White Grape Varieties Research Articles

Effects of Harvest Time on the Aroma of White Wines Made from Cold-Hardy Brianna and Frontenac Gris Grapes Using Headspace Solid-Phase Microextraction and Gas Chromatography-Mass Spectrometry-Olfactometry.

The Midwest wine industry has shown a marked increase in growers, hectares planted, wineries, and wine production. This growth coincides with the release of cold-hardy cultivars such as Brianna and Frontenac gris, in 2001 and 2003, respectively. These white grape varieties account for one-third of the total area grown in the state of Iowa. It is generally accepted that the wine aroma profile plays a crucial role in developing a local, sustainable brand. However, the identity of Brianna/Frontenac Gris-based wine aromas and their link to the grape berry chemistry at harvest is unknown. This study aims to preliminarily characterize key odor-active compounds that can influence the aroma profile in wines made from Brianna and Frontenac gris grapes harvested at different stages of ripening. Brianna and Frontenac gris grapes were harvested approximately 7 days apart, starting at 15.4 °Brix (3.09 pH) and 19.5 °Brix (3.00 pH), respectively. Small batch fermentations were made for each time point with all juices adjusted to the same °Brix prior to fermentation. Odor-active compounds were extracted from wine headspace using solid-phase microextraction (SPME) and analyzed by gas chromatography-mass spectrometry (GC-MS) and simultaneous olfactometry (O). Over 30 odor-active compounds were detected. Aromas in Brianna wines developed from “cotton candy” and “floral”, to “banana” and “butterscotch”, then finally to “honey”, “caramel” and an unknown neutral aroma. Frontenac gris wines changed from an unknown neutral aroma to “fruity” and “rose”. Results from the lay audiences’ flavor and aroma descriptors also indicate a shift with harvest date and associated °Brix. To date, this is the first report of wine aromas from Brianna and Frontenac gris by GC-MS-O. Findings from this research support the hypothesis that aroma profiles of Brianna and Frontenac gris wines can be influenced by harvesting the grapes at different stages of ripening.

The origin of pinking phenomena in white wines: An update

Pinking is the term used to describe the appearance of a salmon-red blush color that may appear in bottled white wines, produced solely from white grape varieties. It is perceived as an undesirable phenomenon for both, wine consumers and winemakers. Although with seasonal and regional variations, the pinking has been observed worldwide, with predominance in white wines produced fromVitis viniferaL. grape varieties. The pinking origin of Síria white grapes has been studied in detail and it has been shown that the origin of the pinking phenomenon in white wines fromVitis viniferaL. Síria grape variety are anthocyanins, mainly malvidin-3-O-glucoside. The minimum amount of anthocyanins needed for the visualization of the wine pink color was 0.3 mg/L. Further studies in other white monovarietal wines that occasionally suffer from this defect, like white wine from Malvasia Fina grape variety, Loureiro grape variety, Sauvignon Blanc grape variety and Albariño grape variety, have shown that this wines produced from this grape varieties also show low amounts of anthocyanins, mainly malvidin-3-O-glucoside. These results show that the presence of low but visible detectable anthocyanins as the origin of the pinking phenomena is also observed in other white grape varieties besides that of Síria.

Mass-spectrometric study on13C/12C carbon and18O/16O oxygen stable isotopes distributions in grapes and wines from the Black Sea regions

