White Grape Varieties Research Articles

Evolution of the Polyphenolic Content of Moravian White Grape Variety Wines of Different Vintages During Storage

Wine is known as a source of bioactive compounds and is one of the alcoholic beverages with the highest phenolic content. There has been growing interest in the composition of wine due to its beneficial properties for human health. This work focuses on biologically active and sensory attributes of white wine and presents research on wine chemical profiles in relation to their geographical origin, varieties and storage. The aim of this study was to investigate the phenolic compound evolution of 35 selected white wine varieties from the Moravian region in the Czech Republic. To separate and identify individual phenolic compounds in the wines, the high-performance liquid chromatographic method was used. A spectrophotometric method was applied for the determination of total polyphenol and total flavonoid content. This research presents results for the total benzoic and cinnamic acid derivatives, flavonols, flavanols and stilbene content of Moravian white grape varieties. Differences were found in the content of these compounds, and the results show that the phenolic concentrations depend on grape variety and storage time.

STUDY OF PECTIN SUBSTANCES DURING STORAGE OF DIFFERENT VARIETIES OF TABLE GRAPE GROWING IN AZERBAIJAN

This study is aimed at solving the problem of providing the population with fresh grapes not only for one or two months, but all year round. To increase the terms of consumption of this valuable raw material, the most appropriate varieties and conditions for storing grapes were determined.
 The objects of study were unripe, ripe (ripe) and overripe table grape varieties widely used in the country (white varieties – Ganja table and Garaburnu, pink grape varieties – Marandi Shamakhinsky, Taifa pink, as well as red grape varieties Chernaya Asma and Pobeda). As a result of the study, it turned out that unripe and overripe red table grape varieties (Chernaya Asma and Pobeda) are richer in pectin compared to other varieties. They contain pectin substances up to 0.40–0.50 g/100 cm3. According to the content of pectin substances, pink varieties of grapes are in second place – 0.42–0.28 g/100 cm3. From a comparison of grape varieties, it is known that the amount of pectin in white table grape varieties is less than in other varieties – 0.36–0.25 g/100 cm3.
 During the storage of white table grape varieties, pectin decreased within the range of 24.0–48.0%, protopectin - by 16.6–38% and for pectin this indicator decreased by 5%. This figure was 7.1–50% in pink and 23.7–45% in red table grape varieties. The decrease in pectin during storage is associated with an increase in the activity of pectin enzymes. Therefore, it is considered expedient to store table grape varieties in a refrigerator according to the first option, i.e. under conditions of RHS 3–4% CO2 and 2–3% O2, at a relative humidity of 85–92%.
 And also studies have shown that for long-term and high-quality storage in a refrigerator, three options are more suitable: from white grape varieties Ganja table, from pink varieties – Marandi Shamakhinsky, and from red varieties – Black Asma.

Vitamin content and MDA levels of certain white grape varieties from different altitudes in Turkey

Grapevine (Vitis vinifera L.) is regarded as one of the world's most important fruit crops in terms of acreage and commercial worth. Grapes are used to make not only wine but also fresh fruit, dried fruit, and juice. The quality of grapes or wine is significantly affected by environmental factors such as altitude, soil type, and climate. In this study, the 5 white grape varieties (Ağın beyazı, Tahannebi, Kabarcık, Şilfoni, and Besni) grown at different altitudes (800 m, 1000 m and 1200 m) in Turkey were investigated for their vitamin, and phytosterol concentrations as well as lipid peroxidation content. Şilfoni grape harvested at 800 m was found to possess the lowest lipid peroxidation content. High altitudes, were found to reduce lipid peroxidation contents in the Ağın beyazı, Tahannebi, and Kabarcık strains. The highest stigmasterol (98.34 µg/g), and beta-sitosterol (86.90 µg/g) concentrations were found within Şilfoni grape variety harvested at 800 m. The highest vitamin D-2 and D-3 levels were found in Ağın beyazı (1.39 µg/g) and Kabarcık (4.13 µg/g) grape varieties, both harvested at 1200 m. Kabarcık grape, however, revealed the highest concentrations of R-tocopherol (63.09 µg/g) and alpha-tocopherol (24.13 µg/g) at 1200 m within the samples. The highest vitamin K-2 level was determined within the Tahannebi grape (15.44 µg/g) from 1200 m. It was observed that the vitamin and phytosterol concentrations of white grape varieties tended to increase, while the lipid peroxidation values tended to decrease at high altitudes, especially at 1200 m. This study also exhibited a strong relationship among Vitamin D3, R-tocopherol, and alpha-tocopherol in the studied white grape cultivars. Keywords: Vitis vinifera; White grape; Vitamin; MDA; Altitude

