Assessment of the nutritional value, techno-functional, and in vitro physiological properties of six edible insects

The demand for more sustainable food production has generated attention in insect consumption. The main reason for this raised interest in insects is their nutritional characteristics: insects are a source of high-quality and easily digestible protein, fat, chitin, and a great variety of micronutrients. Therefore, the objective of this study was to evaluate the nutritional composition, techno-functional, and in vitro physiological properties of flours from six different insect species (mealworm, beetle, caterpillar, ant, locust, and cricket). The chemical composition of insects was evaluated following the standard methods (AOAC). Bulk density, water holding capacity, oil holding capacity, water absorption capacity, swelling capacity, emulsifying activity, foaming capacity, and gelation capacity were measured. In vitro antioxidant capacity was measure by the direct ABTS method. Hypoglycemic (glucose adsorption and the inhibition of α-amylase, glucose diffusion, and starch hydrolysis) and hypolipidemic (cholesterol and bile salts binding and lipase inhibition capacities) were investigated using in vitro methods. Insect flours exhibited high content of protein (39.4-58.1%) and fat (17.7-50.1%) as main components, although the presence of chitin in ant samples was also highlighted. The techno-functional properties showed high oil holding, swelling, and emulsifying capacities in all insect flours analyzed, besides bulk density, hydration properties, and foaming capacity showing average values and no gelation capacity. Insects showed high antioxidant capacity (179-221 mg Trolox equivalents/g). Moreover, these edible insect flours revealed effective hyperglycemic and hyperlipidemic properties. Insect flours inhibited α-amylase activity (47.1-98.0%) and retarded glucose diffusion (17.2-29.6%) and starch hydrolysis (18.2-88.1%). Likewise, they bound cholesterol and bile salts (8.4-98.6%) and inhibited lipase activity (8.9-47.1%). Hence, these insect flours might be of great interest to the food industry being a healthy source of protein, exerting a positive impact on functional food properties, and with a potential role in the prevention of the development of diseases associated with hyperglycemia and hyperlipidemia.