Comparative study of thermosonication and thermal treatments on pectin methylesterase inactivation in mosambi juice

Extent of inactivation of pectin methylesterase (PME) in mosambi juice during thermal and thermosonication treatments was studied to obtain a minimally processed product. Thermal treatments (HT) were carried out at three temperatures 60, 70 and 80°C in a serological water bath for 5, 10, 15 and 20 min. Thermosonication treatments (TS) were also given for same time-temperature combinations in water bath of a thermosonicator. Treated samples were stored in a deep freezer at - 18°C for PME assay. PME activity of untreated sample was also assayed and residual PME activity and % loss in PME activity was calculated at each time-temperature combination. The extent of inactivation of PME increased with increase in temperature and duration. Thermosonication treatments were found more effective than thermal treatments due to cavitation effect of sound waves. Thermosonication treatment at 80°C for 20 min was found best among all thermal and thermosonication treatments for PME inactivation.