An industrial Alfalfa white protein concentrate hydrolysed at pilot plant scale by Delvolase (R) in a continuous enzymatic membrane reactor leads to a hydrolysate exhibiting a high ACE inhibition activity (8.8 mu g/ml). This hydrolysate, fractionated by two chromatography steps (exclusion size fast protein liquid chromatography and reversed-phase high performance liquid chromatography) revealed that around 15% of the total ACE inhibition activity is due to a single ACE inhibitory peptide. This peptide identified by electrospray mass spectrometry as VW, a potent antihypertensive peptide in vivo, contained four times of that in the main Alfalfa white protein (RuBisCO). (c) 2006 Elsevier Ltd. All rights reserved.