The present study continues the 2015–2016 research project on biological characteristics of stable isotopes fractionation in grapes taking into account the agro-climatic growth conditions of this representative of the C3-pathway of photosynthesis group of plants in different geographical Black Sea regions. The first parts of the project were presented at the 39th and 40th Congresses of OIV in Bento Gonçalves (Brazil) and Sofia (Bulgaria). The scientific data on compositions of13C/12C carbon and18O/16O oxygen stable isotopes in carbohydrates, organic acids, and intracellular water were obtained for grapes of 2015–2016 growing seasons in the four areas of the Crimean peninsula as well as in several areas of the Don Basin and the Western Caspian region. This report presents the results of the 2017 season study of13C/12C carbon and18O/16O oxygen stable isotopes in carbohydrates and intracellular water of 12 red and white grape varieties (Aligote, Rkatsiteli, Sauvignon Zeleny, Chardonnay, Cabernet Sauvignon, Sauvignon Blanc, Merlot, Risling, Pinot Noir, Cabernet Franc, Sira, Krasnostop) as well as in ethanol of wines made from corresponding grapes from the Crimean Peninsula and South-West Coast of the Greater Caucasus. To measure the ratio of carbon isotopes13C/12C in grape (must) carbohydrates and wine ethanol the Flash-Combustion technique (FC-IRMS/SIRA) has been used, while the method of isotopic equilibration (EQ-IRMS/SIRA) has been used for the measurement of18O/16O oxygen isotopes ratio in the intracellular water of grapes (must) and in the water fraction of wine. The GC-Combustion technique (GC-IRMS/SIRA) has been used for the first time to measure the carbon isotopes13C/12C distribution in ethanol of studied wines. It has been found that the δ13CVPDBvalues for carbohydrates of red and white grape varieties as a result of biological fractionation of carbon isotopes in the agro-climatic conditions of plant growth (2017 season) for the studied geographical areas formed the following quantitative ranges: from − 26.72 to − 23.35‰ (the Crimean Peninsula) and from − 25.92 to − 23.87‰ (South-West Coast of the Greater Caucasus). The δ13CVPDBvalues for wine ethanol are in the following ranges: from − 28.15 to − 24.47‰ (the Crimean Peninsula) and from − 27.29 to − 25.78‰ (South-West Coast of the Greater Caucasus). The δ18OVSMOWvalues in intracellular water of grapes of the 2017 season range from − 1.24 to 2.17‰ (the Crimean Peninsula) and from 1.08 to 4.09‰ (South-West Coast of the Greater Caucasus). The results of this study show, in comparison with the results of studies of the 2015 and 2016 seasons, a decrease in the δ13CVPDBvalues for carbohydrates of grapes and ethanol of wine, which is explained by the changed climatic conditions of grapes growing in the vegetation period of 2017.

Caracterização físico-química de silagens de bagaço de uvas tintas e brancas

The use of grape marc, a co-product of the viticulture industry, presents itself as an alternative to reduce costs with ruminant feed, also helping the environment, besides giving a destination to this material that is discarded by the industry, still helps reduction of methane production by ruminants. The objective of this work was to present physico-chemical results of grape marc silage, with different varieties of red and white grapes. The silage was distributed in two treatments (white and red grapes) with three grape varieties, containing three replicates, totaling 18 silos. The silage process was carried out in pvc microsilows, in a completely randomized subdivision. The bromatological composition of the white and red grape silages was evaluated separately. In the varieties of white grapes studied, the Chardonnay grape presented higher levels of DM (23.23%), OM (92.10%), CP (12.60%), ADF (43.47%) and EE (7,2 %) in relation to the Gewurztramine and Sauvignon Blanc varieties. There were no differences (P <0.05) in the CP, but the pH values ​​were higher (4.10) in the Cabernet Sauvignon variety. The Merlot and Tannat grapes had similar contents (P <0.05) for DM, OM, MM and pH. The white grape marc silages and paints of this study present low DM values ​​resulting in nutritional losses, with medium BP levels when compared to other studies. Although pH values are adequate for good fermentation of the ensiled material, the lignin and fat contents are very high, making this ensiled material with low nutritional value for use in ruminant feed, where further studies should be performed with this co-product.

Austrian Pinot blanc wines: Typicity, wine styles and the influence of different oenological decisions on the volatile profile of wines

Pinot blanc is found in all wine regions of Austria. However, it plays an economically subordinate role compared to the most important white grape variety, Grüner Veltliner. The concept of wine typicity and terroir is that the geographical origin and oenological practices, along with the grape variety, make an important contribution to the final expression of the finished wine. The purpose of this study was to discuss different styles of Austrian Pinot blanc wines and to discuss the various wine production decisions in terms of wine stylistics and aromatic profile. 131 commercial Austrian wine samples of the Pinot blanc variety of the 2015 to 2017 vintages were collected and the manufacturer's practices were determined by means of a questionnaire related to the wine styles. Using various GC-SIM-MS methods, more than 100 essential volatile substances were quantified. A trained panel, an expert panel and consumers evaluated the wines based on typicity and quality. 15 typical wines were then assessed on a sensory basis by means of predetermined aroma and wine styles. The four Austrian Pinot blanc wine styles previously discussed and presented by the same authors (citrus (1st style), green apple and green pear (2nd style), ripe yellow apple, quince, cooked pear, bread and honey notes (3rd style), as well as intensive oak notes (4th style)) were able to be partially reproduced by the trained panel. The following three wine styles could be better understood by the consumers: fresh fruity (style A), complex aroma with or without moderate wood (style B) and lots of wood aroma (style C). These styles (A–C) were able to withstand a sensory examination and a discriminant analysis by substance. An oenological guideline could help the producers to achieve the respective style. Austria's wine-growing area is probably too small and the importance of the Pinot blanc variety for the individual areas still too low to support the terroir concept for this grape variety.

