Effect of thermosonication on quality improvement of tomato juice

inactivation of pectinmethylesterase (PME) and polygalacturonase (PG) is required to minimize quality loss in tomato products. Tomato juice was subjected to thermosonication (TS) (24 kHz), at amplitudes of 25, 50 and 75 mu m at 60, 65 and 70 degrees C or heat only treatments. The TS treatment at 60 degrees C, 65 degrees C and 70 degrees C for 41.8, 11.7 and 4.3 min exposure, respectively reduced PME activity by 90%. The heat only treatment at 60 degrees C, 65 degrees C and 70 degrees C for 90.1, 23.5 and 3.5 min, respectively inactivated PME by 90%. TS treatments with 25-75 mu m amplitude had no significant impact on the inactivation efficiency between 60 and 70 degrees C. After TS the average particle size decreased noticeably (<30 mu m) and viscosity increased 2-4 fold, compared to the heat treated or untreated juice (180 mu m). These results suggest that TS at 60 and 65 degrees C could be useful to obtain tomato juice with a low residual PME activity and high viscosity. Crown Copyright (C) 2007 Published by Elsevier Ltd. All rights reserved.