Florencia Heller-Fuenzalida

Wine quality depends on grape quality, which is affected by many factors such as edaphic, climatic and genetic, i.e., cultivar and rootstock. Rootstocks have been selected in worldwide viticulture to confer to vines some adaptation to several types of soil conditions in vineyards, but this adaptation may affect vine physiology and consequently may affect the chemical compounds of grapes, especially their phenolic compounds. Thus, this study compares the chemical composition of grapes and wines, and the sensory profile of wines from vines of the cv. Syrah grafted on two rootstocks, 5C and Gravesac, grown under a biodynamical management system. The results showed higher skin total phenols and skin total tannins in grapes from 5C rootstock. In the resulting wines, the same results were observed. The multivariate analysis demonstrated that the 5C wines presented a higher relationship with all the families of the low-molecular-weight phenolic compounds, while the Gravesac wines showed a strong relationship with acetylated and p-coumaroylated anthocyanins. The sensory analysis showed that the 5C wines presented more color intensity, more astringency and more meaty aromas compared with the Gravesac wines. The results proved that it was possible to obtain grapes and wines of different qualities depending on the rootstocks used under the same climatic and agronomical condition.

The influence of the geographical location and clone type on the contents of flavonols and organic acids of Sauvignon blanc grapes over the ripening process was investigated. The assay was carried out on three commercial clones of cv. Sauvignon blanc (Clone 242, Clone 107, and Clone 1-Davis) grown in two zones (referred to as low and high zones) in Casablanca Valley, Chile. The low zone is closer to the Pacific Ocean (i.e., 20 km away) than the high zone (which is 37 km away). Clear differences in the contents of total phenols, flavonols and organic acids of the grapes were observed during ripening. All the clones grown in the low zone exhibited a higher titratable acidity than those grown in the high zone. An analysis of the flavonol contents of the grape skins showed differences among clones associated with the geographical zone of cultivation. There was no difference in the tartaric acid concentration among clone types; however, a higher tartaric acid concentration was found in clones grown in the low zone than those grown in the high zone for all clone types. Similar results were found for the malic acid concentration. A discriminant analysis showed that the chemical analysis for the contents of total phenols, flavonols and organic acids influenced the classification based on the clone type. The results showed that grapes of different qualities can be grown in two geographical subunits into the larger area of Casablanca Valley.