Grape Varieties Research Articles

Combustion and Energy Parameters of Grape Pomace/Skin Waste in Wine Production—Regent Variety Grafted onto Rootstocks

The study presents the potential use of winemaking residues, specifically grape pomace, for energy purposes. The pomace was obtained from the cultivation of the Regent grape variety on three different rootstocks—125AA, 161-49, and SO4—as well as a control group grown on its own roots. The research included determining the calorific value and combustion heat, conducting a technical and elemental analysis of the potential biofuel, as well as estimating emission indicators (CO, CO2, NOx, SO2, and particulate matter) and the theoretical volume of flue gases based on stoichiometric equations. The study revealed significant differences among the combustion heat, tested properties and calorific value, ash content, and the total volume of flue gases. The highest calorific value (17.7 MJ kg−1) and combustion heat (18.9 MJ kg−1) were obtained for pomace from the SO4SO4 rootstock, while the lowest values were observed in the control group (17.0 MJ·kg−1 and 15.8 MJ·kg−1, respectively). The highest ash content was also recorded for the SO4 rootstock (9.2%), with the lowest in the control group (6.7%). The control group exhibited the lowest CO2 emissions at 1390.50 kg·Mg−1, while the highest emissions were found in the pomace from the SO4 rootstock (1478.8 kg·Mg−1). Regarding the total flue gas volume, the highest volume was estimated for the pomace from the 125AA rootstock (7.8 m3·kg−1) and the lowest for the control group (7.3 m3·kg−1). The research demonstrated that grape pomace possesses favorable energy properties and could serve as a potential biofuel, contributing to the fuel and energy balance of agricultural production enterprises. The analyzed biomass exhibits properties similar to agrobiomass.

Physico-chemical and Mineral Composition of White Seeded Raisin Varieties (Vitis vinifera L.) Grown under Semi-arid Condition

Raisins (dried grapes) are preferred for their distinctive, delightful flavor, high nutritional content, and their potential to lower the risk of several serious and chronic conditions. The quality of raisins is crucial, as it has a direct impact on the health and well-being of those who consume them. The present study assessed the physiochemical composition, mineral content, and sensory parameters of white seeded raisins. The physiochemical parameters such as raisin weight, raisin recovery, pH, moisture, ash, carbohydrate, protein, and mineral content (potassium, phosphorus, calcium, magnesium, sodium, copper, iron, and zinc) were assessed. Result revealed that the grape variety Pandhari Sahebi showed higher raisin weight and protein content. Hussain Kadu recorded maximum moisture and carbohydrate content. Significantly, higher potassium and iron content was noted in Hussain Kadu. Based on the results, Hussain Kadu was preferred for raisin colour, texture and overall acceptability.

Influence of different rootstocks on the characteristics of Vermentino wines at altitudes in Santa Catarina

The objective of this study was to determine the best rootstock that enhances the enological characteristics of the Vermentino grape variety cultivated in the high-altitude region of Santa Catarina, Brazil, over three vintages (2018, 2019, and 2020). Four rootstocks were evaluated: '101-14 Mgt', 'Harmony', 'Paulsen 1103', and 'VR 043-43'. The physicochemical and sensory properties of the wines were assessed. The findings revealed that the rootstocks '101-14 Mgt', 'Harmony', 'Paulsen 1103', and 'VR 043-43' produced wines with the lowest total acidity in the 2019 vintage. The alcohol content was notably lower in wines produced with 'VR 043-43' in 2021. Sensory analysis indicated that wines made with the '101-14 Mgt' and 'Harmony' rootstocks in the 2019 vintage exhibited higher turbidity. The herbaceous character was most pronounced in the 2019 vintage, with a stronger herbaceous aroma regardless of the rootstock used. Acidity levels were highest in the wines from the 2021 vintage, particularly in those made with the 'Harmony' and 'VR043-43' rootstocks.

