Tokaj Wine Research Articles

Handling multiblock data in wine authenticity by sequentially orthogonalized one class partial least squares

New approach to deal with food authentication by modelling methods based on data recorded from different sources is proposed and called OC-PLS, combines an orthogonalization step between the different data sets to eliminate redundant information followed by definition of an acceptance area for a target class by OC-PLS. The proposed method was evaluated in two case studies. The first study used a controlled scenario with simulated data. In the second case study, the approach was applied using UV–VIS and IR data, in order to differentiate Slovak Tokaj Selection wines of high quality from other lower market value wines from the Slovak Tokaj wine region. In both cases, better results were reached than when individual blocks of data were achieved. The proposed method proved to be effective in properly exploring common and distinct information in each data block. The best compromise between sensitivity and selectivity in the prediction step was achieved.

Héjon erjesztett natúrborok vizsgálata

The ancient white wine making technology, the “qvevri”, is gaining more and more attention among consumers, not only because it is unique and special, but also because sustainability and closeness to nature are fundamental characteristics of this winemaking process. All of this is demonstrated by the fact that this ancient Georgian process using traditional clay vessels was added to the UNESCO List of Intangible Cultural Heritage of Humanity in 2013, and in 2020, The International Organisation of Vine and Wine (OIV) included skin-fermented white wine in the category of special wines. This wave is also present in Hungary, since “natural” wine and “orange wine” have already appeared in a 2021 law as „Other restricted terms”. The essence of the winemaking process is skin-contact fermentation and microoxidation, for which a number of vessels can be used: amphoras or qvevris, ceramic eggs or spin barrels, as a function of which the chemical composition of the wines may vary, as well as the formation of the precursor compounds of the aroma components. In this study, natural wines produced in the Tokaj wine region, using amphoras and ceramic egg vessels were examined.

The Biocontrol Potential of Endophytic Trichoderma Fungi Isolated from Hungarian Grapevines. Part I. Isolation, Identification and In Vitro Studies.

This paper reports on the identification and in vitro characterization of several Trichoderma strains isolated from the Tokaj Wine Region in North-East Hungary. Ten isolates were analyzed and found to consist of six individual species—T. gamsii, T. orientale, T. simmonsii, T. afroharzianum, T. atrobrunneum and T. harzianum sensu stricto. The growth potential of the strains was assessed at a range of temperatures. We also report here on the in vitro biocontrol properties and fungicide tolerance of the most promising strains.

Comparison study of nanofibers, composite nano/microfiber materials, molecularly imprinted polymers, and core-shell sorbents used for on-line extraction-liquid chromatography of ochratoxins in Tokaj wines

On-line solid phase extraction coupled with liquid chromatography enables high sample throughput, preconcentration of analytes, efficient clean-up, and separation in a single step. Our comparison study focused on the selection of an optimal SPE sorbent for on-line extraction of ochratoxins A and B allowing fast and sensitive control of mycotoxin contamination. Four types of fibrous sorbents including polyethylene microfibers, polypropylene microfibers, polycaprolactone microfibers/nanofibers composite, and polycaprolactone microfibers/polyvinylidene difluoride nanofibers composite together with selective molecularly imprinted polymers, and conventional C18 core–shell particle sorbent were tested, and efficiency of extraction was compared in on-line mode. Clean-up efficiency and ability to remove matrix interferences with the subsequent chromatographic separation were optimized for all extraction materials followed by validation of the methods. Both nanofibers and molecularly imprinted polymer sorbents were packed in a stainless-steel cartridge and directly connected to the HPLC system. Only polyethylene microfibers among all the tested fibers achieved the selectivity desired for resolution of ochratoxins from the wine matrix with the validation parameters comparable to commercial C18 sorbent. The best results featuring a limit of detection 0.03–0.06 µg L-1, recoveries 92–97% with RSD < 2%, and only 6 min overall analysis time were obtained after extraction using C18 particles. Features including stability of fibers in organic solvents, under high pressure, and their multiple reusability were also proven. Comparison of several types of extraction sorbents for ochratoxins was demonstrated with their on-line extraction followed by liquid chromatography with fluorescence determination using Tokaj wine as a complex matrix.

