Volatile and Phenolic Composition of Monovarietal Red Wines of Valpolicella Appellations

Home , Chelva (grape), Corvinone, Croatina, Loureira, Molinara (grape)

Received: 29 June 2020 y Accepted: 27 January 2021 y Published: 15 March 2021 DOI:10.20870/oeno-one.2021.55.1.3865

Volatile and phenolic composition of monovarietal red wines of Valpolicella appellations

Davide Slaghenaufi, Enrico Peruch, Marco De Cosmi, Léa Nouvelet and Maurizio Ugliano* Department of Biotechnology, University of Verona, Italy *corresponding author: [email protected]

a b s t r a c t The volatile and phenolic compositions of nine monovarietal wines from the following grape varieties allowed in the Valpolicella appellation were investigated: Corvina, Corvinone, Rondinella, Molinara, Oseleta, Raboso, Croatina, Sangiovese and Cabernet-Sauvignon. Different clones were also investigated for Corvina and Corvinone, the two main varieties of the appellation. All grapes were harvested from a single experimental block and vinified following a standard protocol. Wines from different clones of Corvina were characterised by higher monoterpenols content, including linalool, α-terpineol and geraniol, as well as by a peculiar pattern of C6-alcohols. Relatively high levels of monoterpene alcohols were also found in Corvinone wines, while Oseleta showed the highest concentration of terpinen-4-ol and cis- and trans- isomers of linalool oxide. The evaluation of the wine aroma profile by means of different aromatic series indicated higher values for the “floral”, “fruity” and “ripe fruit” series for Corvina and Corvinone wines. Major differences in phenolic composition were found between the different varieties of wine. The total phenolics and total tannins values for Corvina, Corvinone, Rondinella and Molinara wines indicated relatively low phenolic content in comparison with Croatina, Oseleta, Cabernet-Sauvignon. There were also major differences in the content of individual phenolic compounds, in particular anthocyanins, between the monovarietal wines.

k e y w o r d s wine aroma, red wine, monoterpenols, Valpolicella

INTRODUCTION wines (Slaghenaufi & Ugliano 2018; Slaghenaufiet al., 2019). Moreover, an evaluation of different In traditional wine producing countries, such as percentages of a combination of Corvina, Italy, France and Spain, the appellation of origin Corvinone and Rondinella has been carried out system is well-established and plays a central for the production of Amarone wine (Bellincontro role in the economic success of local wines in et al., 2016). Nevertheless, a comparative study international markets (Dorfmann, 2016). This that can set the ground for improved vinicultural system aims to convey to the consumer a message and winemaking practices within the appellation of uniqueness of individual products, which has not been carried out to date. reflects the relationship between the characteristics of a given wine and the geographical area in which The aim of this paper is to characterise the volatile it is produced. As such, appellations of origin and polyphenolic profile of different monovarietal have been considered of primary importance wines obtained from Valpolicella varieties, for the sustainable and cultural development of including different clones of Corvina and producing areas (FAO, 2018). Among the many Corvinone, in order to provide useful information specifications that define the characteristics for winemakers with view to improving the of individual appellations of origin, the grape production of Valpolicella wines. varieties used in winemaking are a major element of distinction. While many appellations restrict MATERIALS AND METHODS grape selection to one single variety, others allow 1. Reagents and materials a number of varieties, so that within certain limits producers can opt for different blends, with the aim 2-Octanol (97 %), 1-hexanol (99 %), cis-3-hexenol of optimising the final wine style. In the current (98 %), trans-3-hexenol (97 %), cis-2-hexenol context of climate change, there is great interest (95 %), vanillin (99 %), 2,6-dimethoxyphenol in revisiting the characteristics of different grape (99 %), linalool (97 %), terpinen-4-ol (≥ 95 %), varieties (Hannah et al., 2013), including the so- α-terpineol (90 %), nerol (≥ 97 %), geraniol called ‘minor’ varieties that are often limited to (98 %), linalool oxide (≥ 97 %), β-citronellol particular regions as part of specific appellations. (95 %), β-damascenone (≥ 98 %), isoamyl

2 alcohol (98 %), 1-pentanol (99 %), benzyl alcohol Valpolicella is a hilly area of about 240 km in (≥ 99 %), 2-phenylethanol ((≥ 99 %), vanillyl north-eastern Italy, which is located in the province alcohol (≥ 98 %), ethyl butanoate (99 %), ethyl of Verona between the city of Verona (south) and 3-methyl butanoate (≥ 98 %), isoamyl acetate the Lessini mountains (north). The renowned (≥ 95 %), ethyl hexanoate (≥ 95 %), n-hexyl Denomination of Controlled and Guaranteed acetate (≥ 98 %), ethyl lactate (≥ 98 %), ethyl Origin (DOCG) Amarone and Recioto are octanoate (≥ 98 %), ethyl decanoate (≥ 98 %), produced in this region, as well as Denomination furfural (≥ 99 %), benzaldehyde (≥ 99.5 %), of Controlled Origin (DOC) Valpolicella Classico hexanoic acid (≥ 99 %), octanoic acid (≥ 98 %), and Ripasso. These wines are obtained using local 3-methylbutanoic acid (99 %), α-ionone (90 %), grape varieties, mainly Corvina and Corvinone, β-ionone (96 %), methionol (≥ 98 %), α-ionol with smaller portions of other local varieties like (≥ 90 %), 1-butanol (≥ 99 %), 4-ethyl guaiacol Molinara, Rondinella, Oseleta. A maximum of (≥ 99%), 4-vinyl guaiacol (≥ 98 %), methyl 10 % of other grape varieties authorised in the vanillate (99 %) and ethyl vanillate (99 %) province of Verona can be used, with Raboso, were supplied by Sigma Aldrich (Milan, Italy). Croatina, Sangiovese and Cabernet-Sauvignon Dichloromethane (≥ 99.8 %) and methanol being most frequently used. Although Valpolicella (≥ 99.8 %) were provided by Honeywell (Seelze, wines are an example of blended wines where Germany). minor local varieties contribute to the production of wines with distinctive character and value 2. Wines (Paronetto & Dellaglio, 2011), little is known about the chemical composition of the wines obtained Grapes were harvested from one single experimental from grapes typically used in the Valpolicella plot of about 1 hectare, located in the town of San appellation. Pietro in Cariano (VR; 45.515264°, 10.908528°). Three clones of Corvina (ISV-CV 7, ISV-CV 48 There are a few available data to date with and VCR 446), four clones of Corvinone (ISV-CV regards phenolic characterisation (Nicolini 2, ISV-CV 3, ISV-CV 4 and ISV-CV 6), as well as & Mattivi, 1993; Mattivi et al., 2002) and the study Rondinella (clone VCR 38), Molinara (clone ISV- of certain grape-derived Corvina and Corvinone CV 100), Oseleta (clone VITIVER 1), Sangiovese