Identification and validation of qRT-PCR reference genes for analyzing grape infection with gray mold

BackgroundGrapes are highly valued for their nutritional and economic benefits, and have been widely studied for their biological attributes such as fruit development, quality formation, and stress resistance. One significant threat to grape quality is gray mold, caused by Botrytis cinerea, which can infect the flowers, fruits, leaves, and stems. The quantitative real-time PCR (qRT-PCR), known for its high sensitivity and quantitative accuracy, is an essential tool for analyzing gene expression related to the pathogenesis of gray mold, thereby providing deeper insights into the disease.ResultIn this study, we aim to identify stable internal reference genes crucial for accurate gene expression analysis via qRT-PCR. Utilizing transcriptome data from grapes under various disease stresses, we identified twelve candidate reference genes with consistently high expression levels. The stability of these genes was assessed through delta-CT, geNorm, NormFinder, BestKeeper, and RefFinder analyses after establishing the cycling thresholds (Ct) in different grape varieties treated with Botrytis cinerea.ConclusionsOur findings reveal that VIT-17s0000g02750 and VIT-06s0004g04280 exhibit stable expression and are suitable as new reference genes. This foundational work supports further research into the molecular mechanisms of grape biological processes.

Metabolic Profiling and Stable Isotope Analysis of Wines: Pilot Study for Cross-Border Authentication

Globalization and free market dynamics have significantly impacted state economies, particularly in the wine industry. These forces have introduced greater diversity in wine products but have also heightened the risk of food fraud, especially in high-value commodities like wine. Due to its market value and the premium placed on quality, wine is frequently subject to adulteration. This issue is often addressed through regulatory trademarks on wine labels, such as Protected Designation of Origin (PDO) and Protected Geographic Indication (PGI). In this context, the metabolic profiles (organic acids, carbohydrates, and phenols) and stable isotope signatures (δ13C, δ18O, D/HI, and D/HII) of red and white wines from four agroclimatically similar regions were examined. The study explored how factors such as grape variety, harvest year, and geographical origin affect wine composition, with a particular focus on distinguishing samples from cross-border areas. Multivariate statistical analysis was used to assess the variability in wine composition and to identify distinct groups of samples. Preliminary results revealed that organic acids and volatile compounds were found in lower concentrations than carbohydrates but were significantly higher than phenols, with levels ranging between 1617 mg/L and 6258 mg/L. Carbohydrate content in the wines varied from 8285 mg/L to 14662 mg/L. Principal Component Analysis (PCA) indicated certain separation trends based on the variance in carbohydrates (e.g., fructose, glucose, galactose) and isotopic composition. However, Discriminant Analysis (DA) provided clear distinctions based on harvest year, variety, and geographical origin.

Evaluation of green residues management of selected grape varieties

The paper presents the possibilities of energy management of residues from the cultivation of grapes of the ‘Regent’, ‘Rondo’ and ‘Seyval Blanc’ cultivars. The research was conducted in southeastern Poland in the Sandomierska Upland in 2022. The aim of the research was to demonstrate the influence of grape variety on yield capacity in relation to the extraction of biomass residues in the form of leaves. An attempt was made to identify the variety that is characterised by obtaining the most effective and average parameters, i.e. yield size and quality, leaf mass and surface area, and their impact on energy and fuel parameters. The study analysed the following crop parameters, i.e. number and mass of grapes, number and mass of berries; leaf quality parameters, i.e. mass including petioles and area. An energy assessment in Laboratory in Department of Power Engineering and Transportation was carried out by performing proximate and ultimate analysis and estimating emission factors and volumetric composition of exhaust gas. The study showed that the material with the highest energy potential was characterised by ‘Regent’, while the lowest potential was shown for ‘Rondo’. Grapevines of the ‘Rondo’ cultivar were characterised by the highest obtained biomass among the evaluated varieties. The research showed that the most effective in practical cultivation is the use of the Regent variety, which was characterised by the average parameters of the obtained yield and growth values, and the highest fuel energy potential.

