This work is aimed on stopping of alcoholic fermentation to leave residual sugar and the possibility of sulfur dioxide reduction in wine technology and storage. As a very good opportunity showed mixture of higher saturated fatty acids with a reduced dose of sulfur dioxide. Experiments have confirmed that the concentration of viable yeasts in 1 ml of wine for variants treated with a mixture of fatty acids is significantly lower than in variants treated with sulfur dioxide alone. Then was monitored the influence of fatty acids on stored wine with residual sugar. At this point a dramatically prolongation of interval to secondary fermentation (depreciation of wine) in the bottle was confirmed. Finally, attention was paid to influence on the organoleptic characteristics of wine treated this way. In this case, it is possible to consider the recommended concentration of fatty acid below the threshold of susceptibility.
Abstract:The aim of this project was to study changes in the content of trans-resveratrol in berries and leaves of grapevine (Vitis sp.) (Schw.) Burr, called powdery mildew. In our experiments two white and two blue varieties were used. Contents of trans-resveratrol were determined in healthy and infested leaves and in healthy berries. Infested leaves of white varieties contained more trans-resveratrol than those of blue varieties. The content of trans-resveratrol in berries was lower than that in leaves.
Antioxidant activity and free radicals were studied in various parts of Vitis vinifera plant in vivo and in wines using EPR spectroscopy. Antioxidative properties of polyphenolic substances play an important role for the evaluation of quality of natural products. Determination of antioxidant activity of experimental samples by EPR method was based on measuring the changes of EPR spectrum of stable nitroxide radicals as a result of their interaction with antioxidants. In the leaves of Vitis vinifera vine varieties for the production of red wines there was observed a higher decrease in free Tempol radicals as compared to the leaves of varieties used for the production of white wines. For all monitored wines there was established a clear decrease in free Tempol radicals to the average value of 75.5 ± 15.6% as compared to the original EPR spectrum. A higher antioxidant activity was observed in yeast sediments from the production of red wines than in those from white ones.
This study was aimed on comparison of interspecific and traditional varieties suitable for rosé wines production. For samples of wines – ‘Laurot’, ‘Cerason’, ‘Merlan’, three interspecific Czech varieties and ‘St. Laurent’, ‘Blaufränkisch’ two traditional varieties and furthermore new Slovak variety ‘Nitra’ and Austrian ‘Blauer Wildbacher’ were carried out measurements of fundamental analytical values. Furthermore, total and individual phenolic compounds, total anthocyanins, optical density at 280 nm (OD280), total flavanols, reducing power and antiradical activity were determined. The results show that most phenolic compounds and highest antiradical activity has the Austrian variety ‘Blauer Wildbacher’ which was in sensory evaluation in last place. From Czech varieties it was ‘Cerason’ and ‘Laurot’. In the sensory evaluation landed the best variety ‘Blaufränkisch’. Very good results then reached a variety ‘Laurot’ as in 2008. Due its higher resistance to fungal diseases, health benefits and good sensory properties appears to be interesting for the production of rosé wines, not only from organic production.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.