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Studium antioxidačních komponent u vybraných růžových vín
Valentová, Jana
The growing popularity and consumption of rose wines is going hand by hand with the growing effort to analyze their composition. Great attention is focused on antioxidants for their beneficial properties on the human body. According to valid legislation in Czech republic, allowed methods of rose wine production are pressing of the whole grapes, bleeding and short-term maceration. The lenght of maceration has a major impact on the amount of phenolic substances in the produced wine, as their amount increases from white to pink to red wines. In this work, 25 samples of rose wines produced in 2016 from the following varieties: Blaufrankisch, Pinot noir, Blauer Portugieser, Zweigeltrebe and Sankt Laurent, were tested experimentaly. Antioxidant activity was determined by the DPPH method together with the total content of phenolics, anthocyans and flavanols. The content of hydroxycynnamic acids (coumaric, ferrulic and caftar), catechin, epicatechin, resveratrol and malvidin 3 glycosid was determined by HPLC. Wines from varieties Blaufrankisch and Blauer Portugieser showed a high antixodant activity and contained a high amount of phenolics, flavanols and antocyans. The lowest antioxidant activity and the content of phenolics substances had wines produced from the Pinot noir variety.
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Vliv různých podmínek zrání na změny ve složení fenolických látek ve víně
Beran, Václav
In the experiment the influence of different storage conditions of annual bottle aging on changes in the composition of phenolic compounds in white and red wines was observed. Total phenolics, flavanols, anthocyanins and antiradical activity were observed. A higher content of phenolics and a higher antiradical activity were detected in red wines. Higher temperature induces a higher content of phenolics in white wines. In red wines, higher temperature induces a lower content of total phenols. The content of flavanols in white and red wines decreases more at a higher temperature. The decrease of anthocyanins was observed in all red wines. Antiradical activity has increased in white wines with a cork stopper. In red wines, antiradical activity has decreased. The best storage conditions are low temperature and darkness. Classic cork stopper is the best closure for red wines. White wines closed by a screw cap were sensory evaluated more positively, cork stopper induces a higher antiradical activity.
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Vliv před-fermentační macerace na obsahové látky moštu révy vinné
Sapík, Miloslav
Data shows that if the year is similar to year 2013, as regards to the increased content of titratable acid, there can be a longer maceration pulp, which may serve as the future harmoniousness wine. Appropriate sufficient time of maceration for any decrease in titratable acidity corresponds to the period of maceration form 4 to 12 hours. Regarding the tartaric acid and malic acid, the time of maceration appears to be approximately 8 hours. From this time forth there may be rises in values of malic acid,which can cause microbiological instability. If we wanted to get the largest share of the health-promoting substances of this year, the must had to be macerated at least 48 hours.
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