Pinot Blanc Research Articles

South-Tyrolean pinot blanc identity: Exploration of chemical and sensory profile changes ascribed to vineyard locations and winemaking variables

The sensory and chemical properties of ‘Pinot Blanc’ wine from South Tyrol were studied in relation to vineyard location and winemaking technique. Musts and wines were collected from a local producer. Wines made with the same control vinification but from different vineyards (Aldino 800, Montagna 450, and Klaus 550 m.a.s.l) were analyzed. Then wines from grapes of the same vineyard but made with different vinifications (grape freezing and co-inoculation of yeast with malolactic bacteria, both compared against controls) were compared. The highest-altitude vineyard (cooler temperatures, increased UV radiation, and increased airflow) impacted positively the wine quality. The different vinifications produced differences at various storage times. Finally, sensory attributes predictors for the overall quality and related chemical variables were identified. As climate change pushes growers to increasingly high-altitude viticulture, if/when allowed by the environmental conditions, these results can contribute to understand which winemaking techniques are best in these more challenging conditions.

Chemometric Approach Application in Modern Wine Studies

The wine market is affected by the origin of wines, but the current wine traceability system has some limitations. The idea of geographical authenticity and quality has increased as one of the most important parameters influencing consumers’ preferences. Chemical parameters such as total polyphenolic content (TPC), alcohol and organic acid content (total acids, malic and tartaric acids), and antioxidant activity were observed in this work at 15 dry white wines of varieties Pinot blanc, Riesling, Sauvignon blanc, and Chardonnay, which originated from three different countries. FTIR and spectrophotometry methods (TPC and DPPH) were used and chemometric approaches such as ANOVA and PCA were selected as the most important for evaluation. In general, high levels of malic acid, TPC, and antioxidant activity were detected in Austrian wines. Pinot blanc, Chardonnay, and Sauvignon from the same producing region in Austria showed higher results. The higher overall acid concentration was a distinguishing feature of the Slovakian Sauvignon and Riesling varieties, particularly in the case of tartaric acid. Austrian samples showed significantly higher antioxidant activity compared to Hungarian Chardonnay (p = 0.002) and Sauvignon (p = 0.007), comparable to TPC. The application of statistical analysis was useful in demonstrating many discrepancies, particularly by application of the PCA method.

Bacterial-fungicidal vine disease detection with proximal aerial images

Vine disease detection is considered one of the most crucial components in precision viticulture. It serves as an input for several further modules, including mapping, automatic treatment, and spraying devices. In the last few years, several approaches have been proposed for detecting vine disease based on indoor laboratory conditions or large-scale satellite images integrated with machine learning tools. However, these methods have several limitations, including laboratory-specific conditions or limited visibility into plant-related diseases. To overcome these limitations, this work proposes a low-altitude drone flight approach through which a comprehensive dataset about various vine diseases from a large-scale European dataset is generated. The dataset contains typical diseases such as downy mildew or black rot affecting the large variety of grapes including Muscat of Hamburg, Alphonse Lavallée, Grasă de Cotnari, Rkatsiteli, Napoca, Pinot blanc, Pinot gris, Chambourcin, Fetească regală, Sauvignon blanc, Muscat Ottonel, Merlot, and Seyve-Villard 18402. The dataset contains 10,000 images and more than 100,000 annotated leaves, verified by viticulture specialists. Grape bunches are also annotated for yield estimation. Further, tests were made against state-of-the-art detection methods on this dataset, focusing also on viable solutions on embedded devices, including Android-based phones or Nvidia Jetson boards with GPU. The datasets, as well as the customized embedded models, are available on the project webpage.2

A multi-indicator approach to compare the sustainability of organic vs. integrated management of grape production

