Autumn olive berries: characterization, antioxidant capacity, optimization of solvents and extraction conditions of lycopene

The aim of this study was to investigate and optimize lycopene extraction from autumn olive berries (AOBs). First, the best solvent mixture (hexane:acetone:methanol) was selected using Simplex-Lattice Design (SLD). After that, the conditions of extraction (temperature 20–60 °C, fruit–solvent ratio 1:10–1:70, and time 5–45 min) were optimized using Box–Behnken Design (BBD) to recover the maximum lycopene from AOBs. The results showed that AOBs have a considerable antioxidant activity and possess a high content of lycopene (26 mg/100 g fresh weight). After the validation of the corresponding models, the obtained optimal solvent mixture and conditions of extraction were as follows: 1.5:1:1 (hexane:acetone:methanol), at a temperature of 49 °C, 1:64 of fruit–solvent ratio, and 15 min of extraction time. The application of the optimal point recovered up to 99.61% of lycopene in a single extraction step. Additionally, further analysis of the extract revealed a significant antioxidant capacity. UV–Vis and FTIR spectra clearly showed an absorbance behaviour related to lycopene and an approximate possession of up to 89% of all-trans isomer.