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Effect of skin contact on the free and bound aroma compounds of the white wine of Vitis vinifera L. cv Narince
Food Control 17 (2006) 75–82 www.elsevier.com/locate/foodcont
Effect of skin contact on the free and bound aroma compounds of the white wine of Vitis vinifera L. cv Narince Serkan Selli
a,*
, Ahmet Canbas a, Turgut Cabaroglu a, Huseyin Erten a, Jean-Paul Lepoutre b, Ziya Gunata c
a
c
Department of Food Engineering, Faculty of Agriculture, University of Cukurova, 01330 Adana, Turkey b INRA UMR, Sciences pour l’œnologie, 2 place, Viala 34060 Montpellier, France Universite´ Montpellier II, UMR Inge´nierie de la Re´action Biologique-Bioproductions, place E.Bataillon 34095, Montpellier, France Received 15 March 2004; received in revised form 8 September 2004; accepted 9 September 2004
Abstract Free and glycosidically bound aroma compounds of the Narince wines and the effect of skin contact treatment (15 C, 12 h) on aroma composition have been investigated during two vintages. Free and bound aroma compounds were extracted with dichloromethane and Amberlite XAD-2 resin, respectively, and then analysed by gas chromatography (GC) and gas chromatography–mass spectrometry (GC–MS). According to the results obtained in both vintages, Narince wines were characterized by the presence of high level of fermentative aroma compounds (higher alcohols, fatty acids, and esters, respectively), and skin contact treatment increased the total concentration of free and bound volatiles. 2004 Elsevier Ltd. All rights reserved. Keywords: Skin contact; Aroma compounds; White wine; cv. Narince
1. Introduction Aroma compounds have an important role in wine technology, because they have major contribution to the quality of the final product. These compounds are present as free volatiles which may contribute directly to odour, and non-volatile sugar-bound glycosidic conjugates. Several hundred chemically different aroma compounds such as alcohols, esters, organic acids, volatile phenols, aldehydes, ketones and monoterpenes have been found in wines (Gunata, 1984; Rapp & Mandery, 1986). The wine aroma depends on many factors, such as climate, region, viticultural practices, grape variety,
*
Corresponding author. Fax: +90 322 338 6173. E-mail address: [email protected] (S. Selli).
0956-7135/$ - see front matter 2004 Elsevier Ltd. All rights reserved. doi:10.1016/j.foodcont.2004.09.005
yeast, and wine-making techniques. In white wine-making, skin contact during must preparation is a pre-fermentative process for improving fruity and flowery attributes of wines. This process provides usually good results depending on grape variety and experimental conditions (temperature and time). However, skin contact increases the phenolic compounds of wines and in some cases may cause more astringent and bitter taste (Cabaroglu et al., 1997; Ferreira et al., 1995; Ramey, Bertrand, Ough, Singleton, & Sanders, 1986). Narince is a native grape variety of Vitis vinifera, grown in Middle Anatolia region of Turkey. It is a medium, round and moderately tough-skinned grape variety. The volatiles of various grape varieties and wines have been extensively studied. Aroma composition of Narince must have already been studied by Selli, Cabaroglu, Canbas, Erten, and Nurgel (2003). Narince is a neutral variety with low monoterpene content and it is
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S. Selli et al. / Food Control 17 (2006) 75–82
generally used for the production of dry and semi-dry white wine in Turkey (Go¨kc¸e, 1990; Selli et al., 2003). The volatile compounds of Narince wine have not been reported, yet. The objective of this research was firstly to determine the aromatic profile of Narince wine obtained from over two consecutive vintages and secondly, the effect of skin contact treatment on the content of free and bound aroma compounds.
2. Materials and methods 2.1. Wine-making Healthy grapes of cv. Narince (1650 kg) were manually harvested at optimum maturity during 1998 and 1999 vintages in Tokat province, and transported to the Experimental Winery at the Department of Food Engineering, University of Cukurova (Adana province). After harvest, grapes were divided into two batches. One batch was treated in the standard way without skin contact. In this way grapes were pressed in a horizontal press and 50 mg/l of sulphur dioxide was added. The juice was then settled at 15 C for 24 h, and then racked. For the skin contact experiment, the grapes were destemmed and crushed. The pomace was mixed 50 mg/kg of sulfur dioxide, kept at 15 C for 12 h and then pressed in a horizontal press. The juice was settled and racked as mentioned above. Both batches spontaneously fermented at 18 C. Fermentation was followed by measuring density. When most of the lees settled, the wines were racked, 50 mg/l of sulfur dioxide was added. The wines were stored at 15 C in the tanks. 2.2. Standard chemical analysis Density, ethanol, extract, total acidity, pH, volatile acidity, acetaldehyde, reducing sugar, total and free SO2 and total phenolic compounds (280 index) were analysed (O.I.V., 1990; Ough & Amerine, 1988). 2.3. Analysis of free and bound aroma compounds Extraction of free aroma compounds was performed in dichloromethane which was found to be a suitable solvent for isolating volatiles from the grapes and wines (Blanch, Reglero, Herraiz, & Tabera, 1991; Moio et al., 1995). Before extraction, 34 lg of 4-nonanol as internal standard and 40 ml of dichloromethane were pipetted into 500 ml flask containing 100 ml of wine. The content was magnetically stirred for 30 min under nitrogen gas at 4 C. Then, the mixture was centrifuged at 4 C (9000 · g, 15 min). The organic phase was recovered, filtered through glass wool with anhydrous sodium sulfate and concentrated to a volume of 1 ml with a Vigreux distilla-
tion column (Moio et al., 1995; Schneider, Baumes, Bayonove, & Razungles, 1998). To isolate glycosidically bound aroma compounds, Amberlite XAD-2 resin (20–50 mesh, Merck) was used. The must sample was eluted through an Amberlite XAD-2 column (120 mm · 7 mm i.d.) with 1.5 ml/min of the flow rate. The free and bound aroma compounds were eluted successively with 50 ml each of pentane– dichloromethane (2/1; v/v) and ethyl acetate–methanol (9/1; v/v) (Gunata, 1984; Gunata, Bayonove, Baumes, & Cordonnier, 1985). The pentane–dichloromethane eluant was not used, because free aroma compounds were determined with the above mentioned procedure. The ethyl acetate–methanol was concentrated to dryness in vacuo and dissolved in 0.2 ml of 0.2 M citrate–phosphate buffer (pH 5.0). For enzymatic release of aglycones, 1.2 mg of Pektolase 3 PA (Grinsted/Denmark) was added to this extract and the mixture was incubated at 40 C for 12 h. The released aglycones were extracted with pentane–dichloromethane (2:1; v/v). The organic layer was dried over anhydrous sodium sulfate and 34 lg of 4-nonanol was added as internal standard. Finally, the extract was concentrated and then analysed by GC–MS. 2.4. GC-FID and GC–MS analysis of aroma compounds GC-FID analysis of free and bound aroma compounds was performed using a Varian 3300 chromatograph equipped with a fused capillary column coated with DB-Wax (30 m · 0.32 mm i.d., 0.5 lm film thickness, JW, Folsom, CA, USA) and a flame ionisation detector (FID). Injection mode system was on column and the injection volume was 1 ll. The injector temperature was programmed from 20 to 250 C at 180/min. The oven temperature was at 60 C for 3 min, from 60 to 220 C at 2/min, from 220 C to 245 C at 3/min, then held 20 min at 245 C. The FID temperature was 250 C and flow rate of hydrogen carrier gas was 1.8 ml/min. Identification of the components was performed by GC–MS. A Hewlett–Packard 5890 Series II Chromatograph was used with the DB-Wax column specified as above. The flow rate of helium as carrier gas was 1.5 ml/min and the oven temperature programme was as above. Injection volume was 1 ll. The on-column injector temperature was programmed from 20 to 250 C at 180/min and held at 250 C for 80 min. A Hewlett–Packard 5989A mass spectrometer with a quadruple mass filter was coupled to the GC. Mass spectra (MS) were recorded in the electronic impact (EI) and positive chemical ionization (PCI) modes. The transfer line temperature was 250 C with source temperature of 250 C. Mass spectra were scanned at 70 eV (EIMS) and 230 eV (PCIMS) in the range m/e 29–350 at 1 s intervals (Bureau, Razungles, & Baumes, 2000; Schneider
S. Selli et al. / Food Control 17 (2006) 75–82
et al., 1998). Identification of the compounds was performed by GC–MS by comparing linear retention index and electronic mass spectra with published data or authentic samples (Wirth, Gua, Baumes, & Gunata, 2001). The statistical significance of the effect of skincontact treatment on free and bound aroma compounds obtained in triplicate analysis was determined by oneway analysis of variance (Amerine & Roessler, 1976).
3. Results and discussion 3.1. General wine composition General composition of control and skin contact wines are given in Table 1. Skin contact treatment had no significant effect on general composition of wines. In agreement with other studies (Cabaroglu et al., 1997; Darias-Martin, Rodriguez, Diaz, & Lamuela-Raventas, 2000) absorbance at 420 nm increased with skin contact in both years due to the consequence of skin compounds being extracted into the juice. It has been reported that skin contact caused an increase in flavonoid content of the juice, and this increase correlate with absorbance at 420 nm and browning capacity (Singleton, 1974). 3.2. Free aroma compounds of the wines Table 2 shows the free aroma compounds of Narince wines, expressed as mean (lg/l) of the GC analysis of triplicate extractions. A total of 49 and 46 aroma compounds were identified in the 1998 and 1999 Narince wines, respectively, including C-6 alcohols, higher alcohols, esters, carbonyl compound, lactones, volatile phenols, C-13 norisoprenoids, nitrogenous compound, and
Table 1 General composition of Narince wines 1998
Density (20/20 C) Alcohol (%, h/h) Extract (g/l) Total acidity (g/l)a PH Volatile acidity (g/l)b Absorbance at 420 nm Ash (g/l) Ash alcalinity (me/l) Acetaldehyde (mg/l) Residual sugar (g/l) Free SO2 (mg/l) Total SO2 (mg/l) a b
As tartaric acid. As acetic acid.
