The effect of increasing radiofrequency (RF) electric fields on the activity of oxidative enzymes was studied
in model systems and food. In particular, the mechanisms of enzyme inactivation by RF treatments
were studied on polyphenoloxidase (PPO) and lipoxygenase (LOX) model systems. RF treatments efficiently
inactivated both enzymes, although PPO was more sensitive to an increase in the RF electric field.
RF efficacy was attributed to the generated thermal effect, while the contribution of the electromagnetic
field resulted negligible.
Following, the efficacy of RF in blanching vegetables to obtain color stable derivatives was evaluated. To
this aim, RF and conventionally water blanched apples were processed to get purees which were analyzed
for color, sensory attributes and consumer preference. RF allowed apples to be adequately
blanched. In particular, the puree obtained from the RF blanched apples was judged comparable to the
conventionally water blanched one for color and sensory attributes. However, a slightly higher perceivable
sweetness of the RF blanched sample was found, probably due to the fact that the RF treatment
allowed any contact with water to be avoided.