Sustainable agricultural practices are increasingly becoming a strategic asset for global and national environmental policies and economy. A big challenge is the selection of appropriate indicators to describe the complexity of the agroecosystem management. In the present work, the sustainability of grape production, in vineyard trials of Pinot blanc and Rhine Riesling, managed with integrated (INT) and organic management (organic, with cattle manure ORG1 and organic with green manure ORG2), was compared using a multi-indicator approach. The experiment was set in 2011 (1.5 ha in Trento, Italy) and carbon footprint (CF), nitrogen footprint (NF), water footprint (WF), soil microbial diversity (alpha diversity of bacteria, fungi, oomycetes communities) and soil C stock change, were evaluated in 2018. The CF was 0.213—0.227 kg CO2-eq/kg in the INT, 0.144—0.168 kg CO2-eq/kg in ORG1 and 0.134—0.147 kg CO2-eq/kg in ORG2. The NF was around 1 g Nr/kg for the INT, 0.4 g Nr/kg for ORG1 and 0.5 g Nr/kg for ORG2. The WF, excluding the pesticides impact on grey water, was 666—708 L/kg for INT, 605—655 L/kg for ORG1 and 529—580 L/kg for ORG2. The impact of farming practices on soil microbial alpha diversity showed no significant difference among treatments for oomycetes and significantly higher indexes for fungi and bacteria in the ORG1, with INT and ORG2, being similar. No difference in bulk organic C were observed among treatments. Overall, the multi-indicator approach allowed to demonstrate that the organic management was more beneficial for most of the environmental spheres of the agroecosystem compared to integrated management, without affecting the grape yield.

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.

THE AMINO ACIDS CONTENT IN GRAPE BY-PRODUCTS FROM SLOVAKIA AND AUSTRIA

The aim of the experiment was to determine the amino acid content in 3 grape varieties by-products (bunch, pomace, stem) from Austria (AT) and Slovakia (SK). In total, 54 samples from 3 varieties Zweigelt (ZG), Pinot Blanc (PB) and Green Veltliner (GV) white skinned from 6 different locations (Nitra and Vienna wine region) of Vitis vinifera sp. were analysed. In each variety the amino acids composition was determined for the whole grape (bunch) and by-products of wine industry (pomace, stems). Samples of grape by-products were freeze dried, homogenized and analysed for amino acids concentration using amino acid analyzer AAA 400 (Ingos, Prague). Descriptive statistics (means, standard error of mean, minimum maximum), differences between varieties (Tukey test, p < 0.05) using One-way ANOVA and differences between the countries with independent samples T-test (p < 0.05) by IBM SPSS v. 20.0 were generated. After the amino acid analysis in grape bunch, pomace and stem in general the highest content of glutamic and aspartic acid was found. However, the grape pomace amino acid content is highly variable and statistically different between the varieties and countries. In contrary, lower variability in amino acids content between the varieties was found in grape stem. However, similar pattern in amino acids with the lowest content between the countries and varieties in grape by-products was observed. Finally, low content of Cysteine, Methionine, Histidine and Proline was found.