280 © 2021 International Viticulture and Enology Society - IVES OENO One 2021, 1, 279-294 (clone APSG5), Croatina (clone MICR 9), Raboso chromatograph coupled to a 5977B quadrupole del Piave (clone VCR 19) and Cabernet-Sauvignon mass spectrometer equipped with a Gerstel (clone FV6) were selected for the study. All MPS3 auto sampler (Mülheim/Ruhr, Germany). grapes were in healthy condition. Five kilograms Separation was performed using a DB-WAX of each grape sample were destemmed and one UI capillary column (30 m × 0.25, 0.25 μm film single pool of berries was obtained. Potassium thickness, Agilent Technologies) and helium metabisulfite (100 mg/kg) was added to 800 g as the carrier gas at 1.2 mL/min constant flow of grape berries. The berries were then hand- rate. The GC oven was programmed as follows: crushed and transferred to 1.5 L glass containers. at 40 °C for the first 3 min, then increasing to Fermentations were carried out at 22 ± 1 °C in a 230 °C at 4 °C/min, at which it was maintained for temperature-controlled room. The temperature 20 min. The transfer line was set at 200 °C. The of the liquid was measured twice a day and the mass spectrometer operated in electron ionisation weight loss monitored daily. Saccharomyces (EI) at 70 eV with an ion source temperature of cerevisiae VL3 (Laffort, Floirac, France) was 250 °C and quadrupole temperature of 150 °C. used for inoculation. The yeast was rehydrated Mass spectra were acquired in Scan mode. in 37 °C water for 20 min and was added to individual fermentation batches at a rate of 20 g/ Calibration curves were prepared for each analyte hL, as recommended by the manufacturer. The cap using seven concentration points and three was mixed twice a day by gently pushing it down replicate solutions per point in the model wine with a dedicated plunger, and fermentations were (12 % v/v ethanol, 3.5 g/L tartaric acid, pH 3.5). considered complete when no change in weight 20 μL of internal standard 2-octanol (42 mg/L in ethanol) were added to the solution. SPE was observed for two consecutive days. At the extraction and GC-MS analysis were performed end of fermentation, the wine was separated from as described above for the samples. Calibration the skins by pressing at 1.5 bar for 10 min with curves were obtained using Chemstation software a pneumatic press. Potassium metabisulfite was (Agilent Technologies, Inc.) by linear regression, added in order to reach a concentration of 25 mg/L plotting the response ratio (analyte peak area/ of free SO . The samples were then clarified by 2 internal standard peak area) against concentration centrifugation at 4500 rpm for 10 min at 5 °C and ratio (analyte added concentration/internal stored at 4 °C until analysis. All fermentations standard concentration). Method characteristics were conducted in duplicate. Sulphur dioxide, are reported in Supplementary S.1. The analysis ammonia and primary amino nitrogen (PAN) of 3-oxo-α-ionol, 8-hydroxylinalool, 3-hydroxy- were determined using an automatic analyser β-damascone and 3-hydroxy-7,8-dehydro-α-ionol Y15 Biosystems (Barcelona, Spain). The pH was semi-quantitative and they were expressed as was monitored with a Crison Basic 20+ pHmeter µg/L of 2-octanol equivalent (internal standard), (Barcelona, Spain). Grape juice sugar content was because no commercial standards were available monitored using a HI96801 refractometer (Hanna for these compounds . Instruments, USA). 4. Polyphenols analysis 3. Volatile compounds analysis Folin-Ciocalteu reagent was used to quantify Volatile compounds were extracted and analysed the total phenolics, according to the procedure as described by Slaghenaufi et al. (2020a) with described by Singleton & Rossi (1965). Total minor modification. Fifty milliliters of sample tannins were determined by methyl cellulose were added with 20 μL of internal standard solution precipitation (Sarneckis et al., 2006). Total (2-octanol at 42 mg/L in ethanol) and diluted anthocyanins were determined using the with 50 mL of distilled water. The solution was bisulfite bleaching method. Quantification of loaded onto a BOND ELUT-ENV, SPE cartridge, individual flavonoids, anthocyanins, flavan-3- ols containing 1 g of sorbent (Agilent Technologies, and phenolic acids was performed by liquid USA), previously activated with 20 mL of chromatography as described by Gonzales et al. methanol and equilibrated with 20 mL of water. (2018). The cartridge was then washed with 15 mL of water. Free volatile compounds were eluted with A Jasco HPLC system (Jasco, Oklahoma City, USA) 10 mL of dichloromethane, and then concentrated was used, constituting an AS-2057 autosampler under gentle nitrogen stream to 200 μL prior to and PU-2089+ pumps coupled to a MD-2010+ GC injection. GC–MS analysis was carried out photodiode array detector. Chromatographic on an HP 7890A (Agilent Technologies) gas separation was achieved using an Aces 5 C18

