Purification and characterization of angiotensin-converting enzyme-inhibitory peptides from Nile tilapia (Oreochromis niloticus) skin gelatine produced by an enzymatic membrane reactor

•Collagen was hydrolysed to <1.2kDa peptides in an enzyme membrane reactor.•The hydrolysate exhibited ACE-inhibitory activity.•Novel ACE-inhibitory peptides were identified in active fractions.•Simulated gastrointestinal digestion decreased the activity somewhat.•The hydrolysate may be used for functional foods.