LAUSR

BACKGROUND The ultraviolet-B (UV-B) radiation can alter grape metabolism during berry development, but little is known on the effect of post-harvest UV-B exposure. In this study, we evaluated the effect of post-harvest UV-B exposure on berry primary and secondary metabolites in four grapevine varieties (Aleatico, Moscato bianco, Sangiovese, and Vermentino) in order to evaluate the possibility to increase the grape quality and its nutraceutical properties. RESULTS The treatment did not significantly affect the berry primary metabolism in terms of organic acids, carbohydrates, and amino acids profile, regardless the variety. UV-B exposure reduced the total anthocyanin content, particularly the tri-substituted and di-substituted forms in Aleatico and Sangiovese, respectively. An overall negative effect of UV-B irradiation on the flavonols profile of Aleatico, Moscato bianco, and Vermentino berries was found, whereas it enhanced the quercetin, myricetin and kaempferol concentration in Sangiovese. The free fraction of berry volatile organic compounds increased in UV-B-treated Aleatico and Moscato bianco berries, especially C13 -norisoprenoids and volatile phenols, as well as key monoterpenes, such as the linalool derivatives. On the other hand, higher concentrations of glycosylated monoterpenes and C13 -norisoprenoids were measured in Sangiovese and Vermentino berries treated with UV-B. CONCLUSION This study provides new insights on the effect of post-harvest UV-B radiation on berry secondary metabolism, highlighting a different modulation between varieties and suggesting the potential use of this technique to increase some nutraceutical and quality characteristics of grape berry. This article is protected by copyright. All rights reserved.