Supercritical Fluid Extraction of Carotenoids from Tomato Industrial Wastes

Supercritical CO2 extraction of carotenoids from tomato industrial wastes (mixture of skins and seeds) was carried out in a flow apparatus at the temperature of 60 oC and the pressure of 300 bar. The effect of the moisture content (4.6, 23 and 58%), particle size (0.15, 0.35 and 0.72 mm) and solvent flow-rate was studied. The carotenoids recovery (mass of extracted compounds by supercritical CO2/mass of extracted compounds by Soxhlet) at 60 oC and 300 bar for samples with 4.6 % moisture was higher for the lowest tomato particle size and decreased with the increase of the flow-rate. Extraction of tomato paste wastes with organic solvents showed that the carotenoids concentration in the tomato paste was similar in the fresh tomato wastes (83% of moisture content) and in the samples dried up to a moisture content of 58% and 23%, but decreased to half of the value when samples were dried up to a moisture content of 4.6%. Supercritical CO2 extraction of carotenoids at 60 oC and 300 bar showed that the increase in the moisture content of the samples, from 4.6% to 23%, led to an increase in the yield (mass of extract/mass dry matter) of the extraction and to a decrease in the recovery of the carotenoids. For higher moisture degrees (58%), both the yield and the recovery decreased.