Effect of Grape Pomace Varieties and Soil Characteristics on the Leaching Potential of Total Carbon, Nitrogen and Polyphenols

Grape pomace (GP) has an added value because of its contribution to carbon (C) and nitrogen (N) in soils when applied as an organic fertilizer. Macronutrients from GP are translocated into the soil after amendment, but little is known about the factors that may influence the mobility of C, N and bioactive molecules, i.e., polyphenols, in the soil column. We investigated the mobility of the macronutrient content of GP, derived from two red (Dornfelder and Pinot noir) and two white grape varieties (Riesling and Pinot blanc). For that, three different soils (loamy sand RefeSol01A, silt loam RefeSol02A and a vineyard soil) were evaluated in a column model using a GP application rate of 30 t ha−1. The three-step lab-scale approach included the analysis of total C, N and polyphenols expressed as total polyphenolic content (TPC) in: (a) the fresh GP, representing the total amount of C, N and TPC; (b) the mobility with rainwater, representing the aqueous extractable fraction and (c) the mobility in the soil column and leaching potential. Our results showed that total C/N ratios were wider in the white GP varieties compared with the red ones. Higher TPC values were measured in Dornfelder and Pinot noir compared with white varieties. Analysis of the water-extractable fraction showed that the C recovery may reach up to 48% in Pinot blanc, which also corresponds to the highest N contribution. Extractable polyphenols were higher in the red compared with the white varieties by a factor of 2.4. C and N were mobilized with rainwater from the GP through the soil column. However, the application rate used in the experiment was not indicative of an accumulation in the soil. Compared with the control (no GP application), C values were significantly higher in the leachates from GP-treated soils, in contrast to N values. Up to 10% of the TPC of the pomace was leached into the soil. The TPC recovery in the soils strongly depended on the combination of soil type and GP variety. Generally, the sandy and more acidic soil showed an even distribution of phenolics with a high recovery rate (up to 92%) compared with more neutral and silty soil. Most of the polyphenol content could accumulate in the upper soil layer (0–10 cm). These results provide the first insights on the mobility of macronutrients in the soil using a column model and point out the need to relate those experiments to soil and GP properties in order to avoid the accumulation of nutrients in soil or mobility to adjacent ecosystems.

Assessment of Bioactive Phenolic Compounds in Musts and the Corresponding Wines of White and Red Grape Varieties

Wine contains important amounts of antioxidants, which contribute to the protection of the body from oxidative stress and associated diseases. This study aims to characterize the bioactive characteristics and individual polyphenolic composition of different white and red musts and the corresponding wines obtained at Stefanesti vineyard, Romania, and to observe the evolution of the main phenolic compounds from the musts to the corresponding wines. General bioactive characteristics (total polyphenols, total tannins, total catechins, total anthocyanins contents, total tannin, and antioxidant activity) were determined using UV-Vis spectrometric methods, while phenolic composition (phenolic acids, flavonoids, and stilbenes) was detected using UHPLC–HRMS analysis. The fermentation and stabilization processes that occur during the transformation of musts into the corresponding wines lead to a decrease in the general bioactive characteristics from musts to wines, while the fermentation of the musts leads to an enrichment of the individual phenolic compounds in the corresponding wines, with a significant increase in the content of gallic, syringic, and p-coumaric acids in the wines compared with the musts. A clear distinction of the musts and wines was obtained for both white and red varieties, indicating different phenolic compositions of the musts and wines. The obtained results contribute to the characterization of the polyphenolic fingerprint of the investigated white and red musts and wines.

