Analytica Chimica Acta 563 (2006) 173–179

Influence of winemaking techniques on aroma precursors

M. Esti a,∗, P. Tamborra b,1

a Dipartimento di Scienze e Tecnologie Agroalimentari, Universita degli Studi della Tuscia, via S. Camillo De Lellis, 01100 Viterbo, Italyb CRA Istituto Sperimentale per l’Enologia, SOP Barletta, via Vittorio Veneto, 26-70051 Barletta, Italy

Received 11 August 2005; received in revised form 8 December 2005; accepted 9 December 2005Available online 25 January 2006

Abstract

Nero d’Avola (a red grape) and Fiano (a white grape), traditional not aromatic vines from south Italy, have been subjected to different microvini-fication processes for the purpose of appraising the effects of technology on the aroma precursor composition (both qualitative and quantitative).

The volatile compounds derived from glycosidic precursors of wine odorants have been determined through GC–MS analysis of the extracts,after sample purification followed by enzymatic and acid hydrolysis. The results of the enzymatic and chemical hydrolysis of odorant precursorsfound in the wines produced from Fiano and Nero d’Avola grapes have highlighted the fact that the terpenic, C13-norisoprenoidic, and benzenoidicqualitative compositions of the different wines, after 12 month storage, are very similar to those determined for the grapes. Nero d’Avola is a varietytpgat©

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hat synthesizes only a limited quantity of �-terpineol and of its derivatives. Fiano grapes and wines, on the other hand, showed the remarkableresence of �-terpineol, and its derivatives but the absence of some benzenoids and hydroxycitronellol. Moreover, cold skin maceration of Fianorapes, before settling and alcoholic fermentation, greatly increased the aroma precursors of wines. Only some of the glycosidic precursor ratios,mong all those considered suitable for grape characterization, remained identical in wine compared to those of the corresponding grape, sincehey had not been affected by the winemaking technology adopted.

2005 Elsevier B.V. All rights reserved.

eywords: Glycoconjugate; Monoterpene; C13-norisoprenoid; Benzenoid; Nero d’Avola; Fiano

. Introduction

Grape aroma compounds form a large and complex group ofhemicals that are found in free or glycosidically bound formsn the mesocarp vacuoles and in the pericarp immediately underhe skin of the berry [1,2]. The extraction of these compoundsrom the grape is essentially a diffusion or leaching process, andhe rate and extent of extraction is influenced by the nature of theonstituent, its concentration and localization in the berry, andhe processing methods used (temperature, duration, and dras-icity of maceration, clarification, solubility of the constituent inhe water/alcohol medium, the concentration gradient betweenhe grape ‘solids’ and the wine, and chemical equilibria andeactions in the wine during fining) [3,4]. Odourless precursors,evertheless, undergo enzymatic and chemical hydrolysis dur-ng winemaking and ageing of wine, respectively [5–8]. The

∗ Corresponding author. Tel.: +39 0761 357418; fax: +39 0761 357498.E-mail addresses: esti@unitus.it (M. Esti),

asquale.tamborra@isenologia.it (P. Tamborra).1 Tel.: +39 0883 521346; fax: +39 0883 528955.

released odour-active volatile compounds (reflecting the partic-ular variety, climate, and soil) play a decisive role in the sensorialquality and regional character of wines [9–14]. A number ofstudies have, moreover, demonstrated the key role of flavourlessglycoconjugates of grapes in the characterization and classi-fication of widespread international grape varieties [6,15–19].However, there is a lack of published information about typicalItalian grapes and about the effects of the winemaking processon the glycoconjugate content of red and white wines [20–23]. Inorder to study the effects of technology, particularly of pomacecontact conditions, clarification (white wine) and aging, on thewine odorant precursor composition (both qualitative and quan-titative), Nero d’Avola (red) and Fiano (white) grapes, traditionalnot aromatic vines from south Italy, have been subjected to dif-ferent winemaking processes in small-scale plants.

2. Materials and methods

2.1. Grapes and winemaking procedure

Nero d’Avola (red) and Fiano (white) grapes (Vitis viniferaL.), not aromatic varieties original of south Italy, were obtained

003-2670/$ – see front matter © 2005 Elsevier B.V. All rights reserved.oi:10.1016/j.aca.2005.12.025

174 M. Esti, P. Tamborra / Analytica Chimica Acta 563 (2006) 173–179

from experimental vineyards of the Regional Agency for theDevelopment and Innovation of Lazio Agriculture (ARSIAL)in Velletri (Roma), Lazio region, Italy. The grapes, harvestedmanually at commercial maturity, were processed in the exper-imental wine cellar of the Experimental Institute of Oenology(Velletri) using micro-vinification procedures.