SERBIAN VITICULTURE FROM THE 19TH CENTURY TO THE PRESENT DAY

In Europe, the period from the 17th to the 19th century was marked by scientific and industrial revolution, better traffic communication, which strongly influenced development of viticulture and wine markets. New varieties are introduced into viticulture, intensive working on hybridization, more intensive cultivation methods are applied with use of horses, distance between plants are changed and more modern stock are used. After liberation from the Ottoman Empire, Serbian viticulture is developing again. With arrangement of the principality and then the Serbian Kingdom, in the overall development of Serbia under the Obrenović family, a significant contribution was made by new vine plantation. Apart from the Danube regions, the areas under vines are located around the Kopaonik mountain, which separates southern Serbia from the Novo-Pazarski sandžak and the wine-growing centers such as Negotin, Požarevac, Smederevo, Kruševac, Niš and Šumadija as a separate region (area about 98,326 ha).
 However, the development of viticulture in Serbia is stoped by the appearance of phylloxera. The territory of Serbia was affected by phylloxera starting in 1881, and by 1920 it had reached Metohija. In order to restore damaged vineyards, were formed vine nurseries (Smederevo 1882, Bukovo near Negotin 1886, Jagodina 1889, Aleksandrovac, 1891) where began production of rootstock and grafting of European vine varieties. Since then, for the first time, varieties such as Traminac, Chardonnay, Pinot blanc, Pinot noir, Gamay were introduced into Serbian viticulture.
 The beginning of the 20th century was marked by changing of royal dynasties, so after atending to Serbian throne, King Petar I Karađorđević (since 1903) form an endowment estate at Oplenac. King Petar I Karađorđević, and after them King Alexander, intensively participated in plantation of new vineyards, using planting material from nurseries from Smederevo and from France (1925). By 1935, the total area under vineyards amounted to 37.78,31 ha, of which 4/5 were under wine and 1/5 under table varieties. During the 2nd World War, Serbian vineyards was under significant damage due to the lack of conditions to bad cultivation in appropriate ways.
 After the 2nd World War, viticulture in Serbia had several development stages. The first stage covers the period from 1945 to 1954 and is characterized by an extensive production level. The second stage, from 1954 to 1959, is characterized by vineyard with big inter-row distance of 2–2.5 m and greater mechanization using. The third stage, from 1959 to 1970, is characterized by vineyards with inter-row distance of 2.5 to 4 m. It is the period of intensive vineyards plantating. In the 1970, 106.000 ha belonged to individual sector, and 10.500 ha to the state (goverment) sector. In the 80-is and 90-is of the last century, it is period of the viticulture stagnation with significant reduction of vineyard area. The disintegration of the SFRY, wars that followed, sanctions and international isolation of Serbia and especially NATO bombing affected complete destruction of viticulture as a minor agricultural branch at that time. It is estimated that only about 20,000 ha under vine survived and could be maintained at the beginning of the XXI century. For the last twenty years, have been made efforts to restore Serbian viticulture. With a more modern approach, it started with the selection of clones of varieties mainly for producing of high quality wines. With the formation of smaller and medium-capacity wineries (from 100,000 to 500,000 bottles per year), the situation in viticulture and wine sector has changed significantly through the increase of areas under vines and the improvement of wine quality. Today there are around 360 registered wineries in Serbia.

Microbiome composition and dynamics while grapes turn to wine

Microbial composition and activity were recorded during preparation of Pinot blanc (“Rulandské biele”) from one vineyard during the years 2018, 2019, and 2020. Both fungi and bacteria are important for primary fermentation and malto-lactic fermentation, therefore total DNA and total RNA were isolated, and genes for 16S and 28S rRNA were amplified to determine both bacterial and yeast profiles. Four phases of wine production were selected for testing. We tested the initial grape juice right after crushing the grapes, must ~2-3 days post inoculation, actively fermenting must and finally – young wine before filtration. We experimented on 3 batches with addition of selected strains of Lachancea thermotolerans, Metschnikowia pulcherrima and commercial strains of Saccharomyces cerevisiae. The most apparent was seasonality and the effect of weather at given year. Naturally occurring yeast Hanseniaspora was detected alongside major players like S. cerevisiae. The most dominant bacterial genera were Gluconobacter, Komagataeibacter and Acetobacter. We were able to detect contaminating coliform bacteria as a result of unexpectedly warm and humid conditions during the harvest in 2018. This method even detected plant pathogens Penicillium, Botrytis, and Alternaria in some samples, and might be indicative of the health of a vineyard.

THE WINE QUALITY DESCRIPTION OF DIFFERENT ORIGIN EVALUATED BY MODERN CHEMOMETRIC APPROACH

The main chemical parameters such as content of sugar (glucose and fructose), organic acid (total acids, malic and tartaric acids), total phenolics and the antioxidant activity in 9 dry white wines with PDO of 3 varieties (Pinot Blanc, Riesling, Sauvignon blanc) from 3 countries (Slovakia, Hungary, Austria) were studied in this work in order to identify possible differences in their quality affected by geographical origin. The wine samples were examined by the FTIR and spectrophotometry methods (TPC and DPPH). As supporting parameters, alcohol and glycerol content were used and sensory evaluation of wines was performed. For the statistical evaluation were used ANOVA and PCA methods. Austrian wines in general, were characterized by high glucose and fructose content, high TPC and antioxidant activity. Higher results of these parameters are characteristic especially for the Austrian varieties Pinot blanc and Sauvignon blanc which originated from the same wine-region in Austria. Sauvignon variety from Slovakia was characterized by higher total acid content, especially in the case of tartaric acid. Statistical evaluation was helpful to show several differences, especially in the case of PCA application. Just Riesling variety from all countries of origin was so similar that it was not possible to be strictly distinguished using PCA. Wines from Hungary (Sauvignon and Pinot blanc) showed higher content of alcohol and glycerol, as they are produced by the sugar fermentation. Wines from Slovakia were evaluated as the best samples among selected ones within their sensory evaluation.

