MI EILUNGEN KLOSTERNEUBURG 69 2019: 7682 BENE et al. COMPARISON OF SELECTED PHENOLIC COMPONENTS OF WHITE QVEVRI WINES Z B1, M K2, B O H2 and D N-S2 1 University of Miskolc, Institute of Marketing and Tourism HU-3515 Miskolc, Egyetemváros 2 Szent István University, Department of Oenology HU-1118 Budapest, Ménesi út 45 E-Mail: [email protected] e so-called qvevri wines, on-skin fermented white wines in clay vessels, have been gaining international a ention from winemakers, importers, sommeliers, consumers and journalists over the last decade. Due to the employed Kak- hetian technology, the amount and the composition of polyphenols of these wines are modi ed compared to wines from conventional white wine technology. is could be a valuable feature of qvevri wines, for example, elevated catechin levels could be responsible for more pronounced health bene ts. In Hungary, among others, the grape vari- ety 'Zéta' is used for making qvevri wines, but around the globe various grape varieties are employed. A considerable diff erence between a conventional and a qvevri 'Zéta' wine was found in terms of the total antioxidant status, total polyphenol and catechin contents. During the comparison of the experimental 'Zéta' samples with Georgian and non-Georgian qvevri wines made of various varieties, it was found that only 'Zéta' and 'Ribolla' wines were similar to the Georgian varieties, whereas others have signi cantly lower polyphenol and catechin concentrations. 'Zéta' proved to be a suitable choice for Kakhetian technology, in terms of total polyphenols and catechin. Keywords: Kakhetian technology, 'Zéta', polyphenols, catechin, total antioxidant status Vergleich von ausgewählten phenolischen Komponenten in weißen Amphorenweinen. Die sogenannten Ampho- ren- oder Quevri-Weine, auf der Maische in Tongefäßen vergorene Weißweine (Orange Wine-Technologie), haben im letzten Jahrzehnt internationale Beachtung bei Winzern, Importeuren, Sommeliers, Konsumenten und Journalis- ten gefunden. Aufgrund der Maischegärung sind die Gehalte und die Zusammensetzung der Polyphenole dieser Wei- ne im Vergleich zu Weinen aus konventioneller Weißweinproduktion verändert. Dies könnte ein wertvolles Merkmal von Quevri-Weinen sein, zum Beispiel könnte ein erhöhter Catechingehalt für einen ausgeprägteren gesundheitlichen Nutzen verantwortlich sein. In Ungarn wird unter anderen die Rebsorte 'Zéta' für die Herstellung von Quevri-Wei- nen verwendet, aber weltweit werden verschiedene Rebsorten verwendet. Ein beträchtlicher Unterschied zwischen einem konventionellen und einem Quevri-Zéta-Wein wurde im Hinblick auf die antioxidative Kapazität und die Gesamtgehalte von Polyphenolen und Catechin festgestellt. Beim Vergleich der experimentellen Zéta-Proben mit georgischen und nicht-georgischen Quevri-Weinen verschiedener Sorten wurde festgestellt, dass nur die Zéta- und Ribolla-Weine den georgischen Sorten ähnlich waren, während andere deutlich geringere Polyphenol- und Catechin- konzentrationen aufwiesen. 'Zéta' erwies sich als geeignete Wahl für die Orange Wine-Technologie in Bezug auf Ge- samtpolyphenole und Catechin. Schlagwörter: Orange Wine, Amphorenwein, Quevri, Polyphenole, 'Zéta', Catechin, antioxidative Kapazität --- 76 --- MI EILUNGEN KLOSTERNEUBURG 69 2019: 7682 BENE et al. Georgia is undoubtedly one of the roots of winemaking, roles in winemaking. e composition of phenolic sub- where the ancient Kakhetian method is still kept alive. stances varies with the diff erent grape variety, matura- Since 2013, the uniqueness of the qvevri technology has tion, ecological parameters, oenological and viticultu- been acknowledged as being inscribed to the National ral practices, etc. (S, 1982). Some of these Monument of Intangible Cultural Heritage list of the plant-related compounds, namely the avonoids, have UNESCO. e key of this technology, which is widely a valuable health-promoting eff ect as antioxidants, with employed in Caucasia, is the clay pot/amphora/qvevri anti-in ammatory, anti-carcinogen, cardioprotective, vessel, where not only the (mostly spontaneous) alco- anti-viral, anti-microbial, anti-helminthic, hepatopro- holic fermentation occurs, but which is also an aging tective, anti-hormonal, anti-thrombotic, and anti-neo- container. Another important detail of this method is plastic activities (D B et al., 2002; L and that both white and red wines are produced with long H, 2009). Catechin is a avonoid, non-tannin skin-contact and with a minimum of added chemical phenol according to P and P’ categorisati- agents (B, 2011). e employed local gra- on (1971), which, as an abundant grape polyphenol, pe varieties are speci c to this region and more import- could be responsible for some of the above-mentioned antly suitable for qvevri