| Silkworm oil (SCO) mainly contains polyunsaturated fatty acids (PUFAs), such aslinoleic acid and a-linolenic acid, which have multi-physiological functions. There isabundant resource of silkworm in China, and it is strongly desired to develop oil,especially PUFAs in Silkworm as medicine materials, health products, etc.The supercritical CO2 extraction of SCO was studied. Single factor and orthogonalexperiments were used to study the effects of the parameters such as pressure,temperature and time on the yield of SCO at CO2 flow rate of 8kg.h-1. The resultsshowed that the extraction pressure was the more important factor that affected theyield of SCO, and the optimal conditions of supercritical CO2 extraction were as follows:pressure of 25Mpa, temperature of 45℃, extraction time of 2.5h, and the yield of SCOwas 28.97% under extraction conditions mentioned above.The urea adduction process of PUFAs in SCO was studied. The effects of ration ofurea to fatty acid, adduction time and temperature on purity and yield of PUFAs werediscussed. The optimal adduction conditions were obtained with single factor andorthogonal experiments, as follows:ration of urea to EtOH of 1:3.2(W/V), ration of ureato fatty acid of 1.5:1(W/W) adduction temperature of 5℃, and adduction time of 2h, and the yield of PUFAs was 70%, and the content of PUFAs could be raised from71.0% to 91.1% under adduction conditions mentioned above.Experiments for Separation of ALA from SCO were performed using aqueousAgNO3 extraction. The results showed that polarity of extraction solvents andcomplexing extraction temperature played major role for content of ALA from SCO atconstant concentration of AgNO3 of 2mol/L. The optimal complexation conditions wereobtained with single factor experiments, as follows: concentration of AgNO3 of 2mol/L,volume fraction of CH3OH of 40%, complexation temperature of 0℃, and the yield ofPUFAs was 50%, and the content of PUFAs could be raised from 71% to 99%.
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