1999
Control
Skin contact
Control
Skin contact
0.9907 13.0 23 5.0 3.5 0.24 0.094 2.3 21 44 3.8 18 145
0.9913 13.1 24 6.0 3.6 0.18 0.115 2.9 32 33 2.9 20 143
0.9932 11.8 26 5.0 3.7 0.48 0.102 2.2 24 34 4.5 14 117
0.9935 11.9 25 6.2 3.6 0.30 0.162 2.9 23 26 3.3 14 125
77
acetal compound. In 1998, the control and skin contact wine contained respectively, 140.1 and 187.8 mg/l of free volatiles, and in 1999, 155.6 and 253.0 mg/l, respectively. The wine treated with skin contact presented a very much higher amount of volatiles than the control wine in both vintages. Similar findings have been reported in other studies (Cabaroglu & Canbas, 2002; Falque´ & Fernandez, 1996; Herraiz, Martin-Alvarez, Reglero, Herraiz, & Cabuzedo, 1990). Higher alcohols were the most dominant compounds of wines, as they accounted for the largest proportion (>84%) of the total free volatiles. These compounds are formed during alcoholic fermentation. At concentrations below 300 mg/l, they contribute to the desirable complexity of wine, when their concentration exceeds 400 mg/l, higher alcohols are regarded as a negative quality factor (Ebeler, 2001; Rapp & Mandery, 1986). Three C-6 alcohols, 1-hexanol, (E)-3-hexen-1-ol, and (Z)-3-hexen-1-ol were detected in both vintages. Skin contact treatment did not significantly affect concentration of these compounds (Table 2). C-6 alcohols have a greasy odour, and their origin is mainly due the lipoxygenase activity of grape (Etie´vant & Bayonove, 1983; Ferreira et al., 1995). Their concentration detected in Narince wines was below their threshold values (Etie´vant, 1991). As higher alcohols, 13 compounds were found in wines. Among the higher alcohol identified, isoamyl alcohol, 2-phenyethanol, and isobutanol were the highest amount in the control and skin contact wine in both years. Skin contact increased the total concentration of these compounds, in agreement with previous studies (Cabaroglu et al., 1997; Darias-Martin et al., 2000; Falque´ & Fernandez, 1996; Ramey et al., 1986). This may be attributable to the enrichment of must in amino acids involved in the formation of higher alcohols by Erlich mechanism. Furthermore spontaneous fermentation was performed in this study and significant differences were found among yeast strains with regard to higher alcohols production in wine (Giudici, Romano, & Zambonelli, 1990). As can be seen in Table 2, skin contact treatment significantly increased the level of 2-phenyl ethanol mainly in skin-contact wine from 1999 vintage where its concentration exceeded by sixfold its threshold value. This alcohol has a floral and rose like aroma and contributes positively to wine aroma. It was shown that must composition and particularly yeast species, regardless fermentation temperature play an important role in the levels of 2-phenyl ethanol (Rankine & Pocock, 1969). The wines made from the skin contact treatment contained larger concentration of esters in both vintages (Table 2). Among the esters, important quantities of isoamyl acetate, ethyl lactate, ethyl-3-hydroxy-butanoate, and monoethyl succinate were found in wines. The characteristic fruity flavours of wines are primarily due to
78
S. Selli et al. / Food Control 17 (2006) 75–82
Table 2 Effect of skin contact on free aroma compound levels of Narince wines Compounds (lg/l)
C-6 alcohols 1-Hexanol (E)-3-Hexen-1-ol (Z)-3-Hexen-1-ol Total Higher alcohols Isobutanol 1-Butanol Isoamyl alcohol 3-Methyl-3-buten-1-ol 4-Methyl-1-pentanol 3-Methyl-1-pentanol 3-Ethoxy-1-propanol Heptanol 2,3-Butanediol 2-Methyl thio ethanol Methionol Benzylalcohol 2-Phenylethanol Total Esters Isoamyl acetate Ethyl hexanoate Ethyl lactate Ethyl-3-hydroxy-butanoate Ethyl decanoate Diethyl succinate 2-Phenylethyl acetate Ethyl-4-hydroxy-butanoate Ethyl dodecanoate Diethyl malate Ethylphenyl lactate Monoethyl succinate Total Carbonyl compound Acetoin Total Fatty acids Isobutanoic acid Butanoic acid Hexanoic acid Heptanoic acid Octanoic acid Decanoic acid Dodecanoic acid Tetradecanoic acid 9-Decenoic acid Total Lactones Gamma butyrolactone Pantolactone Total Volatile phenols 4-Vinylphenol Zingorene Vanilloylmethyl ketone Acetovanillone Tyrosol
LRIa
1356 1384 1387
– 1119 1210 1240 1301 1313 1364 1457 1583 – 1723 1869 1905
1132 1230 1353 1524 1635 1690 1786 1819 1851 2041 – 2440
1291
1584 1622 1858 – 2060 2357 2449 2692 –
1635 –
2379 2786 2800 2995 3012
1998
1999 b
Control
Skin contact
Significance
Control
Skin contact
Significanceb
1200 ± 4.7 tr 17 ± 1.8
1201 ± 5.7 31 ± 2.4 17 ± 0.7
ns * ns
1040 ± 12.7 40 ± 4.1 33 ± 1.1
1069 ± 6.4 26 ± 1.6 37 ± 2.4
ns ns ns
1217
1249
1113
1132
9559 ± 14.8 128 ± 2.8 73,737 ± 131 11 ± 0.4 15 ± 0.3 76 ± 2.1 20 ± 1.4 15 ± 0.3 4553 ± 4.3 51 ± 2.1 199 ± 1.8 60 ± 2.8 32,073 ± 26.9
13,000 ± 54.1 70 ± 3.1 112,806 ± 434 6 ± 0.6 16 ± 0.6 73 ± 3.5 20 ± 1.0 23 ± 1.5 3064 ± 5.3 70 ± 1.8 210 ± 9.3 88 ± 2.7 37,990 ± 44.8
13,920 ± 14.3 385 ± 5.3 98,826 ± 197 19 ± 2.8 16 ± 0.4 43 ± 2.1 97 ± 4.9 23 ± 3.5 3064 ± 6.6 70 ± 1.3 210 ± 6.4 88 ± 3.0 14,893 ± 31.7
13,032 ± 47.9 123 ± 2.8 143,540 ± 321 6 ± 0.6 15 ± 2.0 67 ± 6.8 18 ± 2.3 17 ± 3.2 2369 ± 15.0 47 ± 1.6 522 ± 10.6 45 ± 3.1 64,926 ± 58.5
120,497
167,436
131,654
224,727
879 ± 5.7 507 ± 3.2 1309 ± 10.6 150 ± 3.3 279 ± 4.9 tr 6 ± 0.8 320 ± 4.2 28 ± 5.2 29 ± 2.1 83 ± 4.4 474 ± 4.6
999 ± 16.1 627 ± 7.1 343 ± 8.5 178 ± 2.5 744 ± 5.5 90 ± 3.2 255 ± 4.5 699 ± 8.4 93 ± 4.9 34 ± 3.1 37 ± 2.1 209 ± 5.5
640 ± 10.0 560 ± 6.9 3119 ± 13.5 204 ± 3.5 289 ± 11.2 27 ± 3.3 tr 1984 ± 18.4 61 ± 4.9 48 ± 3.5 71 ± 3.7 857 ± 9.9
1803 ± 4.5 246 ± 3.7 3383 ± 18.2 49 ± 2.9 126 ± 4.6 34 ± 4.1 9 ± 1.0 5505 ± 19.9 3 ± 0.6 8 ± 1.3 112 ± 3.1 843 ± 7.1
4064
4308
7860
12121
296 ± 7.7
325 ± 5.0
223 ± 7.7
671 ± 6.1
296
325
223
671
231 ± 4.8 15 ± 1.3 3019 ± 20.1 70 ± 3.9 5245 ± 27.6 1637 ± 9.2 193 ± 4.2 9 ± 1.3 600 ± 6.0
160 ± 4.3 177 ± 5.1 3237 ± 13.6 nd 5851 ± 42.9 2502 ± 8.9 230 ± 4.0 nd 587 ± 8.7
203 ± 2.8 92 ± 6.1 2932 ± 13.7 95 ± 2.5 5260 ± 41.0 1597 ± 9.7 468 ± 6.1 73 ± 2.3 505 ± 6.7
491 ± 4.9 60 ± 1.8 1078 ± 10.2 62 ± 3.4 6983 ± 18.5 1118 ± 8.5 309 ± 3.5 162 ± 2.1 534 ± 5.7
11,019
12,744
11,225
10,797
2192 ± 19.1 5 ± 2.1
1960 ± 12.3 nd
2126 ± 6.9 26 ± 0.6
1296 ± 4.9 37 ± 1.8
2197
1960
2152
1333
4 ± 1.1 nd 5 ± 1.3 79 ± 9.5 1622 ± 22.6
30 ± 2.2 30 ± 3.3 121 ± 6.4 192 ± 5.1 1467 ± 14.7
4 ± 0.3 nd 5 ± 0.7 21 ± 1.3 1181 ± 8.1
41 ± 1.8 nd 67 ± 2.1 70 ± 1.3 2012 ± 9.2
** * ** ** ns ns ns ns *** * ns * *
ns * *** ns *** * *** *** *** ns ** **
ns
ns *** ns ns ns ns ns ns ns
** ns
*** * *** *** ns
** ns ns * ns ns ** ns ns ns * * ***
* * ns *** * ns ** * *** ** * ns
**
** * ** * ns ns * * ns
*** **
** * ** ** ns
S. Selli et al. / Food Control 17 (2006) 75–82
79
Table 2 (continued) Compounds (lg/l)
LRIa
1998
1999
Control
Skin contact
1710
1840
nd nd
15 ± 0.8 30 ± 2.4
–
45
72 ± 2.8
3 ± 0.1
72
3
13 ± 1.8
1 ± 0.2
Total
13
General total
140,880
Total C-13 norisoprenoids 3-Oxo-a-ionol Vomifoliol Total Nitrogenous compound 3-Methylbuthyl acetamide Total Acetal compound 2-Methyl-5-OH-1,3-dioxane
2651 3167
–
–
Significanceb
Control
Skin contact
1211
2190
nd nd
nd nd
–
–
116 ± 3.5
26 ± 1.1
116
26
35 ± 2.4
22 ± 0.3
1
35
22
187,839
155,589
253,019
* *
***
***
Significanceb
– –
*
ns
nd, not detected; tr, trace; ± standard deviation. Results are the means of three repetitions. a LRI: linear retention index calculated on DB-WAX capillary column. b Significance at which means differ as shown by analysis of variance. *, **, *** denote significance at p < 0.05, p < 0.01, p < 0.001 respectively, ns: not significant.
