A method of enzymatically producing a protein hydrolysate from a protein substrate is described, wherein a proline-specific endoprotease or a composition containing a proline-specific endoprotease and optionally a subtilisin or a metallo endoprotease, and other enzymes such as carboxypeptidases, is used to produce a protein hydrolysate enriched in peptide fragments having a carboxy terminal proline residue. Such protein hydrolysates may be used as such or to reduce bitterness in foods nutritionally supplemented by protein hydrolysates, as well as to produce hydrolysate-containing foodstuffs having low antigenicity.