Supercritical CO2 Extraction of Carotene and Lutein from Leaf Protein Concentrates

Supercritical fluid carbon dioxide was used to extract carotene and lutein from leaf protein concentrate (LPC). Extractions were performed using pressures of 10-70 MPa at 40°C and CO2 flow rates of 5-6 L/min. Over 90% of the carotene contained in LPC was removed at extraction pressures in excess of 30 MPa. Removal of lutein from LPC required higher extraction pressures (70 MPa) and gas volumes to attain a 70% recovery level. Experimental results were rationalized with the aid of solubility parameter theory. The described process offers the possibility of obtaining a selective extraction of natural colorants, free of solvent residuals, which can be used as food dyes.