Estimation of polyphenols by using HPLC-DAD in red and white wine grape varieties grown under tropical conditions of India.

Grapes are well known for their high content of phenolic compounds. Polyphenols are classified into flavonoids and non-flavonoids by their primary chemical structures of hydroxybenzene. Flavonoids mainly consist of anthocyanins, flavonoids, and flavonols whereas non-flavonoids include hydroxycinnamic and hydroxybenzoic acids. In the present study, sixteen phenolic compounds from ten red and nine white grape wine varieties were quantified using high-performance liquid chromatography. Gallic acid, Vanillic acid, Rutin hydrate, Ellagic acid, Chlorogenic acid, Sorbic acid, Catechin hydrate, Epicatechin, p-coumaric acid, Quercetin, Myricetin, Kaempferol, Piceatannol, and Resveratrol were major compounds found in red wine grapes. Among the varieties, Petit Verdot, Cabernet Franc showed maximum quantitative phenolics, whereas Cabernet Sauvignon, Niellucio, Cinsaut, and Syrah showed least quantitative phenolics in grape berries. Phenolic profile of white wine grapes showed lower concentration of phenolics than that of red wine grapes. The variety Gros Meseng showed maximum phenolics followed by Sauvignon, while the variety Colombard and Chenin Blanc showed least phenolics.

Effects of Pure and Mixed Autochthonous Torulaspora delbrueckii and Saccharomyces cerevisiae on Fermentation and Volatile Compounds of Narince Wines.

The cultivar of Narince is a native white grape variety of Vitis vinifera, grown in Tokat city, the Mid-Black Sea Region of Anatolia. In this study, the effects of pure and mixed autochthonous Torulaspora delbrueckii-214 and Saccharomyces cerevisiae-1088 cultures on the fermentation behavior and aroma compounds of Narince wines were investigated. Volatile compounds formed in wines were extracted using a liquid–liquid extraction method and determined by GC-MS-FID. Narince grape must was fermented in duplicate, under the following three conditions. Two pure cultures of T. delbrueckii-214 and S. cerevisiae-1088 and a mixture of T. delbrueckii-214 and S. cerevisiae-1088 (1:1). The presence of the non-Saccharomyces T. delbrueckii-214 yeast slowed down the fermentation and produced a lower level of ethanol and a higher levels of glycerol and volatile acid. Only the pure culture of T. delbrueckii-214 was unable to finish fermentation. On the other hand, mixed culture fermentation improved the aroma intensity and complexity of wine due to increased levels of higher alcohols and esters. According to sensory analysis, wine fermented with mixed culture was the most preferred wine followed by wine inoculated with pure S. cerevisiae-1088. This study confirms the role of T. delbrueckii in wine aroma and the potential of non-Saccharomyces use in winemaking.

Growing Season Climate Variability and its Influence on Sauvignon Blanc and Pinot Gris Berries and Wine Quality: Study Case in Romania (2005-2015)

The purpose of our research was to find out what influence climatic variability in the growing season has on the berry and wine composition in two white grape varieties grown in the vineyard of Banat University of Agricultural Sciences and Veterinary Medicine from Timisoara, located in the western area of Romania. The quality and characteristics of the wines produced in a limited area is essentially due to the environment, including natural and human factors. Two white cool-intermediate climate grape varieties - Sauvignon Blanc and Pinot Gris were chosen to study the impact of climate change on the main characteristics of juice and wine. A number of 40 berries from each variety was chosen for phenol extraction, total soluble solids (sugar content), titratable acidity and pH determinations. Wine samples were analysed after one year of ageing in the bottle. Alcohol concentration was not majorly influenced by temperature and rainfall over the years. Some experimental years with hot weather were favourable for sugar accumulation in berries and wine respectively;therefore, potential alcohol also increased. In the last decade, annual and monthly variability of rainfall and temperature influenced the phenological cycle of grapevines most, delaying or accelerating the developing of foliar area, as well as the ripening and harvesting time, which has a direct influence on grapes and wine products.

