Supercritical carbon dioxide co-extraction of tomatoes (Lycopersicum esculentum L.) and hazelnuts (Corylus avellana L.): A new procedure in obtaining a source of natural lycopene

An innovative SC-CO2 procedure for lycopene extraction from a matrix, composed by a mixture of dried tomatoes (pulp and skins without seeds) and roasted hazelnuts, is here described. The supercritical fluid simultaneously extracted oil from hazelnuts and lycopene from tomatoes, dissolving the pigment into the oil (temperature of 60 °C, pressure of 400 bar, flow rate of 10 kg CO2/h). The extraction yields were: 72.5% for lycopene, 80% for hazelnut oil. The final product was an over-saturated solution of lycopene in hazelnut oil, characterized in terms of concentration and isomeric composition of lycopene. A centrifugation-based procedure allowed to obtain a pasty extract, in which lycopene was five-fold more concentrate than the starting solution (4.12% vs. 0.74%, w/w). This protocol allowed to obtain the separation of lycopene isomeric forms: all-trans lycopene was collected as precipitate, cis-lycopene remained in solution in the oil phase.