esters (Herraiz, Reglero, Martin-Alvarez, Herraiz, & Cabuzedo, 1991; Rapp & Mandery, 1986). Esters are an important group of volatile compounds produced by yeast during alcoholic fermentation. The 1999 vintage showed a high content of esters compared to that in the 1998 vintage. The low production of these compounds in 1998 wine was possibly due to the must composition and yeast race as reported by Baumes, Bayonove, Barillere, Samson, and Cordonnier (1989); Guitart, Orte, Ferreira, Pen˜a, and Cacho (1999), and Valero, Moyano, Millan, Medina, and Ortega (2002). With regard to carbonyl compounds, acetoin was detected in Narince wines. The concentration of acetoin in 1999 wine increased significantly (p < 0.01) due to the skin contact treatment. Its production is mainly due to the yeast activity, particularly to that from apiculate yeasts developing in the early steps of must fermentation (Romano & Suzzi, 1996). As mentioned by Herraiz et al. (1991), the occurrence of acetoin in wines was considered unpleasant. In both vintages, the amount of acetoin was much below than its threshold value (150 mg/l) given by Lopez, Ferreira, and Cacho (1999). As indicated in Table 2, the most abundant fatty acids in Narince wines were octanoic acid, hexanoic acid, and decanoic acid, respectively. Similar results were found by Versini, Orriols, and Dalla-Serra (1994), and Falque´, Fernandez, and Dubourdieu (2002) and Selli et al. (2004). The skin contact treatment showed mixed effect on the amount of fatty acids, which corroborate the results obtained by Falque´ and Fernandez (1996), and Cabaroglu and Canbas (2002). The contribution of fatty acids on Narince wine can not be considered important because their concentrations were much lower than their odour threshold values (Etie´vant, 1991).
Two lactones c-butyrolactone and pantolactone were detected in both vintages. Skin contact treatment decreased the level of the c-butyrolactone significantly (Table 2). c-Butyrolactone was isolated for the first time from sherry wines. This substance is found in fermented products and probably comes from glutamic acid or related compounds (succinic, 2-oxoglutaric or c-aminobutyric acids) (Muller, Kepner, & Webb, 1973). Generally, the presence of lactones in white wine is undesirable (Pisarnitskii, 2001). The skin contact wines presented higher volatile phenol values than that in control wines. Except tyrosol, concentration of the volatile phenol compounds in both vintages increased significantly. Similar results were found in Emir wine by Cabaroglu et al. (1997) and Lista´n Blanco wine by Darias-Martin et al. (2000). From C-13 norisoprenoids, 3-oxo-a-ionol and vomifoliol were identified only in 1998 skin contact wine. As previously stated, norisoprenoids were principally found in the glycosidic fraction (Baumes et al., 1989; Gunata, Dugelay, Sapis, Baumes, & Bayonove, 1992). The other compounds identified in both vintages, such as nitrogenous compound (3-methylbuthyl acetamide) and acetal compound (2-methyl-5-OH-1,3-dioxane) were present in small quantities. 3.3. Bound aroma compounds of the wines The volatile compounds released by enzymatic treatment of glycosidic fraction are given in Table 3. A total of 26 and 27 bound aroma compounds were detected in 1998 and 1999 wines, respectively, including C-6 alcohols, terpenols, higher alcohols, fatty acids, volatile phenols, and C-13 norisoprenoids. The total amounts of
80
S. Selli et al. / Food Control 17 (2006) 75–82
Table 3 Effect of skin contact on bound aroma compound levels of Narince wines Compounds (lg/l)
LRIa
1998
1999
Control
Skin contact
Significance
Control
Skin contact
Significanceb
17 ± 4.2 2 ± 0.6 6 ± 1.3
24 ± 3.4 3 ± 0.6 11 ± 1.8
ns ns ns
9 ± 1.1 2 ± 0.4 5 ± 1.6
16 ± 4.4 3 ± 0.4 8 ± 0.4
* ns ns
25
38
16
27
1 ± 0.1 4 ± 0.3
3 ± 1.0 5 ± 0.4
1 ± 0.3 1 ± 0.3
4 ± 1.0 3 ± 0.6
5
8
2
7
nd nd 26 ± 3.8 10 ± 2.5 69 ± 5.4 171 ± 13.9
2 ± 0.4 2 ± 0.1 25 ± 2.9 18 ± 0.8 79 ± 7.1 197 ± 9.3
5 ± 0.7 3 ± 1.0 59 ± 4.8 4 ± 1.0 39 ± 10.6 85 ± 9.6
3 ± 0.6 4 ± 0.4 122 ± 13.7 8 ± 1.7 62 ± 2.8 70 ± 6.2
276
323
195
269
39 ± 1.1 304 ± 21.1 48 ± 4.8 139 ± 13.4 35 ± 5.8 4 ± 0.7 107 ± 10.2
35 ± 3.0 322 ± 9.2 29 ± 3.4 201 ± 6.6 17 ± 1.1 3 ± 0.9 138 ± 13.4
14 ± 1.3 23 ± 4.5 16 ± 3.1 17 ± 4.2 71 ± 8.2 222 ± 14.7 26 ± 3.0
5 ± 0.2 32 ± 0.4 9 ± 1.8 13 ± 3.3 47 ± 3.3 326 ± 5.6 8 ± 0.1
676
745
389
440
5 ± 0.3 6 ± 0.6 6 ± 0.5 nd 9 ± 1.7 21 ± 2.5 384 ± 20.9
2 ± 0.4 2 ± 0.1 5 ± 1.4 nd 10 ± 2.8 15 ± 3.1 327 ± 12.4
6 ± 0.7 21 ± 6.5 7 ± 1.3 3 ± 0.6 11 ± 1.0 12 ± 4.2 90 ± 4.4
3 ± 0.8 4 ± 0.7 4 ± 0.3 19 ± 4.5 40 ± 11.6 14 ± 2.5 120 ± 13.7
431
361
150
204
32 ± 2.8 9 ± 1.1
32 ± 1.0 10 ± 0.4
5 ± 0.6 5 ± 0.4
35 ± 4.1 13 ± 1.3
Total
41
42
10
48
General total
1454
1517
762
995
C-6 alcohols 1-Hexanol (Z)-3-Hexen-1-ol (E)-2-Hexen-1-ol Total Terpenols a-Terpineol Geraniol Total Higher alcohols 1-Butanol 3-Methyl-2-buten-1-ol Isoamyl alcohol 3-Ethyl-4-methyl pentanol Benzylalcohol 2-Phenyl ethanol Total Acids Hexanoic acid Octanoic acid Nonanoic acid Decanoic acid Dodecanoic acid Tetradecanoic acid Hexadecanoic acid Total Volatile phenols 4-Vinyl guaiacol 4-Vinylphenol Zingerone Vanilloylmethyl ketone Ethyl-4-hydroxy benzoate Acetovanillone Tyrosol Total C-13 norisoprenoids 3-Oxo-a-ionol 3-OH-7,8-dihydro-b-ionol
1356 1384 1409
1688 1847
1119 1127 1210 – 1869 1905
1838 2060 2158 2357 2449 2692 –
1729 2379 2786 2800 – 2995 3012
2651 2726
b
ns ns
* * ns ns ns ns
ns * * * ns ns ns
* * – ns ns **
ns ns
* **
ns ns * * ** ns
* ns * ns ns * **
* *** ns *** ** ns ns
*** **
nd, not dedected; tr, trace; ± standard deviation. Results are the means of three repetitions. a LRI: linear retention index calculated on DB-WAX capillary column. b Significance at which means differ as shown by analysis of variance. *, **, *** denote significance at p < 0.05, p < 0.01, p < 0.001 respectively, ns: not significant.
bound aroma compounds were lower in the 1999 wines. Skin contact treatment increased the total concentration of bound aroma compounds in both vintages. Similar results have been reported in other studies (Baumes et al., 1989; Cabaroglu et al., 1997; Cabaroglu & Canbas, 2002). Among the bound compounds, fatty acids were the most abundant compounds in Narince wines, followed by volatile phenols and higher alcohols. From the aromatic point of view, terpenols and norisoprenoids are very important aroma compounds in
wine. These compounds synthesized during berry maturation and their concentration in grapes depends on various factors such as the cultivar, the region or the climatic conditions (Gunata, 1984; Williams, Sefton, & Wilson, 1989). The two terpenols identified in wines were a-terpineol and geraniol. These compounds were present only in bound form as quite low concentration in both vintages. Their contribution to the aroma of Narince wine cannot be considered important because their concentrations were much lower than their thresh-
S. Selli et al. / Food Control 17 (2006) 75–82
old levels reported by Etie´vant (1991). Skin contact treatment increased the level of terpenols. Similar results were found by Carro, Lo´pez, Gunata, Baumes, and Bayonove (1996) and Cabaroglu et al. (1997). With regard to C-13 norisoprenoids, 3-oxo-a-ionol and 3-OH-7,8-dihydro-b-ionol were detected in Narince wine. The concentration of these compounds increased significantly in the 1999 skin contact wine compared to the control wine (Table 3). These compounds occur in the grapes mainly in glycosidic form (Gunata et al., 1992; Sefton, Francis, & Williams, 1993). 3.4. Sensory test A triangle taste test was applied to differentiate control and skin-contact wines in both vintages (Roessler, Pangborn, Sidel, & Stone, 1978). In the year 1998, seven out of seven judges distinguished the different sample (p < 0.001), whereas in 1999 five out of seven (p < 0.05).