Improvement of the production technology of tokay wines based on the revealed effect of enzyme activity on the quality of grape variety

Wines of the Tokay type are produced using a special technology. According to Hungarian technology, for the production of these wines, bunches of white and red grape varieties are twisted on the vine, withered for a certain time, then dropped for processing. At the same time, the percentage of sugar in grapes is artificially increased due to the evaporation of moisture. In pre-dried grapes, the percentage of sugar should be in the range of 40–45 %. For the production of Tokay-type wines, the fermentation of grape must is carried out naturally without the addition of alcohol and other ingredients. After formation in the must of 14‒16 vol. % alcohol, the fermentation process is suspended naturally. As a result, natural sugar and alcohol remain in the wine material. Withered grape varieties, despite their high sugar content, are economically inefficient due to low juice yield and a quantitative decrease in extractive substances. Thus, the enrichment of wine material for the production of Tokay-type wines has not been studied. As an object of research, ripe technical grape varieties Bayan Shirey, Rkatsiteli, Cabernet Sauvignon, Madrasa cultivated in the foothills of the Geygol district and in the low-lying zone of the Samukh district were used. Grape varieties were harvested from the vineyards of the winery, located in the Goygol district and from the farm "Amin", located in the village of Gara-Yeri, Samukh district. For the production of wine, both ripe and separately withered grape varieties were used, twisting on the vine for 10–12 days. However, when twisted on the vine, about 15–20 % of the bunches of grapes break and fall to the ground. Further, in ripe and withered grape varieties, the quantitative content of dry matter, total sugar, including glucose and fructose, phenolic compounds, titratable acidity, vitamin C, and in both variants the yield of unclarified juice was determined separately. The regularities of increasing the activity of enzymes of the class oxidoructase and a representative of hydrolase-pectinesterase were considered. The results make it possible to adjust the quality indicators of grape varieties depending on their zoning and use them for the production of high-quality Tokay-type wines.

Vine Foliar Treatments at Veraison and Post-Veraison with Methyl Jasmonate Enhanced Aromatic, Phenolic and Nitrogen Composition of Tempranillo Blanco Grapes.

Methyl jasmonate (MeJ) is an elicitor that, when applied in the vineyard, can improve grape quality. There are several studies about the MeJ influence on red grape varieties; however, to our knowledge, there is little information about white grape varieties, specifically Tempranillo Blanco. Therefore, the aim of this work is to evaluate the effect of MeJ foliar treatments, carried out at veraison and post-veraison, on the aromatic, phenolic and nitrogen composition of Tempranillo Blanco grapes. The results showed that grape volatile compounds content increased after MeJ application, especially terpenoids, C13 norisoprenoids, benzenoids and alcohols, and, in general, mainly at post-veraison. Regarding phenolic and nitrogen compounds, their concentrations were enhanced after MeJ treatments, regardless of application time. Consequently, MeJ treatment improved grape volatile, phenolic and nitrogen composition, particularly when this elicitor was applied post-veraison. Therefore, this is a good and easy tool to modulate white grape quality.

Comparative Phenolic Profiles of Monovarietal Wines from Different Croatian Regions

The phenolic profile of wines is often used to evaluate their quality and authenticity. The phenolic composition of twenty-five commercial wines produced in different Croatian regions from eight red and nine white grape varieties was studied. A total of twenty-four polyphenols were analyzed using HPLC-DAD and classified into five groups based on their structure: phenolic acids, flavan-3-ols, anthocyanins, flavonoids, and stilbenes. The red wines contained higher concentrations of phenolic constituents than the white wines, of which gallic acid (11.8–90.3 mg/L), procyanidin B1 (13.7–63.8 mg/L), and catechin (10.5–34.5 mg/L) were the most abundant. In contrast to the white wines, great variability was observed in the red wines, with the autochthonous Plavac Mali and Babić showing the most specific phenolic profiles. The most representative phenolic components in the studied Croatian wines showed strong antioxidant activity. Gallic acid proved to be the most effective DPPH (IC50 = 0.33 µg/mL) and NO scavenger (IC50 = 12.36 µg/mL), while myricetin was the most potent inhibitor of lipid peroxidation (IC50 = 1.68 µg/mL). Our research has contributed to the characterization and varietal differentiation of Croatian wines, highlighting those rich in certain polyphenols as potential nutraceuticals.

