Influence of high-intensity ultrasound on bioactive compounds of strawberry juice: Profiles of ascorbic acid, phenolics, antioxidant activity and microstructure

Strawberry is important fruit used for juicing due to its health-promoting bioactive compounds. The aim of the study was to evaluate the influence of ultrasound treatments (0, 4, 8, 12, and 16 min) on the color attributes, ascorbic acid, phenolic compounds content and antioxidant activity of strawberry juice. The microstructural properties of ultrasound treated strawberries were also evaluated. The results indicated 16-min ultrasound treatment significantly increased the color difference of samples (p < 0.05). The total phenols, flavonoids, ascorbic acid content and antioxidant activity of samples were highest in 12-min ultrasound treated among all. Microstructure analysis indicates the formation of irregular shapes, tearing and loss of tissue, distortion of cell walls, which explains why the ultrasound treatment enhances the extraction efficiency of phytochemicals. The current findings presented in this study provide a deeper understanding of ultrasound application in enhancing both of bioactivities compounds and antioxidant activity of strawberry juice.