4. Conclusion This first study on free and bound aroma compounds of Narince wine shows that this wine is characterized by the presence of high levels of higher alcohols, fatty acids, and esters, respectively, as they account for the largest proportion of the total aroma. Skin-contact treatment could be used to enrich Narince wine both in free and bound aroma compounds. Further study is needed to determine the consequence of skin-treatment on overall wine quality both in young wine and aged wine.
Acknowledgements The authors would like to thank the Scientific and _ ¨ BITAK) Technical Research Council of Turkey (TU for financial support for this research project (Project no. TARP-1858). References Amerine, M. A., & Roessler, E. B. (1976). Wines: their sensory evaluation. San Francisco: W.H. Freeman and Co. Baumes, R. L., Bayonove, C. L., Barillere, J. M., Samson, A., & Cordonnier, R. E. (1989). La mace´ration pelliculaire dans la vinification en blanc. Incidence sur la composante volatile des vins. Vitis, 28, 31–48. Blanch, G. P., Reglero, G., Herraiz, M., & Tabera, J. (1991). A comparison of different extraction methods for the volatile components of grape juice. Journal Chromatographic Science, 29, 11–15. Bureau, S. M., Razungles, A., & Baumes, R. L. (2000). The aroma of Muscat of Frogtignan grapes: effect of the light environment of vine or bunch on volatiles and glycoconjugates. Journal of the Science Food and Agriculture, 80, 2012–2020.
81
Cabaroglu, T., Canbas, A., Baumes, R. L., Bayonove, C. L., Lepoutre, J. P., & Gunata, Y. (1997). Aroma composition of a white wine of Vitis vinifera L. cv. Emir as affected by skin contact. Journal of Food Science, 62, 680–683. Cabaroglu, T., & Canbas, A. (2002). Effects of skin-contact on aromatic composition of the white wine of V. vinifera L. cv. Muscat of Alexandria grown in Southern Anatolia. Acta Alimentaria, 31, 45–55. Carro, N., Lo´pez, E., Gunata, Y. Z., Baumes, R. L., & Bayonove, C. L. (1996). Free and glycosidically bound aroma compounds in grape must of four non-floral Vitis vinifera varieties. Analusis, 24, 254–258. Darias-Martin, J. J., Rodriguez, O., Diaz, E., & Lamuela-Raventas, R. (2000). Effect of skin contact on the antioxidant phenolics in white wine. Food Chemistry, 71, 483–487. Ebeler, S. E. (2001). Analytical chemistry: unlocking the secrets of wine flavor. Food Review International, 17, 45–64. Etie´vant, P. X. (1991). In H. Maarse (Ed.), Volatile compounds in food and beverages (pp. 483–546). New York: Marcel Dekker. Etie´vant, P. X., & Bayonove, C. L. (1983). Aroma components of pomaces and wine from the variety Muscat de Frogtignan. Journal of the Science Food and Agriculture, 34, 393–403. Falque´, E., & Fernandez, E. (1996). Effect of different skin contact times on Treixadura wine composition. American Journal of Enology and Viticulture, 47, 309–312. Falque´, E., Fernandez, E., & Dubourdieu, D. (2002). Volatile components of Loureira, Dona Branca, and Treixadura wines. Journal of Agriculture Food and Chemistry, 50, 538–543. Ferreira, B., Hary, C., Bard, M. H., Taisant, C., Olsson, A., & Lefur, Y. (1995). Effects of skin-contact and setting on the level of the C18:2, C18:3 fatty acids and C6 compounds in Burgundy Chardonnay musts and wines. Food Quality Preference, 6, 35– 41. Giudici, P., Romano, P., & Zambonelli, C. (1990). A bimeric study of higher alcohol production in Saccharomyces cerevisiae. Canadian Journal of Microbiology, 36, 61–64. ¨ zu¨m c¸esßitleri katalogu (Grape varieties Go¨kc¸e, M.H. (1990). U catalogue), Tarim ve Koyisleri Bakanligi, No: 15, Ankara. Guitart, A., Orte, P. H., Ferreira, V., Pen˜a, C., & Cacho, J. (1999). Some observations about the correlation between the amino acid content of musts and wines of the Chardonnay variety and their fermentation aromas. American Journal of Enology and Viticulture, 50, 253–258. Gunata, Y.Z. (1984). Recherches sur la fraction lie´e de nature glycosidique de lÕaroˆme du raisin: importance des terpe´nylglcosides, action des glycosidases. The´se Docteur Inge´nieur, Universite´ Sciences et Techniques du Languedoc, Montpellier. Gunata, Y. Z., Bayonove, C. L., Baumes, R. L., & Cordonnier, R. E. (1985). Aroma of grapes. I. Extraction and determination of free and glycosidically bound fraction of some white grape varieties. Journal Chromatography, 331, 83–90. Gunata, Z., Dugelay, I., Sapis, J. C., Baumes, R. L., & Bayonove, C. L. (1992). Role of enzymes in the use of the flavor potential from grapes glycosides in winemaking. In P. Schreier & P. Winterhalter (Eds.), Progress in flavor precursor studies (pp. 219–234). Carol Stream, Germany: Allured Publishing Corporation. Herraiz, T., Martin-Alvarez, P., Reglero, G., Herraiz, M., & Cabuzedo, M. D. (1990). Effects of presence of skins during alcoholic fermentation on the composition of wine volatiles. Vitis, 29, 239–249. Herraiz, T., Reglero, G., Martin-Alvarez, P., Herraiz, M., & Cabuzedo, M. D. (1991). Identification of aroma components of Spanish ÔVerdejoÕ wine. Journal of the Science Food and Agriculture, 55, 103–116. Lopez, R., Ferreira, V., & Cacho, J.F. (1999). Quantitative determination of the odorants of young red wines from different grape varieties. An assessment of their sensory role. In: Aline
82
S. Selli et al. / Food Control 17 (2006) 75–82
Lonvaud-Funel (Ed) 6e Symposium International d ÕOenologie, (pp.15–48), Paris: TEC&DOC. Moio, L., Chambellant, E., Lesschaeve, I., Issanchau, S., Schlich, P., & Etie´vant, P. X. (1995). Production of representative wine extracts for chemical and olfactory analysis. Italian Journal of Food Science, 3, 265–278. Muller, J. C., Kepner, R. E., & Webb, A. D. (1973). Lactones in wines, a review. American Journal of Enology and Viticulture, 24, 5–9. O.I.V. (1990). Recueil des methods internationals dÕanalyse des vins et des mouˆts. Office International de la Vigne et du Vin, Paris. Ough, C. S., & Amerine, M. A. (1988). Methods for analyses of musts and wines (2nd ed.). New York: John Wiley and Sons. Pisarnitskii, A. F. (2001). Formation of wine aroma: tones and imperfections caused by minor components, review. Applied Biochemistry and Microbiology, 37, 552–560. Ramey, D., Bertrand, A., Ough, C. S., Singleton, V. L., & Sanders, E. (1986). Effect on skin contact temperature on Chardonnay must and wine composition. American Journal of Enology and Viticulture, 37, 99–106. Rankine, B. C., & Pocock, K. F. (1969). Phenyl ethanol and n-hexanol in wines: influence of yeast strain, grape variety and other factors and taste thresholds. Vitis, 8, 23–37. Rapp, A., & Mandery, H. (1986). Wine aroma. Experientia, 42, 873–884. Roessler, E. B., Pangborn, R. M., Sidel, J. L., & Stone, H. (1978). Expanded statistical tables for estimating significance in paired preference, paired difference, duo-trio and triangle tests. Journal of Food Science, 43, 940–943. Romano, P., & Suzzi, G. (1996). Origin and production of acetoin during wines yeast fermentation. Applied and Environmental Microbiology, 62, 309–315. Schneider, R., Baumes, R. L., Bayonove, C. L., & Razungles, A. (1998). Volatile compounds involved in the aroma of sweet fortified
wines (vins doux naturels) from Grenache noir. Journal of Agriculture Food and Chemistry, 46, 3230–3237. Sefton, M. A., Francis, I. L., & Williams, P. J. (1993). The volatile composition of Chardonnay juice: a study by flavor precursor analysis. American Journal of Enology and Viticulture, 44, 359–370. Selli, S., Cabaroglu, T., Canbas, A., Erten, H., & Nurgel, C. (2003). Effect of the skin contact on the aroma composition of the musts of Vitis vinifera L. cv. Muscat of Bornova and Narince grown in Turkey. Food Chemistry, 81, 341–347. Selli, S., Cabaroglu, T., Canbas, A., Erten, H., Nurgel, C., Lepoutre, J. P., et al. (2004). Volatile composition of red wine from cv. Kalecik Karasi grown in central Anatolia. Food Chemistry, 85, 207–213. Singleton, V. L. (1974). Analytical fractionation of the phenolic substances of grapes and wine and some practical uses of such analyses. In A. D. Webb (Ed.), Chemistry of winemaking (pp. 184–211). Washington DC, USA: American Chemical Society. Valero, E., Moyano, L., Millan, M. C., Medina, M., & Ortega, J. M. (2002). Higher alcohols and esters production by Saccharomyces cerevisiae. Influence of the initial oxygenation of the grape must. Food Chemistry, 78, 57–61. Versini, G., Orriols, I., & Dalla-Serra, A. (1994). Aroma components of Galician, Albarino, Loureira and Godello wines. Vitis, 33, 165–170. Williams, P. J., Sefton, M. A., & Wilson, B. (1989). Nonvolatile conjugates of secondary metabolits as precursors of varietal grape flavor components. In R. Teranishi, et al. (Eds.), Flavor chemistry trends and developments (pp. 35–48). Washington, DC: American Chemical Society. Wirth, J., Gua, W., Baumes, R., & Gunata, Z. (2001). Volatile compounds released by enzymatic hydrolysis of glycoconjugates of leaves and grape berries from Vitis vinifera Muscat of Alexanria and Shiraz cultivars. Journal of Agriculture Food and Chemistry, 49, 2917–2923.
