Characterization of bioactive peptides produced from green lentil (Lens culinaris) seed protein concentrate using Alcalase and Flavourzyme in single and sequential hydrolysis

This study aimed to produce bioactive peptides with increased angiotensin-converting enzyme (ACE)-inhibitory and antioxidant activities from single and sequential hydrolysis, using Alcalase and Flavourzyme at the enzyme to substrate ratio of 2% and hydrolysis time of 180 min. Results indicated that sequential hydrolysis led to a higher degree of hydrolysis (DH) value (47.05%) compared with single hydrolysis (8.51% and 20.12%). Higher ACE-inhibitory activity and total phenol content were determined for the lentil protein hydrolysates (LPH) compared with lentil protein concentrate, and also higher antioxidant activity was obtained comparing with butylated hydroxytoluene as a synthetic antioxidant. The main amino acid profile of hydrolysates was maintained. The higher DH via hydrolysis was obtained, more small and medium molecular weight peptides were generated according to the gel permeation chromatography and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Hydrolysis did not have a significant effect on the denaturation point of protein, and thus the thermal stability was maintained. Shorter peaks were observed for hydrolysates by atomic force microscopy. Enzymatic hydrolysis increased the umami sensorial taste. Novelty impact statement Using a combination of enzymes in sequential hydrolysis can produce bioactive peptides with improved ACE-inhibitory and antioxidant activities. Alcalase leads to the production of bitter taste peptides which can be altered by applying Flavourzyme to hydrolyze the former peptides to fewer bitter peptides. Lentil protein was hydrolyzed sequentially into bioactive peptides with improved anti-hypertensive and antioxidant activities and increment of umami taste in respect to the produced peptides with specific amino acid profiles.