Purpose: The study evaluated three UVC wavelengths (222 nm, 254 nm and 282 nm) to degrade patulin with absorption maximum at 276 nm introduced into apple juice or apple cider.
Methods: All UV processing conditions were performed in triplicate (n = 3) with completely independent and randomized design using bench scale pathogen reduction box.
Results: The average UV fluences of 19.6, 84.3, 55.0 and 36.6 mJ∙cm-2 resulted in the 90% reduction of patulin in apple juice through the exposure of UV lamps at 222, 254, 282 nm wavelength and the combination, respectively. Therefore, the efficiency order of three wavelengths was: 222 nm > 282 nm > 254 nm. In terms of color, treatment of apple juice with 222 nm resulted in an increase in L* value but decrease in a* and b* values although the changes were insignificantly different (P > 0.05) to non-treated controls based on a sensory evaluation. The ascorbic acid loss in juice treated at 222 nm to support 90% reduction of patulin was 36.5%. This compares to 45.3% and 36.1% ascorbic acid loss with samples treated at 254 nm and 282 nm. The current work demonstrated that the 222 nm wavelength possesses the highest efficiency on patulin reduction in apple juice compared with the 254 nm and 282 nm with no benefit gained from using a combination of wavelengths.
Significance: The advantages of no significant changes in pH, total soluble solid and color changes in apple juice after UV exposure at 222 nm for a time to degrade 90% of patulin (T90) demonstrate potential of further development of this novel UV source for the commercial applications.