EIS measurements were performed using an LCR meter (3532-
50, Hioki E. E. Corporation, Nagano, Japan) in a frequency range of
1 kHze200 kHz using frequency steps of 1 kHz and a measuring
voltage of 1 V. A four-terminal probe (9140-10, Hioki E. E. Corporation,
Nagano, Japan) was used to minimize electrode polarization
impedance. The change in electrical impedance was measured
between two silver needles inserted with a penetration depth of
4 mm and spaced 5 mm apart on the middle part of the pericarp of
the whole fruit. The reactance (X), resistance (R), capacitance (C),
and impedance (Z) as functions of frequency were recorded and
transferred to a computer for further analysis by the Hioki LCRRS232C
V4.01e software package (Nagano, Japan).