About 750 kg of Nero d’Avola grapes, after harvesting[22◦Brix, pH 3.3, TA 7.2 g L−1], were destemmed/crushed andcollected in two stainless steel tanks (500 L). The two batcheswere added of SO2 (5 g/100 kg), of yeast nutrient (Fermaid,20 g/100 L) and inoculum Lalvin-BM45 (25 g/100 kg) fromLallemand Inc., and allowed to ferment checking the temper-ature (in the cap <32 ◦C). The maceration has been extended for12 days (6 days of alcoholic fermentation and 6 days of heat post-maceration at 35 ◦C). One of two batches has been submitted,during the alcoholic fermentation, to two daily gentle punch-downs of the cap (plunging); the other one has been submittedto one daily delestage (rack and return). Delestage consisted ofletting the cap rise, draining all of the fermenting wine fromthe tank, letting the cap fall, then pumping the liquid back inagain over the pomace. After running-off and pression, the twowines were macro-oxygenated (6 mL L−1 in 3 days), then rackedand inoculated (25 g/100 L) with a commercial strain of Oeno-coccus oeni (Uvaferm alpha from Lallemand Inc.), and placedat 20 ◦C. At the end of malo-lactic fermentation (MLF), eachbatch of two wines was subdivided in two lots of 50 L collectediawctawo

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into two lots of 50 L. To one was added yeast nutrient, and itwas fermented under the same conditions as control wine (M);the other one (MC) was fermented as previously, except for theaddition of middle toasted chips (100 g/100 L) before inoculum.

At the end of alcoholic fermentation the two wines, placed at15 ◦C, were racked with the addition of SO2 (5 g/100 L). Duringthe first two weeks, the yeasts had been suspended in the massthrough daily stirring. The same operation was repeated for twomonths at intervals of two weeks. At the end of fining on lees,the wines were placed for several weeks at −5 ◦C, then racked,filtered, and bottled.

Thus, one obtained three wines from Fiano grapes: control(C), macerated before fermentation (M), macerated before fer-mentation, and fermented in presence of chips (MC).

2.2. Extraction and determination of glycoconjugates

The red and white wines, obtained from Nero d’Avola andFiano grapes, respectively, were analyzed 12 months after har-vesting.

Each sample of wine (50 mL) was diluted four times withwater and 1 mL of internal standard (10 mg L−1 of 1-heptanol in40% ethanol) was added. The wine sample solution was passedthrough a 5 g C18 cartridge (Sep Pack Waters, Ireland) previouslysolvated with 25 mL of methanol and then washed with 50 mLof water. The cartridge was rinsed with 100 mL of pure watertff

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n stainless steel tanks. To one of the two ‘plunging’ lots wasdded middle toasted chips (150 g/100 L) from CRC srl, Italy,hile to one of two ‘delestage’ lots was added (10 g/100 L) of

ondensed tannins (Grap’tan PC from INTEC srl, Italy). Thus,here were obtained four lots of wine: plunging + chips (PC)nd plunging (P), delestage + tannins (DT), delestage (D). Theines were finally stored at 18 ◦C for 6 months in a conditionf micro-oxygenation (1.6 mL/L/month) and then bottled.

About 300 kg of Fiano grapes, after harvesting [22◦Brix, pH.2, TA 7.9 g L−1], were divided into two batches of 100 and00 kg, respectively; these were submitted to different whiteinemaking processes as reported below.For control wine (C), the batch of 100 kg was treated in the

tandard way with gentle direct pressing of grapes in a mem-rane press in the presence of CO2. To the juice were addedO2 (3 g/100 L), silica sol (80 mL/100 L of Baykisol), and gela-

ine (5 g/100 L) and, then it was settled at 7 ◦C for 24 h. Afterlarification, an addition was made to the juice of ammonium sul-hate (5 g/100 L), ammonium phosphate (5 g/100 L), thiamine50 mg/100 L), inoculum (20 g/100 L) of commercial strain ofaccharomyces cerevisiae, Lalvin-BA11 from Lallemand Inc.t was allowed to ferment at 18 ◦C. At the end of fermenta-ion, the wine was racked with addition of SO2 (5 g/100 L), andtored at 12 ◦C in a stainless steel tank with CO2 in the head-pace. Before bottling, the wine was placed for several weeks at5 ◦C, then racked and filtered.For the second batch, 200 kg of grapes was initially

estemmed and crushed, macerated before fermentation (MBF)t 10 ◦C for 10 h, and then gently pressed in a membrane pressn presence of CO2. After clarification under the same condi-ions as for the control wine, the juice was racked and divided

o eliminate acids, sugars, and other polar compounds. The freeraction was eluted with 50 mL of dichloromethane, but thisraction was not analyzed in this work.

