Effect of UVC light-emitting diodes on apple juice: Inactivation of Zygosaccharomyces rouxii and determination of quality

The effects of ultraviolet-C light emitting diodes (UVC-LEDs) irradiation on Zygosaccharomyces rouxii levels and physicochemical properties of apple juice were determined. The populations of Z. rouxii in apple juice were reduced by 4.86- and 5.46-log values after UVC-LEDs irradiation at 800 and 1200 mJ/cm(2) (p < 0.05), respectively. The pH, electrical conductivity, titratable acidity, total soluble solids, reducing sugar, and lightness (L*) value of apple juice remained almost constant after UVC-LEDs irradiation up to 1200 mJ/cm(2) (p > 0.05). Nonetheless, the UVC-LEDs irradiation caused reduction in total phenolic content and antioxidant activity of apple juice. Additionally, UVC-LEDs treatment caused significant changes in the color attributes (a*, b*, chroma, hue angle, and total color difference) and browning index of apple juice. These results suggest that UVC-LEDs irradiation may be an effective alternative to conventional thermal treatments in fruit and vegetable juices processing.