RNA-Seq Based Transcriptomic Analysis of Bud Sport Skin Color in Grape Berries

The most common bud sport trait in grapevines is the change in color of grape berry skin, and the color of grapes is mainly developed by the composition and accumulation of anthocyanins. Many studies have shown that MYBA is a key gene regulates the initiation of bud sport color and anthocyanin synthesis in grape peels. In the current study, we used berry skins of ‘Italia’, ‘Benitaka’, ‘Muscat of Alexandria’, ‘Flame Muscat’, ‘Rosario Bianco’, ‘Rosario Rosso’, and ‘Red Rosario’ at the véraison stage (10 weeks post-flowering and 11 weeks post-flowering) as research materials. The relative expressions of genes related to grape berry bud sport skin color were evaluated utilizing RNA-Seq technology. The results revealed that the expressions of the VvMYBA1/A2 gene in the three red grape varieties at the véraison stage were higher than in the three white grape varieties. The VvMYBA1/A2 gene is known to be associated with UFGT in the anthocyanin synthesis pathway. According to the results, VvMYBA1/A2 gene expression could also be associated with the expression of LDOX. In addition, a single gene (gene ID: Vitvi19g01871) displayed the highest expressions in all the samples at the véraison stage for the six varieties. The expression of this gene was much higher in the three green varieties compared to the three red ones. GO molecular function annotation identified it as a putative metallothionein-like protein with the ability to regulate the binding of copper ions to zinc ions and the role of maintaining the internal stable state of copper ions at the cellular level. High expression levels of this screened gene may play an important role in bud sport color of grape berry skin at the véraison stage.

Improving the Aromatic Profiles of Catarratto Wines: Impact of Metschnikowia pulcherrima and Glutathione-Rich Inactivated Yeasts

Catarratto is one of the most widely cultivated grape varieties in Sicily. It is an indigenous non-aromatic white grape variety. Despite its widespread use in winemaking, knowledge of the aroma and chemical and microbiological properties of Catarratto wines is quite limited. The influence of Metschnikowia pulcherrima combined with Saccharomyces cerevisiae on the aromatic expression of Catarratto wines was investigated with and without the addition of glutathione-rich inactivated yeast. The substance is a natural specific inactivated yeast with a guaranteed glutathione level used to limit oxidative processes. The aromatic profiles of the final wines were determined through analysis of the volatile organic compounds using a solid-phase microextraction technique that identified 26 aromatic compounds. The addition of M. pulcherrima in combination with the natural antioxidant undoubtedly increased the aromatic complexity of the wines. Dodecanal was exclusively detected in the wines processed with glutathione-rich inactivated yeasts. Furthermore, the presence of this natural antioxidant increased the concentration of six esters above the perception threshold. Sensory analysis was also performed with a panel of trained judges who confirmed the aromatic differences among the wines. These results suggest the suitability of glutathione-rich inactivated yeasts for determining the oxidative stability of Catarratto wines, thus preserving its aromatic compounds and colour.

