The Effects of Slaughter Methods and Drying Temperatures on the Protein Hydrolysis of Black Soldier Fly Larvae Meal

Abstract

Simple Summary Insects, because of their protein content and environmental advantages, have been considered a promising alternative to other traditional protein sources. The black soldier fly (BSFL) is one of the most studied insects given its use as an alternative feed for farmed animals (mammals, poultry, and fish). This study investigated the effect of the method of slaughter (freezing, blanching, Melacide® + freezing, and liquid nitrogen slaughter) and drying temperature (50, 70, and 90 °C) on the protein digestibility, proximal composition, and organic matter digestibility of BSFL meal. The results show that the best slaughter methods were slaughtering with liquid nitrogen and blanching, and 70 °C was the drying temperature that showed the best digestibility results while maintaining good hygienic–sanitary conditions. Abstract In recent years, the potential of insects as a sustainable protein alternative to feed the growing world population has been explored. Differences in the ways insects are processed can affect their proximate composition and digestibility. This work studied the effects of the combination of different types of slaughter methods and drying temperatures on the proximate composition, organic matter digestibility (OMd), hydrolysis degree (DH/NH2 and DH/100 g DM), total hydrolysis (TH), and hygienic and sanitary characteristics of BSFL (black soldier fly larvae) meal. Four types of slaughter methods were used including freezing (F), blanching + freezing (B), Melacide® + freezing (M), and liquid nitrogen slaughter (N). Each of these was used with three drying temperatures (50, 70, and 90 °C). A negative correlation between the acid detergent fiber (ADF) and protein digestibility parameters was obtained. The most suitable drying temperature was 70 °C, as it produced higher values of protein digestibility (DH and TH), resulting in hygienic and sanitary conditions suitable for food use. Slaughtering with liquid nitrogen and blanching was more conducive to achieving high protein digestibility results than traditional freezing or the use of Melacide®.