Disclosed is a protein hydrolysate having DPP-IV inhibiting activity, the hydrolysate being enriched in peptides having a length of 2-8 amino acids comprising at least one proline residue, an isolated peptide derivable from such a protein hydrolysate, or a mixture thereof, and the use of such protein hydrolysate or isolated peptide for the manufacture of a medicament, food supplement, beverage or food product for prophylaxis and/or treatment of a DPP-IV mediated condition, in particular chosen from the group of obesity, type 2 diabetes mellitus and an immunological disorder.