The bound fraction was then eluted with 30 mL of methanol.he methanol extract was concentrated to dryness under vacuum

rotavapor) at 40 ◦C. The dried glycosidic extract was dissolvedn 3 mL of citrate–phosphate buffer (pH 5.0), added to 200 mLf enzymatic solution with glycosidasic activities (Citolase FL,enencor), and finally put in oven at 40 ◦C for 24 h.To this mixture was then added 1 mL of internal standard

10 mg L−1 of 1-heptanol in 40% ethanol) and passed throughg C18 cartridge (Sep Pack Waters). After washing with 10 mLf water, the enzymatically liberated aroma compounds wereluted with 10 mL of dichloromethane, dried with anhydrousa2SO4, and concentrated to a final volume of 200 �L under a

tream of nitrogen. After analysis of enzymatic compounds withC–MS, the dichloromethane extract was dissolved in 10 mLf buffer pH 3.2 (5 g L−1 of tartaric acid solution neutralizedor one-third with NaOH), 1 g of NaCl was added, and it waseated in boiling water bath for 1 h. The mixture was then passedhrough 300 mg C18 cartridge (Sep Pack Waters), and afterashing with 10 mL of water, the chemically liberated aroma

ompounds were eluted with 10 mL of dichloromethane, driedith anhydrous Na2SO4, and concentrated to a final volume of00 �L under a stream of nitrogen and analyzed with GC–MS.

.3. Gas chromatography–mass spectrometry (GC–MS)nalysis

Two microliters of extract was injected into a HP-FFAPused silica open tubular column (30 m × 0.25 mm × 0.25 �m)

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175Table 1Compounds (�g L−1 of 1-heptanol)a obtained by enzymatic hydrolysis of glycosilated precursors of Nero d’Avola wines

Grapeb Plunging + chips (PC) Plunging (P) Delestage + tannins (DT) Delestage (D) F Significance

Minimum Maximum Mean ± S.D. Mean ± S.D. Mean ± S.D. Mean ± S.D.

