Mitteilungen Klosterneuburg 56 (2006): 124-126 Technical Report

Grapevine Flower Treatment with Gibberellic Acid (GA3) increases o-Aminoacetophenone (AAP) Con- tent in some vinifera L.

1,2* 2 2 MARTIN S. POUR NIKFARDJAM ,K.GAAÂ L and P. TESZLAÂ K

1 Staatliche Lehr- und Versuchsanstalt fuÈ r Wein- und Obstbau D-74189 Weinsberg, Traubenplatz 5 (present address) E-mail: [email protected] 2 FVM Research Institute for & H-7634 PeÂcs, PaÂzmaÂny PeÂter u. 4

Six cultivars of L. ('', '', '', 'Kadarka', 'Lemberger', and '') were sprayed at full bloom with a 20ppm solution of gibberellic acid. Compared to the untreated control some of the wines from gibberellic acid treated grapvines showed higher contents of o-aminoacetophenone (AAP), which is clo- sely linked to the untypical ageing (UTA) off-flavour. These results, thus, support our earlier findings that gibberellic acid treatment of grapevine flowers might lead to higher UTA formation potential in Vitis vinifera L. wines. Key words: gibberellic acid; o-aminoacetophenone (AAP); untypical aging flavour (UTA); GC/MS

Gibberellins are an important class of natural growth ons as low as 0.7mg/L AAP (RAPP et al., 1995). regulators in plants. They are products of the diterpe- An increased AAP content of wines as a result of GA3 noid pathway and their formation is initiated by cycli- treatment of grapevine flowers would, thus, militate sation of the common C20 precursor geranylgeranyl di- against such a treatment. Since our recent findings al- phosphate (GGPP) (GRAEBE et al., 1965; HEDDEN and ready showed that 'Riesling' and 'Sauvignon blanc' wi-

PROEBSTING, 1999). GA3 has been widely used in table nes made from GA3 treated grapevines develop signifi- production and its effects on grape quality have cantly more AAP during storage (POUR NIKFARDJAM et been intensively studied (GUELFAT-REICH and SAFRAN, al., 2005b), we extended our study to more varieties to

1973; BEN-TAL, 1990; KORKAS et al., 1999). Recent re- see if GA3 generally leads to higher AAP concentrati- search has shown, that GA3 treatment not only leads ons in . to higher polyphenol and anthocyanin content, respec- tively, but also to higher concentrations of indole-3- Material and Methods acetic acid and o-aminoacetophenone in 'Riesling' and 'Sauvignon blanc' wine (TESZLAÂ K et al., 2005; POUR NIK- All reagents used were of analytical grade unless other- 1 IKFARDJAM et al., 2005a and b). wise stated. Gibberellic acid (GA3) and Tween 20 Aminoacetophenone (AAP) is an aroma compound, were from Fluka (Buchs, Switzerland). which is associated with the so-called 'untypical ageing parameters: were grown during the off-flavour' (UTA) in Vitis vinifera L. white wines and 2005 in the ¹Szent MikloÂsª vineyard of the generally occurs after a few months storage. The off- FVM Research Institute for Viticulture and Oenology flavour is described by various aroma descriptors, such on the south-facing slopes of the Mecsek Hills in PeÂcs/ as 'acacia blossom, naphthalene, furniture polish, wet (latitude: 46807' N, longitude: 18817' E, 180- wool or fusel alcohol'. Depending on wine flavour 200meters above sea level). The soil is Ramann-type UTA can be organoleptically recognised at concentrati- brown duff on red sandstone. The vines were not irri-

