Wine contains organic acids, which determine its final quality. Tartaric and malic acids are found in dominant concentrations. Also present are citric, lactic and succinic acids, and some volatile acids such as formic and acetic acid. The process of winemaking is associated with changes in the concentration of wine acids. The composition of acids in wine is also affected by the type, quality and ripeness of grapes, grape manufacture and wine production.
The aim of this study was to analyse the concentrations of tartaric, malic, citric, lactic, succinic, formic and acetic acid during the winemaking process in different press fractions of 8 varieties of white wines from the Vineyard centre Mělník - Chloumek and in 5 commercially purchased red wines, using HPLC with DAD detection, and to analyse the trend of changes in different phases of the winemaking process. The white wine press fractions were supplied following the wine press (A), settling of juice (B), in the phase of partially fermented juice (C) and during the maturation of young wine (D-G.). The samples were taken within 2-3 days. There were no red wine press fractions available from the vineyard. 5 bottles of different varieties of red wine were thus purchased from the shop and analysed. The GraphPad Prism programme was used to perform statistical analyses (ANOVA).
The hypothesis suggesting that tartaric acid would be the dominant acid was confirmed in 5 varieties of white wine and in all red wines.
The hypothesis suggesting a difference between red and white wines was also confirmed. There were significant differences in the concentration and composition of acids between young white wines and red wines.
The hypothesis that the concentration of all acids would increase was not confirmed. Tartaric acid showed the most linear trends of decrease, followed by malic acid. The trend of change in the concentrations of succinic, lactic, citric and formic acid increased in some varieties and it decreased in others.
The grape variety, weather during summer and autumn and the manufacturing processes all influence the acid composition in wine. These factors can explain the differences seen between different varieties of wine.
| Identifer | oai:union.ndltd.org:nusl.cz/oai:invenio.nusl.cz:256792 |
| Date | January 2016 |
| Creators | Cindrová, Kristina |
| Contributors | Orsák, Matyáš, Weitosch, Štěpán |
| Publisher | Česká zemědělská univerzita v Praze |
| Source Sets | Czech ETDs |
| Language | Czech |
| Detected Language | English |
| Type | info:eu-repo/semantics/masterThesis |
| Rights | info:eu-repo/semantics/restrictedAccess |
Page generated in 0.0018 seconds