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Journal of Food Composition and Analysis 19 (2006) 694–697

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Original Article

Determination of free and bound terpene compounds in Albarino wine

M. Vilanovaa,�, C. Sieirob

aMision Biologica de Galicia (CSIC), Apdo. de Correos 28, 38080, Pontevedra, SpainbArea de Microbiologıa. Facultad de Biologıa. As Lagoas, Marcosende. Universidad de Vigo, Spain

Received 21 November 2004; received in revised form 25 July 2005; accepted 19 October 2005

Abstract

Aroma compounds were analyzed in Albarino wines of 1999 vintage produced from musts collected at three different vineyards in Val

do Salnes (Denomination of Origin Rıas Baixas—Spain). Free and bound terpenes were quantified by GC with FID. The wines studied

contained a higher concentration of terpenes in free form than in bound form. However, significant differences were found only for

linalool in free form and terpineol in bound form among the wines. To determine the contribution of aroma series in Albarino wines, the

odour activity value (OAV) was calculated for each wine, and balsamic and floral series presented the greatest contribution. Significant

differences were found for all aroma series of compounds (balsamic, floral, fruity, rose-like and sweet) among the Albarino wines

analyzed.

r 2005 Elsevier Inc. All rights reserved.

Keywords: Albarino; Aromatic compounds; OAV; Aroma series; Terpene; Wine

1. Introduction

The aroma of a wine depends on its content of volatilecompounds, over 680 of which have been identified inwines from some white grape varieties (Maarse andVisscher, 1994; Peinado et al., 2004). Quality wines havedifferent flavour properties, which depend on varietalcharacteristics. This typical flavour proceeds from thegrape and is found in free volatile form or in bound form,usually glycoside (Williams et al., 1982). These compoundscontribute to the final aroma of a wine which depends onthe correlation between chemical composition and percep-tion thresholds, because most of the volatile compoundsare present at concentrations just under their individualsensory thresholds (Falque et al., 2001).

Terpenes, because of their high concentrations and lowaroma thresholds, are the principal components respon-sible for the characteristic aroma of a wine (Carballeiraet al., 2001). They are mainly derived from the grape,synthesized during maturation, and qualitatively andquantitatively influenced by the cultivar, soil, climate and

e front matter r 2005 Elsevier Inc. All rights reserved.

a.2005.10.002

ing author. Tel.: +34986 85480.

ess: mvilanova@mbg.cesga.es (M. Vilanova).

viticultural practices, strongly influencing the aromaticcomposition of wine (Belancic et al., 1997; Bertrand andAnocibar-Beloqui, 1996).Albarino, of Vitis vinifera L. grape variety, is a typical

white wine from Galicia, a northwest region of Spainsituated mainly on the Atlantic Ocean. This grape variety iscultivated over an estimated area of o5000 ha (Lopez-Tamames et al., 1997), and is used in the production ofwines of recognized high quality (Denomination of Origin).The Albarino variety is characterized by a high intensity offloral descriptors, free monoterpenes being responsible forthese floral notes (Carballeira et al., 2001). Young whitewines elaborated with Albarino grapes from Galiciacontain high concentrations of terpenes and are dominatedby fruity and floral odours (Carballeira et al., 2001;(Falque et al., 2001).Ribereau-Gayon et al. (1998) compared Albarino

wine to Riesling, Muscadelle and Sauvignon wines andshowed that Albarino wine was the richest in terpenecompounds.The aim of the present study was to determine if

differences exist among monovarietal Albarino wines of1999 vintage from different vineyards in the Denomina-tion of Origin Rıas Baixas and to establish the aroma

ARTICLE IN PRESSM. Vilanova, C. Sieiro / Journal of Food Composition and Analysis 19 (2006) 694–697 695

series of young white wines elaborated from the Albarinovariety.

