Effect of ultrasound treatment on physico-chemical, nutraceutical and microbial quality of strawberry

- Strawberries were treated with ultrasonic waves at different time intervals.
- Physicochemical characteristics, Antioxidant activity and microbial quality were determined.
- The 30-40 US treatment time was found to be effective for retaining maximum quality characteristics.
- The Ultrasound can be used as an alternative physical technique to prevent the post harvest losses of strawberry.

Ultrasound (US) treatment (33 kHz, 60 W) was applied to freshly harvested strawberry for different time (0, 10, 20, 30, 40, 60, min) and analyzed for the storage period of 15 days at 4 °C. The pH, vitamin C, acidity & total soluble solids were better retained between 30 and 40 min, while as firmness and color of the fruit were found to be optimum between 20 and 30 min. At 40 min treatment time, the bacterial count decreased from 5.91 to 3.91 (Log10 CFU g−1) and yeast and mold count decreased from 4.80 to 3.58 (Log10 CFU g−1), while as the DPPH and ABTS % inhibition was increased by 14.41 and 8.53% from control, respectively on day 15. The 30-40 min US treated fruit was shelf stable for all the storage days. The higher exposure time (60 min) increased the microbial load, decreased antioxidant potential and changes the desirable quality of the fruit.