Population Fluctuation of the Peach Fruit Fly, Bactrocera zonata (Saunders) and the Mediterranean Fruit Fly Ceratitis capitata (Wiedemann) (Diptera, Tephritidae) on three Grape Varieties in Nubaria , Egypt.

The population fluctuation of the peach fruit fly (PFF), Bactrocera zonata and the Mediterranean fruit fly (MFF), Ceratitis capitata ondifferent grape varieties (White grape variety (Sbaror), Red grape variety (Filam) and Black grape variety (Autumn royal) were studied throughout three successive seasons 2014-2016, starting from March to September and represented by catch/trap/ daily of males on three different varieties at Nubaria district. Results revealed that the population density was the most abundant during the third season in the Sbaror, Filam and autumn royal varieties. During the three seasons, the population density of MFF was more than of PFF in all varieties. Each of B. zonata and C. capitatahave one peak on Sbaror and Filamand Autumn royal varieties through period from May to July.Seasonal activity of fruit fliesrepresented by total monthly catch of males on three varieties of grape during three successive seasons recorded the highest peak of seasonal abundance on May during the third season with total monthly catch 1050.8 males/month representing 59.2% , while the total monthly catch of males during the two seasons were more in June were 160.46 and367.3 males/month representing 42.64 and 55% from total population, respectively. Results obtained of seasonal fluctuation of B. zonata and C.capitata on three varieties grapesrepresented by total numbers and percentages between varieties were more on Sbaror and Filam than autumn royal where the total population for variety through three seasons 2050.38, 547.84 and 214.79males,were recorded, respectively. The results showed that the percentage of C. capitatawas high in the third season than second and first seasons, on the other hand the percentage of B. zonata was more in the first season than second and third season in all varieties. The highest total numbers of males on' Sbaror variety was 1335.9, 467.8 and 249.67 males /seasons representing 98.73, 87.96 and 79.80% for C.C and 1.27,12.04 and 20.20% for B. zonata of total captured males, during the third, second and first seasons, respectively, while the lowest total number on Autumn royal variety was (96.4,69.4&48.99 males/season) representing (92.12,75.65& 68.09%) and (7.88, 24.35&31.91 %) for C.C and B.Z during third, second and first seasons, respectively. Statistical analysis of variance in 2014 -2016 season showed that combined effect of the weather factors to CTD revealed EV were positively significant, in Sbaror variety, the simple correlation between maximum and minimum temperatures and CTD number were high significant and significant and the percentage ofexplained variance (E.V %) were high significant and significant were 46.02 and 26.78% for during first year and second year for B. zonata. While the simple correlation between and relative humanity and CTD were positive significant for C. capitata during the third years. During 2015, the simple correlation between maximum temperatures and CTD number in Filam variety was significant during second year and the percentage of explained variance (E.V.%) were significant its 26.77 and 28.14% for B. zonata and C. capitata, respectively. In Autumn royal variety, the simple correlation between maximum and minimum temperatures and CTD number were significant and high significant during first season and the percentage of explained variance (E.V.%) were 26.75% for B. zonata, respectively.

Juices enriched with phenolic extracts from grapes

The paper describes the preparation and evaluation of phenolic extracts from waste materials – pomace (grape marc), seeds and press oil cake of the white grape variety Irsai Oliver (Vitis vinifera L.) and their addition to apple and grape juices to increase the nutritional properties. The waste samples were extracted using 50 or 80% ethanol (v/v). Some of the samples were extracted for 60 min at boiling temperature under reflux; the remainder were processed for 24 h on a shaker at room temperature. The highest antioxidant capacity (as measured using DPPH (758 ± 28 mM Trolox/kg of extracted matter)) and content of total polyphenols (74 ± 0.7 g gallic acid/kg of extracted matter) were found in the extract of the seeds obtained through extraction using 50% ethanol (v/v) at boiling temperature for 60 minutes. The press oil cake extract obtained by means of 80% ethanol (v/v) at boiling temperature for 60 min was evaluated as the best for enriching the sensory quality of apple and grape juices. The addition of 1 g of freeze-dried press oil cake extract to 1 l of juice increased the antioxidant capacity and total polyphenol content two-fold