2. Materials and methods

2.1. Grape juice

Musts from V. vinifera cv Albarino were collected fromthree different vineyards in Val do Salnes (Denominationof Origin Rıas Baixas). The characteristics of the grapejuices are shown in Table 1. The musts were transported tothe laboratory refrigerated at 8 1C and were supplementedwith 50mg/L SO2.

The following measurements were made to the musts,according to EU methods for the analysis of wines (EEC,1990): pH (measured with a pH meter), and reducingsugar content (by determination of glucose and fructoseusing an enzymatic method). Determinations were made intriplicate.

2.2. Fermentation

Spontaneous fermentations were performed in 16L glassvessels containing 10L of cv. Albarino grape juice at 18 1Cfor 15 days. The sugar content was measured daily. At theend of fermentation the musts were centrifuged andsulphur dioxide (50mg/L) was added. Fermentations ofthe different wines were carried out in triplicate.

2.3. Analysis of free and bound terpene compounds

Wines were analyzed 3 months after completion ofprimary fermentation. Free and bound terpenes werefractionated by selective retention on SepPak Vac C-18,according to the procedure described by Di Stefano (1991),with some modifications (Cortes, 1997). The free fractionwas eluted with pentane dichloromethane (2:1, 10mL) andthe eluate was dried over anhydrous sodium sulphate andconcentrated to 0.5mL, by evaporation with a stream ofnitrogen, before GC analysis.

The bound fraction was eluted with methanol (10mL)and concentrated to dryness in vacuo before dissolution incitrate-phosphate buffer (pH 5.0, 5mL). AR-2000 (Gist

Table 1

Characteristics of Albarino wine juice

Parameters Albarino must

ALB1 ALB2 ALB3 Sig.

Sugars (g/L) 19771.00a 19070.00b 18471.00c ***

pH 3.570.10a 3.470.00a 3.270.00b *

The data are mean values of triplicates7S.D.

Sig.: significance at which means differ as shown by analysis of variance: *,

*** denote significance at Po0:05 and Po0:001, respectively.The value of line with the same superindexed letter indicates that there are

no significant differences between them (Po0:05).

Brocades, France) was added and the mixture wasincubated at 40 1C for 18 h to accomplish enzymatichydrolysis. Glycoside hydrolysates were extracted withpentane dichloromethane (2:1, 10mL), internal standart(1mL of 3-octanol, 10mg/L) was added, and the extractwas concentrated, by evaporation with a stream ofnitrogen, before GC analysis.Gas chromatographic analysis of extracts of the free

and bound compounds was performed with a Hewlett-Packard 5890 Serie II chromatograph equipped with flameionization detection. Compounds were separated on a50m� 0.25mm i.d. fused-silica capillary column coatedwith a 0.20 mm film of Chrompack CP-Wax57CB.Conditions used for chromatographic analysis were:

injector temperature (250 1C), temperature program (60 1Cfor 5min, increased to 200 1C), detector temperature(260 1C), injection type (Splitless, 30 s) and injection size(1 mL).Qualitative and quantitative analyses of the compounds

in the wines samples analyzed were made by comparison oftheir retention times with those of the standards: a-pinene(7.11min); b-pinene (9.25min); limonene (12.25min; lina-lool (27.33min); terpinen-4-ol (29.85min); a-terpineol(33.55min); citronellol (35.90min); Nelol (37.14min);geraniol (38.77min) and eugenol (48.80min).To evaluate the contribution of a chemical to the aroma

of a wine the odour activity value (OAV) was calculated asthe ratio between the concentration of compound and theperception threshold found in the literature (Chatonnetet al., 1992; (Falque et al., 2001; Cortes et al., 2003;Peinado et al., 2004). Each free compound was assigned toone or several aroma series; this procedure allows one torelate quantitative information derived by chemical analy-sis to sensory perceptions (Peinado et al., 2004).

2.4. Statistical analyses

Differences among the wines with respect to thevariables were assessed by one-way analysis of variance(ANOVA). These analyses were accomplished using theEnterprise Guide 3 System Software (SAS Institute, Cary,NC, USA).

