Evaluation of Non-thermal Process for Decontamination of Orange Juice Using a Pulsed Light System

Non-thermal pulsed light treatments were given to orange juice for inactivating the Escherichia coli while retaining the quality characteristics. A laboratory model Pulsed Light Treatment chamber was designed. To evaluate, the different process parameters were selected viz., number of flashes (120,180 and 240 flashes), depth of the juice layer (5, 10, 15 and 20 mm) shelf height (5, 10 and 15 cm) and an inoculation level (10⁷cfu/ml). E.coli inactivation of the cells increased when the number of pulses were increased. Higher reduction of bacteria (5.385 log reduction) and fungi (4.14 log reduction) were achieved with a thin layer of juice (5mm) and minimum shelf-height from the lamp (5cm). Quality Characteristics such as pH, TSS and colour value were not affected significantly after the Pulsed treatment however, colour of the orange juice had minor change (20 per cent) when applied with higher number of 240 flashes. The results obtained suggest that pulsed light treatment technology could become an alternative preservation method for orange juice.