The cis-lycopene isomers composition in supercritical CO2 extracted tomato by-products

•Tomato by-products oleoresin was extracted using supercritical CO2.•Optimal conditions for cis-lycopene isomers extraction was determined.•Full factorial design was used to understand the effect of process variables.•The optimum conditions were 52 °C, 55 MPa and 180 min.

The use of concentrated carotenoid extracts from red-ripe tomato by-products in traditional foods can improve the functional properties of the product while increasing the efficiency of industrial red-ripe tomatoes processing. In red tomatoes, lycopene is almost exclusively found in the all-trans-form, but during processing lycopene can undergo isomerisation to cis-lycopene isomers. The cis-lycopene isomers offer potentially better health benefits than the trans-lycopene isomers. The objectives of this study were to optimize supercritical carbon dioxide (SC-CO2) extraction parameters for the isolation of the non-polar tomato by-product fraction (oleoresin) and cis-lycopene isomers by using a central composite rotatable design (CCD) model with response surface methodology (RSM). SC-CO2 using CCD and RSM was used for the first time for the isolation of cis-lycopene isomers from tomato by-products. The best results in terms of oleoresin yield were obtained at a temperature of 73.9 °C, a pressure of 53.7 MPa and a time of 155 min, whereas the optimal extraction process parameters of cis-lycopene isomers are a 52 °C temperature, a 55 MPa pressure and a 180 min extraction time. The optimized conditions of SC-CO2 allows to obtain high yields of lycopene rich extracts (oleoresins) comprising higher percentage of cis-lycopene isomers (∼62% of total lycopene).