Techno-functional properties of protein-rich flours from different species of edible insects as affected by drying methods

Abstract

Food-based ingredients from insects can circumvent the challenging disgust factor of consuming edible insects as food. The functional properties of dried edible insect flour could guide the use of edible insects as food ingredients in familiar foods. This study investigated the effect of freeze drying, oven drying, sun drying, solar cabinet drying, boiled before either sun drying or solar cabinet drying techniques on the functional properties of protein-rich flours from edible grasshoppers, crickets, and caterpillars. The Nitrogen solubility indices (NSI), water solubility indices (WSI) and β-sheets for all boiled solar-dried grasshopper, cricket, and caterpillar protein concentrates decreased compared to the other dried forms of grasshopper, cricket and caterpillars. The insect protein concentrates had lower foaming (32–49 %) and emulsion capacities (65–78 %) compared to commercial soy (FC: 55.9 %, EC: 94.3 %) and whey (FC: 52.9–55.6 % EC: 93.7–96.3 %) protein ingredients but exhibited higher foam stability (43.2–52.8 %) and good emulsion stability (83.4–93.0 %). Defatted insect flour could have proteins with intermediate molecular weight (≈100 kDa) that denature and aggregate at air-water interface to form thick viscous films that stabilise the foam. The high foaming and emulsion properties of these protein concentrates suggest they could be good ingredients in bread and sausages, respectively.

HIGHLIGHTS • Functional properties of edible insect protein concentrate depend on the species. • Heat treatment before drying changes secondary structure of edible insect proteins. • Edible insect protein concentrates have potential applications in the food industry.