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Research regarding the phenolic maturity of the red wine varieties in the Dealu Bujorului vineyard
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The aim of this research was to determine ecoclimatic conditions and also to determine the phenolic maturity of Fetească neagră and Merlot from Dealu Bujorului vineyard in the conditions of the 2016 year of culture. Under the ecoclimatic conditions of 2016, the grapes entered in the ripening process prematurely, and full maturity was achieved very early. The results showed the suitability of ecoclimatic conditions and the proper growth and development of the tested varieties for obtaining wines with superior's quality. The variation of the phenolic characteristic represents a strong marker for wines geographical traceability.
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Viticulture is one of the cultures occupying large proportions of the cultivated area on the Globe. It is practiced, in particular, to produce table grapes, juice and other derivatives, and especially (about 70% of the total) to obtain different categories of quality wine and wine-based beverages. Wine can be produced everywhere, as long as the grapes ripen, but not all conditions for ripening the grapes are favorable for the production of quality wines (Teodorescu et al., 1987). If the area where vine is grown is large, the one objective is to evaluate the ecoclimatic and ecopedological conditions of three culture areas (Baia Mare (BM), Şimleul Silvaniei (SS) and Turulung Vii (TUR)) in north-western Romania and their influence on the quality of the varieties: ʻFetească albăʼ, ʻFetească regalăʼ, ʻRiesling italianʼ. The genetic soil types from these locations are: aluvosoil in Baia Mare, luvosoil in Şimleul Silvaniei and preluvosoil in Turulung Vii. 2013 was a year with higher average temperatures than the annual average in Baia Mare and Turulung Vii, but lower in Şimleul Silvaniei, but the precipitations were lower in the same areas, compared to the multiannual average. The higher amount of sugar was accumulated in ʻFetească albăʼ
in Şimleul Silvaniei and the lowest in ʻFetească regalăʼ in Baia Mare, the acidity falling between a normal interval for wine varieties.
Keywords: ecoclimatic and ecopedological conditions, grapes varieties for white wine, quality (sugar, acidity, pH).
Grape harvest date is determined according to the technological and phenolic maturities. These parameters were calculated for different red grape (Vitis vinifera L.) varieties (Cabernet Sauvignon, Merlot, Syrah, Cabernet Franc) over four years (2008, 2009, 2010, and 2011) (642 samples). Titratable acidity and sugar content of the grapes were used to determine the technological maturity, whereas Glories (1 and 2) and ITV (Institut Technique de la Vigne et du Vin) methods were used to monitor their phenolic maturity. The ITV method allows the monitoring of phenolic maturity by the quantification of total polyphenol index and anthocyanins, while the Glories method enables the quantitative evolution of extractable anthocyanins and tannins of the grapes. A correlation was shown between the harvest dates obtained by both ITV and Glories (R² = 0.7 – 0.93). Phenolic maturity of grapes can, therefore, be optimized by the application of both ITV and Glories. Similarly, a correlation was observed between technological and phenolic harvest dates. The effect of climate on the phenolic content of grapes was also studied. The highest temperatures (up to 25 °C) accompanied by the lowest rainfall (null value), induced the maximal concentration of polyphenols in grapes. Thermal and water stresses were also shown to enhance the grapes’ polyphenolic production.
A rich content of phenolic compounds (anthocyans and tannins) is a fundamental technological condition for the obtaining of quality red wines-appreciated by increasing numbers of consumers, aware of the benefic health effects brought about by these biologically active compounds. The biosynthesis of phenols and their accumulation in the grape berries during ripening is influenced by a multitude of factors. In this study we focused on terroir and on the biological potential of the authorized red varieties for wines with controlled denomination of origin in four centres of three well-established viticultural regions: the Hills of Dobrogea, the Hills of Moldova, the Hills of Muntenia and Oltenia. The polyphenolic potential of the grapes was evaluated for the crop of 2015 by the standard Glories method, thus obtaining results for the total polyphenolic potential (ApH1), the extractable anthocyans potential (ApH3,2), the percentage of anthocyans extractability (%AE), the maturity of the seeds (MS) and total polyphenols (PT). By classifying the freshly harvested grapes on the basis of their phenolic potential using the statistical method of Principal Component Analysis, the studied varieties are clearly differentiated based on the viticultural terroir.
Ecoclimatic conditions have a great influence on grapevine growth and development. Favourable conditions (solar radiation, temperature, humidity etc.) are important and have a positive effect on the growth and fruition. Critical conditions have negative influences resulting in low grape production and wine quality. The purpose of this research was to analyse the quality of wine obtained from eight grapevine varieties (four Romanian autochthonous varieties: ‘Feteasca regala’, ‘Feteasca alba’, ‘Babeasca gri’, ‘Sarba’, and four world-wide varieties: ‘Aligoté’, ‘Sauvignon Blanc’, ‘Muscat Ottonel’, and ‘Italian Riesling’). The wine samples were obtained from micro-wine production under local weather conditions of Dealu Bujorului
vineyard, Romania. The physico-chemical analysis of young wines showed that the highest alcohol content was recorded at the ‘Sauvignon blanc’ variety (14.35% vol.) followed by ‘Sarba’ (14.10% vol.). The highest level of acidity was registered to ‘Babeasca gri’ (5.90 g/L C4H6O6) and the lowest acidity in the ‘Muscat Ottonel’ wine (4.40 g/L C4H6O6). The pH values were between limits of 3.62 (‘Feteasca alba’) and 3.27 (‘Aligote’). In order to get a wider perspective about the wine quality, another 11 parameters were examined at these varieties, using spectrophotometric methods (acetic acid, potassium, calcium, free amino nitrogen, tartaric acid, copper, L-lactic acid, iron, L-malic acid, D-gluconic acid and glycerol). The results showed the
suitability of ecoclimatic conditions and the proper growth and development of the tested varieties for obtaining wines with superiors quality.
The highest values for the absolute fertility coefficient (Cfa) and relative fertility coefficient (Cfr) were recorded for the 'Fetească regală' variety (54.5±1.00% fertility; 1.60±1.00 absolute coefficient (Cfa) and 0.86±1.00 relative coefficient (Cfr). The results show that 'Bujoru' had the best values regarding the average weight of the grape bunch (303.5±1.0 g), weight of 100 berries (278.07±1.0 g), sugar content (213.66±0.67 g/L) and average production (4.331±1.0 kg/vine). The new variety obtained, 'Bujoru', has a great potential to produce high quality white wines. Due to the large ammount of sugars that this variety accumulates, it can be successfully grown in other viticultural areas as well.
The prediction of grape composition is becoming more important due to the need to reduce current levels of alcohol and pH of wines, a problem that is exacerbated by climate change. This work presents a 3-year study of the spatial variability of grape composition in a rain-fed Tempranillo vineyard located in Rioja (Spain). It is based on the acquisition of multispectral imagery at veraison (start of the ripening process); and zoning based on normalised difference vegetation index (NDVI) to assess its performance for zonal management. The results reveal a high spatial variability within the plot, with a stable pattern over the years, even with very different climate conditions. NDVI was a good predictor of vegetative growth parameters. However, the prediction of grape composition was more complex. Unexpectedly, anthocyanins were found to be higher in the highest vigour zone, which is particularly discussed in the article. Since vigour is not the only factor affecting grape quality, the delineation of management zones should be done considering other input information together with NDVI.