Abstract: The ultrasound-assisted supercritical?CO2 (UASC-CO2) extraction of lipids from the freeze-dried adipose tissue of Chinese giant salamander (Andrias davidianus) was optimized using a combination of one-factor-at-a-time method and response surface methodology and compared with conventional supercritical?CO2 extraction. The optimum conditions for UASC-CO2 extraction that provided maximum lipid yield (93.66%) were determined as follows: pressure, 36 MPa; temperature, 43.5 ℃; and time, 120 min. However, the optimum conditions for conventional supercritical?CO2 extraction that provided maximum lipid yield (75.25%) were as follows: pressure, 40 MPa; temperature, 43.5 ℃; and time, 120 min. It was observed that the yield of lipids was significantly higher by UASC-CO2 extraction method at lower pressures than by conventional supercritical?CO2 extraction at the same temperature and time. In addition, in terms of physicochemical properties and fatty acid content, no significant difference was seen between the two lipid extracts. The results showed that the yield of lipids from Chinese giant salamander could be significantly improved by ultrasound-assisted treatment, while still maintaining the product quality.

Key words: lipids from Chinese giant salamander, supercritical carbon dioxide, response surface methodology, ultrasound-assisted pretreatment, extraction efficiency