Fungal diversity in the grapes-to-wines chain with emphasis on Penicillium species

The aim of this work was the description of surface and endogenous mycobiota colonisation of grapes, fresh grape juice, grape must, and wine primarily focused to the current spectrum of the penicillium species. One sample of white grape variety Palava and one sample of blue grape variety Dornfelder were collected in Small Carpathian wine growing region of Slovakia in the year 2017. Direct plating of grapes on agar plates was used for analysis of surface mycobiota of grapes while surface sterilsed grapes were used for endogenous mycobiota analysis. Mycobiota of juice, must, and wine was analysed by plate dilution method. Overall, we isolated 148 strains belonging to 13 genera of filamentous microscopic fungi and Mycelia sterilia from grape variety Palava, while the most frequent was Alternaria. Alternaria was the most common genus in the surface and endogenous colonisation with an average relative density 50% and 73.6%, respectively. A total of 2 species of Penicillium were detected from the grapes to wine, potentially toxigenic Penicillium expansum and P. chrysogenum. A total of 39 strains belonging to 6 genera and Mycelia sterilia were identified from grape variety Dornfelder. The most abundant genus was also Alternaria (51.3%), followed by Penicillium (12.8%). Alternaria was the most common genus in the surface and endogenous colonisation and fresh grape juice with an average relative density from 20% (grape juice) to 71% (endogenous colonisation of grapes). A total of 3 species of Penicillium were detected from the grapes to wine, where Penicillium expansum were detected most commonly. In the second part of our work some selected isolates were tested to the ability to produce mycotoxins such as patulin, citrinin, and roquefortin C in in vitro condition by thin layer chromatography method. All tested strains of Penicillium species were able to produce at least one mycotoxin.

New monovarietal grape seed oils derived from white grape bagasse generated on an industrial scale at a winemaking plant

This paper reports the composition of previously uncharacterized oils from seeds of the white grape varieties Albariño, Caíño Blanco and Loureira (Vitis vinifera L.). All three oils were obtained by cold extraction from bagasse-derived seeds collected at a white winemaking plant in northwestern Spain. These oils met the Codex Alimentarius criteria for edible vegetable oils. All had high linoleic acid contents and contained long chain fatty acids such as linolenic and eicosenoic acids. The majority phytosterols were β-sitosterol and apparent β-sitosterol. Among the vitamin E-associated molecules, γ- and α-tocotrienol were the most common. Organoleptically, the three oils were very different. The oil from the variety Loureira in particular stood out in terms of its aromatic richness and high sensorial quality. The present results show that the seeds of these varieties, which are available in large quantities in white winemaking bagasse (which unlike in red winemaking is removed before must fermentation and thus retains its natural qualities), can be used to produce high quality oils with properties beneficial to human health.

Combining color chart, colorimetric measurement and chemical compounds for postharvest quality of white wine grapes.

This paper provides data for the potential use of a color chart to establish the best quality of white wine grapes destined for postharvest processing. Grechetto, Vermentino and Muscat of Alexandria white wine grape varieties were tested by sampling berries at different dates during their quality attribute evolution. A color chart and reflectance spectrocolorimeter were used in combination with analyses of total carotenoids and chlorophylls in all three varieties and of volatile organic compounds (VOCs) in Grechetto alone. Total carotenoids decreased from 0.85 to 0.76 µg g-1 in Grechetto berries and from 0.70 to 0.46 µg g-1 in Vermentino berries while increased from 0.70 to 0.80 µg g-1 in Muscat berries during ripening. Total chlorophylls decreased in all varieties, and a strict correlation was found between hue angle (measured by color chart or spectrocolorimeter) and chlorophyll disappearance, with R2 ranging from 0.81 to 0.95 depending on the variety. VOCs were only measured in Grechetto grapes, and a significant increase in glycosylation was found with ripening. The concentration of different classes of VOCs exhibited a clear decrease during ripening, except for terpenoids and esters which showed a peak at the beginning. The benzenoid class reached the highest concentration, which was almost 50% of the total. Cluster analysis using Ward's method enabled the best grape quality to be identified. This experimental work highlights that a color chart is cheap and easy to use to define the right quality stage for white wine grapes. The color chart enabled the enochemical features to be matched with the VOC results for the aromatic maturity of Grechetto. © 2018 Society of Chemical Industry.