250 x 4.6 mm column (Advanced Chromatography 2.1. Higher Alcohols Technologies, Aberdeen, Scotland). Higher alcohols are a major group of volatile Quantification was done on the 280, 320, 360 compounds produced during alcoholic fermentation and 520 nm recorded chromatograms. A binary by yeast either from amino acid via the Ehrlich gradient consisting of 0.4 % formic acid in pathway or directly from sugars. Higher alcohols water (v/v, solvent A) and 0.4 % formic acid in have an odour of solvent, with the exception of acetonitrile 80 % (v/v, solvent B) were used as 2-phenylethanol and methionol that are described the mobile phase. Elution was performed with a as being like roses and potatoes respectively. flow rate of 1 mL/min and the following gradient 3-methyl-1-butanol and 2-phenylethanol showed programme (v/v): starting at 10 % solvent B for the highest concentrations in all studied wines, 2 min, increasing from10 to 45 % in 18 min, then their concentrations always exceeding the odour from 45 to 100 % in 1 min, and finally maintained threshold (Supplementary S.4.). However, De-La- at 100 % for 5 min. The column was re-equilibrated Fuente-Blanco et al. (2016) showed that the aroma for 6 min before the next injection. An amount of contribution of methionol and 2-phenylethanol 10 μL of wine or calibration standards was injected to model wines was insignificant, even at into the column. All the samples were filtered concentrations well above the odour threshold; through 0.20 μm Microliter PTFE membrane whereas 3-methyl-1-butanol was reported to filters (Wheaton, NJ, USA) into dark glass vials contribute to the green character of wine (Sáenz- and immediately injected into the HPLC system. Navajas et al., 2018). The highest concentration of total higher alcohols was observed in Sangiovese 5. Data treatment and the lowest in Rondinella and Cabernet- Data treatment, ANOVA and Tukey post-hoc test Sauvignon. The same behaviour was observed for were performed using XLSTAT 2017 (Addinsoft the level of 3-methyl-1-butanol. The highest and SARL, Paris, France). the lowest content of 2-phenylethanol were found in Oseleta and Corvina 48 respectively. Croatina RESULTS AND DISCUSSION and Cabernet-Sauvignon showed the lowest levels of methionol, and Molinara and Corvinone 2 the 1. Standard oenological parameters of musts highest, being up to 3 times higher. No statistical and wines differences were observed between the wine The main oenological parameters of musts and varieties for 1-pentanol. wines are shown in Table 1. Although all the 2.2. Acids grapes were harvested on the same date and grown in the same experimental field with the Fatty acids are associated with cheesy, fatty same agronomical practices, differences in °Brix and rancid aromas. They are formed during and nitrogen levels were observed. This could be fermentation as by-products of yeast metabolism. a reflection of varietal differences in grapevine Their concentration in wine is influenced by must response to the pedoclimatic conditions of the composition, oxygen availability and temperature. experimental vineyard. Differences in grape berry Differences in the concentrations of hexanoic, nitrogen content were observed between clones of octanoic, and 3-methyl butanoic acids across the same varieties, as in the case of Corvina and wines were relatively minor except for octanoic Corvinone. acid, which was detected in considerably lower concentrations in Oseleta and Cabernet-Sauvignon. 2. Volatile compounds In all samples, these compounds exceeded their The 46 volatile compounds analysed in the wine odour threshold, therefore potentially contributing samples are shown in Table 2. Depending on to wine aroma. These compounds are characterised their chemical structure, they are grouped into by fatty and cheesy odors and contribute to the generic vinous character of wine. alcohols, C6-compounds, esters, terpenes and norisoprenoids, acids and benzenoids. 2.3. C alcohols Despite a certain degree of volatilisation occurring 6 due to the small size of the fermentation batches, C6 alcohols such as 1-hexanol, cis-3-hexenol and it should be noted that fermentation length was trans-2-hexanol are formed during berry crushing similar in all the batches (varying between 8 and by the enzymatic oxidation of unsaturated fatty

9 days); therefore major differences in the CO2 acids in the grape (Ugliano, 2009); they have stripping rates are likely to be negligible. been reported in association with the “leafy”

MUSTS WINE

Ammonia PAN YAN a Alcohol Glucose + Free SO Total SO °Brix pH 2 2 (mg/L) (mg/L) (mg/L) (% v/v) fructose (g/L) (mg/L) (mg/L)

Corvina 446 24.6 ± 0.4 2.98 ± 0.01 24 ± 1 63 ± 2 88 ± 3 13.5 ± 0.1 0.1 ± 0.02 28 ± 1 100 ± 1 Corvina 48 22.9 ± 0.3 3.17 ± 0.01 30 ± 4 87 ± 12 117 ± 15 13.2 ± 0.2 0.22 ± 0.03 26 ± 2 107 ± 3 Corvina 7 23.9 ± 0.7 2.97 ± 0.01 34 ± 6 74 ± 5 108 ± 11 13.7 ± 0.1 0.39 ± 0.06 29 ± 2 106 ± 2 Corvinone 2 19.1 ± 0.5 3.12 ± 0.01 33 ± 8 60 ± 10 93 ± 18 11 ± 0.1 0.33 ± 0.05 24 ± 1 100 ± 3 Corvinone 3 20.4 ± 0.7 3.04 ± 0.01 36 ± 3 69 ± 9 105 ± 12 11.5 ± 0.1 0.3 ± 0.05 25 ± 1 99 ± 4 Corvinone 4 22.4 ± 0.2 3.02 ± 0.01 19 ± 1 50 ± 2 69 ± 3 12.8 ± 0.2 0.37 ± 0.06 27 ± 2 108 ± 2 Corvinone 6 21.8 ± 0.3 2.98 ± 0.01 24 ± 3 53 ± 2 77 ± 5 12.5 ± 0.2 0.4 ± 0.06 23 ± 1 111 ± 2 Croatina 21.8 ± 0.1 3.17 ± 0.01 39 ± 3 68 ± 3 108 ± 7 12.3 ± 0.1 0.31 ± 0.05 25 ± 1 105 ± 2 Molinara 100 22.9 ± 0.5 3.08 ± 0.01 6 ± 1 53 ± 0 59 ± 1 13 ± 0.3 0.3 ± 0.05 25 ± 3 100 ± 2 Oseleta 22 ± 0.1 3.33 ± 0.01 15 ± 4 69 ± 2 84 ± 5 12.5 ± 0.1 0.19 ± 0.03 22 ± 1 100 ± 4 Rondinella 38 23.2 ± 0.5 3.23 ± 0.01 14 ± 6 61 ± 8 76 ± 14 13.1 ± 0.2 0.44 ± 0.07 26 ± 1 99 ± 4 Raboso 24.3 ± 0.6 2.77 ± 0.01 9 ± 5 56 ± 6 65 ± 1 13.5 ± 0.2 0.5 ± 0.08 30 ± 3 106 ± 2 Sangiovese 23.4 ± 0.8 2.88 ± 0.01 23 ± 3 90 ± 2 114 ± 4 13.2 ± 0.1 0.21 ± 0.03 25 ± 2 98 ± 1

