Tilapia fillets were treated under 50-300 MPa at 25 degrees C to examine the change of their processing quality. The gel strength from the tilapia meat treated at 50 MPa for 1 h was 1.2 times as that of fresh meat, but there was a 25% decrease for that treated at 250 MPa for 1 h. Extraction of water-soluble proteins was barely affected by high-pressure treatment; however, that of salt-soluble proteins decreased 60% after treating at 250 MPa for 1 h. The actomyosin was extracted below 10% for the meat treated beyond 200 MPa. The liability to denaturation indicates that pressure treatment was applicable to tilapia processing not for storage. (c) 2005 Elsevier Ltd. All rights reserved.