Influence of drying and pretreatment methods on certain parameters of yellow mealworm larvae (Tenebrio molitor)

Nowadays alternative protein sources like edible insects are becoming widely used as human food. One of the most popular insect is yellow mealworm (Tenebrio molitor) due to its high nutrition value. However, pretreatment and drying are necessary to increase the food shelf life and the efficiency of its use. Due to this, the purpose of the present work was the determination of influence of pretreatment methods (freezing of larvae for 1 month, freezing for 2 hours, freezing for 1 month followed by defrosting for 2 hours at room temperature, blanching) and drying methods (convection drying at 40 °C and 60 °C, microwave drying) of yellow mealworm on its color (determination of L*, а*, b*, ΔElab, Ch, H, BI), moisture content (gravimetric method), fatty acid composition (determined by gas chromatography with mass spectroscopy) and time of drying (time required to reach constant weight). It was found that all used pretreatment and drying methods had no effect on the fatty acid composition of the larvae. In terms of drying rate and color retention, microwave drying showed better results than convection drying at 40 °C and 60 °C. Meanwhile, convection drying at 40 °C leads to the higher final moisture content of the samples. Among the pretreatment methods, only blanching the larvae samples before drying retained their color better and also accelerated the rate of the convection drying.