Supercritical solvent selection (CO2 versus ethane) and optimization of operating conditions of the extraction of lycopene from tomato residues: Innovative analysis of extraction curves by a response surface methodology and cost of manufacturing hybrid approach

Abstract

Lycopene is an important carotenoid present in the large volumes of tomato residues generated annually. Its SFE was studied here with two main objectives: optimization of operating conditions and selection of supercritical solvent (CO2 versus ethane). Accordingly, a hybrid approach using the response surface methodology and cost of manufacturing (COM) concept was implemented to establish the best conditions independently of the type of extraction curves available. This approach provides accurate results even in the absence of well-defined periods of extraction (i.e., constant extraction rate branch and the maximum plateau). The minimum COM was 1.8 k[SIC] kg(lycopene)(-1) for CO2 at 500 bar/90 degrees C/25 kg(CO2), kg(sample)(-1). At 300 bar/60 degrees C the supercritical ethane achieved better results due to the higher extraction rates observed, which originated shorter extraction cycles and thus greater annual productivity and lower COM. More experiments are necessary for an accurate solvent selection, since at 300 bar/60 degrees C the CO2 is far from its best performance. (C) 2014 Elsevier B.V. All rights reserved.