Exploring the Interplay of Bud Load and Pruning Type in Shaping ‘Xinomavro’ (Vitis vinifera L.) Vine Growth, Yield, and Berry Composition

‘Xinomavro’ (V. vinifera L.) is an important native red wine grape variety in Northern Greece, particularly in PDO (protected designation of origin) regions. Despite its significance, there is limited research on the effects of pruning type and severity on ‘Xinomavro’ vine physiology, yield, and berry quality across diverse environmental conditions. This study aimed to address this knowledge gap and provide growers with crucial information for optimizing vineyard management practices. The study was conducted over two consecutive years (2016 and 2017) in a vineyard in Thessaloniki, Northern Greece. Four treatments (B12: 12 buds on 6 spurs, B24: 24 buds on 12 spurs, M12: 12 buds on 2 canes, and M24: 24 buds on 4 canes) combining two bud load levels (12 or 24 count nodes) and two pruning types (short spurs or long canes) were applied to ‘Xinomavro’ vines in a complete block randomized design. The vine water status, gas exchange, canopy characteristics, yield components, and berry composition were measured. Bud load and pruning type significantly influenced vine canopy development, microclimate, and yield components. Short pruning with high bud load (B24) resulted in denser canopies and higher yields, whereas cane pruning (M12 and M24) led to more open canopies and improved berry quality indicators. Treatment effects on berry composition were inconsistent across years but showed a tendency for higher anthocyanin and total phenol content in cane-pruned vines. This study demonstrates that pruning type (short or long fruiting units) may have a greater impact on vine growth, yield, and berry composition than bud load alone in ‘Xinomavro’ vines. Cane pruning appears to be a more effective strategy for achieving vine balance and potentially improving grape quality under given experimental conditions.

Влияние концентрации и рецептуры макросолей в питательной среде на показатели регенерации меристем, на этапе ввода в культуру in vitro, у некоторых аборигенных донских сортов винограда

Abstract. Rare indigenous grape varieties are of significant value for viticulture, breeding and preservation of genetic material. Often, ancient grape varieties, due to prolonged vegetative propagation, are infected with one or more chronic diseases (viruses, phytoplasmas, bacterial cancer). The most reliable way to improve the health of such plants is the method of apical meristems in in vitro culture. In which, on artificial nutrient medium, it is necessary to regenerate the plant from isolated extremely small apical explants (about 50-100 microns). One of the most important components of nutrient medium are macroelements. Not only their quantity is of great importance, but also the compounds they represent, as well as the balance and ratio of all elements in the nutrient medium. In this regard, the purpose of our study was to study the characteristics of mineral nutrition of grape plants of native Don varieties in in vitro culture. To do this, we studied the effectiveness of the most commonly used nutrient media in microclonal propagation. The experiments were carried out on four rare native Don varieties Plechistik oboepolyi, Bessergenevskiy №10, Musketnyi and Durman. Protocols used: Murashige and Skuug (MS), McCown Wood Plant (WPM), Chee and Pool (C2D), Quoirin & lepoivre (QL) and Anton Rebrov (AR1). The nutrient media differed only in the composition of macrosalts; all other components were added in equal quantities. The varietal response of the studied varieties was different. The Plechistik oboepolyi and Bessergenevskiy №10varieties regenerated best, and the Musketnyi and Durman varieties regenerated more poorly. It has been established that the composition of macroelements significantly affects the regeneration and differentiation of shoots in apical meristems. For most varieties, the most stable results were observed when using WPM and AR1 nutrient media. The worst development of explants in all varieties in the study occurred on MS and C2D media. Key words: apical meristem, introduction into in vitro culture, regeneration of explants, recipes for nutrient media, concentration of macronutrients, native Don varieties

Agrobiological reaction of Centennial Seedless grape variety to changes in the numberof shoots and bunches on bushes

Agrobiological reaction of Centennial Seedless grape variety to changes in the numberof shoots and bunches on bushes

Amur Grape VaMYB4a-VaERF054-Like Module Regulates Cold Tolerance Through a Regulatory Feedback Loop.