Above-ground parts of white grapevine Vitis vinifera cv. Furmint share core members of the fungal microbiome.

Grapevine (Vitis vinifera) is a reservoir of fungal endophytes that may affect its growth, health status and grape production. Although there is growing interest in comparing fungal communities of mainly red grape varieties across various factors using only high-throughput sequencing, the small-scale mycobiome variations in geographically close vineyards need further examination. We aimed to characterize the fungal microbiome of the above-ground tissues of V. vinifera cv. Furmint in different plant parts, seasons and sites using culture-dependent and culture-independent methods, and in planta fluorescent microscopic visualization techniques. Samples were collected from four sites of the Tokaj wine region in Mád and two reference sites in Eger, Hungary, across different seasons for 2 years. Fungal endophytes of young and mature leaves, flowers and grape bunches were collected at different phenological stages. Based on each technique, Aureobasidium pullulans, Cladosporium spp. and the complex species Alternaria alternata dominated the community at every site, season and plant organ. We found no significant difference among communities in distinct neighbouring vineyards, nor when compared with the distant reference sites. We can conclude that the different shoot parts of the Furmint grapevines harbour a common core group of fungal community in these regions.

A fast and inexpensive approach to characterize Slovak Tokaj selection wines using infrared spectroscopy and chemometrics

The Tokaj Selection wines (hungarian equivalent “Aszú”) are typical noble sweet wines produced in Tokaj wine region that falls within two countries, Slovakia and Hungary. Taking into account the economic importance and uniqueness of these wines, in this work, a new, fast and inexpensive method that combines infrared spectroscopy and multivariate models for characterization Slovak Tokaj Selection wines was developed. At first, sample authentication via one class models (dd-SIMCA) considered Slovak Tokaj Selection wines as target class. The non-target sample was considered to be only a Tokaj sample of Slovak origin. The resulting model was able to properly recognize samples of the target class with high sensitivity and specificity. Subsequently, the putňa index was predicted via PLS models. RMSEP equals 0.44; REPpred of 9.6 and R2 0.95 was found in prediction step.

Slovak Tokaj wines classification with respect to geographical origin by means of one class approaches

Tokaj wines could be produced only in so called Tokaj/Tokay wine region that falls within two countries Slovakia and Hungary. Thus, wines bearing Tokaj appellation must be produced only in Hungary and Slovakia by traditional process. Unfortunately, some counterfeit wines from neighbour region in Ukraine could be found in market. The aim of this work is to explore a simple UV–VIS spectrum to recognise true Tokaj/Tokay wines from counterfeits and try to differentiate wines based on their country of origin. This type of question can be duly answered using one class classification approach. Two different approaches, Data Driven Soft Independent Modelling of Class Analogy - DD-SIMCA and One-Class Partial Least Squares – OC-PLS were tested and evaluated for this purpose. In both cases, rigorous way models were built and optimized using only samples of the target class. A set of external samples containing samples from target class and non-target were used to validate the models ability to recognize Slovak samples and reject non-Slovak samples. Model based on DD-SIMCA showed better performance (97% correct rating) compared to OC-PLS models (80% correct rating). Comparing both approaches in terms of sensitivity and specificity, both exhibit high sensitivity (low false negative rate: DD-SIMCA 95% and OC-PLS 100%), however the OC-PLS based model showed low specificity (40%) while DD-SIMCA showed high specificity (100%) rejecting all samples out of Slovak origin. Therefore, the results found in this study show that it is possible to successfully combine UV–VIS spectra and DD-SIMCA models to discriminate Tokaj wine samples of Slovak origin from others. Equally important is environmentally friendly (fast, simple, absence of solvents) classification method in line with green chemistry.

