported an anise-like note in the same area that has been tentatively identified (Martí et al., 2003; Peťka et al., 2006). This compound was found in wine by French researchers (Pons et al., 2008); it was related to the plum note in prematurely aged red wines and was also correlated with a loss of fruitiness (Pons et al., 2013). 3-MND is an intriguing compound that has recently emerged as the most potent known agonist for the human receptor OR1A1, with a submicromolar half-maximal effective concentration (Geithe et al., 2017). These results further emphasise the controversial role of this compound, whose presence at variable concentrations has previously been described as reminiscent of mint, anise, fruit kernels and prunes (Pons et al., 2008) and has been associated with prematurely aged wines, oxidised soybean oil (Kao et al., 1998) and freshly brewed green tea (Guth and Grosch, 1993). The odour description of this compound in wine model solution is strong, depending on its concentration, as reported by Pons et al. (2008). When the concentration is 100 ng L−1 it is perceived as minty, while at around 1 g L−1 it recalls anise, kernel and prune and at 10 g L−1 the perception is of anise.

In order to understand the contribution of this compound to the Verdicchio aroma, 3-MND was added to a “neutral” Verdicchio (3-MND not detectable). The tasting was carried out by ten trained people (eight males, two females), who determined that the fruity note was masked only by the addition of 500 ng L−1 of 3-MND, as the anise note predominated in this wine. The samples preferred by the panellists were those with a 3-MND concentration of between 25 and 50 ng L−1. No oxidative note was detected in any sample. In Verdicchio wines 3-MND instead seems capable of imparting a positive and characteristic note.

Table 3. Odoriferous zones perceived by GC-AEDA.
titre du tableau
RI wax exp RI lit FD Descriptor Impact compound CAS
1006 958 243 Apple ethyl 2-methylpropanoate 97-62-1
1016 938 27 Kiwi ethyl propanoate 105-37-3
1035 1041 81 Bilberry ethyl 3-methylbutanoate 108-64-5
1024 1110 81 Banana isoamyl acetate 123-92-2
1094 - 81 Toasted almonds unknown -
1080 1033 9 Apple/pineapple ethyl butanoate 105-54-4
1201 1118 3 Herbaceous isobutanol 78-83-1
1229 - 3 Balsamic unknown -
1179 1174 27 Harsh, stale isoamyl alcohol 123-51-3
1225 1232 243 Bilberry/fruity ethyl hexanoate 106-32-1
1264 1269 9 Fruity hexyl acetate 142-92-7
1304 1302 27 Mushroom 1-octen-3-one 4312-99-6
1348 1345 3 Yeasty-creamy unknown -
1376 1328 3 Fruity unknown -
1437 1434 27 Fruity/apple ethyl octanoate 106-32-1
1443 1454 27 Boiled potato methional 3268-49-3
1466 1447 3 Vinegar acetic acid 79-09-4
1523 1532 9 Fruity ethyl 3-hydroxybutanoate 5405-41-4
1586 1570 27 Cheese, dog isobutyric acid 503-74-2
1624 1635 3 Creamy, oily ethyl furoate (t.i.) 614-99-3
1646 1620 27 Cheese butyric acid 107-92-6
1634 1637 3 Fruity/sweaty ethyl decanoate 110-38-3
1686 1671 81 Taleggio cheese isovaleric acid 503-74-2
1730 1730 27 Boiled potato 3-methylthio-1-propanol 505-10-2
1732 1747 3 Aniseed 3-methyl-2,4-nonanedione 113486-29-6
1740 1730 9 Not defined methyl salicylate 119-36-8
1739 1743 9 Gasoline TDN 30364-38-6
1815 1838 243 Baked apple -damascenone 23726-93-4
1815 1810 9 Flowery/rose phenethyl acetate/ethyl-4-hydroxybutanoate 103-45-7
1845 1875 3 Tropical/unpleasant 1-hexanol, 3-mercapto 51755-83-0
1864 1855 3 Pungent/chemical hexanoic acid 142-62
1881 1875 9 Floral benzenmethanol 100-51-6
1919 1909 243 Rose 2-phenylethanol 60-12-8
1962 1951 3 Sweet/green unknown -
1956 1939 81 Coconut whiskey lactone I 39212-23-2
1960 1920 81 Violet -ionone 14901-07-6
2003 - 27 Licorice/vegetal 2H-pyran-2,6(3H)-dione (t.i.) 5926-95-4
2045 2047 243 Cotton candy furaneol 3658-77-3
2050 2025 9 Acetic/bad octanoic acid 124-07-2
2093 2080 243 Cotton candy homofuraneol 27538-09-6
2044 - 9 Mushroom unknown -
2098 2123 27 Peach/sweet -decalactone 706-14-9
2137 2168 9 Smoke-roast ethyl 5-oxotetrahydro-2-furancarboxylate (t.i.) 1126-51-8
2196 2186 27 Leather/weiss beer 4-vinylguaiacol 7786-61-0
2200 2202 243 Celery like/sweet sotolone 5579-78-2
2559 2556 243 Pastries, white chocolate vanillin 121-33-5
2571 2555 27 Withered flower/honey phenylacetic acid 103-82-2
2631 2640 27 Wood /clove acetovanillone 498-02-2