Innovation and Winemaking By-Product Valorization: An Ohmic Heating Approach

The by-products of the winemaking process can represent chances for the development of new products. This study focused on the “zero waste” strategy development for by-products generated within winemaking from white and red grape varieties cultivated in the north of Portugal. The phytochemical properties of by-products were identified and characterized. Ohmic heating (OH) as a green extraction method was also applied to grape pomace due to their unknown effects on centesimal and phytochemical compositions. Both protein and carbohydrates were shown to be higher in grape bagasse than in stems. Additionally, red bagasse is richer in bioactive compounds (BC) than white bagasse. The sugar content was 21.91 and 11.01 g/100 g of DW in red and white grape bagasse, respectively. The amount of protein was 12.46 g/100 g of DW for red grape bagasse and 13.18 g/100 g of DW for white. Regarding the extraction methods, two fractions were obtained, a liquid fraction and solid (the remainder after the methodology application). OH presented a higher antioxidant capacity than a conventional (CONV) method. In addition, both extracts presented similar contents of anthocyanins, e.g., delphinidin-3-O-glucoside, petunidin-3-O-glucoside, and peonidin-3-O-glucoside. The solid fraction presented higher amounts of protein and phenols bound to fiber than CONV, which allows its use as a functional ingredient. In conclusion, OH can be an alternative extraction method compared with CONV methods, avoiding non-food grade solvents, thus contributing to circular economy implementation.

Chemical characterization of four ancient white wine grapes (Vitis vinifera L.) from the Amalfi coast

Minor grape varieties often possess key traits to produce wines with specific territorial identity. Italy is home to a wide selection of autochthonous grapevines. In 2005, four white grape varieties from the Amalfi coast, Fenile, Ginestra, Pepella and Ripoli were registered in the National Catalogue grapevines. They are all complementary varieties with a rich biodiversity and linked to an ancient wine heritage. Studies on such varieties have not been conducted yet. Here, the metabolite content of the above four grape varieties is described. Ripoli was the richest in quercetin derivatives while very low was the content of kaempferol derivatives; Pepella possessed an equal amount of quercetins and kaempferols; Ginestra and Fenile featured a quercetins abundance twice that of kaempferols. Also, the (+)-catechin content was higher than (–)-epicatechin's; B-type procyanidins occurred in higher concentrations in Pepella and Ripoli than in Fenile and Ginestra. Hydroxycinnamic acids were also identified and quantified. Seeds from each variety were carefully analyzed and flavanols were identified up to decamers along with their galloylation percentage. The obtained data are a tool of variety differentiation and useful to develop appropriate vinification procedures to ameliorate the quality of wines.

Genetic diversity of some autochthonous white grape varieties from Romanian germplasm collections

We investigated the phenotypic and genetic diversity among 25 grapevine accessions of white grape maintained in a germplasm collection ex situ. The selected varieties were characterised using standardised ampelographic descriptors and microsatellite markers to obtaintheir complete description. The ampelographic analysis based on 24 OIV descriptors and the obtained first dendrogram based on common features, revealed the extent of the phenotypic diversity ranging from 0.29 (between Coarnă albă and Chardonnay) to 0.92 (between Crâmpoşie and Cioinic), without any connection with their supposed origin or the current geographic area of distribution. The SSR allelic analysis with nine standard markers proved and confirmed its high discrimination potential for genotype identification and diversity. The second cluster analysis aimed to evaluate the genetic relationships among analysed accessions,based on Dice’s similarity coefficient, revealed two groups of varieties: the first group (A) included twelve accessions with a degree of similarity between 0.37 and 0.5. The second (B) included eleven accessions, with a similarity degree between 0.33 and 0.67. The genotypic cluster analysis showed a distinct lower similarity between the Majarcă albă variety and all the varieties from the first group, and between Busuioacă de Bohotin and all the analysed varieties. The phenotypic and genetic matrices and dendrograms, although not correlated, were complimentary and provided valuable information about the diversity of the grapevine genotypes and the identification of the synonyms.

The research of factors affecting the amount of aromatic compounds in white muscat wine samples

While the amount of free aromatic compounds in the juice prepared by the White method from the White Muscat grape variety cultivated in the foothill Agsu region located at an altitude of 800 m above sea level was 2040 µg/dm3, the amount of the same compounds was 2626 µg/dm3 in the samples prepared by storage of pomace for 5 hours. In the samples from the Samukh (79 m) region, the amount of free aromatic compounds was much lower compared to the Agsu region. A total of 35 bound aromatic compounds including 4 alcohols, 3 six-carbon compounds, 13 terpenes, 7 volatile acids, 4 volatile phenols, and 4 norisoprenoids were detected in the juice samples made from the White Muscat grape variety grown in both regions. A total of 60 volatile compounds were found in wine samples, including 17 alcohols, 15 ethers, 13 acids, 5 aldehydes and ketones, 1 terpene, 5 volatile phenols, 4 lactones, and 1 aldehyde compound. This is much more compared to the amounts of the same compounds in juice, and it is related to the new formation processes that occur during alcohol fermentation.

