The aim of this research was to investigate the feasibility of using pulsed electric fields (PEF) to inactivate selected
enzymes, namely ascorbic acid oxidase (AAO) and peroxidase (POD), and to reduce the cutting force of carrots
(Daucus carota var. Nantes). The effect of PEF processing parameters (i.e. pulse frequency, electric field strength
and specific energy inputs), pre-conditioning temperature and the direction of carrot fibre (parallel and vertical)
to the PEF electrodes on enzyme inactivation and texture was studied. The positioning of carrot in the chamber significantly
(p b 0.05) affected the enzyme inactivation. Increasing energy inputs up to 166 kJ/kg at electric field
strength of 0.8 kV/cm enhanced enzyme inactivation. Pre-conditioning the carrots at 20, 30 and 40 °C prior to
PEF processing had further enhanced AAO and POD inactivation for at least 20% to 50% when compared to carrots
pre-conditioned at 10 °C. Additionally, significant cutting force reduction up to 60% (on average up to 70–75 N decrease
in cutting force) was found after PEF treatment (162 kJ/kg/80 Hz/3000 pulses/0.6 kV/cm). The carrot cells at
epidermis and xylem region were softened after PEF. The reduction of cutting force was enhanced not only with
increasing energy input, electric field strength and pulse frequency, but also when placing the carrots so that the
direction of fibre was parallel to the electrodes. Due to PEF treatment, the resistance towards cutting became less
and it resulted in a smoother cutting surface and higher cutting accuracy, compared to untreated carrots.
Industrial relevance: PEF processing enhanced tissue softening that could reduce the cutting force and improve the
cutting quality (better cutting accuracy and smoother cutting surface) of carrots. Due to partial enzyme inactivation
obtained after PEF processing, the intensity (temperature-time combination) of sequential blanching to achieve
complete enzyme inactivation could be reduced.