Non-destructive fluorescence sensing for assessing microclimate, site and defoliation effects on flavonol dynamics and sugar prediction in Pinot blanc grapes.

In an era of growing international competition in modern viticulture, the study and implementation of innovative technologies to increase the production of high-quality grapes and wines are of critical importance. In this study, the non-destructive portable sensor Multiplex, based on fluorescence sensing technique, was applied to evaluate grape maturity parameters and flavonol content of the understudied Pinot blanc variety. The effects of environmental and agronomical factors on flavonol content of Pinot blanc grapes were investigated in eight vineyards characterised by different microclimatic and agronomic conditions. Furthermore, the direct impact of canopy management treatment on the flavonol dynamics of the grapes oriented in the four cardinal directions was assessed. Results highlight the positive role of moderate temperatures and direct sunlight exposure on Pinot blanc flavonol content; however, no direct vineyard-elevation effect was observed. The ability to modulate and evaluate the flavonol content in field represent crucial factors because of their potential effect on flavonoids-dependent wine characteristics, such as stability and ageing. In the present study, for the first time, two calibration curves were reported for pre- and post-veraison periods between flavonol indices and the berry skin flavonol content and a good correlation was observed between Multiplex measurement and the total polyphenolic content of grape juice. Moreover, the strong correlation between the chlorophyll index with grape juice sugar content and titratable acidity revealed the practical application of non-destructive sensors to predict the optimal harvest time for Pinot blanc grapes. In conclusion, the non-destructive fluorescence sensor Multiplex is a high-potential tool for innovative viticulture, for evaluating grape skin composition variables in white grape varieties.

Can Comparable Vine and Grape Quality Be Achieved between Organic and Integrated Management in a Warm-Temperate Area?

The high demand for wine in Europe has increased the impact of viticulture on the environment. In line with European objectives, more sustainable agronomic practices have spread as an alternative to traditional management. This study aimed to compare, in a vineyard of Pinot blanc and Rhine Riesling in northeast Italy, the integrated agronomic practices (INT) with two types of organic management (ORG1—cattle manure and ORG2—green manure), in terms of production, grape quality, pest susceptibility, and soil nutrient availability. The results, after the fifth, sixth, and seventh year of testing, showed that organic management obtained a yield and vegetative features comparable to INT. Grape quality also did not show considerable overall differences between the theses in the must properties, despite the higher total sugar content and lower yeast available in ORG1. In the three-year period, the management of downy mildew, powdery mildew, and rot, as well as the soil fertilization, with the products available in organic farming proved to be comparable to the INT method. The application of cattle manure contributed by enriching the soil in K and P, while a balanced green manure mix has proven to be the best agronomic practice in terms of the release of mineral N during the phenological stages of greatest need of the vine. Organic management appears as an agronomic strategy able quantitatively and qualitatively support the vineyard system.

Chemical Composition of White Wines Produced from Different Grape Varieties and Wine Regions in Slovakia

