UV-B radiation on lemons enhances antifungal activity of flavedo extracts against Penicillium digitatum

RUIZ, VERÓNICA EUGENIA; CERIONI, LUCIANA; ZAMPINI, IRIS CATIANA; CUELLO, SOLEDAD; ISLA, MARÍA INÉS; HILAL, MIRNA; RAPISARDA, VIVIANA ANDREA

LEBENSMITTEL-WISSENSCHAFT UND-TECHNOLOGIE-FOOD SCIENCE AND TECHNOLOGY

ELSEVIER SCIENCE BV

Año: 2017

0023-6438

UV-B radiation (UVBR) treatment, previously standardized in our laboratory, contributes to prevent greenmold caused by Penicillium digitatum on postharvest lemons. Here, antifungal activity of flavedo extractsfrom irradiated and non-irradiated lemons was assayed against P. digitatum; also, compounds that could beresponsible for this action were searched. The flavedo extracts from UV-B exposed lemons (UVBLE) exhibiteda higher antimicrobial activity than extracts from control lemons (CLE). Conidia treated with UVBLEshowed a time dependent inhibition of germination and oxygen consumption, a markedly increase in ROS andTBARS production and in membrane permeability. By chemical analysis of lemon extracts, two fractions (Aand B) that responded to the irradiation were detected, showing a decrease in Fraction A and an increase inFraction B. Fraction B showed higher antioxidant and antifungal activities in comparison to Fraction A. Bothfractions were complex samples enriched in flavonoids. The specific composition of each fraction could explainthe difference in the biological activities, and also the higher efficiency of UVBLE to inhibit in vitro thepathogen compared to CLE. Based on our results, UV-B radiation treatment can intensify natural defenses offlavedo lemon by eliciting phenolic compounds synthesis, among other processes.