Cabernet-Sauvignon 24 ± 0.4 3.33 ± 0.01 8 ± 0 61 ± 7 69 ± 7 13.6 ± 0.2 0.15 ± 0.02 24 ± 2 104 ± 2 FV6 a YAN (Yeast Assimilable Nitrogen, calculated as sum of PAN+Ammonia) and “herbaceous” odours of wines (Benkwitz Given that Corvinone had generally lower °Brix et al., 2012). trans-3-Hexenol and cis-2-hexanol values, it is possible that this relationship is true have also been reported by different authors for early-harvested grapes (e.g., < 20 °Brix), (Oliveira et al., 2006; Benkwitz et al., 2012; whereas it is less relevant once full maturity Bindon et al., 2013; Jouanneau et al., 2010), but approaches or is achieved. Garcia et al. (2003) their origin is less clear. The concentration of and, more recently, Vilanova et al. (2012) reported

C6 compounds in finished wines may be linked that C6 compounds during the ripening period tend to grape variety (Versini et al., 1994; Nicolini to initially increase, after which they stabilise and et al., 1995) and maturity (Kalua & Boss, 2009), then decrease; this behaviour occurred in a delta as well as technological factors, such as timing of of sugar level that depends on grape variety. In

SO2 addition (Nicolini et al., 1996) and duration any case, our results indicate a strong varietal of pre-fermentative skin contact (Ramey et al., component in wines C6 alcohols content and 1986). In the present study, differences were profile. observed in all C6 alcohols across different wines, Of particular interest was that Corvina wines with wines from Corvinone clones generally exhibited cis-3-hexenol concentrations that were displaying the highest values, while the Molinara much higher than those detected in all the other sample was nearly three times lower. Considering wines, with this characteristic being consistent for that the vinification protocol was the same for all the tested Corvina clones. As a consequence, all the samples, these differences may be related 3-hexenol isomers distribution could be used to to either grape variety or maturity. With regard distinguish Corvina, Rondinella and Raboso wines to the latter, in a recent study it was found that from the other samples. In fact, the cis/trans ratio wines with higher 1-hexanol concentrations were was 11.7 (± 1.2) in Corvina wines, 11 (± 0.1) in produced from early-harvested grapes (Bindon Rondinella, 2.2 (± 0.02) in Raboso, and less than et al., 2013). In our experimental samples, a 1 in the remaining varieties. These results confirm negative correlation (R2 = 0.719) between grape previous observations in studies by Nicolini et al. °Brix values and 1-hexanol concentrations was (1996) and Oliveira et al. (2006) on the possible only observed in the Corvinone clones subset. role of 3-hexanol isomers as varietal markers

OENO One 2021, 1, 279-294 © 2021 International Viticulture and Enology Society - IVES 283 Davide Slaghenaufi et al. f f f a d a h a a a e a g a a a d a c a a a a a a a a g a a a a a a a a a a a a b a a e a e ef fg ef ef fg fg ab cd ab de de ab gh ab ab cd de cd bc ab bc bc ab ab ab ab ab ab de ab de bc bc ab def efg abc bcd bcd bcde 0 2 2 0 0 0 0 0 0 0 0 0 38 53 24 16 15 20 SD 2.5 2.1 0.6 0.4 SD 0.6 1.7 0.9 1.7 0.4 0.7 0.7 0.5 0.1 0.1 0.2 0.1 0.4 0.1 0.1 0.1 0.1 1.5 710 116 823 76.1 41.8 1.05 0.07 0.14 1.41 2.41 0.04 2.14 2.31 0.11 0.07 0.71 0.02 0.52 0.38 0.01 0.22 0.04 0.03 0.19 1.12 7.09 0.08 27.6 40.8 0.75 0.18 0.06 0.14 1.85 0.01 0.11 0.01 0.71 1.04 1.06 0.03 0.16 4.19 17.9 2076 1390 ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± Corvinone Corvinone 6 3 0 18 38 9.6 0.2 1.3 1.8 2.2 1.4 1.1 4.8 3.4 2.6 0.1 0.5 0.3 1.8 3.5 0.1 9.3 4.6 793 109 823 512 Cabernet-Sauvignon 1.66 0.43 0.15 0.08 14.1 0.48 3.97 9.03 4.66 6.38 4.23 0.02 2.01 0.03 0.25 0.48 0.01 1.23 42.1 22.6 84.5 54.3 22.9 1.82 52.3 15.1 0.12 8.69 mean 1370 1456 1423 1368 1400 mean 1220 1184 1062 123.3 41.21 222.5 58.98 13.32 10.77 98.36 19.57 172.6 991.2 131.3 44.69 25.03 12.44 59.74 26.62 23.61 12.63 49.38 210.3 38582 21589 32276 22376

284 © 2021 International Viticulture and Enology Society - IVES OENO One 2021, 1, 279-294 f f f a d a h a a a e a g a a a d a c a a a a a a a a g a a a a a a a a a a a a b a a e a e ef fg ef ef fg fg ab cd ab de de ab gh ab ab cd de cd bc ab bc bc ab ab ab ab ab ab de ab de bc bc ab def efg abc bcd bcd bcde 0 0 0 0 0 0 0 0 2 2 0 0 53 24 15 16 20 38 SD 0.4 0.1 0.1 0.2 0.1 0.4 0.1 0.1 0.1 1.5 0.6 1.7 0.9 0.7 0.5 1.7 0.1 0.7 SD 0.6 2.5 0.4 2.1 823 710 116 1.06 1.04 4.19 17.9 0.71 0.03 0.16 7.09 0.08 27.6 76.1 40.8 41.8 0.07 0.75 0.14 0.18 1.41 0.06 1.05 0.14 0.11 2.41 1.85 0.07 0.01 0.71 0.11 0.02 0.01 0.52 0.38 0.01 0.22 0.04 0.04 2.14 2.31 1.12 0.03 0.19 1390 2076 ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± Corvinone Corvinone 6 3 0 18 38 9.6 0.2 1.3 1.8 2.2 1.4 1.1 4.8 3.4 2.6 0.1 0.5 0.3 1.8 3.5 0.1 9.3 4.6 793 109 823 512 Cabernet-Sauvignon 1.82 1.66 0.43 0.15 0.08 14.1 0.48 3.97 9.03 4.66 6.38 4.23 0.02 2.01 0.03 0.25 0.48 0.01 1.23 42.1 22.6 84.5 54.3 22.9 52.3 15.1 0.12 8.69 mean mean 1370 1456 1423 1368 1400 1220 1184 1062 123.3 41.21 222.5 58.98 13.32 10.77 98.36 19.57 172.6 991.2 131.3 44.69 25.03 12.44 59.74 26.62 23.61 12.63 49.38 210.3 38582 21589 32276 22376