Hexanol 40 110 132.3 ± 20.2 127.6 ± 18.1 120.6 ± 15.2 94.3 ± 28.4 1.29 n.s.cis-3-Hexenol 30 90 n.d. n.d. n.d. n.d. – –trans-2-Hexenol 10 70 n.d. 45.7 ± 11.2 43.1 ± 14.3 n.d. 0.04 n.s.trans-Furan linalool oxide 15 25 87.4 ± 18.3 55.2 ± 23.1 72.1 ± 31.2 49.6 ± 22.5 1.00 n.s.cis-Furan linalool oxide 10 20 150.4 ± 48.9 89.4 ± 39.4 109.9 ± 28.3 66.6 ± 19.6 1.98 n.s.Linalool 0 30 11.2 ± 0.8 10.8 ± 0.9 13.1 ± 1.2 11.4 ± 2.1 1.12 n.s.�-Terpineol 0 10 8.1 ± 0.5 6.8 ± 0.8 9.8 ± 1.4 6.3 ± 2.3 2.40 n.s.trans-Pyran linalool oxide 10 30 81.1 ± 32.3 66.2 ± 28.4 78.1 ± 22.1 43.6 ± 19.9 0.85 n.s.cis-Pyran linalool oxide 10 40 162.8 ± 45.5 123.1 ± 48.7 141.2 ± 51.2 99.3 ± 21.4 0.77 n.s.Methyl salicylate 10 50 47.9 ± 16.6 73.9 ± 22.8 73.5 ± 31.2 62.4 ± 14.2 0.61 n.s.1-Terpinen-4-ol n.d. n.d. n.d. n.d. n.d. – –Nerol n.d. n.d. n.d. n.d. n.d. – –Geraniol 20 30 27.9 ± 4.8 26.3 ± 3.2 35.8 ± 6.3 23.1 ± 4.7 2.45 n.s.2-Hydroxy-1,8-cineole n.d. 6.6 ± 1.0 n.d. n.d. n.d. – –Benzyl alcohol 600 1100 1019.9 ± 72.4 1034.9 ± 56.3 1167.5 ± 110.2 925.1 ± 87.3 2.82 n.s.2-Phenyl ethanol 200 400 745.5 ± 58.5 880.4 ± 97.5 786.4 ± 88.5 641.7 ± 78.9 2.90 n.s.2,6-Dimethyl-3,7-octadien-2,6-diol 0 60 89.2 ± 31.0 n.d. n.d. n.d. – –2,6-Dimethyl-7-octen-2,6-diol n.d. n.d. n.d. n.d. n.d. – –Terpine 1 n.d. n.d. n.d. n.d. n.d. – –3,7-Dimethyl-1,7-octadien-3,6-diol n.d. n.d. n.d. n.d. n.d. – –Eugenol n.d. 85.2 ± 24.0 46.7 ± 18.9 43.6 ± 17.4 34.8 ± 18.3 2.54 n.s.4-Vinylguaiacol n.d. 337.2 ± 105.9 278.3 ± 169.0 303.1 ± 175.0 173.2 ± 58.3 0.54 n.s.Hydroxycitronellol n.d. 86.7 ± 22.0 105.8 ± 31.4 67.3 ± 25.8 28.4 ± 12.9 3.80 n.s.8-Hydroxydihydrolinalool n.d. 23.9 ± 6.7 30.1 ± 10.3 25.5 ± 8.9 39.9 ± 15.4 0.89 n.s.trans-8-Hydroxy-linalool 20 90 160.9 ± 33.5 156.5 ± 36.6 160.9 ± 31.0 109.8 ± 37.9 1.02 n.s.cis-8-Hydroxy-linalool 100 300 583.4 ± 134.9 500.2 ± 78.9 529.9 ± 144.5 378.8 ± 88.9 1.13 n.s.Geranic acid 0 20 73.2 ± 23.7 67.1 ± 18.4 64.7 ± 15.8 50.4 ± 12.5 0.57 n.s.Isoeugenol 0 20 70.1 ± 22.1 108.5 ± 43.0 96.5 ± 26.5 58.1 ± 23.5 1.20 n.s.p-Menth-1-ene-6,8-diol n.d. n.d. n.d. n.d. n.d. – –4-Vinylphenol 60 700 2950.1 ± 329.8 b 2652.2 ± 147.9 b 1142.3 ± 120.4 a 1171.2 ± 155.6 a 43.28 **

p-Menth-1-ene-7,8-diol n.d. n.d. n.d. n.d. n.d. – –3-Hydroxy-�-damascone 60 260 39.3 ± 18.9 a 189.9 ± 28.9 bc 204.3 ± 35.7 c 116.7 ± 35.9 ab 12.27 *

Vanillin 0 35 n.d. n.d. 19.1 ± 4.5 n.d. – –Methyl vanillate 0 100 n.d. 31.6 ± 8.4 n.d. 22.8 ± 8.7 1.06 n.s.3-Oxo-�-ionol 300 1800 1216.7 ± 230.9 1298.7±221.8 1598.6 ± 241.5 847.9 ± 189.0 3.88 n.s.Acetovanillone 0 100 40.7±18.9 60.2 ± 20.8 69.1 ± 20.3 28.6 ± 7.0 2.16 n.s.3,9-Dihydroxy-megastigma-5 ene 0 70 9.4 ± 0.7 a 72.2 ± 20.7 b 65.5 ± 18.9 b 23.1 ± 6.3 a 9.31 *

Zingerone 40 120 n.d. n.d. 35.6 ± 8.9 18.6 ± 7.9 4.08 n.s.3-Hydroxy-�-ionone 27 110 79.9±29.8 150.6 ± 45.0 189.6 ± 55.9 103.6 ± 43.2 2.42 n.s.Homovanillic alcohol 0 30 n.d. n.d. n.d. n.d. – –Syringaldehyde n.d. n.d. n.d. n.d. n.d. – –Methyl syringate 0 300 n.d. 135.9 ± 37.8 n.d. 314.9 ± 58.9 13.08 *

Dihydroconiferyl alcohol 50 900 424.9 ± 170.5 1081.1 ± 302.7 883.5 ± 289.7 303.9 ± 278.6 3.86 n.s.Vomifoliol 800 3500 1130.8 ± 380.5 1883.2 ± 503.8 2089.9 ± 407.9 1032.3 ± 309.7 3.41 n.s.