124 Mitteilungen Klosterneuburg 56 (2006): 124-126 Pour Nikfardjam et al.

gated. The five-year-old 'Riesling', 'Sauvignon blanc', Tab. 1: 2-Aminoacetophenone (AAP) content of white and and 'Chardonnay' grapevines were grown according to red wines made from GA3 treated and untreated gra- the Lenz-Moser system. The 22-year-old red varieties pevines (n=3) 'Kadarka', 'Lemberger', and 'Merlot' were grown ac- cording to the Pendelbogen system. In each case 100 grapevines were selected from each variety, of which 50 were kept untreated (control) and 50 were treated with GA3 as follows. GA3 treatment: Grapevine flowers were sprayed at full bloom to the drip point with an aqueous 20ppm GA3 solution (containing 0.2% Tween 201). technology: The grapes were harvested manually at physiological ripeness, destemmed, and crushed by means of a Cantinetta C.D.A. TR (Nuova Zambelli, Camisano Vicentino, Saonara, Italy) destem- mer/crusher. The grapes then received 20mg/kgSO2. After destemming and crushing the white mashes were immediately pressed by means of a hydraulic press and the resulting must divided in 20-liter glass balloons re- Our results for 'Riesling' and 'Sauvignon blanc' are sulting in three replicates for each variety and treat- much lower than our recent findings for the 2004 vin- 1 ment. They were then inoculated with Lalvin EC tage. In 2004 we found: 'Riesling': GA3 1.29 mg/L, 1118 (Lallemand, Rexdale, Canada) starter culture and control 0.72 mg/L; 'Sauvignon blanc': GA3 1.26 mg/L, fermented for one week. After fermentation was com- control 0.83 mg/L (POUR NIKFARDJAM et al., 2005b). As plete, the wines were racked off the lees, received 50 already discussed elsewhere (POUR NIKFARDJAM et al., mg/L SO2, and were then stored at 14 8C in the dark 2005c) GA3 treatment of grapevine flowers might artifi- till analysis. cially induce slight water-stress in grapevines and, thus, The red mashes (three replicates for each variety and lead to higher AAP contents in the respective wines. treatment) were also transferred into 20-liter glass bal- The higher precipitation in 2005 compared to 2004 1 loons and Opti-Red (Lallemand, Rexdale, Canada) would, therefore, diminish the impact of GA3 treat- was added to induce fermentation. During open mash ment and explain the lower AAP concentrations mea- fermentation the wines were manually plunged three sured in 2005. In 2004 we had 561mm of rainfall during times a day. After fermentation and prolonged skin the vegetation period (April-October), while in 2005 it contact for a total timeframe of 4 weeks, the wines was 630mm (+12%). were racked off the lees, received 50mg/L SO2 and The lower AAP content in the GA3-treated 'Kadarka' were then stored at 14 8C in the dark till analysis. wine could be due to its very low ripening stage at har- Wine analysis: o-AAP analysis by means of GC/MS vest (75.68Oe, 15.3g/L titratable acidity). Only the was performed as described elsewhere (POUR NIKFARD- 'Lemberger' and 'Merlot' wines contained AAP con- JAM et al., 2005b). centrations above the sensory threshold of 0.7 mg/L as Statistics: All statistical calculations were carried out introduced by RAPP et al. (1995). Although a sensory using Microsoft Excel1 (Microsoft Corp., Redmond, panel has not yet evaluated the wines, we speculate USA) and SPSS1 (SPSS Corp., Chicago, USA). that none of the wines will show UTA off-flavour du- ring the sensory. CHRISTOPH et al. (1995) found a thres- Results and Discussion hold level of 1.5 mg/L for AAP in red wines. Thus, de- spite the AAP concentrations in 'Lemberger' (max. GC/MS analysis showed that AAP content is increased 1.76 mg/L) and 'Merlot' (max. 1.15 mg/L), the off-fla- in 'Chardonnay', 'Riesling', 'Lemberger', and 'Merlot' vour will most likely not be detectable due to the mas- wines made from GA3 treated grapevines, albeit this king effect of polyphenols in these wines as already dis- trend is not always statistically significant at p50.05 le- cussed elsewhere (CHRISTOPH et al., 1995; POUR NIK- vel (Table 1). At p50.13 level the differences are stati- FARDJAM et al., 2005b). stically significant for all four varieties. As a result our results support our earlier findings that