of certain wines, which would appear to be of and ester content in wines. Grape °Brix was particular relevance in the case of Valpolicella observed to be negatively correlated with ethyl red wines. Likewise, 2-hexenol isomers also 3-methyl butanoate (R2 = 0.701) and ethyl lactate seem to be varietal markers; in particular, the (R2 = 0.605) concentrations in the Corvinone highest concentration of cis-2-hexenol was found clones subset only. Antalick et al. (2015) observed in Oseleta, almost double that in other samples. that the influence of grape maturity level on wine Moreover, on average, Corvinone showed a ester concentrations varied in relation to grape concentration that was about 69 % higher than variety. Corvina. Clonal variations for the cis-2-hexenol Interestingly, different clones of either Corvina or concentration were quite low: < 20 % in Corvina Corvinone showed rather large variations in ester and < 10 % in Corvinone. trans-2-Hexenol could content, which should be further investigated. only be quantified in Corvinone, Sangiovese and 2.5. Terpenes and C -norisoprenoids Cabernet. 13 Terpene compounds are associated with floral 2.4. Esters notes and are characteristic of aromatic grape Esters are mainly produced during fermentation varieties such as Muscat (Jackson, 2008). They are and they are related to the fruity character of wines. generally considered to potentially contribute to Out of all the esters analysed, ethyl butanoate, the aroma of white wines (Jackson, 2008). Terpene ethyl 3-methyl butanoate, ethyl hexanoate, ethyl alcohols, in particular linalool and α-terpineol, octanoate and isoamyl acetate exceeded their were found in higher concentrations in Corvina odour threshold in all wine samples (Francis & wines. β-citronellol also varied significantly Newton, 2005), and their concentrations varied across wines, with Corvina, Rondinella, Molinara considerably across individual samples. The and most of the Corvinone samples generally production of esters by yeast during alcoholic showing the highest concentrations. Conversely, fermentation is influenced by several factors, the highest concentrations of terpinen-4-ol and cis- such as those related to must composition; more and trans- isomers of linalool oxide were observed specifically, sugar content, yeast available nitrogen in the Oseleta sample. In comparison with the data (YAN, the sum of primary amino nitrogen and recently reviewed by Black et al. (2015), these ammonia), fermentation temperature, insoluble observations indicate that the terpene content solids concentration, oxygen availability and yeast of wines from certain Valpolicella varieties, in strain (Antalick et al., 2015). As the vinification particular Corvina and to a lesser extent Corvinone, conditions were the same for all wines, it is is not negligible. This should also be considered in likely that the differences in ester content were a light of the observation that terpene alcohols (i.e., result of variations in grape must YAN. Positive linalool, geraniol, α-terpineol and terpinen-4-ol) in correlations were observed between ammonia Corvina wines can act as precursors to the potent and ethyl butanoate, ethyl hexanoate and ethyl balsamic aroma compounds 1,4- and 1,8-cineole during wine aging (Slaghenaufi & Ugliano, 2018). octanoae (Table 3). A tendency for increasing PAN (Primary AminoNitrogen) and isoamyl acetate and Grape-derived terpenes are produced by ethyl 3-methylbutanoate was also observed. YAN both the 1-deoxy-D-xylulose-5-phosphate/ was mostly correlated with ethyl butanoate, ethyl methylerythritol phosphate (DOXP/MEP) 3-methyl-butanoate, isoamyl acetate and ethyl pathway and the mevalonic acid (MVA) pathway. hexanoate. Although these correlations confirm In the case of non-aromatic varieties, such as the the importance of YAN fractions in modulating ones investigated here, terpenes mostly accumulate wine esters content, other grape compositional as non-volatile glycosidic precursors (Black factors may also contribute to wine ester diversity; et al., 2015; Slaghenaufiet al., 2019). Part of these for example, grape lipids availability, which is precursors are converted to free aroma compounds also linked to variety (Pérez-Navarro et al., 2019), during fermentation by both acid and enzymatic can influence the production of ester using yeast hydrolysis, and the liberated compounds can be (Rosi & Bertuccioli, 1992). further transformed by chemical rearrangements or yeast activity (Ugliano et al., 2006; Slaghenaufi The sugar level of musts may play an important et al., 2020b; Slaghenaufi & Ugliano, 2018; Rapp role in yeast ester production (Ugliano & et al., 1985). Terpene precursors tend to accumulate Henschke, 2009; Antalick et al., 2015; Slaghenaufi in the berry during ripening (Wilson et al., 1984; et al., 2020a). However, within the whole dataset, Costantini et al., 2017); however, for non- no correlation emerged between °Brix in musts aromatic varieties complex terpene accumulation