Effect of skin contact on the free and bound aroma compounds of the white wine of Vitis vinifera L. cv Narince Serkan Selli
a,*
, Ahmet Canbas a, Turgut Cabaroglu a, Huseyin Erten a, Jean-Paul Lepoutre b, Ziya Gunata c
a
c
Department of Food Engineering, Faculty of Agriculture, University of Cukurova, 01330 Adana, Turkey b INRA UMR, Sciences pour l’œnologie, 2 place, Viala 34060 Montpellier, France Universite´ Montpellier II, UMR Inge´nierie de la Re´action Biologique-Bioproductions, place E.Bataillon 34095, Montpellier, France Received 15 March 2004; received in revised form 8 September 2004; accepted 9 September 2004
Abstract Free and glycosidically bound aroma compounds of the Narince wines and the effect of skin contact treatment (15 C, 12 h) on aroma composition have been investigated during two vintages. Free and bound aroma compounds were extracted with dichloromethane and Amberlite XAD-2 resin, respectively, and then analysed by gas chromatography (GC) and gas chromatography–mass spectrometry (GC–MS). According to the results obtained in both vintages, Narince wines were characterized by the presence of high level of fermentative aroma compounds (higher alcohols, fatty acids, and esters, respectively), and skin contact treatment increased the total concentration of free and bound volatiles. 2004 Elsevier Ltd. All rights reserved. Keywords: Skin contact; Aroma compounds; White wine; cv. Narince
1. Introduction Aroma compounds have an important role in wine technology, because they have major contribution to the quality of the final product. These compounds are present as free volatiles which may contribute directly to odour, and non-volatile sugar-bound glycosidic conjugates. Several hundred chemically different aroma compounds such as alcohols, esters, organic acids, volatile phenols, aldehydes, ketones and monoterpenes have been found in wines (Gunata, 1984; Rapp & Mandery, 1986). The wine aroma depends on many factors, such as climate, region, viticultural practices, grape variety,
*
Corresponding author. Fax: +90 322 338 6173. E-mail address: [email protected] (S. Selli).
0956-7135/$ - see front matter 2004 Elsevier Ltd. All rights reserved. doi:10.1016/j.foodcont.2004.09.005
yeast, and wine-making techniques. In white wine-making, skin contact during must preparation is a pre-fermentative process for improving fruity and flowery attributes of wines. This process provides usually good results depending on grape variety and experimental conditions (temperature and time). However, skin contact increases the phenolic compounds of wines and in some cases may cause more astringent and bitter taste (Cabaroglu et al., 1997; Ferreira et al., 1995; Ramey, Bertrand, Ough, Singleton, & Sanders, 1986). Narince is a native grape variety of Vitis vinifera, grown in Middle Anatolia region of Turkey. It is a medium, round and moderately tough-skinned grape variety. The volatiles of various grape varieties and wines have been extensively studied. Aroma composition of Narince must have already been studied by Selli, Cabaroglu, Canbas, Erten, and Nurgel (2003). Narince is a neutral variety with low monoterpene content and it is
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S. Selli et al. / Food Control 17 (2006) 75–82
generally used for the production of dry and semi-dry white wine in Turkey (Go¨kc¸e, 1990; Selli et al., 2003). The volatile compounds of Narince wine have not been reported, yet. The objective of this research was firstly to determine the aromatic profile of Narince wine obtained from over two consecutive vintages and secondly, the effect of skin contact treatment on the content of free and bound aroma compounds.
2. Materials and methods 2.1. Wine-making Healthy grapes of cv. Narince (1650 kg) were manually harvested at optimum maturity during 1998 and 1999 vintages in Tokat province, and transported to the Experimental Winery at the Department of Food Engineering, University of Cukurova (Adana province). After harvest, grapes were divided into two batches. One batch was treated in the standard way without skin contact. In this way grapes were pressed in a horizontal press and 50 mg/l of sulphur dioxide was added. The juice was then settled at 15 C for 24 h, and then racked. For the skin contact experiment, the grapes were destemmed and crushed. The pomace was mixed 50 mg/kg of sulfur dioxide, kept at 15 C for 12 h and then pressed in a horizontal press. The juice was settled and racked as mentioned above. Both batches spontaneously fermented at 18 C. Fermentation was followed by measuring density. When most of the lees settled, the wines were racked, 50 mg/l of sulfur dioxide was added. The wines were stored at 15 C in the tanks. 2.2. Standard chemical analysis Density, ethanol, extract, total acidity, pH, volatile acidity, acetaldehyde, reducing sugar, total and free SO2 and total phenolic compounds (280 index) were analysed (O.I.V., 1990; Ough & Amerine, 1988). 2.3. Analysis of free and bound aroma compounds Extraction of free aroma compounds was performed in dichloromethane which was found to be a suitable solvent for isolating volatiles from the grapes and wines (Blanch, Reglero, Herraiz, & Tabera, 1991; Moio et al., 1995). Before extraction, 34 lg of 4-nonanol as internal standard and 40 ml of dichloromethane were pipetted into 500 ml flask containing 100 ml of wine. The content was magnetically stirred for 30 min under nitrogen gas at 4 C. Then, the mixture was centrifuged at 4 C (9000 · g, 15 min). The organic phase was recovered, filtered through glass wool with anhydrous sodium sulfate and concentrated to a volume of 1 ml with a Vigreux distilla-
tion column (Moio et al., 1995; Schneider, Baumes, Bayonove, & Razungles, 1998). To isolate glycosidically bound aroma compounds, Amberlite XAD-2 resin (20–50 mesh, Merck) was used. The must sample was eluted through an Amberlite XAD-2 column (120 mm · 7 mm i.d.) with 1.5 ml/min of the flow rate. The free and bound aroma compounds were eluted successively with 50 ml each of pentane– dichloromethane (2/1; v/v) and ethyl acetate–methanol (9/1; v/v) (Gunata, 1984; Gunata, Bayonove, Baumes, & Cordonnier, 1985). The pentane–dichloromethane eluant was not used, because free aroma compounds were determined with the above mentioned procedure. The ethyl acetate–methanol was concentrated to dryness in vacuo and dissolved in 0.2 ml of 0.2 M citrate–phosphate buffer (pH 5.0). For enzymatic release of aglycones, 1.2 mg of Pektolase 3 PA (Grinsted/Denmark) was added to this extract and the mixture was incubated at 40 C for 12 h. The released aglycones were extracted with pentane–dichloromethane (2:1; v/v). The organic layer was dried over anhydrous sodium sulfate and 34 lg of 4-nonanol was added as internal standard. Finally, the extract was concentrated and then analysed by GC–MS. 2.4. GC-FID and GC–MS analysis of aroma compounds GC-FID analysis of free and bound aroma compounds was performed using a Varian 3300 chromatograph equipped with a fused capillary column coated with DB-Wax (30 m · 0.32 mm i.d., 0.5 lm film thickness, JW, Folsom, CA, USA) and a flame ionisation detector (FID). Injection mode system was on column and the injection volume was 1 ll. The injector temperature was programmed from 20 to 250 C at 180/min. The oven temperature was at 60 C for 3 min, from 60 to 220 C at 2/min, from 220 C to 245 C at 3/min, then held 20 min at 245 C. The FID temperature was 250 C and flow rate of hydrogen carrier gas was 1.8 ml/min. Identification of the components was performed by GC–MS. A Hewlett–Packard 5890 Series II Chromatograph was used with the DB-Wax column specified as above. The flow rate of helium as carrier gas was 1.5 ml/min and the oven temperature programme was as above. Injection volume was 1 ll. The on-column injector temperature was programmed from 20 to 250 C at 180/min and held at 250 C for 80 min. A Hewlett–Packard 5989A mass spectrometer with a quadruple mass filter was coupled to the GC. Mass spectra (MS) were recorded in the electronic impact (EI) and positive chemical ionization (PCI) modes. The transfer line temperature was 250 C with source temperature of 250 C. Mass spectra were scanned at 70 eV (EIMS) and 230 eV (PCIMS) in the range m/e 29–350 at 1 s intervals (Bureau, Razungles, & Baumes, 2000; Schneider
S. Selli et al. / Food Control 17 (2006) 75–82
et al., 1998). Identification of the compounds was performed by GC–MS by comparing linear retention index and electronic mass spectra with published data or authentic samples (Wirth, Gua, Baumes, & Gunata, 2001). The statistical significance of the effect of skincontact treatment on free and bound aroma compounds obtained in triplicate analysis was determined by oneway analysis of variance (Amerine & Roessler, 1976).
3. Results and discussion 3.1. General wine composition General composition of control and skin contact wines are given in Table 1. Skin contact treatment had no significant effect on general composition of wines. In agreement with other studies (Cabaroglu et al., 1997; Darias-Martin, Rodriguez, Diaz, & Lamuela-Raventas, 2000) absorbance at 420 nm increased with skin contact in both years due to the consequence of skin compounds being extracted into the juice. It has been reported that skin contact caused an increase in flavonoid content of the juice, and this increase correlate with absorbance at 420 nm and browning capacity (Singleton, 1974). 3.2. Free aroma compounds of the wines Table 2 shows the free aroma compounds of Narince wines, expressed as mean (lg/l) of the GC analysis of triplicate extractions. A total of 49 and 46 aroma compounds were identified in the 1998 and 1999 Narince wines, respectively, including C-6 alcohols, higher alcohols, esters, carbonyl compound, lactones, volatile phenols, C-13 norisoprenoids, nitrogenous compound, and
Table 1 General composition of Narince wines 1998
Density (20/20 C) Alcohol (%, h/h) Extract (g/l) Total acidity (g/l)a PH Volatile acidity (g/l)b Absorbance at 420 nm Ash (g/l) Ash alcalinity (me/l) Acetaldehyde (mg/l) Residual sugar (g/l) Free SO2 (mg/l) Total SO2 (mg/l) a b
As tartaric acid. As acetic acid.