Duncan’s test p = 0.05 (within the rows, means followed by the same letters (a–d) are not significantly different). n.d.: not detected; n.s.: not significant.a Mean ± S.D. of two replications of the same sample.b The results derived from current works not yet published.* ANOVA, p ≤ 0.05.

** ANOVA, p ≤ 0.01.

176 M. Esti, P. Tamborra / Analytica Chimica Acta 563 (2006) 173–179

Table 2Compounds (�g L−1of 1-heptanol)a obtained by chemical hydrolysis of glycosilated precursors of Nero d’Avola wines

Plunging + chips (PC) Plunging (P) Delestage + tannins (DT) Delestage (D) F Significance

Mean ± S.D. Mean ± S.D. Mean ± S.D. Mean ± S.D.

trans-Furan linalool oxide 202.4 ± 48.9 146.4 ± 35.8 157.7±34.6 79.5 ± 41.2 3.14 n.s.cis-Furan linalool oxide 249.7 ± 79.8 150.7 ± 48.7 208.3 ± 65.4 133.6 ± 48.5 1.48Riesling acetale 60.3 ± 28.3 12.9 ± 8.7 30.9 ± 22.1 22.2 ± 7.8 2.36 n.s.Actinidol 1 173.1 ± 66.8 ab 102.2 ± 29.4 a 273.9 ± 87.6 b 52.1 ± 15.3 a 5.59 *

Actinidol 2 238.1 ± 97.2 ab 152.2 ± 47.8 a 387.4 ± 105.6 b 82.7 ± 32.4 a 5.76 *

1,1,6-Trimethyl-1,2dihydronaphthalene(TDN)

n.d. n.d. n.d. n.d. – –

�-Damascenone n.d. n.d. n.d. n.d. – –

Duncan’s test p = 0.05 (within the rows, means followed by the same letters (a and b) are not significantly different). n.d.: not detected; n.s.: not significant.a Mean ± S.D. of two replications of the same sample.* ANOVA, p ≤ 0.05.

(Hewlett-Packard, Palo Alto, CA) with a splitless system for1 min. GC–MS analysis was carried out using a 5890 gaschromatograph interfaced with 5972 mass selective detector(Hewlett-Packard). The carrier gas was ultra pure helium witha flow rate of 1 mL min−1 and the pressure was set at 7.5 kPa.The transfer line and injector temperatures were both 250 ◦C.Oven temperature was programmed at 30 ◦C for 2 min, from 30to 60 ◦C at a rate of 30 ◦C min−1, from 60 to 190 ◦C at a rate of2 ◦C min−1, and then held to 230 ◦C at a rate of 3.5 ◦C min−1

for 15 min.All mass spectra were recorded at an ion source tempera-

ture of 160 ◦C, an ionizing energy of 70 eV, and scan rangeof 34–250 amu at a rate of 2 scan s−1. The identificationof compounds was performed using an NKS 75 K libraryand confirmed with the retention data of available authen-tic compounds. Moreover, some compounds were identifiedby their retention index or mass spectra reported in litera-ture. The concentration was calculated as 1-heptanol (internalstandard).

2.4. Statistical analysis

All the samples have been analyzed in duplicate and the sta-tistical significance of the results has been calculated throughanalysis of the monofactorial variance (ANOVA).

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ones (homovanillic alcohol, and syringaldehyde). In particular,there was a small amount of �-terpineol but the absence ofits oxygenated derivatives: the p-menth-1-ene-6,8-diol, the p-menth-1-ene-7,8-diol, the 2-hydroxy-1,8-cineol, and the terpin.This is probably attributable to the absence or limited activity ofthe enzymes that convert open-ended terpenol (nerylpyrophos-phate) to the cyclic structure of the �-terpineol and/or to theabsence or limited activity of the allyl-hydroxylating enzymesthat produce its oxygenated derivatives. Among the aglyconsof acid hydrolysate from Nero d’Avola wines (Table 2), it isimportant to note the absence of TDN and �-damascenone,considering their sensory significance for bottle-agedwines.

The different red winemaking processes did not significantlyor consistently affect the levels of glycosidic forms of monoter-penes, C13-norisoprenoids, and shikimate-derived compounds(Tables 1 and 2). Also it is worth noting that plunging which is,in this experiment, a more extractive technique as confirmed bywine phenol content (data not reported), did not produce wineswith a higher content of glycoconjugates compared to the dailydelestage.