Ammonia PANa YANb Sugar (°Brix) Isoamyl acetate 0.331 0.471 0.478 -0.118 n-Hexyl acetate 0.157 0.027 0.114 0.387 Ethyl butanoate 0.597 0.233 0.481 -0.266 Ethyl 3-methyl butanoate 0.430 0.457 0.524 -0.189 Ethyl lactate 0.367 0.233 0.349 -0.069 Ethyl hexanoate 0.651 0.279 0.538 -0.309 Ethyl octanoate 0.528 0.065 0.335 -0.279 Ethyl decanoate 0.457 0.177 0.362 0.089 a PAN (Primary Amino Nitrogen) b YAN (Yeast Assimilable Nitrogen, calculated as sum of PAN+Ammonia) patterns have been observed in response to variety 2.6. Benzenoid compounds and vintage conditions (Luo et al., 2019). From this point of view, although maturity levels varied Relatively low concentrations of vanillin, across the different grapes used in the present vanillic alcohol, ethyl vanillate and methyl study, out of the group of grapes harvested in the vanillate were found in the experimental wines, 23-24 °Brix range (namely Corvina, Molinara, which may be due to the fact that the adopted Rondinella, Raboso, Sangiovese and Cabernet), experimental protocol did not involve any oak Corvina was clearly characterised by increased contact. These benzenoids can contribute to content of monoterpene compounds; nevertheless, aromas of sweet spices. However, in our samples the possibility that Corvinone can also attain they were observed at concentrations below the equally high terpene levels with a delayed harvest olfactory thresholds, although it is possible that still needs to be investigated. some synergistic interactions occured between compounds with similar properties contributing to In the wines of the present study, a positive correlation (Supplementary S.3.) was observed the spicy aroma notes (Cameleyre et al., 2020). between terpinen-4-ol and trans-linalool oxide From a chemical point of view these compounds content (r = 0.609), whereas the r value for the seemed to be characteristic of some varieties; for isomers cis- was considerably lower (0.430). example, vanillin was virtually absent in Cabernet- Linalool concentration was correlated with Sauvignon, Oseleta and Raboso, whereas in most the level of α-terpineol (r = 0.945), geraniol of the other wines it was detected in the range of (r = 0.723), and β-citronellol (r = 0.660). Despite 11-25 µg/L and reached 41 µg/L in Rondinella. nerol being the cis- isomer of geraniol, no strong Benzenoid alcohols, such as vanillic and benzyl correlation was observed with the other terpenes. alcohol, were higher in Oseleta, Rondinella and Corvina 48, whereas Corvinone 6 exhibited low C13-norisoprenoids are very powerful odour concentrations for both compounds. Corvina compounds due to their low odour threshold. always showed a higher level of benzyl alcohol β-Damascenone was quantitatively the most compared to Corvinone, but this differentiation abundant norisoprenoid in the studied wines, was not observed for vanillic alcohol. largely exceeding the odour threshold. The concentration of β-damascenone seemed to be related to wine variety: the highest concentrations Oseleta was by far the richest variety in ethyl were found in Corvinone, followed by Molinara, and methyl vanillate, whereas Molinara was Corvina and Rondinella; while Cabernet showed a characterised by lower concentrations. No concentration similar to Corvina and Rondinella, difference was observed between Corvina and and Croatina, Raboso and Oseleta were found to be Corvinone for ethyl vanillate content. Conversely, 2 to 7 times less abundant than Corvinone. Small a higher methyl vanillate level was found in variations in concentrations of β-damascenone Corvinone than in Corvina. Finally, the volatile between clones of the same variety (Corvina phenols, 4-ethylguaiacol and 4-vinylguaiacol, or Corvinone) were observed (Coefficient of were found at a very low concentrations in all variation between 11 and 13.5 %). samples.

FIGURE 1. Aromatic series in Valpolicella wines. 3. Evaluation of wine aroma profile based on showed high values for all the aromatic series. aromatic series In particular, Corvina wines showed the highest floral value (mainly due to the high linalool Odour activity values (OAV) is often used to concentration), followed by Corvinone. In general, identify the compounds that contribute the most local varieties had higher floral levels than Raboso, to wine aroma. Compounds with a concentration Croatina, Sangiovese and Cabernet. Corvina also higher than the olfactory threshold (OAV > 1) showed the highest value for the green series, are considered to have an impact on wine aroma. which was even higher than Corvinone, despite However, compounds below their odour threshold it being well-recognised that green/herbaceous should also be considered as they can contribute notes are more characteristic of Corvinone aroma to wine aroma through synergistic effects (Lopez than of Corvina (Nicolini & Mattivi, 1993). et al., 1999). This may be due to the possible contribution of some compounds responsible for the green In order to estimate the olfactory profile of studied wines, the compounds were grouped into different aroma, like methoxy pyrazines (Heymann et al., aromatic series according to their odour descriptor, 1986; Kotseridis et al., 1998), which were not and the OAV were summed to give the intensity for analysed in the present study. Sangiovese was also each series. The six series were formed according characterised by high values for the green series, to Sánchez-Palomo et al. (2019) with some less than Corvina, but more than Corvinone. modification: fruity, floral, vinous, green, spicy and ripe fruit (Supplementary S2). The “fatty” Sangiovese showed the highest value for the fruity and “sweet” series proposed by Sánchez-Palomo series. This high value was related to the ester et al. (2019) were replaced by “vinous”, including content and, more specifically, to the concentration all fermentative aromas. The “Ripe fruit” series of isoamyl acetate, which was twice as high included norisoprenoids and vanillin. The “green” as in the other wines. Corvinone 3, Corvinone 6 and Corvina 7, in that order, showed the next series included C6 compounds, as well as 3-methyl- 1-butanol as it was recently reported to contribute highest fruity values. High diversity was observed to the green character of wine (Sáenz-Navajas between the clones of Corvinone, with Corvinone et al., 2018). The “floral” series was composed of 3 and 6 showing a value almost the double of terpenes. These modifications were made in order Corvinone 4, and clone Corvinone 2 being in the to obtain a better representation of the aroma middle. In Corvina, clone 7 showed higher fruity descriptors commonly used in wine tasting, and levels, but clonal differences were less prominent. they also took into account the aroma families In the vinous series, sample behaviour was similar proposed by Ferreira et al. (2007). to that of the “fruity” series.

As can be seen in Figure 1, the vinous, fruity Of the Verona local varieties, Corvina, 1Corvinone, and ripe fruit series contributed the most to the Molinara and Rondinella were characterised by aroma profile of all the studied wines. The main “ripe fruit”; in particular, Corvinone showed the Valpolicella varieties, Corvina and Corvinone, highest value in this series, followed by Corvina,

