A potential of ultrasound on minerals, micro-organisms, phenolic compounds and colouring pigments of grapefruit juice

Summary The grapefruit juice was sonicated in an ultrasonic bath at 28 kHz frequency (amplitude 70%), for 0, 30, 60 and 90 min at 20 °C. This research was focused on the effects of ultrasound treatment on phenolic compounds, minerals, viscosity, lycopene, total anthocyanins, total carotenoids, micro-organism analysis and sugars. A statistically significant increase was observed in total carotenoids, lycopene, sugar contents (sucrose, glucose and fructose) and phenolic compounds, whereas a decrease in viscosity and micro-organisms were found in all the grapefruit juice samples sonicated for 30, 60 and 90 min as compared to control. However, maximum improvement was observed in the sonication treatment for 90 min. The results of this study suggest that ultrasound treatment may improve the quality of grapefruit juice.