Enhancement of Antioxidant Activity and Bioactive Compounds in Eggplants Using Postharvest LEDs Irradiation

Abstract

Eggplant (Solanum melongena L.), one of the major vegetable crops, is recognized for its availability of numerous bioactive compounds and antioxidant activity. The accumulation of these compounds in plant tissues can be increased by exogenous stimuli, including light exposure. This study aimed at enhancing the antioxidant activity and bioactive compounds of eggplant using light-emitting diode (LEDs) irradiation after harvest. For this purpose, eggplant fruits were irradiated under LEDs at different wavelengths, including red (650–660 nm), blue (450–460 nm), or the combination of red and blue (red + blue) LEDs, for 48 h. The results indicated that red + blue LED exposure during postharvest significantly (p < 0.05) elevated the accumulation of bioactive compounds and antioxidant activity. The accumulation of major phenolic compounds, chlorogenic acid (58.59 mg/100 g FW), and gallic acid (14.25 mg/100 g FW) in the eggplant fruits was increased significantly under red + blue irradiation when compared with the control (under dark condition). The total phenolic (821.86 mg GAE/100 g FW) and the total flavonoid (595.98 mg CE/100 g FW) contents were shown to have a considerably high accumulation in the peels of eggplant after irradiation under red + blue LEDs, whereas the total carotenoid content was relatively high in the flesh of eggplant fruits. Consequently, red + blue LED irradiation can be considered as a convenient tool used for the postharvest of eggplant, with a positive effect in the increasing of important secondary metabolites. The obtained eggplant fruits proved to be a promising source of bioactive and antioxidant compounds for functional food production.