Fiano wines, just as for the berries, showed (Table 3) theremarkable presence, as enzymatically generated products, of�-terpineol, and its derivatives. On the other hand, hydroxyc-itronellol, and several shikimate derivatives (vanillin, methylvanillate, zingerone, homovanillic alcohol, syringaldehyde, andmTytmlaa�w

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. Results and discussion

The results of GC–MS analysis of aglicons, that were liber-ted in the enzymatic and acid hydrolysates from glycosidicxtracts of Nero d’Avola and Fiano wines, are reported inables 1–4. Forty-four and seven aglycons are detected anduantified in the enzymatic and acid hydrolysates, respectively.he wines produced from Fiano and Nero d’Avola grapes, after2 month storage, showed a qualitative glycoconjugates com-osition that was very similar to those determined for the grapesf the same cultivar, even if produced in other regions of southtaly.

Table 1 shows that, as in the berries, the Nero d’Avola winesack some cyclic terpene compounds and shikimate pathway

ethyl syringate), were not found, as they had been for grapes.he concentration of aglycons, liberated by enzymatic hydrol-sis, was much higher in the Fiano wines which had undergonehe skin maceration (at 10 ◦C) before settling and alcoholic fer-

entation (Table 3). This selective extraction technique has alsoed to the presence in the wines of acid generated free forms ofctinidol 1 and 2 (Table 4). However, among the aglycons ofll Fiano acid hydrolysates, it is worthy to note the absence of-damascenone, riesling acetale, and TDN (present only in MCine) (Table 4).Seven glycosidic precursor ratios (enzymatic liberated forms)

f Nero d’Avola and Fiano grapes and wines are reported inables 5 and 6. Among all the ratios considered (Table 5),nly the trans-furan linalool oxide versus cis-furan linalool

M. Esti, P. Tamborra / Analytica Chimica Acta 563 (2006) 173–179 177

Table 3Compounds (�g L−1of 1-heptanol)a obtained by enzymatic hydrolysis of glycosilated precursors of Fiano wines

Grapeb Control (C) Macerated + chips (MC) Macerated (M) F Significance

Minimum Maximum Mean ± S.D. Mean ± S.D. Mean ± S.D.

Hexanol 10 80 18.7 ± 2.2 a 25.6 ± 3.9 a 39.2 ± 5.2 b 13.9 *

cis-3-Hexenol 3 40 n.d. n.d. n.d. – –trans-2-Hexenol 0 20 n.d. n.d. n.d. – –trans-Furan linalool oxide 20 130 37.6 ± 5.4 a 80.5 ± 8.5 b 89.7 ± 8.5 b 26.7 *

cis-Furan linalool oxide 10 80 30.7 ± 4.9 a 62.6 ± 7.4 b 67.3 ± 6.4 b 19.9 *

Linalool 40 360 7.1 ± 0.8 a 59.3 ± 12.9 b 66.7 ± 13.1 b 18.7 *

�-Terpineol 30 220 22.6 ± 2.5 a 89.3 ± 12.6 b 87.7 ± 15.2 b 21.9 *

trans-Pyran linalool oxide 10 100 36.6 ± 5.3 71.7 ± 15.2 65.4 ± 10.4 5.7 n.s.cis-Pyran linalool oxide 10 80 26.3 ± 3.5 a 47.7 ± 6.5 b 55.8 ± 6.9 b 13.7 *

Methyl salicylate 30 250 66.2 ± 11.6 81.7 ± 14.7 88.1 ± 14.7 1.3 n.s.1-Terpinen-4-ol n.d. n.d. 31.0 ± 1.4 n.d. – –Nerol 4 30 6.4 ± 1.0 a 15.1 ± 3.1 b 11.1 ± 1.9 ab 8.0 *

Geraniol 10 70 8.4 ± 4.8 a 22.7 ± 3.9 b 22.1 ± 2.8 b 8.5 *

2-Hydroxy-1,8-cineole 10 60 18.4 ± 2.2 a 42.2 ± 5.3 b 45.2 ± 4.8 b 23.1 *

Benzyl alcohol 400 1500 201.8 ± 22.4 a 281.4 ± 20.9 b 323.5 ± 28.9 b 12.9 *

2-Phenyl ethanol 90 800 138.7 ± 18.5 a 194.1 ± 15.8 b 210.4 ± 17.6 b 9.4 *

2,6-Dimethyl-3,7-octadien-2,6-diol 10 130 36.7 ± 4.5 a 65.8 ± 8.8 b 81.4 ± 9.3 b 16.8 *

