Simulated digestion of proanthocyanidins in grape skin and seed extracts and the effects of digestion on the angiotensin I-converting enzyme (ACE) inhibitory activity

► In vitro gastrointestinal digestion of flavan-3-ols from grape skin and seed was studied. ► Inhibition of angiotensin-converting enzyme by the digested extracts was evaluated. ► Under gastric conditions, the mean degree of polymerisation of the seed extracts (raw and purified) was stable. ► ACE inhibition by raw seed and skin extracts was preserved (80%) after digestion. ► Purified extracts lost their ability to inhibit ACE after intestinal digestion.