Effects of the treatment with oak chips on color-related phenolics, volatile composition, and sensory profile of red wines: the case of Aglianico and Montepulciano

The effects of the treatment of two important Italian wines, Aglianico and Montepulciano, with French oak chips were analyzed. The study was focused on the changes of color-related compounds such as anthocyanins and tannins, and of volatile and sensory profiles. An overall characterization of the wines was also performed. With reference to the phenolic profile, the behaviors of the two wines were different due to their different initial phenolic composition. The oak-chip treatments favored the polymerization of anthocyanins and tannins, whose concentrations in the oak-treated Aglianico samples were lower than in the controls (anthocyanins, -84 %; tannins, -71 %), while in the oak-treated Montepulciano wine the decrease concerned only anthocyanins (-57 %). The concentrations of polymeric phenols increased with aging in all the samples and, after 12 months, were higher in oak-treated wines than in the controls (+43 % in Aglianico, +39 % in Montepulciano). After 12 months of aging, the volatile profile of Aglianico oak-treated wines highlighted the highest acid (+68 %), terpene (+371 %), and lactone (+60 %) concentrations, while the oak-treated Montepulciano wine showed higher acid (+15 %), alcohol (+5 %), and lactone (+50 %) concentrations than the control wine. The sensory profile of the treated wines was characterized by high scores assigned to astringency and appearance of the typical oak aromas (woody, vanilla, and spicy notes) and the attenuation of floral and fruity attributes. These changes were responsible for the increase in intensity of the tannic character in Aglianico wine and the improvement of the Montepulciano wine aroma with respect to the corresponding untreated wines.