Effects of pulsed thermosonication treatment on fungal growth and bioactive compounds of Berberis vulgaris juice

In this study, the single and combined effects of pulsed-ultrasound amplitude (100W, 30 kHz with 25 and 50% amplitude levels for up to 30min) and temperature (65 degrees C and 75 degrees C) on fungal growth, total phenolics, flavonoids and antioxidant activity of Berberis vulgaris juice were investigated. The combination of pulsed ultrasound at 50% amplitude for 30min at temperature of 75 degrees C as the most effective treatment was resulted in a reduction of about-3.083 +/- 0.02, -3.04 +/- 0.03, -3.10 +/- 0.01 and -2.88 +/- 0.02 log (N/N-0) on S.cerevisiae, A.flavus, A.versicolor and B.fulva, respectively. Additionally, the highest total phenolics, flavonoids and antioxidant activity were noted for the barberry juice after 30min of sonication with 50% pulsed-ultrasound amplitude at either 65 degrees C or 75 degrees C. Pulsed thermosonication is a promising technology to extend the shelf life of B.vulgaris fruit juice because of the improvement of antioxidant activity as well as microbial quality.