Ultrasound assisted lycopene extraction from tomato skin waste by volatile natural deep eutectic solvent

In this work, a completely green method was applied for the extraction of lycopene from tomato skins waste. The combination of the ultrasound-assisted technique (UAE) and the use of volatile natural deep eutectic solvent (VNADES) menthol: thymol 1:1 allowed to obtain a green extraction process. Lycopene content was assessed by HPLC-DAD and compared with the lycopene extraction yields obtained using α-pinene and n-hexane as extraction solvents. The evaporation of the DES menthol:thymol was conducted using a Vacuum Vortex Evaporator. The highest concentration of extracted lycopene was obtained with n-hexane (735.9 mg/g of dried extract (DE)) compared to terpene-based solvents; 468.1 mg/g and 358.7-484.2 mg/g DE were recovered from α-pinene and DES menthol/thymol as azeotropic mixture and as such, respectively.