Cold stress can limit the growth and development of grapevines, which can ultimately reduce productivity. However, the mechanisms by which grapevines respond to cold stress are not yet fully understood. Here, we characterized an APETALA2/ethylene response factor (AP2/ERF) which was shown to be a target gene of our previously identified VaMYB4a from Amur grape. We further investigated the molecular interactions between VaMYB4a and VaERF054-like transcription factors in grapes and their role in cold stress tolerance. Our results demonstrated that VaMYB4a directly binds to and activates the VaERF054-like gene promoter, leading to its enhanced expression. Moreover, we also explored the influence of ethylene precursors and inhibitors on VaERF054-like expression and grape cold tolerance. Our findings indicate that VaERF054-like contribute to cold tolerance in grapes through modulation of the ethylene pathway and the CBF signal pathway. Overexpression of VaERF054-like in Vitis vinifera 'Chardonnay' calli and transgenic grape lines resulted in increased freezing stress tolerance, confirming its role in the cold stress response. We further confirmed the interaction between VaMYB4a and VaERF054-like in vivo and in vitro. The co-transformation of VaMYB4a and VaERF054-like in grape calli demonstrates a synergistic interaction, enhancing the cold tolerance through a regulatory feedback mechanism. Our finding provides new insights into grape cold tolerance mechanisms, potentially contributing to the development of cold-resistant grape varieties.

Comprehensive amino acids profiling: Grape varieties grown in California and in Tuscany, Italy.

Twenty-three amino acids and glutathione were profiled in 33 juices: Cabernet sauvignon, Cabernet franc, and Merlot grown in Bolgheri, Tuscany, Italy, and Napa Valley, CA, as well as Petit Verdot grown in Napa Valley, CA. The method was carried out by online pre-column derivatization followed by ultra-high performance liquid chromatography with fluorescence detection; residual standard deviation values for repeatability (n=20) were<5%. All amino acids could be successfully separated in these samples within 18 min. The most abundant amino acids, PRO, γ-aminobutyric acid, and ARG, varied by two-, two-, and three-fold, respectively, across all of the grape juices sampled. Comparisons between grape juices based on their geographic origin and variety were made with principal component analysis and hierarchical cluster analysis. Merlot juices from both regions were correlated differently by amino acids profile than Cabernet sauvignon and Cabernet franc juices. The amino acids profile in Merlot juices was more similar between most sites in Bolgheri. In contrast, Cabernet sauvignon and Cabernet franc juices had a higher similarity between vineyards in Bolgheri and vineyards in Napa Valley. Overall, most of the amino acids quantified in Cabernet franc juices and, to a lesser degree, Cabernet sauvignon juices from Bolgheri and Napa Valley vineyards were strongly correlated with each other.

Закладка виноградника на основе принципов энерго-ресурсосбережения

Abstract. The article contains materials that form the basis of a feasibility study (FS) for laying a vineyard (from planting to fructification), developed according to the principle of energy and resource conservation provided for in the project assignment. The project documentation is being developed in order to optimize the complex of sequential technological operations and production processes aimed at creating a sustainably functioning viticultural economy. The general principles of energy and resource conservation include: the latest achievements of science and best practices in the field of viticulture, rational use of land funds, thanks to preliminary soil surveys, optimized varietal composition, design of plantings and compact placement of arrays with the prospect of irrigation, reduction of energy losses to the level of operationally unavoidable, the use of highly concentrated, complex agrochemicals and methods of their application, the availability of appropriate infrastructure, design estimates optimized with the prospect of improvement and modernization (energy and resource-saving object estimates), planned economic productivity of plantations, measures to maintain the economic fertility of soils corresponding to the biological requirements of grape culture, which determines the stability and productivity of perennial plantations. Methodological approaches and current methods, publications of a recommendatory nature used for the development of a feasibility study are indicated. The successive stages of the development of project documentation are considered, the techniques that contribute to reducing the costs of production processes are outlined. The recommended regionalized and promising assortment of grapes for the formation of highly productive stable ampelocenoses ensuring stable highly profitable functioning of enterprises of the grape-growing industry in the Krasnodar region is presented and justified. The recommended current varietal composition of plantings is compiled taking into account the edaphoclimatic conditions of the design object, the agrobiological characteristics of grape varieties, as well as taking into account current global trends in the organization of a sustainably functioning highly efficient industrial enterprise for the production of viticulture products. Keywords: ampelocenosis, project assignment, long-term planning, varietal policy, energy and resource conservation