In this work, chemical parameters such as sugar (glucose and fructose) content, organic acid (total acids, malic and tartaric acids), total phenolic content and the antioxidant activity of 12 white wines (chardonnay, pinot blanc and pinot gris) from various wine regions in Slovakia were studied in order to identify differences among the varieties and wine-growing regions. The wine samples were examined by Fourier-transform infrared spectroscopy (FTIR) and UV-VIS spectrophotometry (for determination of total polyphenolic content (TPC) and total antioxidant activity (TAA)) methods. Content of alcohol ranged between 11.50% and 13.80% with the mean value 12.52%. Mean content of total acids varied between 4.63 ± 0.09 and 6.63 ± 0.05 g.L−1, tartaric acid varied between 1.62 ± 0.09 and 2.93 ± 0.03 g L−1, malic acid was found in the concentrations ranged from 0.07 ± 0.05 and 2.50 ± 0.08 g L−1 and lactic acid was present between 1.53 and 0.01 g L−1. The content of fructose was, in general, higher in the samples from the Južnoslovenská and Nitrianska wine regions and glucose was higher in the Malokarpatská wine region. Chardonnay wines showed the highest content of total polyphenols and the antioxidant activity in the samples ranged from 51.06 ± 027 to 72.53 ± 0.35% inhibition of DPPH. The PCA analysis based on chemical descriptors distinguished the Nitrianska and Stredoslovenská wine regions. According to similarities among the wine samples, four main classes were formed by cluster analysis.

Modeling malic acid dynamics to ensure quality, aroma and freshness of Pinot blanc wines in South Tyrol (Italy)

Pinot blanc is a leading grapevine variety in South Tyrol (Italy) for wine production. The high quality of its wines derives from a typical aroma of elegant apple notes and lively acidity. The typicity of the final wine depends on the origin of the vine, the soil, the oenological practices and time of harvest. The South Tyrolean mountainous areas meet the cold climatic requirements of Pinot blanc, which guarantee its sweet-acidic harmony obtained when organic acids are in balance with the other components of the wine. However, increasing temperatures in valley sites during the berry development period boost the activity of malic acid (MA) enzymes, which negatively affect the final sugar/acid ratio. Researchers are currently focused on understanding acid dynamics in wines, and there are no references for the best sugar/acid ratio for Pinot blanc. Moreover, the contribution of individual acids to the sensory profile of this wine has not yet been studied. In this study we address the effect of different climate conditions and site elevations on the sugar/acid ratio in developmental grapevine berries, and we evaluate the effect on wine bouquet. Even if different models and indices have been proposed for predicting sugar content, no predictive models exist for MA in white grapes. In a three-year study (2017, 2018 and 2019) that involved eight vineyards in four different location in South Tyrol at various elevations ranging from 223 to 730 m a.s.l., the relationships between bioclimatic indices, such as growing-degree day (GDD) and grapevine sugar ripeness (GSR) and grapevine berry content were investigated. The analysis reveals that GDD may potentially predict MA dynamics in Pinot blanc; hence, a GDD-based model was used to determine the GDD to reach target MA concentrations (3.5, 3.0, 2.5, 2.0 g/L). This simple model was improved with additional temperature-based parameters by feature selection, and the best three advanced models were selected and evaluated by 5-fold cross-validation. These models could be used to support location and harvest date choice to produce high-quality Pinot blanc wines.

Aromatypicity of Austrian Pinot Blanc Wines

Pinot blanc is a grape variety found in all wine-growing regions of Austria. However, there are only few scientific studies which deal with the aroma of wines of this variety. In the course of this project, the relationship between aroma profile and the typicity of Austrian Pinot blanc wines was studied. The aim was to describe the typicity and to find significant differences in aroma profiles and aroma descriptors of typical and atypical Pinot blanc wines. Since the typicity of a jointly anchored prototype is embedded in the memory, typical attributes for Austrian Pinot blanc wines were first identified by consumers and experts or producers. According to this, 131 flawless commercial Austrian wines of the variety Pinot blanc of the vintages 2015 to 2017 were analysed for more than 100 volatile substances. The wines of the vintages 2015 to 2017 were judged by a panel of producers and experts for their typicity; furthermore, the wines of the vintage 2017 were also evaluated by a consumer panel and a trained descriptive panel. Subsequently, typical and atypical wines were described by the trained descriptive panel. It was found that Pinot blanc wines typical of Austria showed significantly higher concentrations of the ester compounds ethyl hexanoate, ethyl butanoate, ethyl octanoate, ethyl decanoate, methyl hexanoate, hexyl acetate and isoamyl acetate, while atypical wines had higher concentrations of free monoterpenes such as linalool, trans-linalool oxide, nerol oxide, nerol and alpha-terpineol. The sensory description of typical Pinot blanc wines was significantly more pronounced for the attribute “yellow pome fruit”, and tended to be more pronounced for the attributes “green pome fruit”, “pear”, “walnut”, “pineapple”, “banana” and “vanilla”, while the atypical Pinot blanc wines were described more by the attribute “citrus”. These findings could help to ensure that, through targeted measures, Austrian Pinot blanc wines become even more typical and distinguish themselves from other origins such as Germany or South Tyrol through a clear concept of typicity.

