Co-solvent-modified supercritical carbon dioxide extractions of cholesterol and free amino acids from soft-shell turtle fish egg

This study examines the co-solvent-modified supercritical carbon dioxide (SC-CO2) extraction of cholesterol and free amino acids from soft-shell turtle fish egg powder. Extraction efficiencies and concentration factors of cholesterol and free amino acids in the SC-CO2 extracts were determined. Experimental data demonstrate that the initial extraction rate of cholesterol increased with temperature following static ethanol-modified SC-CO2 extractions at 300 bar. The 70.1% of extraction efficiency of cholesterol was obtained by continuous SC-CO2 extraction at 338 K and 300 bar. The response surface methodology was used to design SC-CO2 extractions of ethanol modified egg powder at 338 K, which revealed that increasing pressure and adding ethanol equally promoted the extraction efficiency of cholesterol. Concentration factors of cholesterol increased from 0.46% in egg powder to 7.88% in the SC-CO2 extracts. Experimentally designed SC-CO2 extractions of water-modified egg powder indicated that temperature substantially influenced the extraction efficiency of free amino acids. Concentration factors of free amino acids increased from 1.05% in egg powder to 29.46% in SC-CO2 extracts.