Each GC-O analysis was performed by six experienced judges, FD mean of three judges.

Unfortunately, a well-perceived smell on the nose (olfactometry) is frequently not detected by chemical detectors (FID or MS). This is the case of some sulphur compounds and some carbonyl compounds, such as 3-MND. In such cases, it is necessary to use specific tests for the quantification of trace compounds. In order to quantify these compounds in our samples we used a derivatisation method with headspace solid phase microextraction using GC- tandem mass spectrometry. The derivatisation reagent PFBHA reacts with the carbonyl group formed oximes, which showed relatively specific mass spectra and high sensitivity. This method has been extensively employed to identify and quantify aroma components in several matrices, including wine (Flamini et al., 2005) and beverages (López-Vázquez et al., 2012; Saison et al., 2009). Our method was modified from that of Moreira et al. (2013) and Saison et al. (2009), where the determination of carbonyl compounds in beer was reported. Table 1 shows the content of 3-MND in our samples.

As Verdicchio is not an aromatic grape, one of the special characteristics of this variety that has been shown in previous studies (Versini et al., 2005) is the presence of a large amount of methyl salicylate. Methyl salicylate was found in V. riparia grapes (Schreier and Paroschy, 1980), in V. vinifera sp. (Cabaroglu et al., 1997) and in the Frontenac interspecific hybrid (Mansfield et al., 2011). The sensory impact of this compound in wine is not altogether clear. In the literature it is described as having an odour of wintergreen, mint and a fresh green character (Mansfield et al., 2011). We found that in the free forms the concentration was in the range 25–40 g L−1, while in the bound forms, after hydrolysis, a higher concentration of up to 0.5 mg L−1 was found (Table 2). As the olfactory threshold of this compound is 50–100 g L−1, it is possible that in some Verdicchio wines the balsamic note of methyl salicylate contributes to the fresh/anise scent. It is well known that wine odours are complex mixtures of many volatile chemicals, present in different concentrations. These chemicals can interact synergistically or additionally in the mixtures according to unpredictable rules and are the basis of the overall odour sensation (Brattoli et al., 2013). A recent study (Parker et al., 2017) proposed the sensory role of monoterpene glycosides during tasting through retronasal perception of odorant aglycones released in-mouth. For this reason, studies are underway to quantify the precursors of methyl salicylate in wines, hence the total quantity, not only that deriving from hydrolysis of glycosylated compounds. In the literature it has been suggested that it can be bound as methyl salicylate 2-O--D-glucoside or as methyl salicylate 2-O- -D-xylopyranosyl(1–6)–D-glucopyranoside (primeveroside), although nine different glycosides have been reported in plants to date (Mao et al., 2014).

Conclusion

This work confirms that it is possible to obtain wines with very different characteristics from this variety of grapes, producing premium wines with a distinctive pattern of volatiles, reproducible across several vintages and variable depending on the different location of the vineyard and winemaking techniques. Young wines are characterised by fruity, thiolic notes, while wines aged for longer are distinguished by their norisoprenoid content and by balsamic, anise and liquorice notes, which can be attributed to methyl salicylate released by precursors and the presence of 3-MND and pantolactone. With a new derivatisation and GC-MS-MS method it was possible to quantify 3-MND in the range10–50 ng L−1. With the use of GC-O, 48 sensorially important compounds were found for this wine. Analysis of the compounds after hydrolysis confirmed that a high amount of methyl salicylate characterised this variety. Methyl salicylate has a balsamic note from wintergreen oil that is often perceived in Verdicchio tasting. In-depth studies are underway to understand which precursors are present in grapes and whether they are in any way dependent on agro-climatic variables.

Funding

This study was supported by Fazi Battaglia winery.

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