3. Results and discussion

The general composition of the musts is shown inTable 1. Significant differences among the musts wereobserved for reducing sugar content and pH, which may beattributed to climatic variations.Table 2 shows the free and bound terpenes of Albarino

wines, expressed as means (mg/L), for the three fermenta-tions. Free terpenes, the compounds showing the highestvalues in the analyses of volatiles, were identified in threeAlbarino wines by GC. Linalool is one of the mostimportant monoterpene, being present at levels higher thanits perception threshold (50 mg/L) (Etievant, 1991). In thisstudy, the level of linalool in free form was higher than that

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Table 2

Determination of free and bound terpenes (mg/L) in Albarino wines

Compound Albarino wines

ALB1 ALB2 ALB3

Free terpenes

a-Pinene 105.88716.67 85.7675.45 85.3875.22

b-Pinene 15.4077.47 13.1773.71 11.8270.63

Limonene 17.9070.95 19.5671.50 19.1570.83

Linalool* 28.2877.34 18.4671.78 17.2271.20

Terpinen-4-ol 28.57711.06 19.9572.54 22.2471.64

a-Terpineol 8.9172.17 9.7673.29 8.3971.45

Citronellol 9.4173.25 6.8670.38 7.2471.72

Nerol 4.4071.53 5.5770.86 5.3772.09

Geraniol 53.40711.43 55.92710.23 60.3570.94

Eugenol 28.13719.24 12.0277.17 11.3471.89

Bound terpenes

a-Pinene 152.71743.45 185.4478.45 176.60723.72

b-Pinene n.d. n.d. n.d.

Limonene 21.9274.83 21.0471.43 20.5372.76

Linalool 17.7975.69 10.5173.10 11.3672.06

Terpinen-4-ol 8.7571.70 5.0372.74 5.0671.73

a-Terpineol* 26.46720.10 9.0077.67 16.29712.35

Citronellol 6.2771.15 5.0771.88 5.9973.51

Nerol 20.7073.04 16.8176.51 11.2873.99

Geraniol 56.06711.49 57.76710.55 61.7871.19

Eugenol 21.6371.2 23.2070.91 21.5370.83

Concentrations are reported in mg/L. The data are mean values of

triplicates7S.D.

*Significantly different (Po0:05). n.d. not detected.

Table 3

Odour activity values (OAVs) for the free terpene compounds in Albarino

wines

Compound Aroma

series

ALB1 Albarino wines

ALB2 ALB3

a-Pinene 3 1.05970.16 0.8570.05 0.8570.05

b-Pinene 3 0.11070.05 0.09470.02 0.08470.00

Limonene 1 0.08570.00 0.09370.00 0.09170.00

Linalool 1,2,4,5 1.88670.48 1.23170.11 1.14870.08

Terpinen-4-ol 2 0.57170.22 0.39970.05 0.44570.03

a-Terpineol 2,4 0.02270.00 0.02470.00 0.02170.00

Citronellol 1 0.52370.18 0.38170.02 0.40270.09

Nerol 1,2,5 0.01170.00 0.01470.00 0.01370.00

Geraniol 2,5 0.41170.08 0.43070.07 0.46470.00

Eugenol 3 4.68873.20 3.00471.19 1.89170.31

Aroma series: 1. fruity, 2. floral, 3. balsamic, 4. sweet and 5. rose-like.

The data are mean values of triplicates7S.D.

M. Vilanova, C. Sieiro / Journal of Food Composition and Analysis 19 (2006) 694–697696

in bound form and it was the only compound to showsignificant differences (Po0:05) among the wines. Albarinowines have showed others low aroma threshold mono-terpenes, citronellol and geraniol, in both forms in the threewines analyzed. The concentrations of citronellol andgeraniol, citrus and flowery aroma, respectively, weresimilar for both the free and bound forms in all wines(Table 2). Geraniol levels were always higher than those ofnerol, the ratio of geraniol to nerol being 43, as reportedby Carballeira et al. (2001).