125 Mitteilungen Klosterneuburg 56 (2006): 124-126 Pour Nikfardjam et al.

GA treatment of grapevine flowers might increase HEDDEN, P. and PROEBSTING, W.M. 1999: Genetic analysis of 3 gibberellin biosynthesis. Plant Physiol. 119: 365-370 AAP content in some varieties. The application of this KORKAS, E., NERANTZIS, E., KOURTIDOU-TYMBA, P. und BANILAS, phytohormone to achieve looser grape clusters (as a G. 1999: Einfluss einer variierten GibberellinsaÈure-Ap- means against bunch rot and related diseases) is, thus, plikation zu verschiedenen phaÈnologischen Entwick- lungsstadien auf Ertrags- und QualitaÈtsparameter bei connected with certain risk factors. More studies are der Tafeltraube Sultanina (Vitis vinifera L.) in Griechen- necessary to analyse the influence of GA during va- land, Teil I: Bei der VergroÈ sserung der Gescheine und 3 zum Fruchtansatz oder zur BluÈ te. Vitic. Enol. Sci. 54: rying weather conditions on the AAP content of Vitis 44-53 vinifera L. wines. POUR NIKFARDJAM, M.S., GAAÂ L, K. and TESZLAÂ K, P. 2005a: In- fluence of grapevine flower treatment with gibberellic acid (GA3) on indole-3-acetic acid (IAA) content of References . Mitt. Klosterneuburg 55(3/4): 114-117 POUR NIKFARDJAM, M.S., GAAÂ L, K., TESZLAÂ K, P., K RECK, M. and BEN-TAL, Y. 1990: Effects of gibberellin treatments on ripening DIETRICH, H. 2005b: Influence of grapevine flower treat- and berry drop from Thompson Seedless grapes. Am. J. ment with gibberellic acid (GA3) on o-aminoacetophe- Enol. Vitic. 41: 142-146 none (AAP) content and sensory properties of white CHRISTOPH, N., BAUER-CHRISTOPH, C., GESSNER, M. und KOÈ H- wine. Mitt. Klosterneuburg 55(5/6): 184-190 LER, H.J. 1995: Die ªUntypische Alterungsnoteª im POUR NIKFARDJAM, M.S., GAAÂ L, K. und TESZLAÂ K, P. 2005c: Was Wein, Teil I: Untersuchungen zum Auftreten und zur verbindet Gibberellin mit UTA? Dt. Weinbau (15): 22-25 sensorischen Charakterisierung der ªUntypischen Alte- RAPP, A., VERSINI, G. und ENGEL, L. 1995: Nachweis und Be- rungsnoteª. Rebe und Wein 48(10): 350-356 stimmung von 2-Aminoacetophenon in vergorenen Mo- GRAEBE, J.E., DENNIS, D.T., UPPER, C.D. and WEST, C.A. 1965: delloÈ sungen. Vitis 34: 193-194 Biosynthesis of gibberellins, I. The biosynthesis of (-)- TESZLAÂ K, P., G AAÂ L, K. and POUR NIKFARDJAM, M.S. 2005: In- kaurene, (-)-kauren-19-ol, and trans-geranylgeraniol in fluence of grapevine flower treatment with gibberellic endosperm nucellus of Echinocystis macrocarpa greene. acid (GA3) on polyphenol content of Vitis vinifera L. J. Biol. Chem. 240: 1847-1854 wine. Anal. Chim. Acta 543: 275-281 GUELFAT-REICH, S. and SAFRAN, B. 1973: Maturity responses of Sultanina grapes to gibberellic acid treatments. Vitis 12: 33-37 Received June 8, 2006

Erratum Der Artikel ¹Polyphenole und antioxidative KapazitaÈt in oÈ sterreichischen Weinen aus konventioneller und biologischer Traubenproduktionª von OTREBA, J.B. et al. (Heft 1-2, 2006) wurde irrtuÈ mlicherweise nicht in der endkorrigierten Version in Druck ge- geben. Auf Seite 24, rechte Spalte, letzter Absatz muss der Satz ¹Unvermeidlich, wenngleich auch umstritten ist der Einsatz von KupferpraÈparaten gegen Oidium.ª richtig heiûen ¹Unvermeidlich, wenngleich auch umstritten ist der Einsatz von KupferpraÈparaten gegen Peronospora.ª Wir bedauern das Versehen. Die Redaktion

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