Influence of edaphoclimatic conditions on the growth and development of the autochthonous Don grape variety Sibirkovyi

Influence of edaphoclimatic conditions on the growth and development of the autochthonous Don grape variety Sibirkovyi

Influence of Grape Heterogeneity on Berry Quality Traits in Table Grapes A Study on the ‘Alphonse Lavallée’ Variety

The study, conducted in 2023 at the vineyard of the Agricultural Research and Application Center of Tokat Gaziosmanpaşa University, focused on the Alphonse Lavallée grape variety, a significant cultivar among table grapes. The research aimed to assess the impact of berry density on various quality parameters. Grape berries were selected across five different density categories (Y0-Y4), including a control group, to evaluate their physical characteristics (including width, length, weight, firmness, and skin color), chemical properties (pH, total titratable acidity, and soluble solids content), and phytochemical attributes (encompassing total phenol content, total antioxidant capacity, and total monomeric anthocyanin levels). The findings revealed that critical quality indicators—namely, soluble solids content, pH, total antioxidant capacity, and total monomeric anthocyanin—were maximized under the Y4 treatment. In contrast, the highest total phenol content was recorded in the Y2 and Y3 treatments. These results underscore the importance of berry density and berry/skin volume as key determinants of grape berry quality. The study contributes valuable insights into the role of these factors in enhancing the overall quality of table grapes, particularly in the context of the Alphonse Lavallée variety.

Exploring the Biological Value of Red Grape Skin: Its Incorporation and Impact on Yogurt Quality.

The study was conducted to study the sustainability and enhanced nutrition gains obtained from incorporating grape skin powder (GSP) extracted from both Fetească Neagră and Rară Neagră grape varieties into yogurt. Grape skins are major leftovers from wineries, having high amounts of phenolic compounds and dietary fiber responsible for their ability to improve the characteristics of food. The research aimed to evaluate the effect of GSP addition at varying concentrations (0.5%, 1.0%, and 1.5%) on the yogurt's physicochemical properties, antioxidant activity, color parameters, and sensory attributes. Analysis revealed that both Fetească Neagră and Rară Neagră GSP increased the total phenolic content and antioxidant activity; however, Fetească Neagră showed greater improvements, with TPC reaching 1.52 mg GAE/100 g and DPPH inhibition up to 26.63%. Although slightly lower, TPC rose to 1.43 mg GAE/100 g and DPPH inhibition increased to 18.93% with Rară Neagră enhancing these parameters conversely. Color changes were observed in fortified yogurts where lightness decreased (L*) and redness increased (a*) due to the pH-dependent anthocyanin stability. Syneresis, indicative of yogurt's water-holding capacity, was reduced at higher concentrations of GSP from both varieties, suggesting improved textural integrity. Sensory evaluation indicated that consumers generally favored yogurts with lower concentrations of GSP. Yogurts fortified with Fetească Neagră GSP received higher overall preference, while those with Rară Neagră GSP were also well-received for their distinct flavor profiles when used at suitable levels. These results show that GSP from both types of grapes improves the nutritional value of yogurt and complies with the principles of sustainable food production through reutilizing agro-industrial waste.

