The optimization of mealworm (Tenebrio molitor) sacrifice methods and examination of sacrificed mealworm post-cooking characteristics

Edible insects are gaining notable attention as an alternative human dietary protein source. However, despite its importance in food preparation, an optimal sacrifice method for insects is under research. Therefore, this study sought a suitable sacrifice method for mealworm (Tenebrio molitor), a representative edible insect. Mealworms were sacrificed via freezing, sonication, blanching, and roasting and processed into powder, the predominant form in food industries. Freezing and sonication increased the free amino acid content but significantly decreased water-adhesion capacity and acceptance scores. Blanching and roasting produced mealworm powders with higher overall acceptance scores (3.33±1.06 and 3.53±1.20, respectively) than freezing and sonication (2.00±1.00 and 2.33±1.07, respectively) (p<0.05). Moreover, blanching yielded higher water- (1.84±0.01 g/g) and oil- (1.53±0.07 g/g) adhesion capacities than roasting (1.29±0.02 and 1.21±0.14 g/g, respectively) (p<0.05). Therefore, blanching was deemed a suitable sacrifice method that potentially enhances mealworm powder usability in the food industry. Additionally, to expand the application of blanching-sacrificed mealworms, we cooked them via steaming, boiling, panfrying, and deep-fat frying and verified their characteristics. Moist-heat cooking methods (steaming and boiling) conferred chewy/juicy textures and steamed-grain/mushroom odors to mealworms; conversely, dry heat-cooked (panfrying and deep-fat frying) mealworms exhibited a crispy texture, roasting odor, and savory taste. Among the four cooking methods, panfrying yielded the highest volatile compound content, with 2-methylbutanal and isobutyraldehyde being the most abundant. Our findings provide insights into optimizing sacrifice and cooking methods to improve the quality and sensory traits of mealworms and their derived products.