Fabrizio Torchio

In this study we investigated the effect of the grape withering process occurring during the production of Italian passito wines on the variability of the (D/H)_I, (D/H)_II, δ¹³C, and δ¹⁸O of wine ethanol and the δ¹⁸O of wine water. The production of PDO Erbaluce di Caluso Passito in five different cellars in Piedmont (Italy) was considered in two successive years. Moreover, samples of 17 different traditional Italian passito wines taken at different stages of maturation were taken into account. We found that the δ¹⁸O of must and wine water and the δ¹⁸O of ethanol decrease in the case of passito wines produced in northern and central Italy using postharvest drying of the grapes in dedicated ventilated or unventilated fruit drying rooms (fruttaio), during autumn–winter. For passito wines produced in southern Italy, where the main technique involves withering on the plant (en plein air), δ¹⁸O tends to increase. The (DH)_I of wine ethanol did not change during withering, whereas the (DH)_II and δ¹³C values changed slightly, but without any clear trend. Particular attention must be therefore paid in the evaluation of the δ¹⁸O data of passito wines for fraud detection.

In this work, the chemical compositions and texture characteristics of three native Romanian wine grape varieties (Fetească regală, Fetească alba, and Fetească neagră) were studied. We assessed the distinct characteristics directly linked to their phenolic compositions, volatile profiles, and mechanical properties and compared these characteristics with those of Pinot noir grapes. The effect of the growing zone was also evaluated. Various spectrophotometric indices directly related to the phenolic compositions of berry skins and seeds were determined. The detailed phenolic compositions (anthocyanins, hydroxycinnamoyl tartaric acids, and stilbenes) of the skins were determined using high-performance liquid chromatography methods. Free and bound volatile compounds in the berries were quantified by gas chromatography/mass spectrometry. The textural properties of the skins and seeds were measured by instrumental texture analysis. The results showed high diversity among the varieties and zones that affected the enological potential. Among the white varieties, Fetească albă grapes could be less susceptible to browning as a consequence of their lower trans-caffeoyltartaric acid concentration, whereas Fetească regală grapes from Cluj had the highest concentrations of total free and bound volatile compounds, particularly terpenes and norisoprenoids. Among the red varieties, Fetească neagră was identified as a promising variety to be exploited in the future for its particular phenolic characteristics, particularly those grapes grown in Mica. Nevertheless, Fetească neagră grapes grown in Cluj had the highest total glycosidically bound terpene concentrations. Finally, differences in the mechanical and/or acoustic properties of the skins and seeds could strongly influence the kinetics and completeness of phenolic compound extractions.