Spraying ozonated water on Bobal grapevines: Effect on grape quality.

Ozone is a powerful oxidant that is increasingly used as sanitizing agent in the wine industry and even in the vineyard to control grapevine diseases. In this study, we evaluated the effect on grape enological quality of ozonated water spraying treatments carried out in Bobal grapevines during two consecutive harvest seasons. In the first season, ozonated water was applied once during the ripening period on grapevines trained on the traditional gobelet system (S). In the second season, ozonated water was applied three times between the fruit set and harvest on grapevines grown on a vertical trellis system (S). Grape quality on harvest day was evaluated through several enological and chromatic parameters, the phenolic maturity, the Varietal Aroma Potential Index (IPAv) and the phenolic and volatile composition. The S treatment had a positive effect on the technological maturity, the chromatic parameters, the seed maturity and the content of glycosylated aroma precursors, phenolic compounds and free terpenoids of grapes. The S treatment also improved the technological maturity and the content of total anthocyanins (pH 1.0) and free terpenoids, but had a negative impact on the chromatic parameters, the anthocyanin extractability and the content of glycosylated aroma precursors and phenolic compounds. Therefore, ozonated water sprayed on Bobal grapevines affected the quality of grapes, but the effect seemed to depend on the number of applications.