Theoretical and experimental assessment of supercritical CO_2 in the extraction of phytosterols from rapeseed oil deodorizer distillates

摘要

Phytosterols, a group of naturally occurring compounds found in plant cell membranes, are structurally similar to the body's cholesterol and compete with that for absorption in the digestive system leads to the reduction of its blood level. This work is focused on the applying supercritical fluid extraction to isolate phytosterols from rapeseed oil deodorizer distillate (RODD). A thermodynamic model, the Peng Robinson equation of state model, was applied to show phase equilibrium behavior of the multicomponent oil-type material CO2 mixture and optimize the supercritical extraction process parameters. The extraction of sterols in the saponified RODD sample at 35 MPa, 313 K, and solvent to feed mass ratio (S/F) of 5, showed a recovery of 76 wt% with a purity of 60 wt%. Furthermore, the use of ethanol (5 wt%) as co-solvent, increased the phytosterol efficiency and purity. By coupling experimental studies with thermodynamic modeling, supercritical extraction processes could be analyzed more efficiently and rapidly.