Effect of antioxidant supplementation on the polysulfides of white wines

Sulfur chemistry remains one of the most intriguing and elusive fields in wine science. In particular, the possibility for symmetric and asymmetric glutathionylated and cysteinylated polysulfides to act as latent reservoirs for H2S warrants new research on the factors influencing the formation and accumulation of these molecules.The present research studies the impact of pre-fermentative additions of commonly employed antioxidants: glutathione, ascorbic acid, and ellagic tannin. Musts from four different white grape varieties (Riesling, Pinot gris, Pinot blanc, and Johanniter) were analysed using our comprehensive HPLC-HRMS method. Seven symmetric and asymmetric glutathionylated (G) and cysteinylated (C) polysulfides (GS2C, GS3C, GS4C, GS3G, GS4G, CS3C, and CS4C) were detected in the final 48 wine samples. Finally, this work describes for the first time the impact of an accelerated ageing of wine on the polysulfides present. All variables (Must, Treatment, and Time) were shown to impart statistically significant effects (p = 0.0001) in the PERMANOVA model. The PCAs based on polysulfides present in young and aged wine explained more than 80% of the total variance for each grape variety and showed that Asc or GSH additions have tend to produce lower levels of polysulfides in the resultant wines.

1H NMR chemometric models for classification of Czech wine type and variety

A set of 917 wines of Czech origin were analysed using nuclear magnetic resonance spectroscopy (NMR) with the aim of building and evaluating multivariate statistical models and machine learning methods for the classification of 6 types based on colour and residual sugar content, 13 wine grape varieties and 4 locations based on 1H NMR spectra. The predictive models afforded greater than 93% correctness for classifying dry and medium dry, medium, and sweet white wines and dry red wines. The trained Random Forest (RF) model classified Pinot noir with 96% correctness, Blaufränkisch 96%, Riesling 92%, Cabernet Sauvignon 77%, Chardonnay 76%, Gewürtztraminer 60%, Hibernal 60%, Grüner Veltliner 52%, Pinot gris 48%, Sauvignon Blanc 45%, and Pálava 40%. Pinot blanc and Chardonnay, varieties that are often mistakenly interchanged, were discriminated with 71% correctness. The findings support chemometrics as a tool for predicting important features in wine, particularly for quality assessment and fraud detection.

Pinot Blanc: Impact of the Winemaking Variables on the Evolution of the Phenolic, Volatile and Sensory Profiles.

The impact of two different winemaking practices on the chemical and sensory complexity of Pinot Blanc wines from South Tyrol (Italy), from grape pressing to the bottled wine stored for nine months, was studied. New chemical markers of Pinot blanc were identified: astilbin and trans-caftaric acid differentiated the wines according to the vinification; S-glutathionylcaftaric acid correlated with the temporal trends. Fluorescence analysis displayed strong time-evolution and differentiation of the two wines for gallocatechin and epigallocatechin, respectively. After nine months of storage in bottle, the control wine showed higher amounts of most ethyl esters, acetate esters and octanoic acid, whereas higher alcohols characterized instead the wine obtained with prefermentative cold maceration. The sensory panel found notes of apple and tropical fruit in the control wine and attributed a higher overall quality judgement to it, whereas the cold-macerated wine was described by olfactory intensity, spicy and pear attributes.

