Supercritical CO2 extraction of trans-lycopene from Portuguese tomato industrial waste

Supercritical CO2 extraction of trans-lycopene from Portuguese tomato industrial wastes (skins and seeds) was carried out in a flow apparatus. The effects of moisture content, feed initial composition, particle size, solvent flow-rate, pressure and temperature on the extraction yield and recovery were evaluated.The recovery of trans-lycopene depended on the content of the compound in the starting material and increased with increases in pressure and solvent flow-rate, and with a decrease in the particle size. The effects of temperature and feed moisture content were more complex. When temperature rose from 40 to 60 °C the recovery increased, but a further rise of the temperature to 80 °C led to a decrease in the trans-lycopene recovery, although the total lycopene (cis + trans) remained the same as that obtained at 60 °C. On the other hand, an increase in the moisture content of the samples, from 4.6% to 22.8% led to a rise in the extraction yield and to a decrease in the recovery of trans-lycopene. At higher moisture contents (58.1%), both yield and recovery decreased. Moreover, the highest trans-lycopene recovery, 93%, was obtained at 60 °C, 300 bar, solvent flow-rate of 0.59 g/min, particle size of 0.36 mm and feed moisture content of 4.6%.