Quantification of Wine Mixtures with an Electronic Nose and a Human Panel.

In this work, an electronic nose and a human panel were used for the quantification of wines formed by binary mixtures of four white grape varieties and two varieties of red wines at different percentages (from 0 to 100% in 10% steps for the electronic nose and from 0 to 100% in 25% steps for the human panel). The wines were prepared using the traditional method with commercial yeasts. Both techniques were able to quantify the mixtures tested, but it is important to note that the technology of the electronic nose is faster, simpler, and more objective than the human panel. In addition, better results of quantification were also obtained using the electronic nose.

Assessment of Major Volatile and Phenolic Compounds from ‘Fetească Regală’ Wine Samples after Pre-fermentative Treatments using GC-MS Analysis and HPLC Analysis

‘Fetească regală’, the most cultivated white Romanian grape variety produces elegant wines with flowery notes and white fruits (especially apricot and citrus) hues, with a good acidity. Its volatile profile (esters, terpenes, higher alcohols) and phenolic compounds are of great interest to the wine industry, especially regarding the influence pre-fermentative stages have on their extraction, as most producers choose to follow this path. This study analyses how different pre-fermentative treatments (addition of bentonite, glutathione, tannins, clarifying enzymes) change the final profile of the product. The four variants are the most used prefermentative methods. A sensorial analysis of the obtained wines was performed and the obtained data was correlated with GC-MS and HPLC analysis. 25 volatile compounds were identified and quantified through headspace analysis, using different compound libraries, while through HPLC the presence and quantity of 14 major phenolic compounds was determined. Statistical analysis (One Way Anova) was applied to establish the influence of the pre-fermentative treatments on the quantitative presence of the analysed groups of compounds. The applied treatments bring changes to the final wines’ profile by increasing the quantity of some phenolic compounds (gallic, protocatechic, p-hydroxybenzoic, gentisic, vanillic and caffeic acid ). From a sensorial point of view, all prefermentative treatments bring a smoother feel of obtained wines, with lower acidities and less of a ‘green’ character. The final results can be used by industry by adding or removing from their technological process certain steps that have influence on aroma compounds of ‘Fetească regală’ wines.

Yeast Monitoring of Wine Mixed or Sequential Fermentations Made by Native Strains from D.O. "Vinos de Madrid" Using Real-Time Quantitative PCR.

There is an increasing trend toward understanding the impact of non-Saccharomyces yeasts on the winemaking process. Although Saccharomyces cerevisiae is the predominant species at the end of fermentation, it has been recognized that the presence of non-Saccharomyces species during alcoholic fermentation can produce an improvement in the quality and complexity of the final wines. A previous work was developed for selecting the best combinations between S. cerevisiae and five non-Saccharomyces (Torulaspora delbrueckii, Schizosaccharomyces pombe, Candida stellata, Metschnikowia pulcherrima, and Lachancea thermotolorans) native yeast strains from D.O. “Vinos de Madrid” at the laboratory scale. The best inoculation strategies between S. cerevisiae and non-Saccharomyces strains were chosen to analyze, by real-time quantitative PCR (qPCR) combined with the use of specific primers, the dynamics of inoculated populations throughout the fermentation process at the pilot scale using the Malvar white grape variety. The efficiency of the qPCR system was verified independently of the samples matrix, founding the inoculated yeast species throughout alcoholic fermentation. Finally, we can validate the positive effect of selected co-cultures in the Malvar wine quality, highlighting the sequential cultures of T. delbrueckii CLI 918/S. cerevisiae CLI 889 and C. stellata CLI 920/S. cerevisiae CLI 889 and, mixed and sequential cultures of L. thermotolerans 9-6C combined with S. cerevisiae CLI 889.

Oxidation of Wine Polyphenols by Secretomes of Wild Botrytis cinerea Strains from White and Red Grape Varieties and Determination of Their Specific Laccase Activity.