1999
Control
Skin contact
Control
Skin contact
0.9907 13.0 23 5.0 3.5 0.24 0.094 2.3 21 44 3.8 18 145
0.9913 13.1 24 6.0 3.6 0.18 0.115 2.9 32 33 2.9 20 143
0.9932 11.8 26 5.0 3.7 0.48 0.102 2.2 24 34 4.5 14 117
0.9935 11.9 25 6.2 3.6 0.30 0.162 2.9 23 26 3.3 14 125
77
acetal compound. In 1998, the control and skin contact wine contained respectively, 140.1 and 187.8 mg/l of free volatiles, and in 1999, 155.6 and 253.0 mg/l, respectively. The wine treated with skin contact presented a very much higher amount of volatiles than the control wine in both vintages. Similar findings have been reported in other studies (Cabaroglu & Canbas, 2002; Falque´ & Fernandez, 1996; Herraiz, Martin-Alvarez, Reglero, Herraiz, & Cabuzedo, 1990). Higher alcohols were the most dominant compounds of wines, as they accounted for the largest proportion (>84%) of the total free volatiles. These compounds are formed during alcoholic fermentation. At concentrations below 300 mg/l, they contribute to the desirable complexity of wine, when their concentration exceeds 400 mg/l, higher alcohols are regarded as a negative quality factor (Ebeler, 2001; Rapp & Mandery, 1986). Three C-6 alcohols, 1-hexanol, (E)-3-hexen-1-ol, and (Z)-3-hexen-1-ol were detected in both vintages. Skin contact treatment did not significantly affect concentration of these compounds (Table 2). C-6 alcohols have a greasy odour, and their origin is mainly due the lipoxygenase activity of grape (Etie´vant & Bayonove, 1983; Ferreira et al., 1995). Their concentration detected in Narince wines was below their threshold values (Etie´vant, 1991). As higher alcohols, 13 compounds were found in wines. Among the higher alcohol identified, isoamyl alcohol, 2-phenyethanol, and isobutanol were the highest amount in the control and skin contact wine in both years. Skin contact increased the total concentration of these compounds, in agreement with previous studies (Cabaroglu et al., 1997; Darias-Martin et al., 2000; Falque´ & Fernandez, 1996; Ramey et al., 1986). This may be attributable to the enrichment of must in amino acids involved in the formation of higher alcohols by Erlich mechanism. Furthermore spontaneous fermentation was performed in this study and significant differences were found among yeast strains with regard to higher alcohols production in wine (Giudici, Romano, & Zambonelli, 1990). As can be seen in Table 2, skin contact treatment significantly increased the level of 2-phenyl ethanol mainly in skin-contact wine from 1999 vintage where its concentration exceeded by sixfold its threshold value. This alcohol has a floral and rose like aroma and contributes positively to wine aroma. It was shown that must composition and particularly yeast species, regardless fermentation temperature play an important role in the levels of 2-phenyl ethanol (Rankine & Pocock, 1969). The wines made from the skin contact treatment contained larger concentration of esters in both vintages (Table 2). Among the esters, important quantities of isoamyl acetate, ethyl lactate, ethyl-3-hydroxy-butanoate, and monoethyl succinate were found in wines. The characteristic fruity flavours of wines are primarily due to
78
S. Selli et al. / Food Control 17 (2006) 75–82
Table 2 Effect of skin contact on free aroma compound levels of Narince wines Compounds (lg/l)
C-6 alcohols 1-Hexanol (E)-3-Hexen-1-ol (Z)-3-Hexen-1-ol Total Higher alcohols Isobutanol 1-Butanol Isoamyl alcohol 3-Methyl-3-buten-1-ol 4-Methyl-1-pentanol 3-Methyl-1-pentanol 3-Ethoxy-1-propanol Heptanol 2,3-Butanediol 2-Methyl thio ethanol Methionol Benzylalcohol 2-Phenylethanol Total Esters Isoamyl acetate Ethyl hexanoate Ethyl lactate Ethyl-3-hydroxy-butanoate Ethyl decanoate Diethyl succinate 2-Phenylethyl acetate Ethyl-4-hydroxy-butanoate Ethyl dodecanoate Diethyl malate Ethylphenyl lactate Monoethyl succinate Total Carbonyl compound Acetoin Total Fatty acids Isobutanoic acid Butanoic acid Hexanoic acid Heptanoic acid Octanoic acid Decanoic acid Dodecanoic acid Tetradecanoic acid 9-Decenoic acid Total Lactones Gamma butyrolactone Pantolactone Total Volatile phenols 4-Vinylphenol Zingorene Vanilloylmethyl ketone Acetovanillone Tyrosol
LRIa
1356 1384 1387
– 1119 1210 1240 1301 1313 1364 1457 1583 – 1723 1869 1905
1132 1230 1353 1524 1635 1690 1786 1819 1851 2041 – 2440
1291
1584 1622 1858 – 2060 2357 2449 2692 –
1635 –
2379 2786 2800 2995 3012
1998
1999 b
Control
Skin contact
Significance
Control
Skin contact
Significanceb
1200 ± 4.7 tr 17 ± 1.8
1201 ± 5.7 31 ± 2.4 17 ± 0.7
ns * ns
1040 ± 12.7 40 ± 4.1 33 ± 1.1
1069 ± 6.4 26 ± 1.6 37 ± 2.4
ns ns ns
1217
1249
1113
1132
9559 ± 14.8 128 ± 2.8 73,737 ± 131 11 ± 0.4 15 ± 0.3 76 ± 2.1 20 ± 1.4 15 ± 0.3 4553 ± 4.3 51 ± 2.1 199 ± 1.8 60 ± 2.8 32,073 ± 26.9
13,000 ± 54.1 70 ± 3.1 112,806 ± 434 6 ± 0.6 16 ± 0.6 73 ± 3.5 20 ± 1.0 23 ± 1.5 3064 ± 5.3 70 ± 1.8 210 ± 9.3 88 ± 2.7 37,990 ± 44.8
13,920 ± 14.3 385 ± 5.3 98,826 ± 197 19 ± 2.8 16 ± 0.4 43 ± 2.1 97 ± 4.9 23 ± 3.5 3064 ± 6.6 70 ± 1.3 210 ± 6.4 88 ± 3.0 14,893 ± 31.7
13,032 ± 47.9 123 ± 2.8 143,540 ± 321 6 ± 0.6 15 ± 2.0 67 ± 6.8 18 ± 2.3 17 ± 3.2 2369 ± 15.0 47 ± 1.6 522 ± 10.6 45 ± 3.1 64,926 ± 58.5
120,497
167,436
131,654
224,727
879 ± 5.7 507 ± 3.2 1309 ± 10.6 150 ± 3.3 279 ± 4.9 tr 6 ± 0.8 320 ± 4.2 28 ± 5.2 29 ± 2.1 83 ± 4.4 474 ± 4.6
999 ± 16.1 627 ± 7.1 343 ± 8.5 178 ± 2.5 744 ± 5.5 90 ± 3.2 255 ± 4.5 699 ± 8.4 93 ± 4.9 34 ± 3.1 37 ± 2.1 209 ± 5.5
640 ± 10.0 560 ± 6.9 3119 ± 13.5 204 ± 3.5 289 ± 11.2 27 ± 3.3 tr 1984 ± 18.4 61 ± 4.9 48 ± 3.5 71 ± 3.7 857 ± 9.9
1803 ± 4.5 246 ± 3.7 3383 ± 18.2 49 ± 2.9 126 ± 4.6 34 ± 4.1 9 ± 1.0 5505 ± 19.9 3 ± 0.6 8 ± 1.3 112 ± 3.1 843 ± 7.1
4064
4308
7860
12121
296 ± 7.7
325 ± 5.0
223 ± 7.7
671 ± 6.1
296
325
223
671
231 ± 4.8 15 ± 1.3 3019 ± 20.1 70 ± 3.9 5245 ± 27.6 1637 ± 9.2 193 ± 4.2 9 ± 1.3 600 ± 6.0
160 ± 4.3 177 ± 5.1 3237 ± 13.6 nd 5851 ± 42.9 2502 ± 8.9 230 ± 4.0 nd 587 ± 8.7
203 ± 2.8 92 ± 6.1 2932 ± 13.7 95 ± 2.5 5260 ± 41.0 1597 ± 9.7 468 ± 6.1 73 ± 2.3 505 ± 6.7
491 ± 4.9 60 ± 1.8 1078 ± 10.2 62 ± 3.4 6983 ± 18.5 1118 ± 8.5 309 ± 3.5 162 ± 2.1 534 ± 5.7
11,019
12,744
11,225
10,797
2192 ± 19.1 5 ± 2.1
1960 ± 12.3 nd
2126 ± 6.9 26 ± 0.6
1296 ± 4.9 37 ± 1.8
2197
1960
2152
1333
4 ± 1.1 nd 5 ± 1.3 79 ± 9.5 1622 ± 22.6
30 ± 2.2 30 ± 3.3 121 ± 6.4 192 ± 5.1 1467 ± 14.7
4 ± 0.3 nd 5 ± 0.7 21 ± 1.3 1181 ± 8.1
41 ± 1.8 nd 67 ± 2.1 70 ± 1.3 2012 ± 9.2
** * ** ** ns ns ns ns *** * ns * *
ns * *** ns *** * *** *** *** ns ** **
ns
ns *** ns ns ns ns ns ns ns
** ns
*** * *** *** ns
** ns ns * ns ns ** ns ns ns * * ***
* * ns *** * ns ** * *** ** * ns
**
** * ** * ns ns * * ns
*** **
** * ** ** ns
S. Selli et al. / Food Control 17 (2006) 75–82
79
Table 2 (continued) Compounds (lg/l)
LRIa
1998
1999
Control
Skin contact
1710
1840
nd nd
15 ± 0.8 30 ± 2.4
–
45
72 ± 2.8
3 ± 0.1
72
3
13 ± 1.8
1 ± 0.2
Total
13
General total
140,880
Total C-13 norisoprenoids 3-Oxo-a-ionol Vomifoliol Total Nitrogenous compound 3-Methylbuthyl acetamide Total Acetal compound 2-Methyl-5-OH-1,3-dioxane
2651 3167
–
–
Significanceb
Control
Skin contact
1211
2190
nd nd
nd nd
–
–
116 ± 3.5
26 ± 1.1
116
26
35 ± 2.4
22 ± 0.3
1
35
22
187,839
155,589
253,019
* *
***
***
Significanceb
– –
*
ns
nd, not detected; tr, trace; ± standard deviation. Results are the means of three repetitions. a LRI: linear retention index calculated on DB-WAX capillary column. b Significance at which means differ as shown by analysis of variance. *, **, *** denote significance at p < 0.05, p < 0.01, p < 0.001 respectively, ns: not significant.
