Table 5.2 Effect on natural bioactive compounds of experiments where magnetic or electric fields
was the stress factor on plants or food with a commercial interest
Food or cultivar/Reference
MF or EF treatment
Result
Apples var. Golden
Delicious
(Whole fruit)/Ribas-Agustí
et al. (2019)
PEF:
(a) 0.4 kV cm
−1
, 5 pulses
(0.01 kJ kg
−1
, 20 ls total
treatment time)
(b) 2.0 kV cm
−1
, 35 pulses
(1.8 kJ kg
−1
, 140 ls total
treatment time)
(c) 3.0 kV cm
−1
, 65 pulses
(7.3 kJ kg
−1
, 260 ls total
treatment time)
The system supplied 4 ls
monopolar pulses at a fixed
frequency of 0.1 Hz
(") AC. 24% at (a) just after
treatment. (Not significant
24 h after treatment)
(#) AC. 39% at (c) just after
treatment. At (b) 46% and
(c) 62% after 24 h
(") TPC and flavan-3-ol. 25–
26% in TPC and 43–35% in
total flavan-3-ols just after
and 24 h after treatment
(respectively) with (a)
(#) TPC by 32% at (b) and
43% at (c) just after
treatment and 50% at (b) and
66% at (c) after 24 h
(#) Total flavan-3-ols by
19% at (b) and 51% at
(c) just after treatment and
52% at (b) and 59% at
(c) after 24 h
(#) TFC by 28% at (b) and
50% at (c) just after
treatment and 60% at (b) and
68% at (c) 24 h after
treatment
Orange, pomelo and lemon
fruits/El Kantar et al. (2018)
PEF of 3 kV cm
−1 for whole
fruits and 10 kV cm
−1 for
stacks of skins. Time interval
between pulses: 2 s. Pulse
duration: 70 ls
(") by approximately 39%
for orange, 66% for pomelo,
and 135% for lemon in the
release of polyphenols from
the inner parts of the cells
Apples var. Golden
delicious (Whole fruit)/
Soliva-Fortuny et al. (2017)
PEF intensities of 0.4 –
2 kV cm
−1
, using 5–35
monopolar pulses of 4 ls at
a frequency of 0.1 Hz,
corresponding to an specific
energy input of 0.008 –
1.3 kJ kg
−1
(") TPC (13%) and
flavan-3-ol (92%). Best
result with 0.008 kJ kg
−1 in
apples stored 24 h at 22 °C
(") Flavonoids (58%). Stored
at 4 °C for
(") AC enhanced by 43%
after 12 h at 4 °C and by
15% after 24 h at 22 °C
Tissues of apple var. Ligol
and carrot var. Baltimore/
Wiktor et al. (2015)
PEF intensities of 1.85, 3
and 5 kV cm
−1 with the
combination of 10, 50 and
100 exponential shaped
pulses of average 10 ls
width each. Interval between
pulses was set at 2 s
(") TCC up to 11.34% in
carrots with 1.85 kV cm
−1
regardless of the applied
pulse number
(") Maximal TPC and
antioxidant activity (EC50)
in 10 pulses at
1.85 kV cm
−1 in apple tissue
(continued)
5 Role of Stress and Defense in Plant Secondary Metabolites …
161
was the stress factor on plants or food with a commercial interest
Food or cultivar/Reference
MF or EF treatment
Result
Apples var. Golden
Delicious
(Whole fruit)/Ribas-Agustí
et al. (2019)
PEF:
(a) 0.4 kV cm
−1
, 5 pulses
(0.01 kJ kg
−1
, 20 ls total
treatment time)
(b) 2.0 kV cm
−1
, 35 pulses
(1.8 kJ kg
−1
, 140 ls total
treatment time)
(c) 3.0 kV cm
−1
, 65 pulses
(7.3 kJ kg
−1
, 260 ls total
treatment time)
The system supplied 4 ls
monopolar pulses at a fixed
frequency of 0.1 Hz
(") AC. 24% at (a) just after
treatment. (Not significant
24 h after treatment)
(#) AC. 39% at (c) just after
treatment. At (b) 46% and
(c) 62% after 24 h
(") TPC and flavan-3-ol. 25–
26% in TPC and 43–35% in
total flavan-3-ols just after
and 24 h after treatment
(respectively) with (a)
(#) TPC by 32% at (b) and
43% at (c) just after
treatment and 50% at (b) and
66% at (c) after 24 h
(#) Total flavan-3-ols by
19% at (b) and 51% at
(c) just after treatment and
52% at (b) and 59% at
(c) after 24 h
(#) TFC by 28% at (b) and
50% at (c) just after
treatment and 60% at (b) and
68% at (c) 24 h after
treatment
Orange, pomelo and lemon
fruits/El Kantar et al. (2018)
PEF of 3 kV cm
−1 for whole
fruits and 10 kV cm
−1 for
stacks of skins. Time interval
between pulses: 2 s. Pulse
duration: 70 ls
(") by approximately 39%
for orange, 66% for pomelo,
and 135% for lemon in the
release of polyphenols from
the inner parts of the cells
Apples var. Golden
delicious (Whole fruit)/
Soliva-Fortuny et al. (2017)
PEF intensities of 0.4 –
2 kV cm
−1
, using 5–35
monopolar pulses of 4 ls at
a frequency of 0.1 Hz,
corresponding to an specific
energy input of 0.008 –
1.3 kJ kg
−1
(") TPC (13%) and
flavan-3-ol (92%). Best
result with 0.008 kJ kg
−1 in
apples stored 24 h at 22 °C
(") Flavonoids (58%). Stored
at 4 °C for
(") AC enhanced by 43%
after 12 h at 4 °C and by
15% after 24 h at 22 °C
Tissues of apple var. Ligol
and carrot var. Baltimore/
Wiktor et al. (2015)
PEF intensities of 1.85, 3
and 5 kV cm
−1 with the
combination of 10, 50 and
100 exponential shaped
pulses of average 10 ls
width each. Interval between
pulses was set at 2 s
(") TCC up to 11.34% in
carrots with 1.85 kV cm
−1
regardless of the applied
pulse number
(") Maximal TPC and
antioxidant activity (EC50)
in 10 pulses at
1.85 kV cm
−1 in apple tissue
(continued)
5 Role of Stress and Defense in Plant Secondary Metabolites …
161