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

Abstract BACKGROUNDBlack soldier fly (BSF; Hermetia illucens) is considered as a potential sustainable insect alternative source of protein for animal feed; however, the quality of BSF meal is greatly influenced by the killing method. Therefore, the purpose of this article is to compare the quality of BSF obtained by different killing methods.RESULTSBSF at the 18-day-old prepupae stage were separated into six different killing methods (n = 3): 1. blending, 2. freezing, 3. CO2 treatment, 4. vacuum, 5. Blanching and 6. humane method. After killing, were obtained by hot air oven drying and grinding. The chemical composition and in vitro digestibility calculated from sediment was not affected by the killing method, except that blending provided the worst BSF quality for all measured parameters (P < 0.05). The highest quality of BSF was obtained from the heat treatment procedures (blanching and the humane method), as they produced lower acidity after killing, total viable counts, browning reaction (enzymatic and non-enzymatic), darkness, moisture, fat acidity, protein and lipid oxidation during storage compared with other killing procedures (P < 0.05). Interestingly, the highest of free amino acids in the supernatant after in vitro digestibility of BSF samples was observed with the humane killing method (P < 0.05), whereas other parameters were similar to those obtained with blanching.CONCLIUSIONBlanching and humane method produce BSF with the nutritional quality, safety and stability. humane method did not produce clearly different outcomes to blanching; therefore, the selection of one of these techniques over the other should depend on the regulations in each country.