Effects of Killing Methods on Lipid Oxidation, Colour and Microbial Load of Black Soldier Fly ( Hermetia illucens ) Larvae

• Published in: Animals (Basel) Vol. 9; no. 4; p. 182
• Main Authors: Larouche, Jennifer, Deschamps, Marie-Hélène, Saucier, Linda, Lebeuf, Yolaine, Doyen, Alain, Vandenberg, Grant W
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 21-04-2019; MDPI
• Subjects: Animal feed; Bacteria; black soldier fly larvae; Blanching; Carbon dioxide; chemical composition; Color; colour stability; Dehydration; Desiccation; Eggs; Experiments; Fatty acids; Feeds; food processing; Freeze drying; Freezing; Heat; Humidity; Hydrostatic pressure; Insects; killing; Laboratories; Larvae; lipid oxidation; Lipid peroxidation; Lipids; Liquid nitrogen; Malondialdehyde; Metabolism; Methods; Microbial contamination; microbial load; Microorganisms; Microwaves; Moisture content; Oxidation; Polyphenols; Post-production processing; Processing industry; Proteins; Quality; thermal and non-thermal technologies; Tonic immobility; Vacuum; Water content; Water pollution; Canada; United States > US; Baltimore Maryland; killing; pH; dehydration; lipid oxidation; microbial load; black soldier fly larvae; thermal and non-thermal technologies; chemical composition; food processing; colour stability
• DOI: 10.3390/ani9040182
• EISSN: 2076-2615

Black soldier fly (BSF) larvae represent a promising alternative ingredient for animal feed. Post-production processing can, however, affect their quality. This project aimed to optimize larval killing by comparing the effects on the nutritional and microbiological quality of 10 methods, 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 (CO
= 120 h; N
= 144 h; vacuum conditioning, V = 120 h). Some methods affected the pH (B, asphyxiation), total moisture (B, asphyxiation and D) and ash contents (B,
< 0.001). The lipid content (asphyxiation) and their oxidation levels (B, asphyxiation and D) were also affected (
< 0.001). Killing methods altered the larvae colour during freeze-drying and in the final product. Blanching appears to be the most appropriate strategy since it minimizes lipid oxidation (primary = 4.6 ± 0.7 mg cumen hydroperoxide (CHP) equivalents/kg; secondary = 1.0 ± 0.1 mg malondialdehyde/kg), reduces microbial contamination and initiates dehydration (water content = 78.1 ± 1.0%). We propose herein, an optimized protocol to kill BSF that meet the Canadian regulatory requirements of the insect production and processing industry.