Removal of fat from crushed black soldier fly larvae by carbon dioxide supercritical extraction

Abstract

The larvae of the black soldier fly, Hermetia illucens, contain high amounts of protein and fat, and so are a good feed source. However, this high fat content hinders the production of such feed. The excess fat must thus be removed to enable the larvae to be used as a feedstock e.g., for aquaculture and livestock. Firstly, the use of hot water treatment as a strategy for extracting fat from dried larvae was tested. It was found that this process reduced the fat content of the raw material (from 30 to about 16%). However, the resulting product was still not suitable for feed processing. Next, the use of a carbon dioxide supercritical extraction system on crushed larvae was studied. This system time-dependently reduced the fat content to less than 6.6% and less than 4.6% after treatments for 2 and 6 h, respectively, with a pressure of 350 bar used on larval particles of 10-18 mesh in size. Therefore, subjecting 10-18 mesh crushed larval powder to carbon dioxide supercritical extraction at 350 bar for 6 h yielded a larval powder with a fat content of 5% or less. Based on this finding, this method is proposed to be a suitable alternative for further processing of larvae feedstock.