Effects of defoliation on quality attributes of Nero di Troia (Vitis vinifera L.) grape and wine

Field studies were conducted in Puglia (Italy) to evaluate the influence of defoliation around cluster zones on grape and wine quality. Nero di Troia grapes were subjected to four different treatments: N: no leaf removal; E: leaf removal in the area of the clusters along the east side (at complete veraison); E/W: leaf removal in the area of the clusters along the east and west side (at complete veraison); and F: almost complete leaf removal along the west side (at complete veraison) and at pre-harvest also along the east side. Grapes of defoliated vines generally showed higher sugar content, lower titratable acidity, total flavonoids, flavonoids different from anthocyanins, and total phenolic content than grapes from non-defoliated vines while their total anthocyanin concentration was not affected by defoliation at a significant level. Concerning wines, alcohol content, residual soluble solids, different forms of anthocyanins but also volatile acidity were generally higher in samples from defoliated vines. Differences were also highlighted among the defoliation treatments: the best results in terms of dry matter, sugar and alcohol content were observed in the samples submitted to the more severe defoliation as a consequence of the higher light availability and berry temperature. Concerning the concentration of the individual phenolics, significant differences were highlighted for: caffeic and caftaric acids, peonidin- and malvidin-3-p-coumaroylglucoside, which were higher in the E wines; quercetin-3-glucoside, galactoside, and rhamnoside, and procyanidins, which were higher in F wines.

Influence of type of amphora on physico-chemical properties and antioxidant capacity of 'Falanghina' white wines

The present research was aimed to evaluate the effects of ageing and type of container on physico-chemical indices and on antioxidant compounds of 'Falanghina' wines. Wines were stored for 12months in raw, glazed, and engobe amphorae, and in stainless steel tanks. Lactic, acetic, citric, succinic, and hydroxycinnamoyl tartaric acids, and the antioxidant capacity (DPPH assay) were not affected by the type of container for the duration of the ageing. Flavonoids decreased by about 85% in all the containers. The concentrations of flavans reactive with vanilline were reduced by 100% in raw and glazed amphorae, 23% in engobe amphorae, and 59% in stainless steel tanks. The hydroxycinnamoyl tartaric acids decreased by about 11% in raw and engobe amphorae and by ∼22% in glazed amphorae and in stainless steel tanks. During the whole ageing time, the decrease of the antioxidant capacity ranged from 28% (raw amphorae) to 43% (stainless steel tanks).