Yellow Mealworm Composition after Convective and Freeze Drying—Preliminary Results

Abstract

Insects are a potential source of food and feed for humans and livestock, and they can be consumed in different forms. A combination of freezing, blanching, and drying methods are often recommended to prolong the shelf life of insect-based foods and reduce their microbial loads. However, these processes affect the quality of the end product. Therefore, the aim of this study was to determine the extent to which various drying methods influence the selected physical and chemical parameters of yellow mealworm (Tenebrio molitor L.) larvae. Insects were blanched (for 60 and 120 s) and dried with the use of two methods: convective drying (at a temperature of 60 °C and 80 °C) and freeze-drying (−30 °C) for 12, 16 or 24 h. Blanched and dried insects were subjected to laboratory analyses. The examined samples were characterized by low moisture content in the range of 3.15% to 5.47%, and they differed considerably in water activity (0.06–0.55). Moisture content and water activity were substantially higher in larvae blanched for 60 s and freeze-dried than in larvae dried with the use of the remaining methods. However, no significant changes in the protein, fiber, or fat content of insects were found when drying parameters were modified. Therefore, nutritional composition and microbial loads in dried mealworm larvae should be investigated in the future.

Keywords

• edible insects
• feed proximate analysis
• protein
• water activity
• <i>Tenebrio molitor</i>
• food safety