Comparison of UV-LED treatments at 255 and 281 nm in continuous-flow on bacterial inactivation, quality, nutrients and electrical efficiency in beverages

Abstract

Ultraviolet light emitting diodes (UV-LEDs) have emerged as an alternative UV source. We compared the treatment of coconut water (CW), blue lemonade (BL) and ascorbic acid (AA) solution at 255 and 281 nm UV-LEDs in continuous-flow in terms of bacterial inactivation and effects on physical, quality and nutritional parameters and electrical efficiency. A 5-log10 reduction of Escherichia coli was achieved in CW and BL at both wavelengths. At similar fluence levels, a decrease in absorption coefficient (CW and BL), ascorbic acid and antioxidants (CW) was observed at both wavelengths. An increase in colour lightness of BL was observed at 281 nm. Treatment with 281 nm was more electrically efficient at achieving a 5-log10 reduction in beverages compared to 255 nm. This was confirmed in AA solution where 281 nm showed less photo-oxidation compared to 255 nm. Use of UV-LEDs allows for selection of optimal wavelengths to achieve higher microbial and electrical efficiency while maintaining product quality.