UVC light-emitting diodes (UVC-LEDs) is a novel eco-friendly alternative source of UV light. This study evaluated inactivation and membrane damage of spoilage yeast Saccharomyces cerevisiae by UVC-LEDs and its application in orange juice pasteurization. The results demonstrated that the antimicrobial effect of UVC-LED treatment against S. cerevisiae enhanced with the increase of radiation dose. When the dose of UVC-LED radiation was up to 1420 mJ/cm 2 , the population of S. cerevisiae in YPD broth was reduced by 4.86 log 10 CFU/mL. Through scanning electron microscope and fluorescent staining approaches, the structure and function of plasma membrane was observed severely damaged by UVC-LED treatment. The inactivation efficacy of UVC-LEDs against S. cerevisiae in orange juice also increased with increasing radiation dose. Radiation at dose of 1420 mJ/cm 2 highly reduced the number of S. cerevisiae in orange juice by 4.44 log 10 CFU/mL and did not induce remarkable changes in pH, total soluble solids, titratable acidity, and color parameters. However, total phenolic content in orange juice was found significantly decreased by UVC-LEDs. These findings contribute to a better comprehension of UVC-LED inactivation and provide theoretical support for its potential application in fruit and vegetable juices processing.
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