Dimitar Dimitrov, Neli Prodanova-Marinova, Tatyana Yoncheva
Gas chromatographic study (GC-FID) to determine the volatile composition of wines (two harvests - 2018 and 2019) of the Cabernet Sauvignon variety with the treatment of experimental plantations with herbicides Pledge 50 WP (flumioxazin), Lumax 538 SC (s-metolachlor + terbuthylazine + mesotrione) and Guild (pyraflufen-ethyl + glyphosate) was performed. The results were compared with untreated control. The wines of the 2018 harvest showed a higher total content of volatile compounds compared to the 2019 harvest. Herbicide treatment had the effect of increasing the content of higher alcohols in the experimental wines. This was a possible effect of blocking competition for nutrients needful for the vine metabolism by weeds elimination. The wines of the 2018 harvest contain 9 higher alcohols, the main ones were 1-propanol, 2-methyl-1-butanol, 3-methyl-1-butanol and 4-methyl-2-pentanol. The wines from the next harvest showed a poorer species composition of higher alcohols - 5 representatives, with the main presence of 2-methyl-1-butanol and 3-methyl-1-butanol. The experimental variants for the wines of the 2018 harvest showed a higher total ester content compared to the control and the main esters were ethyl acetate and ethyl decanoate. In the next harvest this tendency was absent, and the main representative of the esters was propyl acetate. The aldehyde fraction was represented by acetaldehyde. A low total terpene content in the wines was found, which was normal, as Cabernet Sauvignon is a non-muscat variety. Methyl alcohol concentrations were defined. They were many times lower than the maximum allowable, which characterized wines as toxicologically harmless. The study showed that the treatment with the herbicides Guild, Lumax 538 SC and Pledge 50 WP of experimental plantations of Cabernet Sauvignon led to improved synthesis of higher alcohols and esters in wines, which reflected in improving of their volatile and aromatic quality.
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