Postharvest UV-C-irradiated grapes as a potential source for producing stilbene-enriched red wines.

The use of postharvest controlled irradiation by UV pulses is proposed as a potential method to produce stilbene-enriched red wine. "Monastrell" grapes were UV-C-irradiated to increase stilbene content. The main inducible stilbenes were resveratrol and piceatannol, which are molecules with reported health-beneficial activities. The evolution of both compounds was followed in the different steps of an "analytical" traditional maceration wine-making process. The final wine made from UV-C-irradiated grapes was enriched about 2- and 1.5-fold in resveratrol and piceatannol, respectively, when compared to the control wine. In addition, no difference was detected regarding the standard enological parameters (color, acidity, etc.). It is strongly suggested that, with the use of more susceptible wine grapes to induce bioactive stilbenes upon UV-C irradiation, the stilbene-enrichment of wine can be much higher.