esters (Herraiz, Reglero, Martin-Alvarez, Herraiz, & Cabuzedo, 1991; Rapp & Mandery, 1986). Esters are an important group of volatile compounds produced by yeast during alcoholic fermentation. The 1999 vintage showed a high content of esters compared to that in the 1998 vintage. The low production of these compounds in 1998 wine was possibly due to the must composition and yeast race as reported by Baumes, Bayonove, Barillere, Samson, and Cordonnier (1989); Guitart, Orte, Ferreira, Pen˜a, and Cacho (1999), and Valero, Moyano, Millan, Medina, and Ortega (2002). With regard to carbonyl compounds, acetoin was detected in Narince wines. The concentration of acetoin in 1999 wine increased significantly (p < 0.01) due to the skin contact treatment. Its production is mainly due to the yeast activity, particularly to that from apiculate yeasts developing in the early steps of must fermentation (Romano & Suzzi, 1996). As mentioned by Herraiz et al. (1991), the occurrence of acetoin in wines was considered unpleasant. In both vintages, the amount of acetoin was much below than its threshold value (150 mg/l) given by Lopez, Ferreira, and Cacho (1999). As indicated in Table 2, the most abundant fatty acids in Narince wines were octanoic acid, hexanoic acid, and decanoic acid, respectively. Similar results were found by Versini, Orriols, and Dalla-Serra (1994), and Falque´, Fernandez, and Dubourdieu (2002) and Selli et al. (2004). The skin contact treatment showed mixed effect on the amount of fatty acids, which corroborate the results obtained by Falque´ and Fernandez (1996), and Cabaroglu and Canbas (2002). The contribution of fatty acids on Narince wine can not be considered important because their concentrations were much lower than their odour threshold values (Etie´vant, 1991).
Two lactones c-butyrolactone and pantolactone were detected in both vintages. Skin contact treatment decreased the level of the c-butyrolactone significantly (Table 2). c-Butyrolactone was isolated for the first time from sherry wines. This substance is found in fermented products and probably comes from glutamic acid or related compounds (succinic, 2-oxoglutaric or c-aminobutyric acids) (Muller, Kepner, & Webb, 1973). Generally, the presence of lactones in white wine is undesirable (Pisarnitskii, 2001). The skin contact wines presented higher volatile phenol values than that in control wines. Except tyrosol, concentration of the volatile phenol compounds in both vintages increased significantly. Similar results were found in Emir wine by Cabaroglu et al. (1997) and Lista´n Blanco wine by Darias-Martin et al. (2000). From C-13 norisoprenoids, 3-oxo-a-ionol and vomifoliol were identified only in 1998 skin contact wine. As previously stated, norisoprenoids were principally found in the glycosidic fraction (Baumes et al., 1989; Gunata, Dugelay, Sapis, Baumes, & Bayonove, 1992). The other compounds identified in both vintages, such as nitrogenous compound (3-methylbuthyl acetamide) and acetal compound (2-methyl-5-OH-1,3-dioxane) were present in small quantities. 3.3. Bound aroma compounds of the wines The volatile compounds released by enzymatic treatment of glycosidic fraction are given in Table 3. A total of 26 and 27 bound aroma compounds were detected in 1998 and 1999 wines, respectively, including C-6 alcohols, terpenols, higher alcohols, fatty acids, volatile phenols, and C-13 norisoprenoids. The total amounts of
80
S. Selli et al. / Food Control 17 (2006) 75–82
Table 3 Effect of skin contact on bound aroma compound levels of Narince wines Compounds (lg/l)
LRIa
1998
1999
Control
Skin contact
Significance
Control
Skin contact
Significanceb
17 ± 4.2 2 ± 0.6 6 ± 1.3
24 ± 3.4 3 ± 0.6 11 ± 1.8
ns ns ns
9 ± 1.1 2 ± 0.4 5 ± 1.6
16 ± 4.4 3 ± 0.4 8 ± 0.4
* ns ns
25
38
16
27
1 ± 0.1 4 ± 0.3
3 ± 1.0 5 ± 0.4
1 ± 0.3 1 ± 0.3
4 ± 1.0 3 ± 0.6
5
8
2
7
nd nd 26 ± 3.8 10 ± 2.5 69 ± 5.4 171 ± 13.9
2 ± 0.4 2 ± 0.1 25 ± 2.9 18 ± 0.8 79 ± 7.1 197 ± 9.3
5 ± 0.7 3 ± 1.0 59 ± 4.8 4 ± 1.0 39 ± 10.6 85 ± 9.6
3 ± 0.6 4 ± 0.4 122 ± 13.7 8 ± 1.7 62 ± 2.8 70 ± 6.2
276
323
195
269
39 ± 1.1 304 ± 21.1 48 ± 4.8 139 ± 13.4 35 ± 5.8 4 ± 0.7 107 ± 10.2
35 ± 3.0 322 ± 9.2 29 ± 3.4 201 ± 6.6 17 ± 1.1 3 ± 0.9 138 ± 13.4
14 ± 1.3 23 ± 4.5 16 ± 3.1 17 ± 4.2 71 ± 8.2 222 ± 14.7 26 ± 3.0
5 ± 0.2 32 ± 0.4 9 ± 1.8 13 ± 3.3 47 ± 3.3 326 ± 5.6 8 ± 0.1
676
745
389
440
5 ± 0.3 6 ± 0.6 6 ± 0.5 nd 9 ± 1.7 21 ± 2.5 384 ± 20.9
2 ± 0.4 2 ± 0.1 5 ± 1.4 nd 10 ± 2.8 15 ± 3.1 327 ± 12.4
6 ± 0.7 21 ± 6.5 7 ± 1.3 3 ± 0.6 11 ± 1.0 12 ± 4.2 90 ± 4.4
3 ± 0.8 4 ± 0.7 4 ± 0.3 19 ± 4.5 40 ± 11.6 14 ± 2.5 120 ± 13.7
431
361
150
204
32 ± 2.8 9 ± 1.1
32 ± 1.0 10 ± 0.4
5 ± 0.6 5 ± 0.4
35 ± 4.1 13 ± 1.3
Total
41
42
10
48
General total
1454
1517
762
995
C-6 alcohols 1-Hexanol (Z)-3-Hexen-1-ol (E)-2-Hexen-1-ol Total Terpenols a-Terpineol Geraniol Total Higher alcohols 1-Butanol 3-Methyl-2-buten-1-ol Isoamyl alcohol 3-Ethyl-4-methyl pentanol Benzylalcohol 2-Phenyl ethanol Total Acids Hexanoic acid Octanoic acid Nonanoic acid Decanoic acid Dodecanoic acid Tetradecanoic acid Hexadecanoic acid Total Volatile phenols 4-Vinyl guaiacol 4-Vinylphenol Zingerone Vanilloylmethyl ketone Ethyl-4-hydroxy benzoate Acetovanillone Tyrosol Total C-13 norisoprenoids 3-Oxo-a-ionol 3-OH-7,8-dihydro-b-ionol
1356 1384 1409
1688 1847
1119 1127 1210 – 1869 1905
1838 2060 2158 2357 2449 2692 –
1729 2379 2786 2800 – 2995 3012
2651 2726
b
ns ns
* * ns ns ns ns
ns * * * ns ns ns
* * – ns ns **
ns ns
* **
ns ns * * ** ns
* ns * ns ns * **
* *** ns *** ** ns ns
*** **
nd, not dedected; tr, trace; ± standard deviation. Results are the means of three repetitions. a LRI: linear retention index calculated on DB-WAX capillary column. b Significance at which means differ as shown by analysis of variance. *, **, *** denote significance at p < 0.05, p < 0.01, p < 0.001 respectively, ns: not significant.
bound aroma compounds were lower in the 1999 wines. Skin contact treatment increased the total concentration of bound aroma compounds in both vintages. Similar results have been reported in other studies (Baumes et al., 1989; Cabaroglu et al., 1997; Cabaroglu & Canbas, 2002). Among the bound compounds, fatty acids were the most abundant compounds in Narince wines, followed by volatile phenols and higher alcohols. From the aromatic point of view, terpenols and norisoprenoids are very important aroma compounds in
wine. These compounds synthesized during berry maturation and their concentration in grapes depends on various factors such as the cultivar, the region or the climatic conditions (Gunata, 1984; Williams, Sefton, & Wilson, 1989). The two terpenols identified in wines were a-terpineol and geraniol. These compounds were present only in bound form as quite low concentration in both vintages. Their contribution to the aroma of Narince wine cannot be considered important because their concentrations were much lower than their thresh-
S. Selli et al. / Food Control 17 (2006) 75–82
old levels reported by Etie´vant (1991). Skin contact treatment increased the level of terpenols. Similar results were found by Carro, Lo´pez, Gunata, Baumes, and Bayonove (1996) and Cabaroglu et al. (1997). With regard to C-13 norisoprenoids, 3-oxo-a-ionol and 3-OH-7,8-dihydro-b-ionol were detected in Narince wine. The concentration of these compounds increased significantly in the 1999 skin contact wine compared to the control wine (Table 3). These compounds occur in the grapes mainly in glycosidic form (Gunata et al., 1992; Sefton, Francis, & Williams, 1993). 3.4. Sensory test A triangle taste test was applied to differentiate control and skin-contact wines in both vintages (Roessler, Pangborn, Sidel, & Stone, 1978). In the year 1998, seven out of seven judges distinguished the different sample (p < 0.001), whereas in 1999 five out of seven (p < 0.05).