NEW TENDENCIES IN WINE TOURISM IN TOKAJ WINE REGION (HUNGARY): THE DECREASING ROLE OF TOKAJI ASZÚ AS A DOMINANT BRAND

: The aim of paper is to explore the economic, social and political changes in Tokaj Wine Region (Hungary) in last 30 years and present their consequences on wine tourism. We analysed the data regarding European Union grant application of economic enterprises and we conducted personal interviews with the leaders of some of the major wineries of the region. Among significant changes which have taken place in Tokaj Wine Region since 1990s the following have to be mentioned: change in ownership of wineries, the evolution in the techn ology of winemaking, the new activity of state government and local authorities, the increase in the number of wine varieties produced and European Union financial support. Wine tourism in the region has undergone significant changes (increase role of smaller wineries and wine varieties). Settlements on the western side of the region are becoming increasingly important.

Distinct volatile signatures of bunch rot and noble rot

Bunch rot and noble rot development were simultaneously instigated on healthy Vitis vinifera cv. Furmint bunches collected in the Tokaj wine region in Hungary. Bunches transferred into a growth chamber with controlled temperature and humidity exhibited symptoms of the two forms of botrytization. Berries exposed to noble rot-inducing conditions gradually dehydrated and showed higher level of soluble solids but less biomass of Botrytis cinerea in comparison with berries subjected to bunch rot. GC-MS analysis of volatile compounds produced by the berries revealed obvious differences in the emission of odorants between bunch rot and noble rot.

Regional hydrogeology of the Tokaj Mountains world heritage site, North-East Hungary

Tokaj Mountains, as a large Miocene volcanic region in North-East Hungary, is the homeland of the famous Tokaj wine. The Tokaj wine region can be found on the world heritage list of UNESCO. Although there were several mineral prospecting activities at the Tokaj Mountains in the 1960s and 1970s, the groundwater resources on a regional scale have not been revealed yet. The regional water budget and the groundwater flow systems were not known before the complex hydrogeological investigations recently carried out by the University of Miskolc. Although shallow groundwater is being produced at some small-scale waterworks to cover local drinking water demands, it has believed that there is no chance to find thermal water and to extract underground heat in this volcanic area because of the average hydraulic conductivity of the subsurface formations is very low. It is encouraging that intensive tectonic lines were determined by geophysical methods during the recent field campaigns. The presence of valuable thermal water resources was discovered along these tectonic lines opening new perspectives in geothermal exploration in this region. After the extensive field measurements, a regional scale groundwater-flow model was constructed to characterize the subsurface flow systems and the available shallow and deep groundwater resources of the Tokaj Mountains. A special prospecting methodology involving geological, hydrogeological and surface geophysical methods was elaborated to find thermal water resources in this complex geological/ecological environment.

Determination of Ochratoxin A and Ochratoxin B in Archived Tokaj Wines (Vintage 1959-2017) Using On-Line Solid Phase Extraction Coupled to Liquid Chromatography.

According to the EU legislation, ochratoxin A contamination is controlled in wines. Tokaj wine is a special type of sweet wine produced from botrytized grapes infected by “noble rot” Botrytis cinerea. Although a high contamination was reported in sweet wines and noble rot grapes could be susceptible to coinfection with other fungi, including ochratoxigenic species, no screening of Tokaj wines for mycotoxin contamination has been carried out so far. Therefore, we developed an analytical method for the determination of ochratoxin A (OTA) and ochratoxin B (OTB) involving online SPE coupled to HPLC-FD using column switching to achieve the fast and sensitive control of mycotoxin contamination. The method was validated with recoveries ranging from 91.6% to 99.1% with an RSD less than 2%. The limits of quantification were 0.1 and 0.2 µg L−1 for OTA and OTB, respectively. The total analysis time of the online SPE-HPLC-FD method was a mere 6 min. This high throughput enables routine analysis. Finally, we carried out an extensive investigation of the ochratoxin contamination in 59 Slovak Tokaj wines of 1959–2017 vintage. Only a few positives were detected. The OTA content in most of the checked wines did not exceed the EU maximum tolerable limit of 2 µg L−1, indicating a good quality of winegrowing and storing.

