Recovery and techno-functionality of flours and proteins from two edible insect species: Meal worm ( Tenebrio molitor ) and black soldier fly ( Hermetia illucens ) larvae

Depending on the species, edible insects are highly nutritious and thus represent a noteworthy alternative food and feed source. The current work investigates the protein extractability and techno-functionality of insect flour fractions recovered from <i>Tenebrio molitor</i> and <i>Hermetia illucens</i>. <i>T. molitor</i> and <i>H. illucens</i> flours contained about 20% crude fat and 60% and 36 % crude protein, respectively. Defatting reduced the crude fat content to 2.8% (<i>T. molitor</i>) and 8.8% (<i>H. illucens</i>) and increased the crude protein content to 68% and 47%, respectively. To isolate proteins from the flours, protein solubility was optimized by varying the pH, the ionic strength, and the extraction temperature of the solvent. All products and by-products accumulated in the protein production process were characterized by composition, selected techno-functional properties, protein solubility, composition and structure as well as their microbial load.