Influence of the killing method of the black soldier fly on its lipid composition

Abstract

Black soldier fly (BSF, Hermetia illucens) represents a valuable source of biomolecules and it also constitutes an economic way to valorise residual biomasses. BSF prepupae contain high amounts of lipids (37% DM basis). The present investigation aimed at studying the composition of BSF lipids and the effect of killing/storage on their quality. The main fatty acid was lauric acid, sterols were represented primarily by beta-sitosterol and campesterol. Global fatty acid and sterol profiles, determined by GC-MS, were only slightly affected by the killing procedure, while lipid classes distribution, determined by 1 H NMR, strongly changed. Prepupae killed by freezing showed a drastic reduction of acylglycerols during storage and a relevant release of free fatty acids, likely due to activation of lipases. On the contrary, prepupae killed by blanching have a stable lipid fraction constituted mainly by triacylglycerols. Therefore, killing procedure strongly influences BSF oil composition and the potential applications.

Use of organic acids to improve fractionation of the black soldier fly larvae juice into lipid- and protein-enriched fractions

“…These insects were killed rapidly (30 min at − 20 °C followed by nitrogen immersion). The same results were obtained after blanching (98% triglycerides) [30]. TLC analysis in the current study (data not shown) also indicated a major presence of triglycerides (no polyanionic group), thus implying that the interaction between proteins and lipids in this study is different.…”

“…Ushakova et al [29] reported 87% of lipids to be free fatty acids when the larvae were killed by freezing. Caligiani et al [30] found a free fatty acid content of 78% in larvae that were frozen. However, they stated that the storage length influenced the free fatty acids content (35% immediately after freezing, 90% after 2 months in frozen storage).…”

“…In addition, the results for these conditions also indicate that a low pH favored lipid fractionation since the lipid content was higher in the upper layer at pH 2 (85% versus 78%). Literature on the BSFL reports the presence of a large amount of free fatty acids, depending on the killing method [29,30]. Ushakova et al [29] reported 87% of lipids to be free fatty acids when the larvae were killed by freezing.…”

Killing process on the nutrient content, product stability and in vitro digestibility of black soldier fly (Hermetia illucens) larvae meals

“…As we know, the diet is the most in uential factor on the quality of black soldier y pupae meal (BSF) [5]. However, the killing method is also a highly in uential factor on BSF quality [1,[6][7][8]. Heat treatment, freezing, asphyxiation and mechanical disruption are the general procedures to euthanize black soldier y prepupae [7].…”

“…Heat treatment, freezing, asphyxiation and mechanical disruption are the general procedures to euthanize black soldier y prepupae [7]. The fast killing method with heat treatment (blanching in boiling water for a short time) has been suggested and can decrease the amount of microbial contamination, conserve nutrient quality, prevent degeneration of the end product and provide a bright colour which is acceptable to consumers, whereas slow killing methods without heat treatment (freezing, asphyxiation and blending) provided adverse consequences [6][7][8]. In contrast, Montevecchi et al [9].…”