288 © 2021 International Viticulture and Enology Society - IVES OENO One 2021, 1, 279-294 Molinara and Rondinella, which showed more or almost twice as many anthocyanins as clone “3” less the same values. Oseleta showed by far the (the lowest Corvinone). As regards monomers, lowest level of ripe fruit. Raboso, Croatina, Oseleta, Cabernet and Sangiovese had a high concentration of malvidin- Cabernet-Sauvignon showed the lowest values in 3-glucoside (between 400 and 600 mg/L), which almost all of the aromatic series, except for the was 4-6 times higher than that found in Corvina. ripe fruit series for which it showed a higher value Corvinone showed an intermediate level of than the other varieties due to its β-damascenone malvidin-3-glucoside with a great variability content. The variety that seemed to have values between clones (between 216 and 373 mg/L) with similar to Corvina were Molinara and Rondinella, Corvinone 4 reaching the level of Sangiovese. even though both varieties showed lower values Peonidin was detected only in Oseleta, Raboso, for the floral and green series. Furthermore, Croatina, Rondinella and Sangiovese. Oseleta and Rondinella were characterised by the highest level Raboso were characterised by very high levels of spicy aromas in the whole data set. of delphinidin (more than 300 mg/L), which is over one order of magnitude higher than that in 4. Phenolic compounds the other varieties. Peonidin and delphinidin have Polyphenols play an important role in red previously been reported as markers of Oseleta wine quality, in terms of, for example, colour, and Raboso (De Rosso et al., 2010). astringency and protection from oxidation. 5. Oenological implications for the volatile and Phenolic data are shown in Table 4. Corvina phenolic composition of the monovarietal wines and Corvinone are generally characterised as having low polyphenolic content; likewise, in The current regulation of the Valpolicella our experimental wines, Corvina and Corvinone appellation stipulates that Corvina and Corvinone had low total polyphenol content, and only that must be the two main varieties in the final blends, of Molinara was lower. The amount of total varying from a minimum of 45 % to a maximum polyphenols found in Oseleta, Croatina, Raboso of 95 %. Rondinella is limited to the 5-30 % and Cabernet-Sauvignon was 3-, 2.5-, 2- and 2-fold range, and other varieties to a maximum of 25 %, higher respectively than in the main Valpolicella with a maximum limit of 10 % for each grape varieties, Corvina and Corvinone. Wine tannin variety. Figure 2 summarises some of the main content was relatively low for most Valpolicella characteristics of the monovarietal wines studied. varieties, the only exception being Oseleta and Based on their phenolic and aroma features, it Croatina. Oseleta wines also exhibited the highest was possible to categorise the wines into two concentration of the monomers catechin and main groups. The first group, characterised by epicatechin, while epicatechin gallate was absent high values in the aromatic series, but with lower in this variety. Corvinone was generally richer in polyphenols content, included wines from Corvina, monomers than Corvina Corvinone, Rondinella and Molinara grapes, Looking at flavonols, kampferol was detected only which are the main varieties of the Valpolicella in Croatina, Molinara and Cabernet-Sauvignon. blends. These wines are likely to exhibit an aroma Quercetin-3-glucoside was found to be below profile leaning towards floral, fruity and spicy 10 mg/L in all the Corvina, Corvinone and aroma attributes, but their content in phenolic Molinara samples, while Oseleta and Sangiovese compounds which contribute to colour, mouthfeel were the richest with a concentration of 51.5 and and longevity is rather low. 37 mg/L respectively. Phenolic acids were almost absent in Corvina and Corvinone, but they were Conversely, the second group was characterised present in all the other varieties. by a high level of tannins and anthocyanins, but lower values for aroma features, and it included The anthocyanin content of Corvina, Corvinone Oseleta, Croatina, Raboso, Sangiovese and and Rondinella wines was generally rather low, Cabernet-Sauvignon. Interestingly, the varieties which is in agreement with previous findings of the first group have also been reported tobe (Bellincontro et al., 2016). Conversely, Oseleta, phylogenetically related (Vantini et al., 2003; Raboso and Croatina wines were characterised Cipriani et al., 2010), implying that their chemical by high anthocyanin content (Mattivi et al., proximity reflects a common genetic background. 1990; De Rosso et al., 2010). Total anthocyanin It was therefore surprising to observe that content depended on the clone; this was very Oseleta, which is also genetically related to the apparent for Corvinone where clone “2” had varieties of the first group (Vantini et al., 2003;