The influence of grape seed drying temperature on the quality of grape seed oil

As a by-product of the winemaking process, grape seeds have been receiving increased attention worldwide due to a number of beneficial nutritional properties. Moreover, grape seed oil has also been gaining prominence for its high content of unsaturated fatty acids, primarily linoleic acid (C18:2) (72-76%). The objective of this paper was to determine the influence of three different grape seed drying temperatures (20, 40 and 60 °C) on the quality of cold-pressed oils from five different grape varieties (Pinot noir, Pinot blanc, Muscat, Cabernet sauvignon and Grasevina). The oils extracted were tested for the acid number (as an indicator of hydrolysis), the percentage of free fatty acids and the peroxide value (as an indicator of autoxidation). The peroxide values of the oil samples considered increased with the increasing drying temperature of grape seeds. The highest peroxide value was observed in the oil samples produced from the Grasevina seeds (regardless of the grape seed drying temperature), whereas the Muscat oil samples exhibited the lowest peroxide values. The acid number and the percentage of free fatty acids of the oil samples considered were found to be variety specific and independent of the grape seed drying temperature.

Investigating variability of the cultivar ‘Pinot blanc’ under different aspects

Several certified 'Pinot blanc' clones available at a local market were evaluated under specific viticultural conditions. Small but relevant differences in agronomic behaviour could be recognized. Clones A9-1, Fr74, H31 and N81 showed higher yield, while clones Lb16 and 18, Fr70 and 74 and N81 reached higher berry sugar contents. Clone Fr74 showed the most vigorous growth. Clones Fr70 and Dreher209 produced wines with the highest quality ratings. Analysis of essential aroma compounds by HS-SPME-GC-SIM-MS reveals that the clone Dreher209 is characterized by high values of terpenes and floral aroma. Pear-specific odour activity values (OAVpear) presented as sensorial-analytical typograms were calculated from the analysed concentrations of eight esters in clones. The overall OAVpear of the wines ranged from 37.5 (H31, 2016) to 84.3 (N81, 2017). The largest contributors to the pear OAV were the impressions for “exotic pear candy” and “oily waxy pear-like”. The sum of OAV “fresh pear” and “overripe pear” ranged from 6.9 (H31, 2016) to 16.1 (N81, 2017). However, an influence of vintage on the sensorial descriptors “overripe pear” and “OAV pear” was determined. A positive correlation between sugar content °Babo KMW and the descriptors for “fresh pear” and “overripe pear” is likely. Thus, clone H31 showed the lowest sugar content and lowest OAV fresh pear and OAV overripe pear content. The genetic variability was estimated by applying fingerprints with simple sequence repeat (SSR), inter-SSR and single-nucleotide polymorphism (SNP) markers. The certified clones are characterized by less variability compared with some other candidate genotypes involved in this study. No stable differences could be found in A9-1, A9-3, A9-4, C311, Fr70, or N81. That means that the clones investigated do not cover the broader genetic base of the cultivar, and that some of these clones are almost identical.

Semi-Minimal Pruned Hedge: A Potential Climate Change Adaptation Strategy in Viticulture

The low-input viticultural training system ‘Semi-minimal pruned hedge’ (SMPH) is progressively being more widely applied in the Central European grapegrowing regions. The present study examined the influence of (i) the training system (SMPH versus the vertical shoot position (VSP) system), (ii) the timing of shoot topping in SMPH, and (iii) the effects of mechanical thinning in SMPH on the bunch rot epidemic, grape maturity, and yield. Six-year field trials on Pinot blanc in Luxembourg demonstrated that yield levels in non-thinned SMPH treatments were 74% higher, and total soluble solids (TSS) at harvest 2.2 brix lower than in VSP. Non-thinned SMPH delayed the bunch rot epidemic and the maturity progress by 18 and 11 days compared to VSP, respectively. Different shoot-topping timings in SMPH did not affect the tested parameters. Mechanical thinning regimes reduced the yield by 28% (moderate thinning) and 53% (severe thinning) compared to non-thinned SMPH and increased TSS by 0.8 and 1.3 brix, respectively. Delayed bunch rot epidemic and maturity progress give rise to the opportunity for a longer maturity period in cooler conditions, making this system of particular interest in future, warmer climatic conditions. Providing that yield levels are managed properly, SMPH might represent an interesting climate change adaptation strategy.