Study On Extraction,separation And Recovery Of Lipids From Hermetia Illucens

As a rot-torn insect,Hermetia illucens(black soldier fly)is an environmentally friendly and sustainable resource insect with low feeding cost and high contents of lipids,which has strong ability to dispose of kitchen residue.This paper mainly studies three continuous and complete technological processes,namely,homogenizing method for extracting oil of black soldier fly,urea adduction method for separation and purification of unsaturated fatty acid,and acid leaching method for recovery of fatty acid and urea,which provides a theoretical basis for the development and utilization of black soldier fly lipids.The main results are as follows:(1)The lipids is extracted by homogenizing method from fresh and wet black soldier fly larvae,and the feasibility of this method is confirmed by comparing the cell electron microscope and infrared image of black soldier fly before and after homogenization.The effects of solvent type,solvent ratio,solid-liquid ratio,water content,homogenization speed and time on the lipids extraction efficiency are studied,and the results indicate that the optimal lipids extraction efficiency 75.92% is achieved when the volume ratio of petroleum ether to isopropanol is 5:3,biomass/solvent is 1:4,water content is 70%,homogenization speed is 10000 rpm,and the time is 1 min.According to the influence of the homogenization speed and time of a high speed homogeniser on the lipids extraction efficiency,the kinetic model of the lipids extraction from the ruptured black soldier fly cell is established,and the rate constants at different homogenization speeds is determined.(2)The urea adduction method is used to separate and purify black soldier fly lipids,and the effects of mass ratio of urea to mixed fatty acids,volume mass ratio of ethanol to urea,adduction temperature,adduction time and adduction times on the purity and yield of unsaturated fatty acids are studied.The results indicate that the purity of unsaturated fatty acids is improved from 42.20% to 80.89%,and the yield is 36.33% when mass ratio of urea to mixed fatty acids is 2:1,volume mass ratio of ethanol to urea is 8:1,adduction temperature is 0 ?,adduction time is 18 h,continuous adduction 3 times.The sensory indexes and physicochemical properties of insect lipids before and after urea adduction are compared,and the results indicate that the color and smell of lipids becomes lighter,the freezing point decreases,the viscosity becomes smaller,liquid fluidity increases,and the acid value,saponification value,iodine value and peroxide value increase,and the functional groups and thermal stability has also changed after urea adduction.(3)The urea adduction complex is dissolved to recover fatty acid and urea by acid leaching method,and the effects of dissolution temperature,solid-liquid ratio and crystallization temperature on the recovery rate are studied.The response surface method is used to optimize the recovery process conditions,and the results show that the simulated recovery is 92.86% and the actual recovery is 92.08% when the dissolution temperature is 69 ?,solid-liquid ratio is 1.65:1,and crystallization temperature is 7.5 ?.The purity of recovered urea is 98.18%,and fatty acids mainly includes oleic acid(30.10%),lauric acid(19.32%)and palmitic acid(17.18%).