國立屏東科技大學食品科學系碩士班
專題報告
應用電解水在蔬果清洗時對品質影響之研究
Effect of electrolyzed water for improving
quality on fruits & vegetables
指導教授: 林頎生 老師
研究生: 何申雅
Introduction
 Literatures review
 Conclusions

Introduction
Preparation of electrolyzed water.
 Alkaline electrolyzed water has pH 12,
ORP-880 mV that showed reductive activity.
 Acidic electrolyzed water has pH 2.8 , ORP +1100
mV and 50 ppm HOCl that showed bactericidal
effect against most pathogenic bacteria.
 Agricultural application potential:
fruits & vegetables washing, pesticides eliminating,
planting in greenhouse, and soil modification.
Literatures review
(I)
Tap water + Diluted 0.1% NaCl solution
Anode :
Cathode :
Acidic electrolyzed Water
pH 2.8,
H2O = 2H++1/2O2+2eORP +1100 mV
HOCl,Cl2
Alkaline electrolyzed water
pH 12,
2H2O+2e- = 2OH-+H2
ORP -880 mV
diaphragm
+
-
Figure 1. Preparation of electrolyzed water.
Tap water
Anode :
Cathode :
Acidic electrolyzed Water
pH 2.8,
H2O = 2H++1/2O2+2eORP +1100 mV
Alkaline electrolyzed water
pH 12,
2H2O+2e- = 2OH-+H2
ORP -880 mV
diaphragm
+
-
Figure 1-2. Preparation of electrolyzed water.
Table 1. Physicochemical parameters of electrolyzed
NaCl solutions
Acidic water
Alkaline water
EW(+)
EW(-)
2.50±0.06
11.65±0.12
5.82±0.04
39.4±0.89
0.51±0.08
ND
[mM]
[0.75±0.02]
[0.01±0.002]
[ND]
Dissolved
oxygen
(ppm)
14.4±0.99
1.9±0.11
5.0±0.27
ORP (mV)
1,164±33.62
-878±8.43
264±26.48
Parameter
pH
Available
chlorine
(ppm)
Ultrapure water
(Suzuki et al. 2002)
(II)
Scavenging activity(%)
25
A
DPPH
20
15
B
Hydrogen peroxide
C
a
D
a
10
E
b
b
5
b
0
A
B
C
D
E
Figure 2. Effect of various alkaline electrolyzed water on the
hydrogen peroxide and DPPH radical scavenging
activity of L-ascorbic acid.
* A: Alkaline electrolyzed water generated by electrolyzing diluted NaCl.
B: Alkaline electrolyzed water generated by electrolyzing tap water on level 1.
C: Alkaline electrolyzed water generated by electrolyzing tap water on level 2.
D: Alkaline electrolyzed water generated by electrolyzing tap water on level 3.
E: Alkaline electrolyzed water generated by electrolyzing tap water on level 5.
a,b,c,d,e Means in the same treatment followed by different letters are significantly
different (p<0.05).
(柯 2005)
Table 3. Effect of two types alkaline electrolyzed water used in
bread making on color and textural properties of bread
Bread
Properties
AEW (NaCl added) AEW (No NaCl added)
Deionized water
EMS*
pH
11.11
9.45
6.04
Specific
volume (cm3)
164a
165a
160a
77.50
H2O(%)
39.02a
38.80a
38.46a
<0.01
Water activity
0.934a
0.933a
0.932a
2.33
L value
84.99a
84.64a
83.80b
0.20
a value
1.48a
1.39a
1.33a
0.04
b value
25.39a
23.10b
22.36c
0.09
Whiteness
70.46b
72.23a
72.36a
0.11
Hardness (N)
3.30a
3.33a
3.34a
0.01
Cohesiveness
0.48a
0.48a
0.48a
0.01
Springiness
(mm)
4.48a
4.50a
4.49a
0.01
Chewiness
(kg×mm)
0.72a
0.73a
0.73a
1.16
a,b,c
Means in the same raw followed by different letters are significantly different (p<0.05). *EMS: error
mean squre.
(柯 2005)
(III) Table 2. Inactivity of Escherichia Coli O157:H7, Salmonella
enteritidis, and Listeria monocytogens by
electrolyzed water at 35 ℃
Bacterial species
Surviving bacterial population
(mean log CFU/ml) after exposure for:
0 min
2 min
4 min
6 min
E. Coli O157:H7
7.97±0.03
0b
0b
0b
Control
7.97±0.03
7.94±0.04
7.96±0.03
7.94±0.04
S. enteritidis
7.68±0.14
<1.0a
0b
0b
Control
7.68±0.14
7.63±0.06
7.59±0.11
7.64±0.11
L. monocytogens
7.91±0.10
0b
0b
0b
Control
7.91±0.10
7.88±0.11
7.86±0.08
7.81±0.12
a.Positive
by enrichment .
b.Negative by enrichment and no detectable survivors by a direct plating procedure.
