Of the
fresh-cut apples, the Fuji and Golden Delicious were most responsive
to treatment and reached half %RΔE after only 20 min exposure
(52.3 ± 7.0 and 49.3 ± 4.0, respectively). The effectiveness of UV-A
LED treatment has already been demonstrated among several fruit cultivars
by Falguera, Pagán & Ibarz (2011b) and Falguera et al. (2014).
These studies showed that PPO was inactivated at different rates in various
fresh apple and pear juices that were subjected to UV–visible treatment
for 120 min with a high-pressure mercury lamp of 400 W which
was placed at 22.5 cm distance from juice surface and emitted in a
range between 250 and 740 nm with a resulting incident energy of
3.88 · 10−7 E·min−1