## 2 Materials and Methods
### Composition of Wines  
The oenological parameters of wines, such as total and volatile acidities, pH, alcohol degree, free and total SO2 and total polyphenolic index were analysed according to OIV methods [12]. Hydroxycinnamic acids and flavonoids were measured using UV absorbance at 320 and 365 nm, respectively [13]. Glories' method was used to determine the chromatic characteristics. This method is based on the determination of the absorbance of wines at 420, 520 and 620 nm. Colour intensity was obtained by calculating the sum of the three absorbances, tonality was determined as the ratio between the absorbance at 420 and 520 nm, and % yellow, % red and % blue colours were the ratio between the absorbance at 420, 520 or 620 nm, respectively, and the sum of the three absorbances [14]. Total proteins were analysed by the colorimetric method described by [PERSON] [15]. The formol titration method was employed for the quantification of free amino nitrogen. Total polysaccharides were evaluated according to phenol-sulfuric acid method [16]. Total tannin and anthocyanin contents were quantified following the methodologies described by [PERSON] [17]. Astringency measurement was carried out using a method based on the precipitation of wine tannins with ovalbumin [18]. All analysis were carried out in triplicate.  
Quantification of Volatile Organic Compounds (VOCs) of Wine by Headspace-Solid-Phase Microextraction-Gas Chromatography-Mass Spectrometry (HS-SPME-GC-MS)  
A CombiPal RSI 120 autosampler (CTC Analytics AG, Zwingen, Switzerland) connected with a 7890A gas chromatograph (Agilent Technologies, Santa Clara, CA, USA) and a 5977 mass selective detector (Agilent Technologies) was used to determine wine VOCs. HS-SPME was carried out for the extraction of wine volatile compounds following the method proposed by [PERSON] et al. [19] with minor modifications. Five mL of wine was transferred into a vial of 20 mL. An amount of 50 mL of methyl nonanoate (0.059 mg/L) as an internal standard and 3 g of sodium chloride (NaCl) were added to each vial. The vials were sealed with a magnetic screw cap provided with a PTFE/silicone septum and incubated at 40 \({}^{\circ}\)C for 15 min with agitation (250 rpm). Then, a 50/30 \(\upmu\)m DVB/CAR/PDMS fibre (Supelco, Inc., Bellefonte, PA, USA), preconditioned at 270 \({}^{\circ}\)C for 15 min before daily use, was exposed to the head space of each vial at 40 \({}^{\circ}\)C for 30 min with agitation (250 rpm). After equilibration, the fibre was injected into the injector of the chromatograph, and 15 min were allowed for the desorption of volatiles. The injector temperature was 250 \({}^{\circ}\)C, working in splitless mode (1 min). The chromatographic separation of the volatiles was performed on a HP-Innowax column (60 m, 0.250 mm, 0.5 \(\upmu\)m) (J & W Scientific, Folsom, CA, USA). The oven temperature program was as follows: 40 \({}^{\circ}\)C held for 5 min, then ramped up to 230 \({}^{\circ}\)C at 2.5 \({}^{\circ}\)C/min and finally held for 20 min. Helium gas at a flow of 1.2 mL/min (pressure of 22.413 psi) was used as carrier gas. The MS detector was operated in full scan mode over a range of m/z of 30-500. Compounds were identified by cross-referencing their mass spectra with pure standards and with spectral data from the NIST08 y Wiley7 libraries. Identification was carried out with only both spectral data libraries when no standards were available [20]. Quantification was carried out using the internal standard quantification method as equivalents [21; 22] of 2-octanol.