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Release of angiotensin converting enzyme-inhibitory peptides during in vitro gastro-intestinal digestion of camel milk

Tagliazucchi, Davide, Shamsia, Sherif, Conte, Angela
International dairy journal 2016 v.56 pp. 119-128
bioactive properties, camel milk, digestion, hydrolysis, kappa-casein, mass spectrometry, milk, peptides, peptidyl-dipeptidase A, reversed-phase high performance liquid chromatography, structure-activity relationships
Angiotensin-converting enzyme (ACE)-inhibitory peptides released from camel milk after simulated gastro-intestinal digestion were identified. The hydrolysis degree increased during digestion. The highest ACE-inhibitory activity was found in the post-pancreatic <3 kDa fraction. Peptides responsible for the biological activity were isolated by reversed-phase high-performance liquid chromatography and identified by mass spectrometry. Among the identified sequences, 17 were identical to known bioactive peptides with ACE-inhibitory activity. Based on previous structure–activity relationship studies, the sequence of some peptides allowed us to anticipate the presence of biological activities. The anti-hypertensive tripeptide isoleucine-proline-proline (IPP) was identified and quantified in digested camel milk. The amount of released IPP was 2.56 ± 0.15 mg L−1 of milk. For the first time, we showed that IPP is released during the gastro-intestinal digestion of camel milk κ-casein. This research provides the basis to increase the exploitation of the health benefits of camel milk.