Enantiomer composition of chiral compounds present in traditional Slovak Tokaj wines

In the presented study volatile organic compounds (VOC) profiles of the most valuable products from Slovak Tokaj wine region were characterized using SPME-GC-MS. Identified volatile organic compounds in studied samples of Tokaj selection wines and Tokaj essences belonged to esters, terpenes, higher alcohols, volatile acids, lactones and aldehydes. From identified VOC, chiral compounds were selected, and their enantiomers were separated by heart-cut two-dimensional GC system. Enantiomer separation was optimized, and this advanced method was applied to determine enantiomeric ratios (ER) of studied compounds in 53 traditional botrytized Tokaj wines. Terpenic compounds linalool and limonene were present in ER resembling the racemic mixture, hotrienol expressed the slight dominancy of S-enantiomer (51–82 %) and S-α-terpineol varied from 47 to 70 %. Moreover, linalool and limonene were present only in wines of younger vintages. ER of 2,3-butanediol has shown the predominance of 2R,3R-enantiomer in all samples even though reached also values that were not usual for common white wines (55–100 %). Whiskey lactones were identified in all wines aged in oak barrels and exclusive presence of (4S,5S)-cis- and (4S,5R)-trans- enantiomers was confirmed.

Introducing historical landscape in the cultural heritage conservation through the example of the Tokaj wine region in Hungary

The Tokaj wine region has been declared as a historical landscape by the decree of the National Ministry of Human Capacities in 2012. The historical landscape is defined in the Act LXIV of 2001 on the Protection of Cultural Heritage as an area under the preservation of Historical Monuments. The Tokaj Wine Region is the only legally recognized historical landscape in Hungary. This protection aims to preserve the historical built and natural environment as well as the traditional land use methods. The historical landscape, in the case of Tokaj, is a legal tool to increase the heritage protection level of the wine region. Nevertheless, no further details have yet been communicated on the preservation method. In this matter, protection remains on the level of discourse which puts emphasis on the expected perspectives in territorial planning and development. It may create a narrative that might potentially transform the territory. The region of our case study has been inscribed as a cultural landscape on the UNESCO World Heritage List and was added to the World Heritage List in 2002. Besides, the national government recognized the region as a territory of priority development in 2014 and a territory of priority touristic development in 2017. The area in question is marked by the stark contrast between social inequality and the image of the prestigious wine sector. In this paper, after providing a discussion of the institutional background of the adoption of the historical landscape in Hungary, I describe the different protection tools from the perspective of heritage conservation in order to reflect on the conception of the historical landscape: how was the region recognized as a historical landscape, and what was the purpose of this recognition? The main aim of the paper is to analyse the institutional process that led to the integration of a new object of protection in Hungary, called historical landscape.

Expression Activity of Allergen Coding Genes in Grape Varieties Used for Tokaj Wine Production

Abstract Vitis vinifera L. is adapted to a very variable range of climates but it mostly grows in the temperate regions of continental Europe. In the Slovak Republic, the Tokaj wine region is one of the territories, where wine production is concentrated. Grape is a popular fruit and when processed, it is used as musts, juices or wine. Some people may suffer from allergic reactions to grapes. Up to now, endochitinases, lipid-transfer protein, and thaumatin were identified as grape allergens. In this study, expression of chitinase and thaumatin allergen was analysed in the grapes of Tokaj region varieties – Hachat Lovelin, Tokay and Muskat Blanc. Expression changes were calculated by the delta delta Ct method. Expression differences of chitinase were found to be similar in these varieties. Thaumatin was found to be variable in its transcription.

Comparison of Different Categories of Slovak Tokaj Wines in Terms of Profiles of Volatile Organic Compounds.

