High-Intensity Ultrasound Processing of Pineapple Juice

The influence of ultrasound processing on the physicochemical characteristics of pineapple juice was investigated through an experimental design changing ultrasound time and intensity. After processing, the polyphenoloxidase (PPO) activity in the pineapple juice was reduced by 20% as result of the treatment with longer exposure and higher intensity (376 W/cm2 and 10 min). The effect on phenolic compounds compared to the fresh pineapple juice (non-sonicated) was not statistically significant. Ultrasound processing reduced juice viscosity by 75% of the initial value (non-sonicated juice). The higher the ultrasound intensity and the juice exposure (processing time), the higher the final temperature of the juice, reaching a maximum of 54 °C. Ultrasound processing enhanced the juice color and its stabilization along 42 days of storage compared to the non-sonicated juice. Thermal treatment at the highest temperature reached due to juice sonication (54 °C) showed no effect on PPO inactivation.