The application of high-pressure treatment to a hard caprine milk cheese was studied as a method of acceleration of proteolysis during ripening. Levels of proteolysis in the cheese subjected to treatment at 50 MPa for 72 h were only slightly different to those in control cheese, with differences being less apparent by the end of ripening. Treatment at 400 MPa for 5 min caused more significant quantitative and qualitative changes in proteolysis that persisted throughout the ripening. This treatment resulted in increased levels of free amino acids, although cheese treated at 400 MPa had profiles of peptides and caseins, obtained by HPLC and PAGE, similar to younger untreated cheese or cheese treated at 50 MPa. Plasmin activity in cheese was unaffected by pressure treatment, whereas coagulant activity was decreased by treatment at 400 MPa. Overall, application of high pressure at the beginning of ripening significantly increased secondary proteolysis, or conversion of peptides into free amino acids. (C) 2002 Elsevier Science Ltd. All rights reserved.