Recovery and purification of cholesterol from cholesterol-β-cyclodextrin inclusion complex using ultrasound-assisted extraction

Response surface methodology was used to optimize ultrasound-assisted ethanol extraction (UAE) of cholesterol from cholesterol-β-cyclodextrin (C-β-CD) inclusion complex prepared from duck yolk oil. The best extraction conditions were solvent-solid ratio 10 mL/g, ultrasonic power 251 W, extraction temperature 56 °C and sonication time 36 min. Under these conditions, the highest cholesterol extraction yield and cholesterol content obtained 98.12 ± 0.25% and 43.38 ± 0.61 mg/g inclusion complex, respectively. As compared with Reflux extraction and Soxhlet extraction, the UAE was more efficient and economical. To increase the purity of crude cholesterol extraction, silica gel column chromatography and crystallization were carried out. Finally, cholesterol was obtained at 95.1% purity, 71.7% recovery and 22.0% yield.