Supercritical carbon dioxide extraction of Polygonum cuspidatum powders: Experiments and modelling

Abstract

In recent years, the natural anticancer components resveratrol and emodin have attracted significant attention. This study employs supercritical carbon dioxide (ScCO₂) extraction, using ethanol as a cosolvent, to extract resveratrol and emodin from Polygonum cuspidatum powders. Experiments were conducted at temperatures ranging from 308 to 328 K, pressures from 15 to 30 MPa, ethanol contents of 60 to 160 mL/L, and extraction times between 1800 and 7200 s. The maximum extraction yields of resveratrol and emodin were 2.516 and 2.765 mg/g, respectively, under optimal conditions (temperature: 323 K, pressure: 25 MPa, ethanol content: 100 mL/L, extraction time: 3600 s), determined through one-way experiments. Additionally, a mathematical model of the ScCO₂ extraction process was developed. The mass transfer coefficient (K_f) was used as a fitting parameter and the kinetic model, based on mass conservation, was validated with experimental data. The model demonstrated good accuracy, with a low average absolute relative deviation (AARD) of 4.05%. This model provides theoretical support for industrial scaling and process optimization, achieving maximum extraction efficiency while minimizing CO₂ and ethanol consumption, thereby reducing costs and enhancing environmental benefits. Its establishment framework and methodology offer valuable references for optimizing similar ScCO₂ extraction processes.