HIGH PRESSURE RESEARCH, cilt.27, ss.93-99, 2007 (SCI İndekslerine Giren Dergi)
In this study, we aimed to describe the temperature profile in the pressure vessel and the compression heating during high hydrostatic pressure (HHP) processing. Regression coefficients (R-2), root mean square error (RMSE) values and residual plots suggested that fourth-order polynomial function produced reasonable fits to define the temperature profile for all the pressures studied (300-600 MPa). If all the coefficients of this empirical model are determined, initial and final temperatures, a value close to the treatment temperature and maximum temperature reached during pressurization can be obtained or calculated theoretically. Temperature increase of the pressure transmitting fluid (ethylene glycol) at different inital temperatures (-2.5 to 17.5 degrees C and at the pressure range studied showed linear dependence with pressure. Maximum temperature increase (about 20 degrees C) was observed at 600 MPa and at initial temperatures of 14 and 17.5 degrees C. Minimum temperature increase (about 10 degrees C) was observed at 300 MPa and at initial temperatures of -2.5 and 8.5 degrees C. Although compression heating of ethylene glycol highly depends on the applied pressure, it was observed that it has little dependence to initial temperature.