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

Adil Gani, Waqas N. Baba, Mudasir Ahmad, Umar Shah, Asma Ashraf Khan, Idrees Ahmed Wani, F.A. Masoodi, Asir Gani

Department of Food Science and Technology, University of Kashmir, Hazratbal, Srinagar, 190006, India.

Abstract

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 (Log₁₀CFU g^-1) and yeast and mold count decreased from 4.80 to 3.58 (Log₁₀CFU 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.

Keywords: Minimal processing; Shelf-life; Antioxidant activity; Fruit quality; Microbial count.