Effect of hot melt extrusion on physical and functional properties of insect based extruded products

The use of alternative protein sources is widely investigated nowadays to ensure a sufficient and nutritious diet for the society. Among different possibilities, insects are currently considered a sustainable and efficient alternative to study more in deep. To this purpose, the present work investigates the use of hot melt extrusion to produce pellets made of insect flour (Hermetia illucens) used alone or mixed in different ratios (1:1 to 1:3) with corn flour. The samples were analysed in terms of physical properties as moisture content, color, water activity, and functional properties as water absorption index, water solubility index, oil sorption and viscosity. The results of the physical properties showed that the color of the pellets was greatly influenced by the blends used: dark brown for insect flour and yellowish for corn flour. Pure insect flour pellets had the lowest water absorption index (2.1 +/- 0.3%) and the highest water solubility index (16.8 +/- 0.3). The viscoamilographic profiles showed that the addition of the insect flour affected the pasting properties of the formulations. Overall, the results indicate the possibility to include insect flour during the extrusion process as potential source of proteins.