Impact of ultrasonication and pulsed light treatments on phenolics concentration and antioxidant activities of lactic-acid-fermented mulberry juice

This study sought to assess the effect of ultrasonication (28 kHz, 60 W, 15 min), pulsed light (1.213 Jcm−2pulse−1, 360 μs, 3 Hz, 4 s) and their combined usage on the phenolics concentration and antioxidant activities of lactic-acid-fermented mulberry juice (LFMJ). The results showed significant improvement in the total phenolic concentration, total flavonoid concentration, total anthocyanin concentration, antiradical activity against 2,2-diphenyl-1-picrylhydrazyl scavenging activity (DPPH
- -SA), 2,2′-azino-bis 3-ethylbenzothiazoline-6-sulfonic acid radical cation scavenging activity (ABTS
- +-SA) and reducing power capacity (RP-CA) in all the non-thermal treated fermented juice compared to the control sample. Among the individual non-thermal treatments, ultrasonication caused a significant (p < 0.05) upsurge in the phenolic and antioxidant properties of the LFMJ compared to the pulsed light treatment. In the case of the combined treatments, the application of pulsed light before ultrasonication (PUT) exhibited the utmost performance. This suggests that PUT technique could successfully be implemented on industrial scale for the processing of LFMJ.