Optimization of pectinase-assisted and tri-solvent-mediated extraction and recovery of lycopene from waste tomato peels

In the present work, optimization of pectinase-assisted and tri-solvent-mediated extraction of lycopene from waste tomato peels was carried out. The optimized parameters for enzymatic pre-treatment were 2% pectinase concentration, pH 5.5, 4-h incubation, 45 °C and 150 rpm. Maximum recovery of lycopene from tomato peels using optimized tri-solvent extraction was achieved at 45 °C, 120-min incubation and 200 rpm. The extracted lycopene was confirmed through functional and characteristic peaks in UV-Vis and FTIR spectra and with retention time in HPLC. The radical scavenging activity was 72.30 ± 2.70 and 43.40 ± 2.01 µg ascorbic acid equivalents (AAE)/ml for 1,1-diphenyl-2-picrylhydrzyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radicals, respectively. The optimized method resulted in 7.38, 4.65 and 1.59 times enhancement in lycopene extraction and recovery in correlation with single solvent, enzyme-treated and tri-solvent extraction methods, respectively.