Special characteristics of technological indicators of white aboriginal grape varieties

Sparkling wines are high in demand, and they firmly occupy their strong position in wine market. In recent years, there was a reorientation of consumers from the low-price segment of sparkling wines to the mid-price and premium ones, motivating the manufacturer to be searching for new solutions for the unique high-quality wine production. One of the ways of its producing is the use of aboriginal grape varieties. At the same time, there is insufficient information about the distinctive technological characteristics of aboriginal grape varieties, which makes it difficult to release a product of high-quality. As a research result, significant indicators were established (the mass concentrations of titratable acids, proteins, polysaccharides, the content of phenolic substances in the must without contact with the pulp, the content of phenolic substances in the must after extraction of the pulp for 4 hours, the technological stock of phenolic substances) to differentiate grapes in accordance with the origin, and characterize their technological potential. A comparative analysis of aboriginal grape varieties with classical cultivars traditionally used in sparkling wine production was carried out. Deviations in the criterion technological indicators of aboriginal grape varieties were established to be taken into account when selecting grape processing technology for high-quality sparkling wine production.

Kaolin foliar-application improves the photosynthetic performance and fruit quality of Verdejo grapevines

Currently there is an urgent need to adapt vineyards to climate change in order to maintain and improve the quality of wines. In this context, it has been shown that the creation of a film of mineral particles, such as kaolin, on the vegetation can reduce stress caused by high temperatures in plants. The present study evaluated the effects of kaolin foliar-applications, from fruit set to veraison, on the physiological and agronomic behavior of a Verdejo white variety vineyard located in DOP Rueda (Spain). Compared to the controls, treated plants showed an increase in the photosynthetic performance, registering higher values of chlorophyll fluorescence parameters such as Fv/Fm, ΦPSII and ETR, and lower values of F0. Without affecting vigor and yield, grapes from treated vines produced musts with lower pH and phenolic content and greater color luminosity than those of untreated vines. The presented results suggest that kaolin treatments could be an effective tool to minimize the negative effects of climate change on the quality potential of white grape varieties grown in continental areas.

Influence of grapevine age on general physicochemical and phenolic parameters of Rabigato (Vitis viniferaL.) white variety: Results from three vintages

The preservation of the old vine heritage, combined with the fact that old vines could present greater resistance to biotic and abiotic factors, has led to an increase in research studies about the contribution of vine age on grape and wine quality. Thus, the main goal of this work was to evaluate the potential influence of grapevine age on several general physicochemical and phenolic parameters during grape maturation of a Rabigato white grape variety. Therefore, grapes from two adjacent vineyards, with an age difference of 30 years (one with 20 years and the other with 50 years, at the beginning of this study) were studied. At technological maturation, the results obtained for the three consecutive vintages studied (2019 to 2021), and for the general physicochemical parameters analysed, do not seem to indicate a clear differentiation between the grape musts obtained from the younger and the older vineyards. However, for grape phenolics, the results suggest that vine age could be a potential factor on phenolic content, nevertheless not totally confirmed by the results at technological maturation during the three consecutive vintages considered. With this work we will contribute to expand the knowledge about the potential impact of the vine age on grape composition.