The present work deals with the characterization of volatile organic compounds (VOCs) in wines from the Slovak Tokaj wine region. Studied wine samples were divided into three groups—varietal wines from registered Tokaj vine varieties, film wines Tokajské samorodné dry, and naturally sweet botrytized wines Tokaj selections. The VOCs from wines were extracted using optimized solid phase microextraction (SPME) and analyzed by comprehensive two-dimensional gas chromatography (GC×GC) coupled to high-resolution time-of-flight mass spectrometry (HRTOF-MS). In total, 176 VOCs were identified in all 46 studied samples. It was found that the total number of VOCs in varietal wines was generally higher than in botrytized wines. All three studied categories showed characteristic VOC profiles with significant differences. Varietal wines were characterized by higher concentrations of esters and terpenoids originating from grapes. The presence of γ-octalactone, (E)-6-methylhept-2-en-4-one, and lack of benzaldehyde were typical for Tokajské samorodné dry. Tokaj selections expressed the highest concentration of diethyl malate, benzaldehyde, and furfurals. Several interesting trends were also observed. The concentration of fermentation products was highest in varietal wines, while long-term matured Tokaj special wines were typified by the presence of compounds related to noble-rotten raisins (2-phenylacetaldehyde, ethyl 2-phenylacetate, and 2-phenylethanol), wood (cis-whisky lactone), and aging (1,1,6-trimethyl-2H-naphthalene, furfural, and 5-methylfurfural).

Detection of microbiota in the vineyards of the Tokaj wine region

Tokaj is an important Central European wine-growing area with controlled planting and authorized varieties of white vines. This area has a specific microflora composition which changes based on its climate dependence, as well as during the fermentation process of wine production. Therefore, the aim of this study was, by culture examination of the samples, to detect the microbiota of soil, leaves, berries and fermentation must from two vineyards from the Slovak part of Tokaj. The highest total viable count (5.60 ±0.01 log cfu.g-1) and the highest total yeast and mould count (4.32 ±0.01 log cfu.g-1) in soil samples were recorded in vineyard Berecký. The highest total viable count in soil samples (6.71 ±0.01 log cfu.g-1) was confirmed by examination of samples originating from the vineyard of Čierna Hora. When determining the total yeast and mould count, the highest numbers were recorded in the must samples (4.15 ±0.01 log cfu.mL-1). Lactic acid bacteria were collected in samples from both vineyards, only in very low numbers. Overall, statistically significant differences (p &lt;0.001) were detected by comparing the microbiota of the samples taken from the Berecký and Čierna Hora vineyards. The specific characterisation and identification of yeast was carried out using ITS-PCR-RFLP methods. The analysis confirmed the presence of yeasts of Saccharomyces cerevisiae, Zygosaccharomyces bailii, Zygosaccharomyces rouxii, Candida parapsilosis and Candida tenuis and their subsequent transfer to the must at varying percentages.

Assessment of Tokaj varietal wines with comprehensive two-dimensional gas chromatography coupled to high resolution mass spectrometry

Botrytised wines produced in Tokaj region belong to a special category of sweet wines described with a pleasant honey-like taste and a distinctive fruit flavour. Specific technological process of wine-making developed on macerating of noble-rotten berries in fermented juice or wine, results in alcoholic beverage indicated with the 'Protected Designation of Origin' label. A limited number of publications is devoted to analysis of Tokaj wines or by-products (e.g. individual varietal wines, essencia and must) which directly related to final characteristics of botrytized wine. A combination of two-dimensional gas chromatography connected to high-resolution mass spectrometry (GC × GC-HRTOFMS) offers enhanced separation and reliable identification of organic compounds presented in complex samples. In our study, this technique was applied to analyse varietal wines of the Tokaj wine region produced from three main grape cultivars (Furmint, Lipovina and Muscat Blanc à Petits Grains). The primary task was reliable separation and identification of low volatility compounds (acetamides, 2H-pyrrole- and 2H-pyran-based heterocyclic compounds and sulphur containing compounds) because of the lack of available information in this area. Thus, it revealed the presence of 1(3H)-isobenzofuranone, ethyl 1H-indole-3-acetate and 2-(methylmercapto)benzothiazole which were not previously detected in wine. Furthermore, trace aroma compounds (terpenoids and lactones) was quantified with modified stir bar sorptive extraction method which provided LOD and LOQ values of 2.3–4.7 ng/L and 7.7–15.8 ng/L, respectively. Linear calibration dependencies with correlation coefficients varying between 0.960 – 0.996 were obtained.

