Angiotensin I-converting enzyme inhibitory activity in lima bean (Phaseolus Lunatus) protein hydrolysates produced with alcalase or pepsin-pancreatin

Protein concentrates from ungerminated and germinated lima bean Phaseolus lunatus seed flours were hydrolyzed with alcalase 2.4L or pepsin-pancreatin sequential hydrolysis, and ACE inhibitory activity measured in the different hydrolysis treatments. A 2³ factorial design with four replicates of the central trial was used. Evaluated factors were protein concentrate source (ungerminated seeds, PC₁; germinated seeds, PC₂), enzyme/substrate ratio E/S (1/50 or 1/10) and hydrolysis time (0.5 or 2.0 h for alcalase; 1 or 3 h for pepsin-pancreatin). Degree of hydrolysis (DH) was high for the alcalase hydrolysates (24.12-58.94%), but the pepsin-pancreatin hydrolysates exhibited the highest ACE inhibitory activity (IC₅₀ = 0.250-0.692 mg/mL). Under the tested conditions, the hydrolysates with the highest ACE inhibitory activity were produced with sequential pepsin-pancreatin using either PC₁ at 1 h hydrolysis time and a 1/10 E/S ratio or PC₂ at 1 h hydrolysis time and a 1/50 E/S ratio. Lima bean protein hydrolysates prepared with alcalase or pepsin-pancreatin are a potential ingredient in the production of physiologically functional foods with antihypertensive activity.