Determining quality indicators of table grape varieties during storage in a refrigerating chamber in different variants

This study considers determining the quality indicators of table grape varieties when stored in a refrigerating chamber for different variants. The objects were white table grape variety, widely used in Azerbaijan, Ganja table grape variety, pink grape variety – Marandi Shamakhi, as well as the red grape variety Black Asma. Grape varieties stored in the refrigerator were studied according to five options. Table grape varieties were stored in a refrigerating chamber under conditions of an adjustable gas environment (3–4 % CO2, 2–3 % О2) at a temperature of –1 and –2 °C, with air humidity of 90–95 %. It was found that at a temperature inside the pulp of 0+1 °C, the activity of enzymes decreased significantly compared to other options. In addition to the enzyme ascorbate oxidase, the activity of the studied enzymes o-diphenol oxidase, peroxidase, and catalase was 100 % suppressed in the Marandi Shamakhi grape variety. The inactivation of enzyme activity prevented the consumption during respiration of the nutrients that make up the grapes. As a result of slowing down metabolic processes, the appearance, naturalness, and nutritional value of the Marandi Shamakhi grape variety are significantly superior to other varieties. When storing grape varieties according to option 5, the smallest total losses were observed in the Marandi Shamakhi grape variety. Very few microbiological losses were detected during the storage of the Marandi Shamakhi grape variety compared to other variants and varieties. It was stored in a refrigerating chamber in a controlled gas environment (3...4 % CO2, 2–3 % О2, at the temperature of the chamber of –2…–3 °C). A tasting was also carried out to determine the quality indicators when storing grape varieties in different versions; for version 5, the assessment was high

АГРОБИОЛОГИЧЕСКАЯ И ТЕХНОЛОГИЧЕСКАЯ ОЦЕНКА СОРТОВ ВИНОГРАДА СПАРТАНЕЦ МАГАРАЧА И РИСЛИНГ МАГАРАЧА В ЗАПАДНОМ ПРЕДГОРНО-ПРИМОСРКОМ РАЙОНЕ ВИНОГРАДАРСТВА КРЫМА

Agrobiological and technological indicators of wine grapevine varieties ‘Riesling Magaracha’ and ‘Spartanets Magaracha’ bred in the Institute Magarach and cultivated in the piedmont-coastal region of Crimean viticulture are presented. The variety ‘Aligote’ is taken as a control. The production period duration for ‘Spartanets Magaracha’ variety was 132 days, corresponding to the early-medium time of ripening, and for ‘Riesling Magaracha’ variety - 144 days, corresponding to the medium ripening period. According to the potential of heat supply, the soil-climatic conditions of the western piedmont-coastal region of Crimean viticulture (3640 ºС) can be considered as favorable for cultivation of the studied grape varieties. The varieties studied exceed the control variety in terms of the indicators: "fruiting coefficient" ‒ 1.1‒1.16, "average bunch weight" ‒ 220.0‒240.0 g, "yield per bush" - 3.36-3.52 kg/bush, and "shoot productivity by the raw bunch weight" ‒ 242.0‒278.4 g/shoot. In accordance with tasting assessment, table (7.80‒7.85) and dessert (7.80) base wines made of white grape varieties ‘Riesling Magaracha’ and ‘Spartanets Magaracha’ are promising for both table and dessert winemaking.

Characterization of Polyphenols in a Sicilian Autochthonous White Grape Variety (PDO) for Monitoring Production Process and Shelf-Life of Wines

Sicilian wines have shown a growing expansion in the international market, and over 60% of the production of them is focused on quality products. Grillo is a white grape variety, and it is among the best-known variety, with a cultivated area of 6300 ha and with the vocation of being particularly predisposed to aging for years or even decades. This paper aimed to perform a physiochemical (SSC and pH) and polyphenolic characterization of Grillo wines that were produced by a selected winery in the years 2011–2021 using an optimized RP-HPLC-DAD method. The polyphenols fraction was assessed by means a semiquantitative analysis on which, statistical processing was carried out. The HCA and PCA highlighted the presence of three clusters in the samples. Cluster 1 was composed of the samples from the years 2011–2014, cluster 2 composed of the samples from 2015–2017, and cluster 3 composed of the samples from 2019–2021. Using an HSD Tukey test, it was possible to point out that some compounds were makers of specific clusters and therefore, specific vintages. This preliminary study showed that polyphenols are suitable markers that can be used to identify Grillo vintages, and they should be also related to the storage conditions or different production processes.