2,6-Dimethyl-7-octen-2,6-diol 0 10 9.2 ± 2.1 17.6 ± 4.1 29.5 ± 8.1 7.2 n.s.Terpine 1 5 50 9.5 ± 1.4 17.7 ± 3.4 21.7 ± 4.4 7.1 n.s.3,7-Dimethyl-1,7-octadien-3,6-diol 0 30 5.6 ± 0.9 a 21.5 ± 3.7 b 19.9 ± 2.3 b 23.2 *

Eugenol 0 20 9.7 ± 2.0 15.2 ± 3.1 23.1 ± 5.2 6.7 *

4-Vinylguaiacol n.d. 67.9 ± 10.9 a 70.9 ± 7.8 a 112.7 ± 16.3 b 8.5 *

Hydroxycitronellol n.d. n.d. n.d. n.d. – –8-Hydroxydihydrolinalool 10 50 32.2 ± 3.7 a 57.1 ± 6.7 b 69.1 ± 6.8 b 20.3 *

trans-8-Hydroxy-linalool 20 160 51.8 ± 7.5 a 126.9 ± 14.6 b 132.6 ± 15.8 b 23.5 *

cis-8-Hydroxy-linalool 30 330 103.4 ± 14.9 a 213.7 ± 25.0 b 224.7 ± 29.0 b 16.0 *

Geranic acid 10 70 29.3 ± 5.7 52.8 ± 7.7 54.4 ± 7.9 7.7 n.s.Isoeugenol 0 50 11.8 ± 2.1 a 22.9 ± 3.5 b 23.4 ± 2.5 b 11.3 *

p-Menth-1-ene-6,8-diol 3 40 13.8 ± 2.4 a 28.6 ± 4.4 b 24.1 ± 3.2 ab 9.8 *

4-Vinylphenol 10 40 20.9 ± 3.8 ab 12.2 ± 2.1 a 27.2 ± 4.1 b 9.6 *

p-Menth-1-ene-7,8-diol 40 320 113.9 ± 19.7 a 213.2 ± 23.5 b 230.7 ± 21.0 b 17.2 *

3-Hydroxy-�-damascone 20 200 74.8 ± 8.9 a 133.2 ± 19.4 b 141.2 ± 18.4 b 9.9 *

Vanillin n.d. n.d. n.d. n.d. – –Methyl vanillate n.d. n.d. n.d. n.d. – –3-Oxo-�-ionol 60 500 104.9 ± 18.9 a 271.2 ± 29.2 b 257.6 ± 27.9 b 25.7 *

Acetovanillone 0 80 9.9 ± 1.1 15.7 ± 2.1 15.8 ± 1.9 7.4 n.s.3,9-Dihydroxy-megastigma-5 ene 10 90 9.6 ± 0.7 a 22.9 ± 1.7 b 28.9 ± 2.3 c 67.5 **

Zingerone 0 50 n.d. n.d. n.d. – –3-Hydroxy-�-ionone 15 160 31.6 ± 4.8 a 91.9 ± 8.8 b 86.3 ± 9.4 b 35.3 **

Homovanillic alcohol n.d. n.d. n.d. n.d. – –Syringaldehyde n.d. n.d. n.d. n.d. – –Methyl syringate n.d. n.d. n.d. n.d. – –Dihydroconiferyl alcohol 20 300 141.2 ± 17.5 143.9 ± 15.3 120.8 ± 11.2 1.4 n.s.Vomifoliol 300 3000 100.7 ± 18.5 a 251.5 ± 30.5 b 229.1 ± 29.3 b 18.6 *

Duncan’s test p = 0.05 (within the rows, means followed by the same letters (a–c) are not significantly different). n.d.: not detected; n.s.: not significant.a Mean ± S.D. of two replications of the same sample.b The results derived from current works not yet published.* ANOVA, p ≤ 0.05.

** ANOVA, p ≤ 0.01.

oxide ratio, which was determined in Nero d’Avola grapesto be >1, turned out to be different in the wines (<1).In Fiano wines, on the contrary, the two ratios involvinglinalool, geraniol, and �-terpineol were all different fromthose of the grapes. These ratios are less important in whitewines because of the limited solubilization of glycoconjugatesfrom skins and/or because of their different hydrolysis ratein wine.

Thus, among the seven precursor ratios considered suitablefor grape characterization [23,24], four ratios (bold charactersin Tables 5 and 6) were found to be identical in both wine andcorresponding grape. Such ratios, on the basis of these experi-mental results, can be considered as not being affected by thewinemaking (red or white) technology adopted and, therefore,useful parameters not only for the grape characterization but alsofor the ascertainment of the respective wines’ varietal profile.