OENO One 2021, 1, 279-294 © 2021 International Viticulture and Enology Society - IVES 289 Davide Slaghenaufi et al. a a a a a a e c a d d b b b c ef ab ab ab bc bc bc ab ab ab cd cd abc abc abc efg bcd bcd abcd 3 73 SD 0.6 0.2 SD 0.1 49.1 0.12 27.34 65.85 2.964 1.128 0.576 3.312 0.708 0.084 0.312 16.03 5.556 2.184 0.384 3.516 0.492 0.492 0.516 1.284 0.792 30.756 56.844 ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± Corvinone Corvinone 6 1 25 2.2 9.4 4.8 5.9 0.7 2.6 1.1 3.2 4.1 4.1 4.3 6.6 Cabernet-Sauvignon 24.7 <0.7 <0.9 27.6 <1.2 <0.2 <0.5 46.3 <0.7 18.2 29.3 10.7 2070 267.3 256.3 473.7 means means 931.33 586.08 1283.6 1385.12 f f a a a b a a a b a e a b b c bc ab ab ab bc bc cd cd ab ab cd cd bc cde def abc bcd abcd 6 SD 0.2 SD 0.1 25.5 1.42 0.12 49.2 0.12 4.44 0.54 74.22 4.296 0.552 4.116 0.564 2.052 0.552 54.74 40.96 7.572 0.312 4.836 2.172 0.528 0.096 1.212 0.672 44.784 ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± Sangiovese Sangiovese Corvinone Corvinone 4 1 1 37 1.8 4.6 4.7 4.6 1.8 2.6 4.5 4.4 0.8 5.6 410 35.8 <0.7 <0.8 <0.9 34.3 17.1 <0.2 <0.5 63.1 <0.9 40.3 18.1 10.1 1347 617.6 334.6 373.2 540.3 means means 957.28 1171.33 f f a a a a g b b d d d e a fg ab ab cd bc ab ab cd ab bc cd ab ab de de ab cd abc bcd abcd SD 0.2 SD 0.2 19.8 39.6 11.1 3.96 0.96 0.66 1.788 0.384 0.312 1.932 0.132 0.588 33.94 12.89 280.2 0.504 3.048 1.824 1.824 2.244 1.224 1.236 0.084 1.632 28.188 66.864 10.524 ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± Croatina Corvinone Corvinone 3 8 33 <1 3.2 3.2 2.6 1.1 4.9 1.5 4.2 5.5 0.7 986 14.9 <0.7 <0.9 16.1 <0.2 <0.5 87.7 25.4 15.2 15.2 18.7 10.2 10.3 13.6 2626 222.2 234.9 557.2 means means 716.32 1490.6 2203.36 f f a a a a a a d e d a g c b a d b c d bc ab ab bc ab cd de bc ab bc abc abc cde abcd SD 0.2 1.2 SD 0.1 76.1 2.64 0.36 0.06 1.14 69.9 0.54 1.44 0.48 57.98 48.65 4.764 0.456 66.47 0.684 1.572 0.264 5.424 0.948 0.396 1.764 25.968 238.95 72.636 39.852 ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± Corvinone Corvinone 2 Raboso del piave 3 4 22 10 12 1.2 3.8 0.5 9.5 0.9 5.7 2.2 4.5 7.9 3.3 <0.7 <0.8 <0.9 39.7 <0.2 <0.5 13.1 <0.9 45.2 14.7 2192 442.3 216.4 605.3 332.1 means means 544.16 1810.8 1035.67 1675.84 a a a a e a c f c a e e a e e b g g d d de ab de ab ab ab bc cd efg bcd abc abc abc bcd SD 6.2 0.5 SD 0.1 0.54 0.42 6.18 0.84 132.6 3.816 0.324 3.132 0.576 0.408 0.504 26.25 260.5 1.644 0.672 8.088 1.392 0.492 1.596 2.124 127.75 16.152 261.63 55.896 64.908 ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± Oseleta Corvina Corvina 446 7 4.3 4.5 2.7 4.8 3.5 3.4 4.2 0.9 5.6 4.1 31.8 <0.7 <0.9 26.1 <0.2 <0.5 13.7 51.5 <0.9 67.4 11.6 <1.2 13.3 17.7 3318 236.3 134.6 465.8 540.9 means means 2448.3 1221.67 1006.08 2190.08 a a a b a a a d a a a b b ab cd ab ab ab de bc ab ab bc bc ab cd bc de ab abc abc bcd bcd abcd SD 0.5 SD 0.4 0.6 4.98 39.6 0.72 0.36 1.08 0.48 19.2 0.12 46.67 2.184 0.576 0.984 0.108 29.23 92.77 5.724 2.256 4.212 0.552 0.612 0.156 0.708 0.312 12.456 25.656 ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± Corvina Corvina 48 Rondinella 6 3 9 4 1 5 3.2 4.8 8.2 0.9 2.3 4.6 5.1 1.3 5.9 2.6 504 18.2 <0.7 <0.9 <0.2 <0.5 47.7 18.8 <1.1 <0.9 35.1 1562 204.8 103.8 222.7 213.8 means means 633.92 1029.67 e a a a a a a a a a a c a a a a b b f bc ab ab ab ab ab de ab bc bc ab bcd abc bcd abc SD 4.3 0.8 SD 6.8 2.7 16.5 0.36 4.08 0.36 2.688 1.032 0.468 0.648 0.108 0.336 0.444 92.87 2.652 0.372 0.648 3.228 0.312 0.096 0.312 172.19 14.844 141.42 ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± Molinara Corvina Corvina 7 3 3 34 <1 5.4 8.6 3.9 5.4 0.9 2.8 3.7 8.3 3.1 5.4 2.6 0.8 2.6 681 22.4 46.8 22.1 26.9 1067 <0.7 <0.9 <0.7 <0.8 <1.1 <1.2 <0.2 169.3 123.7 means means 910.56 388.32 T/A T/A Peonidin Catechin Peonidin Catechin Myricetin Myricetin Gallic acid Gallic acid Kaempferol Epicatechin Kaempferol Epicatechin Delphinidin Caffeic acid Feluric acid Delphinidin Caffeic acid Feluric acid p-Coumaric acid p-Coumaric acid Epicatechin gallate Epicatechin gallate Malvidin-3-glucoside Malvidin-3-glucoside Quercetin-3-glucoside Quercetin-3-glucoside Phenolic composition of studied wines: mean (mg/L) and standard deviation (SD). Tannins (mg/L of catechin Tannins equivalent) (mg/L of catechin Tannins equivalent) (mg/L of catechin Total Total Polyphenols (mg/L of gallic equivalent) acid Total Polyphenols (mg/L of gallic equivalent) acid TABLE 4. TABLE Total Anthocyanins Total (mg/L Anthocyanins equivalent) malvidin-3-glucoside Total (mg/L Anthocyanins equivalent) malvidin-3-glucoside

290 © 2021 International Viticulture and Enology Society - IVES OENO One 2021, 1, 279-294 FIGURE 2. Spider charts summarising the main monovarietal wines features. T/A = tannins/anthocyanins ratio. For better visualisation, the values of “ripe fruit”, “anthocyanins”, “tannins”, “T/A” and “fruity” have been multiplied by 2, 3, 25, 10 and 1.5 respectively, while floral value has been divided by 30. Corvina and Corvinone values are averages of the respective clones. Cipriani et al., 2010), showed such a different grape varieties Oseleta, Raboso, Croatina and chemical profile, having in particular very high Cabernet-Sauvignon generally had reduced values for phenolic parameters. terpene content and higher phenolic levels. As Also of particular relevance was the high variability regards Corvina and Corvinone, a certain degree of the anthocyanins/tannin ratio, indicating of variability in terms of both volatile and phenolic different potential for colour stabilisation during composition was also observed across clones; this aging (Gambuti et al., 2017). This component must constitutes potentially useful information for new be carefully considered, particularly in the case vineyard planting. of wines destined for aging, such as Valpolicella Superiore which should be aged in the cellar for at The present study was carried out using grapes least 12 months. from a single experimental block, and therefore it did not take into account the variability potentially CONCLUSIONS associated with the complex interaction between The present paper characterises aroma and different varieties/clones and the pedoclimatic phenolic compounds of monovarietal red conditions of different sub-regions. These aspects wines included in the Valpolicella appellations. will need to be further investigated. Nevertheless, The main Valpolicella varieties Corvina and the results reported in the present paper provide a Corvinone have a relatively low phenolic content, useful approach to the study of the characteristics but compared to the other varieties they generally of blend-based appellation of origins. As such, in had a higher amount of volatile compounds, such the case of Valpolicella, they indicate that terpenes as terpenes and norisoprenoids. Terpene richness could play an important role in defining the aroma appears to be a common characteristic of most character of Valpolicella wines - this feature being Valpolicella local varieties, as Rondinella and mostly associated with Corvina. Attention should Molinara also exhibited relatively high terpene be paid to the relatively low phenolic content of levels. Vice-versa, wines produced from the the main Valpolicella varieties, especially in terms

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