Optimization of supercritical carbon dioxide extraction of silkworm pupal oil applying the response surface methodology

Supercritical carbon dioxide extraction (SC-CO2) of oil from desilked silkworm pupae was performed. Response surface methodology (RSM) was applied to optimize the parameters of SC-CO2 extraction. The effects of independent variables, including pressure, temperature, CO2 flow rate, and extraction time, on the yield of oil were investigated. The statistical analysis showed that the pressure, extraction time, and the quadratics of pressure, extraction time, and CO2 flow rate, as well as the interactions between pressure and temperature, and temperature and flow rate, showed significant effects on oil yield. The optimal extraction condition for oil yield within the experimental range of the variables researched was at 324.5 bar, 39.6 °C, 131.2 min, and 19.3 L/h. At this condition, the yield of oil was predicted to be 29.73%. The obtained silkworm pupal oil contained more than 68% total unsaturated fatty acids, and alpha-linolenic acid (ALA) accounted for 27.99% in the total oil.