Sequential two-stage extraction of Xanthoceras sorbifolia seed oil using supercritical CO2 and CO2-expanded ethanol

Abstract

A new method of seed oil extraction from X. Sorbifolia was developed using a two-stage process with supercritical CO2 (SC-CO2) and CO2-expanded ethanol (CXE). The BIC model was employed to optimize the extraction process. During the SC-CO2 extraction stage, the CLSM imaging showed rapid release of EAO from the broken cells at the edge of the particles with an oil yield of 74.11% after 4 h. The follow-up CXE extraction at 10 MPa, 333 K, and 1.5 kg/h, with a CO2 molar fraction of 0.5 resulted in 68% broken cells by SEM imaging, and obtained 18.42% of remaining HAO, with a total oil yield of 92.53%. The whole process was completed in 60% less time compared to the Soxhlet method. Lipid composition analysis found a small amount of fatty acid ethyl ester in CXE oil and a higher content of functional fatty acid nervonic acid at 4.12%.