Study On The Nature Of Silkworm Oil And The Purification Of α-Linolenic Acid From It

Silkworm chrysalis is the pupa of silkworm when they got into cocoon,is also important by-product of sericulture.The output of dried silkworm pupa of our country is beyond 120 thousands tons every year, Silkworm has a lot of advantage,such as hypoglycemic, anti-tumor, enhanced immunity and intelligence. I got research in major physical and chemical characters, factors of hunidity of silkworm oil, fatty acid composition, extraction of silkworm oil, purification of a-linolenic acid from it. The reseach results are showed as follows.1. I respectively used the methods of Soxhlet extraction and Supercritical CO2 extraction to separate and extract the silkworm oil. the petroleum ether is for good. and extraction time for 7 hours is appropriate, extraction rate can reach to 28.53%. Supercritical CO2 extraction:extracting pressure 30MPa, extracting temperature 45℃and extracting time 3 hours,by above conditions, the extraction rate of oil is up to 28.37%.2. The higher the temperature and time got, the faster the peroxide value and the acid value of silkworm oil and fat increased. Best storage humidity situation of silkworm was 70%～80% RH.The quality of inferior silkworm oil and fat was worst. Silk reeling and post-processing played a key role in the quality of silkworm oil. Drying in time could reduce the rancidity of residual pupa of silk reeling at high temperature in the summer and autumn, providng theoretical basis for further development of silkworm.3. The best hydrolysis temperature was 70℃, The best time was 70 minutes, The best appropriate concentration ratio of Sodium hydroxide with ethanol was 4 percentage. and the best ratio of silkworm pupa oil and the of NaOH with ethanol was 1:3. In this condition, the acid value of maxied fatty acids which got after hydrolyzing was 161.32. mgKOH/g. 4. The maxied fatty acid of silkworm oil was soluted with acetone at the ratio of 6:1. Next step.kept the solution in the low temperature refrigerator for 5 hours at-30℃. the concerntion of alpha-linolenie acid in the fatty acid sample was 65.94% Separated crystallization from solution by filtration.Urea Fractionation.the ratio of fatty acid and urea was 1:3, the ratio of fatty acid and methaol was 1:8, kept in the low temperature refrigerator at 0℃for 16 hours.Analysis with the gas chromatography, the concerntion of alpha-linolenie acid in the fatty acid sample reached to 74.26% from 30.45%.