Supercritical CO2 extraction of tomato pomace: Evaluation of the solubility of lycopene in tomato oil as limiting factor of the process performance

Abstract

This work considered lycopene (lyc) amount and (all-E)-lyc:Z-lyc (E:Z) ratio as driving parameters of the tomato pomace (TP) supercritical CO₂ extraction (SFE_CO₂) performance. By testing lyc concentrations solubilization in tomato seed oil and E:Z ratios of 75:25, 59:39 and 25:75, full and partial equations (SE) were calculated. The application of mass balances to experimental TP_SFE_CO₂ highlighted an extraction yield of 84.6% TP lyc, although the recovery into the extract was 48.4% of the extracted lyc (lyc = 1339 μg g^-1 oil). The SE application to TP_SFE_CO₂ data confirmed that partial solubilization mainly depended on oil availability vs. lyc amount. Thus an improved TP_SFE_CO₂ was designed in which 703 g of exogenous tomato oil will be fluxed from the co-solvent tank: the new process will produce 884 g kg^-1 d.m. of extract with an expected recovery of 99.3% of the extractable lyc (lyc = 502 μg g^-1 oil).

Keywords: Aggregates; Carotenoids; Co-solvent; E:Z-isomerization; Solanum lycopersicum; Solubility model.