**Giulia Leni 1, Lise Soetemans 1,2, Augusta Caligiani 1, Stefano Sforza <sup>1</sup> and Leen Bastiaens 2,\***


Received: 28 February 2020; Accepted: 22 March 2020; Published: 25 March 2020

**Abstract:** Protein hydrolysates from lesser mealworm (*Alphitobius diaperinus*, LM) were obtained by enzymatic hydrolysis with protease from *Bacillus licheniformis*. A preliminary test performed for five hours of hydrolysis generated an insect protein hydrolysate with 15% of degree of hydrolysis (DH), optimum solubility property and oil holding capacity, but emulsifying and foaming ability were completely impaired. In order to investigate the potential implication of DH on techno-functional properties, a set of protein hydrolysates with a different DH was obtained by sub-sampling at different time points during three hours of enzymatic hydrolysis process. An increase in DH% had positive effects on the solubility property and oil holding ability, while a reduced emulsifying ability was observed up to five hours of hydrolysis. These results demonstrated that the enzymatic hydrolysis, if performed under controlled conditions and not for a long period, represents a valid method to extract high quality protein from insects with tailored techno-functionality, in order to produce tailored ingredients for feed and food purpose.

**Keywords:** edible insect; protein hydrolysate; enzymatic hydrolysis; degree of hydrolysis; techno-functional properties; novel proteins
