Effect of ultrasound treatment on the physicochemical properties and bioactive compounds of yellow passion fruit juice

Abstract

The use of non-thermal processing such as ultrasound has become important as an efficient technology to preserve the quality of fruit juice. This study aims to evaluate the effect of sonication time and amplitude on the physicochemical properties and bioactive compounds of yellow passion fruit juice. Freshly squeezed yellow passion fruit juice was sonicated at various amplitude levels (50% and 100%) for different sonication periods (1 min and 100 min). Untreated juice, which is freshly squeezed juice, was used as a control in this study. Thermal treatment of the juice was done at 80 °C for 1 min and 100 min, and used as control samples as well. The pH, colour (L*, a*, b*), total soluble solid (TSS), total carotenoid, and total phenolic content of the sonicated, heated, and untreated passion fruit juices were determined. Results show significant changes in the pH, TSS, colour, total carotenoid, and total phenolic content of the passion fruit juice after sonication. After being sonicated for 1 min, higher total phenolic content in the passion fruit juice was obtained. However, heating caused a reduction of total phenolic content in the passion fruit juice. Hence, it is concluded that the ultrasound treatment has potential to help shorten the time for yellow passion fruit juice processing compared to the use of conventional thermal processing.