Published in Scientific Papers. Series B, Horticulture, Volume LXII
Written by George Adrian COJOCARU, Arina Oana ANTOCE
Red wine grape varieties 'Fetească neagră’ and 'Cabernet Sauvignon’ were produced in Murfatlar wine region under organic and conventional viticultural systems. For both varieties and viticultural systems, 30% cluster thinning was performed in some variants during summer, at the beginning of veraison. The resulted grapes, harvested in the autumn of 2014, were vinified using the same winemaking protocol and the differences in aromatic profile of the wine samples were assessed by using a GC e-nose from Alpha MOS. The chromatographic peaks were recorded and analysed with Alpha Soft ver. 12.42 and AroChemBase. The discrimination of the samples was based on multivariate DFA statistical analysis. The results showed that 30% cluster thinning did not influence significantly the major wine aroma compounds, only small differences being observed in the DFA diagram for samples with and without cluster thinning. However, the grape variety and the application of organic cultivation technology led to a good discrimination, with a validation score of 92, of the samples on the DFA diagram. An even better discrimination, with a validation score of 96, was observed on wine samples from grapes produced in conventional and organic system when the cluster thinning was disregarded and samples with or without this intervention in the vineyard were included in the same group. These results show that, as far as the aromatic profile is concerned, the wines produced from grapes to which cluster thinning was applied are difficult to differentiate from the controls produced from vines with normal yield, even with a sensitive equipment such as an e-nose. On the other hand, the organic and conventional growing led to wine samples easily differentiated by the electronic nose, suggesting that these differences can also be perceived by consumers. Some of the aroma compounds significant for the discrimination of wines produced from organic or conventional grapes were identified and their expected sensory effect is discussed.
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