Release of the Antihypertensive Tripeptides Valine-Proline-Proline and Isoleucine-Proline-Proline from Bovine Milk Caseins during in Vitro Gastrointestinal Digestion

The aim of this study was to identify and quantify the release of antihypertensive tripeptides valine-proline-proline (VPP) and isoleucine-proline-proline (IPP) during in vitro oro-gastro-intestinal (OGI) digestion of bovine skimmed milk. The experimental approach combined the recently developed harmonized static in vitro digestion (IVD) model and targeted mass spectrometry to monitor peptide generation. We first demonstrated that VPP and IPP are released from bovine milk proteins during in vitro OGI digestion at final concentrations of 354.3 ± 29.8 and 973.8 ± 155.7 μg/L, respectively. In silico analysis of cleavage sites and mass spectrometry revealed that tetrapeptides VPPF, IPPL, and IPPK are precursors of VPP and IPP. The release of other ACE-inhibitory peptides, such as FVAP, VAP, AW, and VY, was demonstrated, and their fate and the time course were investigated. This research underlines the suitability of an IVD system to study the release of short bioactive peptides during OGI transit.