4. Conclusion This first study on free and bound aroma compounds of Narince wine shows that this wine is characterized by the presence of high levels of higher alcohols, fatty acids, and esters, respectively, as they account for the largest proportion of the total aroma. Skin-contact treatment could be used to enrich Narince wine both in free and bound aroma compounds. Further study is needed to determine the consequence of skin-treatment on overall wine quality both in young wine and aged wine.
Acknowledgements The authors would like to thank the Scientific and _ ¨ BITAK) Technical Research Council of Turkey (TU for financial support for this research project (Project no. TARP-1858). References Amerine, M. A., & Roessler, E. B. (1976). Wines: their sensory evaluation. San Francisco: W.H. Freeman and Co. Baumes, R. L., Bayonove, C. L., Barillere, J. M., Samson, A., & Cordonnier, R. E. (1989). La mace´ration pelliculaire dans la vinification en blanc. Incidence sur la composante volatile des vins. Vitis, 28, 31–48. Blanch, G. P., Reglero, G., Herraiz, M., & Tabera, J. (1991). A comparison of different extraction methods for the volatile components of grape juice. Journal Chromatographic Science, 29, 11–15. Bureau, S. M., Razungles, A., & Baumes, R. L. (2000). The aroma of Muscat of Frogtignan grapes: effect of the light environment of vine or bunch on volatiles and glycoconjugates. Journal of the Science Food and Agriculture, 80, 2012–2020.
81
Cabaroglu, T., Canbas, A., Baumes, R. L., Bayonove, C. L., Lepoutre, J. P., & Gunata, Y. (1997). Aroma composition of a white wine of Vitis vinifera L. cv. Emir as affected by skin contact. Journal of Food Science, 62, 680–683. Cabaroglu, T., & Canbas, A. (2002). Effects of skin-contact on aromatic composition of the white wine of V. vinifera L. cv. Muscat of Alexandria grown in Southern Anatolia. Acta Alimentaria, 31, 45–55. Carro, N., Lo´pez, E., Gunata, Y. Z., Baumes, R. L., & Bayonove, C. L. (1996). Free and glycosidically bound aroma compounds in grape must of four non-floral Vitis vinifera varieties. Analusis, 24, 254–258. Darias-Martin, J. J., Rodriguez, O., Diaz, E., & Lamuela-Raventas, R. (2000). Effect of skin contact on the antioxidant phenolics in white wine. Food Chemistry, 71, 483–487. Ebeler, S. E. (2001). Analytical chemistry: unlocking the secrets of wine flavor. Food Review International, 17, 45–64. Etie´vant, P. X. (1991). In H. Maarse (Ed.), Volatile compounds in food and beverages (pp. 483–546). New York: Marcel Dekker. Etie´vant, P. X., & Bayonove, C. L. (1983). Aroma components of pomaces and wine from the variety Muscat de Frogtignan. Journal of the Science Food and Agriculture, 34, 393–403. Falque´, E., & Fernandez, E. (1996). Effect of different skin contact times on Treixadura wine composition. American Journal of Enology and Viticulture, 47, 309–312. Falque´, E., Fernandez, E., & Dubourdieu, D. (2002). Volatile components of Loureira, Dona Branca, and Treixadura wines. Journal of Agriculture Food and Chemistry, 50, 538–543. Ferreira, B., Hary, C., Bard, M. H., Taisant, C., Olsson, A., & Lefur, Y. (1995). Effects of skin-contact and setting on the level of the C18:2, C18:3 fatty acids and C6 compounds in Burgundy Chardonnay musts and wines. Food Quality Preference, 6, 35– 41. Giudici, P., Romano, P., & Zambonelli, C. (1990). A bimeric study of higher alcohol production in Saccharomyces cerevisiae. Canadian Journal of Microbiology, 36, 61–64. ¨ zu¨m c¸esßitleri katalogu (Grape varieties Go¨kc¸e, M.H. (1990). U catalogue), Tarim ve Koyisleri Bakanligi, No: 15, Ankara. Guitart, A., Orte, P. H., Ferreira, V., Pen˜a, C., & Cacho, J. (1999). Some observations about the correlation between the amino acid content of musts and wines of the Chardonnay variety and their fermentation aromas. American Journal of Enology and Viticulture, 50, 253–258. Gunata, Y.Z. (1984). Recherches sur la fraction lie´e de nature glycosidique de lÕaroˆme du raisin: importance des terpe´nylglcosides, action des glycosidases. The´se Docteur Inge´nieur, Universite´ Sciences et Techniques du Languedoc, Montpellier. Gunata, Y. Z., Bayonove, C. L., Baumes, R. L., & Cordonnier, R. E. (1985). Aroma of grapes. I. Extraction and determination of free and glycosidically bound fraction of some white grape varieties. Journal Chromatography, 331, 83–90. Gunata, Z., Dugelay, I., Sapis, J. C., Baumes, R. L., & Bayonove, C. L. (1992). Role of enzymes in the use of the flavor potential from grapes glycosides in winemaking. In P. Schreier & P. Winterhalter (Eds.), Progress in flavor precursor studies (pp. 219–234). Carol Stream, Germany: Allured Publishing Corporation. Herraiz, T., Martin-Alvarez, P., Reglero, G., Herraiz, M., & Cabuzedo, M. D. (1990). Effects of presence of skins during alcoholic fermentation on the composition of wine volatiles. Vitis, 29, 239–249. Herraiz, T., Reglero, G., Martin-Alvarez, P., Herraiz, M., & Cabuzedo, M. D. (1991). Identification of aroma components of Spanish ÔVerdejoÕ wine. Journal of the Science Food and Agriculture, 55, 103–116. Lopez, R., Ferreira, V., & Cacho, J.F. (1999). Quantitative determination of the odorants of young red wines from different grape varieties. An assessment of their sensory role. In: Aline
82
S. Selli et al. / Food Control 17 (2006) 75–82
Lonvaud-Funel (Ed) 6e Symposium International d ÕOenologie, (pp.15–48), Paris: TEC&DOC. Moio, L., Chambellant, E., Lesschaeve, I., Issanchau, S., Schlich, P., & Etie´vant, P. X. (1995). Production of representative wine extracts for chemical and olfactory analysis. Italian Journal of Food Science, 3, 265–278. Muller, J. C., Kepner, R. E., & Webb, A. D. (1973). Lactones in wines, a review. American Journal of Enology and Viticulture, 24, 5–9. O.I.V. (1990). Recueil des methods internationals dÕanalyse des vins et des mouˆts. Office International de la Vigne et du Vin, Paris. Ough, C. S., & Amerine, M. A. (1988). Methods for analyses of musts and wines (2nd ed.). New York: John Wiley and Sons. Pisarnitskii, A. F. (2001). Formation of wine aroma: tones and imperfections caused by minor components, review. Applied Biochemistry and Microbiology, 37, 552–560. Ramey, D., Bertrand, A., Ough, C. S., Singleton, V. L., & Sanders, E. (1986). Effect on skin contact temperature on Chardonnay must and wine composition. American Journal of Enology and Viticulture, 37, 99–106. Rankine, B. C., & Pocock, K. F. (1969). Phenyl ethanol and n-hexanol in wines: influence of yeast strain, grape variety and other factors and taste thresholds. Vitis, 8, 23–37. Rapp, A., & Mandery, H. (1986). Wine aroma. Experientia, 42, 873–884. Roessler, E. B., Pangborn, R. M., Sidel, J. L., & Stone, H. (1978). Expanded statistical tables for estimating significance in paired preference, paired difference, duo-trio and triangle tests. Journal of Food Science, 43, 940–943. Romano, P., & Suzzi, G. (1996). Origin and production of acetoin during wines yeast fermentation. Applied and Environmental Microbiology, 62, 309–315. Schneider, R., Baumes, R. L., Bayonove, C. L., & Razungles, A. (1998). Volatile compounds involved in the aroma of sweet fortified
wines (vins doux naturels) from Grenache noir. Journal of Agriculture Food and Chemistry, 46, 3230–3237. Sefton, M. A., Francis, I. L., & Williams, P. J. (1993). The volatile composition of Chardonnay juice: a study by flavor precursor analysis. American Journal of Enology and Viticulture, 44, 359–370. Selli, S., Cabaroglu, T., Canbas, A., Erten, H., & Nurgel, C. (2003). Effect of the skin contact on the aroma composition of the musts of Vitis vinifera L. cv. Muscat of Bornova and Narince grown in Turkey. Food Chemistry, 81, 341–347. Selli, S., Cabaroglu, T., Canbas, A., Erten, H., Nurgel, C., Lepoutre, J. P., et al. (2004). Volatile composition of red wine from cv. Kalecik Karasi grown in central Anatolia. Food Chemistry, 85, 207–213. Singleton, V. L. (1974). Analytical fractionation of the phenolic substances of grapes and wine and some practical uses of such analyses. In A. D. Webb (Ed.), Chemistry of winemaking (pp. 184–211). Washington DC, USA: American Chemical Society. Valero, E., Moyano, L., Millan, M. C., Medina, M., & Ortega, J. M. (2002). Higher alcohols and esters production by Saccharomyces cerevisiae. Influence of the initial oxygenation of the grape must. Food Chemistry, 78, 57–61. Versini, G., Orriols, I., & Dalla-Serra, A. (1994). Aroma components of Galician, Albarino, Loureira and Godello wines. Vitis, 33, 165–170. Williams, P. J., Sefton, M. A., & Wilson, B. (1989). Nonvolatile conjugates of secondary metabolits as precursors of varietal grape flavor components. In R. Teranishi, et al. (Eds.), Flavor chemistry trends and developments (pp. 35–48). Washington, DC: American Chemical Society. Wirth, J., Gua, W., Baumes, R., & Gunata, Z. (2001). Volatile compounds released by enzymatic hydrolysis of glycoconjugates of leaves and grape berries from Vitis vinifera Muscat of Alexanria and Shiraz cultivars. Journal of Agriculture Food and Chemistry, 49, 2917–2923.