Pollen biology and metaxenic studies on early maturing grape (Vitis vinifera) genotypes

The present experiment was conducted during 2020–21 and 2021–22 at ICAR-Indian Agricultural Research Institute, New Delhi to study the impact of open-, self-, and cross-pollination on metaxenic traits (berries) and the incidence of cleistogamy in grapes (Vitis vinifera L.). Seven different cross-combinations were used on the grape variety Pusa Navrang, which were planted at 3 m × 3 m spacing and trained on the Y-trellis training system. The experiment was laid out in a randomized block design (RBD) with four replications. The incidence of cleistogamy, berry set, retention percentage, and the metaxenia effect of pollen grains in different grapevine varieties, namely, Pusa Navrang (PN), Black Muscat (BM), Pusa Swarnika (PS), Beauty Seedless (BS), Perlette (PER), Male Hybrid (MH), were studied. Also, pollen quantity and viability were determined for the different grapevine varieties under study. Depending on the genotypes and whether the fruit set is obtained inside the covered flowers, cleistogamy was confirmed. A significantly higher berry set (40–85%) and retention (32–77%) were recorded in open- and self-pollinated flowers. The total number of pollens/anther in six grape genotypes ranged from 7916.62–23832.02, whereas the maximum active pollen rates were noted in the Male Hybrid (70.01%) and Black Muscat (66.80%). The pollens from the Beauty Seedless genotype exhibited significant enhancement of metaxenic traits such as berry set, retention, and size in Pusa Navrang. Therefore, utilizing Beauty Seedless as a pollen parent in grape breeding programmes holds promise for enhancing berry set and overall berry quality, thus enhancing the hybridization efficiency.

The study of biochemical composition of grape and wine from Armenian selectionvariety Nrneni

Background: In Armenia, autochthonous, modern cultivars, and wild grape populations are highly diverse. Different types of wine can be produced due to the climatic zones. Grapes are a popular fruit all over the world, consisting of bioactive compounds and antioxidants, such as proanthocyanidins, anthocyanins, flavonols, organic and phenolic acids, and stilbenes. It is well known that grape varieties have different yields as well as quantitative and qualitative characteristics of the berry, which impact the quality of wine. Objective: Conduct an in-depth study of Indigenous grape varieties and clones is essential in the development of the best wine. Our focus is to specifically study Nrneni, an artificially selected Armenian grape variety. P.K. Ayvazyan, G.P.Ayvazyan created this variety by crossing a combination of Alikante Bouchet and Cabernet Sauvignion with Saperavi. The resulting product has pulp and juice that are an intense red color. Methods: In the Ararat Valley region, the grapes were hand-harvested at the end of September once they reached full technical maturity. The wine was made by the classic red winemaking method. Physicochemical analyses of grape and wine were carried out by OIV methods. Organic acids were separated and identified using liquid chromatography. A photocalorimetric method was used to determine the total phenolic compounds. Results: The chemical composition of red wine made from Nrneni grapes was assessed. In the process of wine production, storage, and maturation, grapes produce a variety of other substances, including organic acids, polysaccharides, and polyphenols, some of which contribute to the wine's sensory properties (such as flavor, color, and taste) and health benefits. Grapes are excellent sources of bioactive compounds, especially polyphenols. The total and extractable anthocyanin and flavonoid content of the Nrneni grape variety was determined. The conducted studies showed that Anthocyanins were present in high amounts of 2366.4 mg/kg. Flavonoids were present in 10183.0 mg/kg in the 2022 vintage, and 3159.9 mg/kg and 12563.7 mg/kg in the 2023 vintage. Extractable anthocyanin and flavonoid amounts were 1135.87 and 4684.18 mg/kg in 2022, 1540.32 and 5836.67 mg/kg in 2023 respectively. These indicators are also high in the wine: 502.18mg/l and 2971.15mg/l in 2022 vintage, while 975.7and 4208 mg/l in 2023 vintage. Theoretical varieties are present in 8.9 g/l and 2.02 g/l in 2022, and 6.5 g/l and 1.6 g/l in 2023. Licosaccharides, acetic acids, citric acids, and succinic acids are produced by alcoholic and malolactic fermentation. Conclusion: There is a wide range of bioactive compounds in red grapes and red wine that have been shown to have potential health benefits. According to studies, the Nrneni grape variety and the wine produced with these grapes have functional and oenological potential due to their high levels of biologically active substances, such as phenolic compounds and organic acids. Keywords: bioactive compounds, grape, organic acids, phenolic compounds, red wine.

