Processing methods for the black soldier fly (Hermetia illucens) larvae : From feed withdrawal periods to killing methods

Authors: Larouche, Jennifer
Advisor: Vandenberg, Grant William
Abstract: Black soldier fly (BSF) larvae represents a promising alternative ingredient for animal feed, but post-production processing can affect their quality. Feed withdrawal periods (FWP) used to evacuate fecal matter from the gastrointestinal tract, reducing the microbial load (ML), and killing methods are variable and poorly documented. This project aims to optimize the FWP and killing methods of BSF larvae to maximize product quality. Indeed, a prolonged FWP and an inappropriate killing method could alter larvae composition and ML. The gastrointestinal evacuation time (GET) of BSF larvae fed on coloured Gainesville diet was determined by following frass excretion every 12 h for 108 h. Then, FWP impact on the proximate composition and ML was measured daily over four days. Finally, the effects on the chemical composition, ML and colour of 10 killing methods were compared, i.e., blanching (B = 40 s), desiccation (D = 60 °C, 30 min), freezing (F20 = − 20 °C, 1 h; F40 = − 40 °C, 1 h; N = liquid nitrogen, 40 s), high hydrostatic pressure (HHP = 3 min, 600 MPa), grinding (G = 2 min) and asphyxiation (CO2 = 120 h; N2 = 144 h ; vacuum conditioning, V = 120 h). Although, the median GET was 72 h, a 96 h FWP did not reduce larvae ML. Certain killing methods affected the pH (B, asphyxiation), total moisture (B, asphyxiation and D), ash (B), lipid content (asphyxiation) and lipid oxidation (B, asphyxiation and D), as well as the colour stability during freeze-drying. FWP were ineffective in reducing the ML. Blanching appeared as the most appropriate method since it minimizes lipid oxidation, reduces ML and total moisture (78.1 ± 1.0%). Our studies propose a standardize protocol to kill BSF that meet the Canadian regulatory requirements of the insect production and processing industry.
Document Type: Mémoire de maîtrise
Issue Date: 2019
Open Access Date: 29 January 2020
Grantor: Université Laval
Collection:Thèses et mémoires

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