Mass transfer and hydrodynamic study of supercritical carbon dioxide extraction of 1,8-cineole from small cardamom seeds

This study investigates mass transfer and hydrodynamic parameters of supercritical carbon dioxide (sc-CO2) extraction of 1,8-cineole from small cardamom seeds (SCs). Solubility of 1,8-cineole in sc-CO2, its diffusivity, and release kinetics from SCs have been explored. A correlated Chrastil equation has been developed for predicting solubility under varying extraction conditions. Empirical correlations among Reynolds, Schmidt, and Sherwood numbers considering Wilke-Chang equation for diffusivity showed a better fit as compared with those obtained using Stokes-Einstein equation. The extraction kinetics was in agreement with the Sovova model showing plug flow behavior. Release kinetics of 1,8-cineole from SCs was best explained by the Higuchi model. A high R-2 value (0.93) of the empirical equation involving dimensionless numbers suggested that the extraction process has been satisfactorily modeled. This model would help in scaling up the production of this significant biotherapeutic molecule from cardamom and similar seed matrices.