Protein hydrolysates from black soldier fly larvae (Hermetia illucens): Experimental design, ultrafiltration fractionation, and kinetics of bioactive peptide production

The improvement of the biological properties of insect proteins has been widely studied with a view to their inclusion in foods for humans and animals. The aim of this work was to study the production of bioactive peptides through enzymatic hydrolysis of proteins from black soldier fly larvae. For this purpose, an experimental mixture design was employed using the proteases Flavourzyme, Alcalase and Neutrase as factors, and antioxidant activity of the protein hydrolysates as the response of interest. The results revealed that the combination of Flavourzyme (2/3), Alcalase (1/6) and Neutrase (1/6) resulted in protein hydrolysates with the highest values of antioxidant activity, quantified by the ABTS (588.04 µmol TE/g), DPPH (30.15 µmol TE/g) and FRAP (76.29 µmol TE/g) methods. The kinetic study demonstrated that the proteases in combination maintained 80% of the enzymatic activity through 180 min of hydrolysis. Furthermore, the hydrolysates were ultrafiltered and the peptides between 5-3 kDa showed greater antioxidant activity. According to data obtained from liquid chromatography-mass spectrometry (LC-MS/MS) and in silico analysis, the peptides YPGEL, AIGGW, LAWQF, and LGPPGAG showed the most promising antioxidant activity. The results obtained demonstrated the potential of enzymatic hydrolysis to selectively modify the proteins of black soldier fly larvae.