Red Grape By-Products from the Demarcated Douro Region: Chemical Analysis, Antioxidant Potential and Antimicrobial Activity against Food-Borne Pathogens.

Wine production is one of the most important agricultural activities. The winemaking process generates a considerable volume of different residues characterized as by-products, such as pomace, seeds, stems, and skins. By-products are rich in polyphenols with antioxidant and antibacterial properties and may act as bacteriostatic or bactericidal agents against food-borne pathogens, improving food safety by enhancing antibiotic efficacy and reducing bacterial resistance. The aim of this study was to evaluate the phenolic composition and antioxidant activity of grape components (skins, seeds, and stems) from three red grape varieties (Periquita, Gamay, and Donzelinho Tinto) and determine their antibacterial activity against antibiotic-resistant bacteria, including Escherichia coli in food-producing animals and Listeria monocytogenes from food products and food-related environments. Ten phenolic compounds were quantified in these red grape varieties, with specific compounds found in different parts of the grape, including phenolic acids and flavonoids. Flavonoids are abundant in seeds and stems, malvidin-3-O-glucoside being the main anthocyanin in skins. The ethanolic extract from the seeds showed in vitro concentration-dependent activity against reactive species like •NO and O2•-. Gamay extract was the most effective, followed by Donzelinho Tinto and Periquita. Extracts showed varying antibacterial activity against Gram-positive and Gram-negative bacteria, with stronger effects on Gram-positive bacteria. L. monocytogenes was more susceptible, while E. coli was limited to three strains. Seeds exhibited the strongest antibacterial activity, followed by stems. The results of our study provide evidence of the potential of grape by-products, particularly seeds, as sources of bioactive compounds with antioxidant and antibacterial properties, offering promising avenues for enhancing food safety and combating antibiotic resistance in food production and related environments.

Effects of Seaweed Applications on Phenological Development Stages and Total Effective Temperature in Yuvarlak Çekirdeksiz Grape Variety Grown in Siirt Conditions

This study was carried out on the Yuvarlak Çekirdeksiz grape variety grown in the Siirt University application vineyard. Three different times and four different doses [control (0 ppm), 1st application (1000 ppm before flowering), 2nd application (1000 ppm before flowering + 1000 ppm after flowering), 3rd application (1000 ppm before flowering + after flowering) 1000 ppm + veraison 1000 ppm)] applied liquid seaweed on phenological stages and its effects on Total Effective temperature (TET) were compared. When the phenological periods were compared with the control; It was determined that the first application took the full flowering phase three days earlier and the veraison phase six days earlier. The Total Effective Temperature value between full bloom and veraison was determined to be between 659.78-819.98 gd, and it was determined that the first application shortened the vegetation period compared to the control, while the other two applications extended the vegetation period.

Enantioselective-GCxGC determination of α-terpinyl ethyl ether in wine: Quantitative analysis and identification of main terpene precursors

The present study investigates the presence of α-terpinyl ethyl ether in wine and gives insights on the chemical processes leading to its formation. The analytical determination of (S)-α-terpinyl ethyl ether and (R)-α-terpinyl ethyl ether enantiomers was obtained by enantioselective comprehensive two-dimensional gas chromatography. Applying the two isomers as variables in combination with closely related terpenes, an accurate classification model of wines for the grape variety was successfully applied to a representative set of single-variety wine samples. Although presenting relatively low absolute concentrations, α-terpinyl ethyl ether (along with α-terpineol) resulted to be an inevitable and irreversible degradation product of linalool. In fact, a conversion study from enantiomerically pure (R)-linalool showed a major loss of the initial chiral configuration, i.e. only a very small enantiomeric excess characterized the product. α-Terpineol itself was also confirmed to be a precursor of α-terpinyl ethyl ether, however this process showed a smaller conversion over two weeks than from linalool, and without losses of the initial chiral configuration. In the real samples, the concentration of α-terpinyl ethyl ether was found to be much lower than that of α-terpineol, regardless of the alcohol-to-water ratio. Finally, olfactory descriptors were qualitatively attributed to each α-terpinyl ethyl ether enantiomer.