technology. Nowadays, this tra- positive eff ects on human health. During the Kakhetian ditional way of winemaking is gaining more and more technology, the elongated maceration in the qvevri ves- a ention outside the Caucasian area, in Hungary as well. sel enables the juice to extract higher amounts of these It could have multiple importance, rst, as an alternative components as far as they are available in the grape berry method, which widens the white wine assortment of the skin. Consequently, these wines could be more eff ective wineries; secondly, in the market and the gastronomy in health-protection (S et al., 2012; T- these wines are highly valued; thirdly, it supports the et al., 2015). global trend to minimize the necessary chemical treat- In Hungary 'Pinot gris', 'Tranimi' and 'Zéta' qvevri wines ments in the industry, so it enables low-intervention wi- are available on the market, either fresh, non-aged ones nemaking (D et al., 2013). with considerable fruitiness or more complex ones with e Georgian qvevri wines have a number of special che- roasted character. (B and P, 2017). In terms mical properties due to the technology employed. e of the polyphenols and health bene ts, the question most obvious is the increased amount and unique com- emerges whether the Georgian grape varieties are more position of polyphenols and antioxidants (S suitable or other grape varieties employed all around the et al., 2007; S et al., 2012). Besides, there world for this particular technology are just as approp- are several earlier studies about the increased amount of riate. mineral components from the clay contact (D et al., In the present study, the total polyphenol and catechin 2013; J C et al., 2018) and the unique volati- content of a Hungarian qvevri wine made of 'Zéta' gra- le composition (M et al., 2018) and the interes- pe variety was investigated and compared with litera- ting indigenous yeast microbiota (C et al., 2013; ture ndings, about qvevri wines made of Georgian and V et al., 2016). other grape varieties. Grape berries are rich in polyphenols, whose secondary metabolites form a heterogeneous group with various --- 77 --- MI EILUNGEN KLOSTERNEUBURG 69 2019: 7682 BENE et al. MATERIAL AND METHODS e grape material came from a organic vineyard. well multiple comparison test and an α = 0.05 criteria 'Zéta' (Vitis vinifera L., Furmint × Bouvier) is a using IBM SPSS so ware, Statistics for Windows, Versi- Hungarian grape variety, which has an import- on 23.0 (IBM Corporation, Armonk/New York, USA). ance in the Tokaj wine region. (H, 2013). Pilot-scale fermentation was carried out from the same RESULTS AND DISCUSSION grape crop with diff erent technologies in triplicates. Conventional white wine technology (Conventional Alcoholic fermentation was completed in case of both 'Zéta' = CZ): grape processing, must treatments, pres- technologies, each experimental wine was dry (Table sing and fermentation in stainless steel containers with 1). Fortunately, the volatile acidity did not increase si- a neutral commercial Saccharomyces cerevisiae starter gni cantly due to the Kakhetian technology (QZ: long, culture (Uvaferm 228; Lallemand, Blagnac, France). spontaneous fermentation, without sulphur dioxide pro- Kakhetian wine technology (Qvevri 'Zéta' = QZ): tection). In the measured major parameters, the two tech- destemmed and crushed grapes were racked into nologies did not result in considerable diff erences, except glazed amphoras (from Légli Pot Manufacture, for the colour intensity, which could be explained by the Szőlőskislak, Hungary), spontaneous fermentati- longer skin-contact and micro-oxidization trough the clay on for 5 weeks, pressing, then aging in amphoras. pores. ere was a signi cant diff erence in the TAS bet- A er 6 months of aging, samples were taken from ween the CZ and QZ samples due to the technology em- each container and stored at -18 °C until analysis. ployed. However, both values are in correspondence with Analytical methods were employed according to the re- earlier reports, since the usual range in case of normal commendation of the International Organisation of Vine white wines is 4,3 to 8,4 mmol/l (S et al., 2008), and Wine (OIV), if available. Alcohol (OIV-MA-AS312- in case of qvevri wines 3,6 to 18,2 (D et al., 2013). 01A), volatile acidity (OIV-MA-AS313-02), colour in- Due to the long on-skin fermentation, the total polyphenol tensity (OIV-MA-AS2-07B), total polyphenol content in content of the QZ samples is closer to the usual red wine gallic acid equivalent (OIV-MA-AS2-10), reducing sugar interval (1800 to 4000 mg/l), than that of the conventional (Schoorl’s method), titratable acidity (expressed as g white wines (170 to 300 mg/l). Similarly, the health-protec- tartaric acid/), catechin