Coumarins content in wine: application of HPLC, fluorescence spectrometry, and chemometric approach.

In this work, high performance liquid chromatography (HPLC) and fluorescence spectrometry methods for determination of natural coumarins in Tokaj wine were developed and compared. Molecularly imprinted solid phase extraction procedure was applied for sample preparation. The separation of esculin, coumarin, herniarin, 4-methylumbelliferone, scoparone, scopoletin was performed on core-shell C18 type of stationary phase (100 × 4.6mm, 5µm) with a gradient elution of mobile phase containing 1% aqueous solution of acetic acid and methanol, UV-VIS (280nm for coumarin) and fluorescence detection (Ex 320nm, Em 450nm for other coumarins). The HPLC method was validated in term of linearity, limit of detection, limit of quantification, precision and accuracy. Fluorescence detection offers high sensitivity with limit of detection in the ngmL-1 range. Scopoletine and 4-methylumbelliferone were identified and quantified in tested wines. Emission spectral data, synchronous fluorescence spectra of coumarins from fluorescence spectrometry and total concentrations of coumarins quantified by the HPLC method were used in the partial least squares regression. The linear regression between the concentrations predicted by the partial least squares model versus true values obtained by HPLC method confirmed good agreement between the two methods.

Application of solid-phase extraction for isolation of coumarins from wine samples

Abstract Coumarins can be as a result wine storage and aging in wood drums and they can affect organoleptic characteristics of wine. The aim of this work was to determine the content of coumarins in wine samples originated from Slovak Tokaj wine region. The HPLC method with high specificity, accuracy, precision, and recovery was proposed. SPE sorbents of C18 type, styrene-divinylbenzene copolymer and molecularly imprinted polymers were compared for extraction of six coumarins, coumarin, aesculin, scoparone, scopoletin, 4-methylumbelliferone, and herniarin. Higher recoveries (above 89 %; except aesculin – recoveries higher from 68 %, RSDs less than 6 %) were obtained with selective polymeric sorbent laboratory prepared by molecularly imprinted technology. The results showed that content of coumarins in wine samples are in ng.mL−1 concentration levels and depend on the age and wine puttony.

Preservation of diversity and oenological properties of wine yeasts during long-term laboratory maintenance: A study of strains of a century-old Tokaj wine yeast collection

The effect of long-term laboratory maintenance on the biological diversity and certain oenolological properties of wine yeasts was investigated by the analysis of 17 strains isolated from Tokaj (Hungary) wines more than a century ago and maintained since then in culture collections. The analysis of the D1/D2 domains of the large subunit ribosomal RNA genes and the ITS sequences assigned them all to S. cerevisiae but divided them into two groups. One group showed sequence identity with wine strains occurring mainly in countries of the region. The combined results of the interdelta, RAPD, microsatellite-primed PCR (MSP), mtDNA and karyotype analyses found both groups diverse and defined each strain as unique, demonstrating that the long period of maintenance under identical conditions has not resulted in convergent evolution in their genomes. High diversity was detected also in certain phenotypic traits of oenological relevance (osmotolerance, killer phenotype, production of glycerol, ethanol, H2S and volatile acids). In the microvinification experiments all strains performed better than the laboratory strain S288c and were comparable to the industrial strain used as a control or even surpassed it in certain parameters. Thus, the oenological abilities of wine yeasts can be preserved over long periods of maintenance under laboratory conditions.