Alternatives to Traditional Aging of Bobal Red Wines from Semi-Arid Climate: Influence on Phenolic Composition and Related Properties

The effect of oak chips on the phenolic composition, color characteristics, and antioxidant capacity of Bobal red wines caused by contact with oak chips at different stages of the winemaking process has been studied. Performance liquid chromatography–diode array detection (HPLC-DAD) was used to determine the detailed phenolic composition of wines and antioxidant activity, and chromatic characteristics were determined by spectrophotometric methods. Standard red winemaking process was applied to make the Bobal control wine. The rest of the wines were elaborated with oak chip contact at two dose levels (3 and 6 g/L) in different phases of the winemaking process: during alcoholic fermentation (AF), during malolactic fermentation (MLF), and in young wines. The phenolic composition, antioxidant activity, and chromatic characteristics of Bobal control wines were slightly but significantly modified by contact with the oak chips. Wines in contact with oak chips during malolactic fermentation showed a decrease in the concentration of resveratrol-monomer stilbenes, monomeric anthocyanins, and pyranoanthocyanins. In general, the concentration of total resveratrol is influenced by the dose level used, resulting in a 10% decrease when the dose level is 6 g/L compared to the 3 g/L dose.