Carballeira et al. (2001) and Falque et al. (2001) foundthat wines made from Albarino grapes of Galicia containhigh concentrations of terpenes and have fruity and floralodours.

The bound compounds, monoterpenes, do not contri-bute directly to the aroma, but are a reservoir of odourlessprecursors of flavour. Enzymatic or acid hydrolysis releasesthe free forms and increases the aroma (Cabaroglu et al.,2002; Strauss et al., 1986). The levels of bound terpenes inthe Albarino wines analyzed were similar for the threewines (Table 2). However, only a-terpineol showedsignificant differences (Po0:05) among the wines. None-theless, it would be necessary to characterize thesecompounds during storage of the wines, because possiblyglycosidic forms do exist or could exist. One compound(b-pinene) was not detected in bound form.

One way to quantify the odour activity of a compound isto determine the number of its olfactory units (NOU);another is the so-called aroma value or OAV. This value iscalculated by dividing the concentration of the compoundin the wine into its perception threshold (Cabaroglu et al.,2002; Falque et al., 2001). The odour impact of a substanceincreases in proportion to its OAV when this value is 41.Table 3 shows the OAV for each compound. Only linalool(flowery odour) and eugenol (balsamic odour) had OAVsexceeding unity in all Albarino wines, whereas a-pinene(balsamic odour) exceeded unity only in the ALB1 wine.Based on these criteria, the above-mentioned compoundscan be assumed to be those with the strongest odourimpact, thereby contributing to a great extent to the aromaof Albarino wines. However, the contribution to the aromaof compounds with near-unity OAVs cannot be ignored,because they can enhance some existing notes by synergywith other compounds (Freitas et al., 1999; Lopez et al.,1999).Each free compound was assigned to one or several

aroma series, according to the principal odour descriptorsfound in the literature (Etievant, 1991; Ferreira et al., 2001;Peinado et al., 2004): fruity, floral, balsamic, sweet androse-like series (Table 3). Grouping the aroma compoundswith similar descriptors into aroma series gives anorganoleptic profile of the wine. The OAVs for eachindividual compound in the aroma series were combined toobtain a global OAV for each series (Fig. 1). The resultsshown that the balsamic series, followed by the floral series,had the highest contribution to the overall aroma of thewine. This high intensity of floral descriptors was alsoobserved by Carballeira et al. (2001), who showed that freemonoterpenes were responsible for these floral notes.The results were subjected to an analysis of variance to

identify significant differences between Albarino wines.Significant differences (Po0:001) were found for all aromaseries of compounds (balsamic, floral, fruity, rose-like and

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0

1

2

3

4

5

6

7

Fruity Floral Balsamic Sweet Rose-likeAroma serie

OA

V

ALB1 ALB2 ALB3

Fig. 1. Odour activity values (OAV) of aroma series in Albarino wines.

M. Vilanova, C. Sieiro / Journal of Food Composition and Analysis 19 (2006) 694–697 697

sweet) among the Albarino wines analyzed. The AlbarinoALB1 showed the highest OAV in the all aroma series.

4. Conclusions

Some aromatic compounds were identified in differentAlbarino wines of 1999 vintage elaborated with grapesgrown in different vineyards in Val do Salnes (Denomina-tion of Origin Rıas Baixas). Free terpenes were thecompounds that showed the highest values in the analysesof volatiles among the wines analyzed. Significant differ-ences were found in the levels of linalool in free form anda-terpineol in bound form. The levels of the free and boundforms of the other terpene compounds were similar in theAlbarino wines analyzed. Only linalool and eugenol hadOAVs exceeding unity in all Albarino wines, whereasa-pinene exceeded unity only in the ALB1 wine; thosecompounds can be assumed to have the strongest odourimpact on the aroma of Albarino wines. Significantdifferences were found in all aroma series among theAlbarino wines, with the contribution of the balsamic andfloral series being the greatest.

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