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Supercritical fluid extraction of evening primrose oil kinetic and mass transfer effects

King, J.W., Cygnarowicz-Provost, M., Favati, F.
Italian journal of food science : IJFS = Rivista italiana di scienza degli alimenti 1997 v.9 no.3 pp. 193
seed oils, extraction, food processing, mass transfer, kinetics, pressure, temperature, density, flow, carbon dioxide, solubility, models
For processing utilization, supercritical fluid extraction requires a thorough understanding of the relevant phase equilibria, mass balance, and kinetic factors that impact on the succesfull recovery of extracts. In this study, we have determined the factors contributing to the kinetics and mass transfer of evening primrose oil (EPO) from its ground seed matrix, to supplement previously determined solubility data and chemical characterization of this oil moietry. The effect of extraction pressure, temperature, fluid density and flow rate (over a threefold range) have been ascertained, the flow rate being correlated in terms of the extracted seed mass to similar data from the literature, performed on a pilot and production plant scale. Using a dual mass transfer model, we have correlated the theory with extraction experiments conducted over a pressure range from 20-70 MPa, temperatures from 40-60 deg C, and carbon dioxide flow rates in the interval from 9-27 g/min. The agreement between the model calculations and experimental data is excellent, allowing potential use of the data in process design