Processing of Botrytis cinerea-infected grapes leads to enhanced enzymatic browning reactions mainly caused by the enzyme laccase which is able to oxidize a wide range of phenolic compounds. The extent of color deterioration depends on the activity of the enzymes secreted by the fungus. The present study revealed significant differences in the oxidative properties of secretomes of several B. cinerea strains isolated from five grape varieties. The presumed laccase-containing secretomes varied in their catalytic activity toward six phenolic compounds present in grapes. All strains led to identical product profiles for five of six substrates, but two strains showed deviating product profiles during gallic acid oxidation. Fast oxidation of caffeic acid, ferulic acid, and malvidin 3-O-glucoside was observed. Product formation rates and relative product concentrations were determined. The results reflect the wide range of enzyme activity and the corresponding different impact on color deterioration by B. cinerea.

Detailed phenolic composition of Vidal grape pomace by ultrahigh-performance liquid chromatography-tandem mass spectrometry.

Vidal Blanc grape (Vitis vinifera cv.) is the predominant white grape variety used for the production of icewine in China's Liaoning province. In this paper, the development and validation of the method by ultrahigh-performance liquid chromatography-tandem mass spectrometry has been performed for determination of the detailed phenolic composition in the skin, seed and stem of Vidal grapes. The validation of the method was realized by calculating the linearity, repeatability, precision, stability and the limits of detection (LOD) and quantification (LOQ) of standard solutions. All the curves exhibited good linearity (r2>0.9997) and the LOD and LOQ were in the range of 0.002-0.025 and 0.006-0.086μg/ml, respectively. Good repeatability (RSD<4.3%) and stability (RSD<3.7%) were also found. Results confirmed that the developed method was more effective and sensitive for simultaneous determination of the major phenolic compounds in Vidal grape pomace. The optimized and validated method of ultrahigh-performance liquid chromatography tandem two complementary techniques, fourier transform ion cyclotron resonance mass spectrometry and triple-quadrupole mass spectrometry, allowed to identify and quantify up to 35 phenolic compounds in Vidal grape pomace, which has, as far as we know, been reported this grapevine variety for the first time. Seeds, skins and stems exhibited different qualitative and quantitative phenolic profiles. These results provided useful information for recovery of phenolic antioxidants from different parts of icewine pomace.

Studies Regarding the Efficiency of Grape Tannins Greening Plastics

Grape marc, also known as grape pomace, is one of the most investigated bio-wastes derived mainly from grape skin and seeds, which is produced as a by-product of winemaking on the million-ton scale annually. Presently, the most important high-value use of grape pomace is in the production of oenological tannins, widely-used additives in the food and beverage industry. This article studies the possible use of grape waste in the plastic industry, as request of the consumer for green plastics with regards to environmental impact, and in the case of packaging, to improve the shelf-life and safety of the products contained. 4 white grape varieties and 4 red grape varieties (most cultivated grape varieties in Romania) were taken into study, processed using different technological methods and the spent material (grape skins and seeds) were analysed regarding their total phenolic compounds and total tannins.

Projection of phenology response to climate change in rainfed vineyards in north-east Spain

The aim of this research was to predict the changes in vine phenology of some white grape varieties when rainfed vineyards are subjected to climate change. The research was conducted in the north east of Spain, in an area with a Mediterranean climate. Temperature and precipitation changes under two Representative Concentration Pathway (RCP) scenarios – RCP4.5 and RCP8.5 – were simulated based on an ensemble of models. Water losses by runoff were predicted using the WEPP model and changes in evapotranspiration were estimated according to the predicted changes in temperature, wind speed and solar radiation for the same scenarios. Dates of budbreak, bloom, veraison and harvest of three varieties were evaluated: Chardonnay, during the period 1998–2012; and Parellada and Macabeo during the period 1998–2009. Projections for 2030, 2050 and 2070 were made based on the observed phenological dates and the heat accumulation needed to reach each stage and water available recorded in different periods along the growing cycle. An advance of all phenological dates was predicted, higher for veraison and harvest than for the earlier stages and higher for Parellada than for Macabeo and Chardonnay. These stages may advance up to 10 and 16days, respectively, for 2050 and up to 12 and 20days for 2070 under the RCP4.5 scenario. Under RCP8.5 scenario, the advance by 2070 could be up to 23 and 28days. These changes resulted in a shortening of the periods between phenological dates (>10days), higher for Parellada than for Chardonnay and Macabeo. The results also showed an additional advance of bloom for Chardonnay and Macabeo associated with decreasing water available, and an advance of veraison and harvest for all three varieties, associated with decreasing water available, particularly between budbreak and bloom and between bloom and veraison, depending on the variety.