178 M. Esti, P. Tamborra / Analytica Chimica Acta 563 (2006) 173–179

Table 4Compounds (�g L−1 of 1-heptanol)a obtained by chemical hydrolysis of glycosilated precursors of Fiano wines

Control (C) Macerated + chips (MC) Macerated (M) F Significance

Mean ± S.D. Mean ± S.D. Mean ± S.D.

trans-Furan linalool oxide 81.9 ± 21.3 144.8 ± 43.7 160.1 ± 39.1 2.65 n.s.cis-Furan linalool oxide 76.1 ± 16.0 115.2 ± 22.9 132.7 ± 33.2 2.68 n.s.Riesling acetale n.d. 9.3 ± 4.1 n.d. – –Actinidol 1 n.d. 32.7 ± 12.2 37.1 ± 12.9 1.70 n.s.Actinidol 2 n.d. 53.1 ± 16.5 58.7 ± 14.7 0.13 n.s.1,1,6-Trimethyl-1,2dihydronaphthalene (TDN) n.d. 3.1 ± 1.0 n.d. – –�-Damascenone n.d. n.d. n.d. – –

Duncan’s test p = 0.05. n.d.: not detected; n.s.: not significant.a Mean ± S.D. of two replications of the same sample.

Table 5Ratios between some free forms of glycoconjugates from the enzymatic hydrolysates of Nero d’Avola wines

Grapea Plunging + chips (PC) Plunging (P) Delestage + tannins (DT) Delestage (D)

trans-Furan linalool oxide/cis-furan linalool oxide 1.3 0.6 0.6 0.7 0.7trans-Pyran linalool oxide/cis-pyran linalool oxide 0.8 0.5 0.5 0.6 0.4trans-8-Hydroxy-linalool/cis-8-hydroxy-linalool 0.3 0.3 0.3 0.3 0.3Linalool/geraniol 0.6 0.4 0.4 0.4 0.5Linalool/�-terpineol 3.0 1.4 1.6 1.3 1.8trans + cis-8-hydroxy-linalool/p-menth-1-ene-7,8-diol �1 �1 �1 �1 �13-Hydroxy-�-damascone/3-oxo-�-ionol 0.2 0.1 0.1 0.1 0.1

a Data derived from the means of results not yet published.

Table 6Ratios between some free forms of glycoconjugates from the enzymatic hydrolysates of Fiano wines

Grapea Control (C) Macerated + chips (MC) Macerated (M)

trans-Furan linalool oxide/cis-furan linalool oxide 1.7 1.2 1.3 1.3trans-Pyran linalool oxide/cis-pyran linalool oxide 1.2 1.4 1.5 1.2trans-8-Hydroxy-linalool/cis-8-hydroxy-linalool 0.5 0.5 0.6 0.6Linalool/geraniol 1.6 0.8 2.6 3.0Linalool/�-terpineol 1.6 0.3 0.7 0.8trans + cis-8-hydroxy-linalool/p-menth-1-ene-7,8-diol 1.5 1.4 1.6 1.53-Hydroxy-�-damascone/3-oxo-�-ionol 0.4 0.7 0.5 0.5

a Data derived from the means of results not yet published.

4. Conclusions

The work confirms the importance of analyzing the flavourprecursors of grapes and wines in order to determine varietalprofiles and differences.

The results of analyzing both the enzymatic and chemical lib-erated forms of the glycoconjugates found in wines, producedfrom Fiano and Nero d’Avola grapes, have highlighted the factthat the terpenic, C13-norisoprenoidic, and benzenoidic qualita-tive compositions of the different wines, after 12 month storage,are similar to those determined for the grapes. Moreover, theskin maceration of Fiano grapes at 10 ◦C, before settling andalcoholic fermentation, greatly increased the odorant precursorsin the resulting wines. On the other hand, for Nero d’Avolared wines the frequency and intensity of maceration proce-dures, performed during and after alcoholic fermentation, didnot significantly affect the concentration of glyconjugates. Inconclusion, only some of the precursor ratios considered suit-able for grape characterization were shown to be identical both

in grape and wine. Such parameters can, thus, be considerednot affected by the winemaking (red or white) technology and,therefore, are useful parameters not only for the grape charac-terization but also for the ascertainment of the respective wines’varietal profile.

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