Lipídeos da larva da mosca soldado negra (Hermetia illucens): uso potencial na alimentação humana

Abstract

The use of insects as an alternative food source is a worldwide trend. Among them, the black soldier fly (BSF, Hermetia illucens) stands out due to the high lipid content of its larvae, which can replace vegetable oils in animal feed and be integrated into human food. In this context, the first chapter of the present work contains a literature review on the extraction, composition, and application of lipids from edible insects. Since the extraction of lipids from BSF larvae is still poorly studied, in the second chapter, the separation of lipids from BSF larvae was evaluated with two extractive methods, aqueous extraction (EAQ) and Bligh-Dyer (EBD). The analyses performed during the experiments aimed to determine (i) the proximate composition (proteins, lipids, ash, and moisture) of the BSF larvae, the flour dried in the oven and freeze-dryer, and the biomass originating from the two extraction techniques (EAQ and EBD); and (ii) the yield, color, and fatty acids of the lipid extract. All BSF larvae were fed with corn bran until the 25th day of development. After this period, BSF larvae were fasted for approximately 24 h and stored in a freezer at -20 °C. Subsequently, they were added to liquid nitrogen and crushed. In the EAQ process, the ground larvae were lyophilized until reaching constant mass, added to water, maintained under sonication for 15 min, and then filtered in a 300 μm sieve. The filtrate was centrifuged at 15000g for 30 min at 4 °C. The lipid fraction formed was centrifuged at 15000g for 30 min at 40 °C, resulting in the lipid extract. In EBD, the ground larvae were dried in an oven at 60 °C until constant mass. The lipids were extracted with a mixture of chloroform, methanol, and water in the proportion 1:2:0.8 and sodium sulfate solution at 1.5% (w/v). The dominant colors of the lipid extracts originating in the EAQ and EBD were greenish-yellow and reddish-brown, respectively. This color difference can be correlated with the drying operations applied during lipid extraction. High levels of proteins (39.85-42.68%) and lipids (25.33-24.80%) were quantified in the meal of BSF larvae dried in the oven and in the freeze dryer. The EBD biomass presented higher protein, ash, and moisture contents than the EAQ biomass. The lipid yield (3.08%) and efficiency (50%) of EBD were higher, but EAQ does not use organic solvents to obtain lipids from BSF larvae. The same types of fatty acids were identified in the lipids extracted from BSF larvae by using the two extraction techniques, EAQ and EBD (C12:0; C14:0, C16:0, C18:210,12, C18:19, C18:0). Therefore, EAQ can be considered an alternative for obtaining lipids for use as a food ingredient, as it does not use organic solvents. However, the lipid yield is lower in EAQ than in EBD. Additionally, further studies are needed to enable the use of lipids from BSF larvae in human food.