Effects of pressure-shift freezing conditions on the quality characteristics and histological changes of pork

This study investigated the effect of various pressure-shift freezing (PSF) conditions (0.1-200 MPa) on the quality characteristics of pork. Pork was pressurized and cooled down to corresponding freezing temperature at given pressure level, and thereafter, the pork was finally frozen in a -50 degrees C freezer for 24 h. The frozen pork was thawed in a 4 degrees C refrigerator for 24 h, and quality parameters were analyzed. As quality parameters, pH, water-binding properties, shear force, histological change and color were evaluated. The PSF operating at higher pressure than 150 MPa manifested high moisture loss and discoloration, while the PSF at 50 MPa had no advantageous effect on the quality of pork compared to atmospheric freezing (0.1 MPa). The best PSF condition was observed at 100 MPa, where the pork quality did not differ from an unfrozen control after thawing. Consequently, the results reflected that PSF at 100 MPa had a potential application in providing rapid freezing without quality deterioration in the frozen meat industry. (C) 2015 Elsevier Ltd. All rights reserved.