Fats Extraction, Fatty Acids Composition Analysis And Purification Of α-Linolenic Acid From Insects

As important raw materials of industry and fat chemical industry, fatty acid has been widely used in industrial production, food, health care and other fields. Currently, most fatty acid is from plants, fish, micro-organisms, algae et al., and the present production level can not meet the demand of fatty acid. As a dominant animal group in the world, insect brings the biggest biomass in the nature and is to be considered as an abundant fatty acid sources. Thus, it is worth developing insect fatty acid resources and it may bring a promising prospect to human being.After extracting fats from five species of insects, this study analyzed the composition and contents of fatty acid in the fats, isolated and purifiedα-ALA from the fatty acid. Furthermore, the value of insect fatty acid was studied, and the commercial prospect of insect fatty acid was discussed.The study was carried out of three aspects. The first aspect is to identify the best conditions for extracting insects fats through single-factor and orthogonal experiments (Eligma narcissus Gramer for materials). Results showed that the best condition: solvents (petroleum ether)-180ml, temperature-50℃, duration-10h, raw materials-5g and extracting times-1.The second aspect mainly compared the composition and contents of fatty acid got from eight samples through gas chromatography analysis. Results showed that, (1) The larva, adult and pupa of Eligma narcissus Gramer has different contents of fatty acid, but they all contain more than 79% unsaturated fatty acid, among which the contents of linolenic acid and oleic acid are 27%-36% and 30%-35%, respectively. (2) The larva and adult of Metabolus tumidifrons Fairm both have rich oleic acid (43%) and linoleic acid while they are different in contents of fatty acid. (3) The adult of Dastarcus longulus Sharp contains about 86.3% unsaturated fatty acid, among which there are a lot of monounsaturated fatty acid(MUFA). (4) The adult of Lycorma delictula White has rich oleic acid and can be good source of fatty acid. (5) The adult of Erthesina fullo Thunberg contains more than 50% fats, among which there are more than 50% MUFA-Palm oil acid and can match with those from whales and fishes, eight kind of insects can be served as good fatty acid source.The third aspect isolated and purified the a-linolenic acid from Eligma narcissus Gramer larvae through combinating the methods of column chromatography and urea inclusion. After urea inclusion once, linoleic acid increased from 11.25% to 18.13%, oleic acid decreased from 34.06% to 11.83% and alpha-linolenic acid increased from 35.46% to 70.04%, which indicated urea inclusion can separate alpha-linolenic acid effectively, and the best condition for separation: solvents-ethanol,the ratio of fatty acid, ethanol and urea-1:2.5:8, temperature-(-5℃) , duration-15h, separating times-once. Then column chromatography was employed to further isolate Alpha-linolenic acid, results showed the content of linolenic acid ethyl ester was 98.9%, production rate was 71.5% and the purification multiplier was 1.67.