The dissertation thesis focused on investigation of the influence of the leaf area on chosen quality parameters of grapes, on observation of the malolactic fermentation process and possibilities of its control. Literary section of the thesis includes characteristics of individual phenophases of grape wine with emphasis on the changes of substances content of grapes. Mechanism of sugars and acids creation and modification in grapes during ripening is described in detail. Possibilities of leaf area regulation and their influence on substances content of grapes are characterized. Another section deals with biochemical changes during wine production, especially with changes in substances content of wine during malolactic fermentation. The experimental part evaluates the influence of the leaf area on chosen quality parameters of grapes (soluble solids, titratable acids, pH, tartaric and malic acids content) of cultivars 'Pinot Gris', 'Sauvignon' and 'Riesling' in years 2008 -- 2010. The leaf area of each variety was measured in the 1st phase and average leaf area of one bush was calculated. The bushes were treated in three variants with different leaf area. It is obvious that the leaf area of the bush has positive influence especially on accumulation of sugars in grapes. The content of titratable acids in grapes was the highest by the bushes with the largest leaf area, though it was not statistically significant because there were big differences among vintages. The malic and tartaric acid ratio was ambiguous with regard to the leaf area, pH value of musts was ambiguous too. The influence of added pure cultures of lactic bacteria on the malolactic fermentation process was observed on three cultivars ('Blaufränkisch', 'Merlot', 'Cabernet Moravia') in the years 2008 to 2010. The effect of addition of lactic bacteria was observed on 5 preparations (Lalvin 31, BioStar Vitale SK11, Viniflora Oenos, Viniflora CH35 and Enartis ML Silver) and it was compared to spontaneous process of degradation. It was confirmed that the addition of pure cultures significantly accelerates the process of malolactic fermentation, it increases the antioxidant activity of wine, it decreases the production of diacetyl and other carbonyl compounds. Malolactic fermentation caused significant changes in color of biologically degraded red wines.
| Identifer | oai:union.ndltd.org:nusl.cz/oai:invenio.nusl.cz:425510 |
| Date | January 2015 |
| Creators | Horák, Miroslav |
| Source Sets | Czech ETDs |
| Language | Czech |
| Detected Language | English |
| Type | info:eu-repo/semantics/doctoralThesis |
| Rights | info:eu-repo/semantics/restrictedAccess |
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