Frozen storage of lesser mealworm larvae (Alphitobius diaperinus) changes chemical properties and functionalities of the derived ingredients.

The effect of frozen storage on the chemical properties and ingredient functionalities of Lesser mealworms was investigated at -20 °C for 2 months. Major changes occurred in the first week of frozen storage. Proteins, among which heavy chain myosin, underwent denaturation and aggregation, as shown by a decrease in solubility, SDS-PAGE pattern, and Confocal Laser Scanning Microscopy. The ice melting point in larvae was -32.5 °C as determined by DSC: 25% of water is not frozen at -20 °C, possibly due to anti-freezing proteins preventing ice formation. The presence of unfrozen water favoured various enzymatic activities as shown by a pH decrease, indicating protein hydrolysis. The molecular changes during frozen storage increased the browning reactions due to phenoloxidase activity. Foaming ability, foam stability and gel network stability increased upon frozen storage due to protein denaturation. Results provide important information regarding the opportunity of frozen storage of insect larvae for both research and industrial purposes.

On printability, quality and nutritional properties of 3D printed cereal based snacks enriched with edible insects.

3D printing technology was employed to obtain snacks with a designed cylindrical geometry from wheat flour dough enriched by ground larvae of Yellow mealworms (Tenebrio molitor) as novel source of proteins. The main microstructural features, overall quality, and nutritional attributes were studied as a function of formulation, time and temperature of baking. The addition of ground insects up to 20 g/100 g (d.b.) resulted in softer dough. This caused an overflow in dough deposition producing the increase in diameter, height and weight of snacks. Baking conditions did not alter the overall aspect of the snacks, but modification of the main dimensional and microstructure attributes were observed due to the better water evaporation. The optimization of baking conditions found that 22 min and 200 °C allowed obtaining a maximum desirability of 0.693. Baked in these conditions, the printed snacks enriched with 10 and 20% of ground insects significantly increased the total essential amino acid, from 32.5 (0% insects) to 38.2 and 41.3 g/100 g protein, respectively. The protein digestibility corrected amino acid score increased from 41.6 to 65.2 from 0 to 20% insect enrichment, with lysine and methionine + cysteine being the respective limiting amino acid. Our results evidenced the rational promotion of insects based on nutritional arguments and validated the use of 3D printing as technology to manufacture innovative printed snacks without adverse impact on technological quality.