(Venkitanarayanan et al. 1999)
(IV)
Table 4-1. Total microbial count and pH of fresh-cut vegetables
treated with tap water or electrolyzed water containing
20 ppm available chlorine followed by rinsing with
running tap water
Treatment d
Log 10 CFU/g
Surface e
pH
Macerate f
Surface
Whole
Carrot slices
Nontreatment
3.5a
4.2a
6.1a
6.4a
Control
2.7b
3.8b
6.1a
6.4a
Rinsing
2.2c
3.1c
6.1a
6.3a
Dipping
2.6b
3.4c
6.1a
6.3a
Dipping/Blowing
2.0c
3.3c
6.1a
6.3a
a-c Means
with different letters within each fresh-cut vegetable in same column are significantly different
(p<0.05)
d
Control =rinsing with tap water 4 min ;Rinsing =rinsing with electrolyzed water 3 min followed
by rinsing with tap water 1 min;Dipping =dipping in electrolyzed water 3 min followed by rising
with tap water 1 min ;Dipping /Blowing =dipping and blowing are at 25 L/min in electrolyzed
water 3 min followed by rinsing with tap water 1 min.
e Total CFU on tissue surface.
f
Total CFU in tissue macerate.
(Izumi 1999)
Table 4-2. Total microbial count and pH of fresh-cut vegetables
treated with tap water or electrolyzed water containing
20 ppm available chlorine followed by rinsing with
running tap water (continue)
Treatment d
Log 10 CFU/g
Surface e
pH
Macerate f
Surface
Whole
Trimmed spinach leaves
Nontreatment
4.2a
4.3a
5.9a
6.1a
Control
3.0b
4.0a
5.9a
6.1a
Rinsing
2.7b
3.0b
5.8a
6.0a
Dipping
2.6b
2.9b
5.8a
6.0a
Dipping/Blowing
2.6b
3.3b
5.9a
6.0a
Chopped bell peppers
Nontreatment
4.4a
4.9a
5.6b
5.8a
Control
3.1b
3.5b
5.9a
5.9a
Rinsing
2.9b
3.6b
5.8a
5.9a
Dipping
2.8b
3.3b
5.9a
5.9a
Dipping/Blowing
2.8b
3.2b
5.8a
5.9a
(Izumi 1999)
Table 4-3. Total microbial count and pH of fresh-cut vegetables
treated with tap water or electrolyzed water containing
20 ppm available chlorine followed by rinsing with
running tap water (continue)
Treatment d
Log 10 CFU/g
Surface e
pH
Macerate f
Surface
Whole
Japanese radish shreds
Nontreatment
4.3a
4.4a
6.2a
6.4a
Control
3.6b
3.9b
5.7b
6.0b
Rinsing
3.3c
3.7b
5.7b
6.1ab
Dipping
3.5bc
3.8b
5.7b
6.1ab
Dipping/Blowing
3.3c
3.7b
5.7b
6.1ab
Nontreatment
5.9a
6.2a
6.2b
6.2a
Control
4.5b
5.0b
5.9ab
6.1a
Rinsing
4.2bc
4.8ab
5.8b
6.1a
Dipping
4.5b
4.6b
5.9ab
6.1a
Dipping/Blowing
3.8c
4.2c
6.0ab
Diced potatoes
6.1a
(Izumi 1999)
Table 5-1.Total microbial count of fresh-cut vegetable rinsed
with tap water as a control or electrolyzed water
containing different concentrations of available chlorine
for 4 min
Log 10 CFU/g
Treatment
Surface color e
Surface c
Macerate d
Control
3.5a
4.1a
37.6a
15 ppm
3.0b
4.0a
35.8a
30 ppm
3.1ab
3.8a
35.6a
50 ppm
2.9b
3.8a
34.9a
Carrot slices
ab Means
with different letters within each fresh-cut vegetable in the same column are
significantly different (p<0.05)
c Total CFU on tissue surface.
d Total CFU in tissue macerate.
e Hue angle value (tan-1b/a) with spinach and cucumber and chroma value [(a2+b2)0.5] with
carrot.
(Izumi 1999)
Table 5-2. Total microbial count of fresh-cut vegetable rinsed
with tap water as a control or electrolyzed water
containing different concentrations of available
chlorine for 4 min (continue)
Treatment
Log 10 CFU/g
Surface c
Surface color e
Macerate d
Trimmed spinach leaves
Control
2.9a
4.3a
102.2a
15 ppm
<2.4b
2.5b
102.2a
30 ppm
<2.4b
2.5b
104.2a
50 ppm
ND
2.7b
101.6a
Control
4.4a
4.9a
112.5a
15 ppm
4.1a
4.6a
112.0a
30 ppm
4.0a
4.8a
111.6a
50 ppm
3.6b
4.5a
112.2a
Cucumber slices
ND=Not detectable.
(Izumi 1999)
Table 6. Effects of acidic or alkaline electrolyzed water
wash with shaking on different vegetables
Variety
Washing
condition
Leafy Vegetables
Chinjon
AC-9*
AK-3
Leafy cabbage AC-9
AK-3
Spinach
AC-9
AK-3
Fruit vegetables
Cucumber
AC-15
AK-3
Green pepper
AC-15
AK-3
Snap bean
AC-15
AK-3
Aerobic plate count (log CFU/g)
Before
After
Log reduction
washing
washing
6.6
7.3
7.9
7.0
7.4
7.4
5.2
6.9
6.8
6.6
5.8
7.2
1.4ab
0.4d
1.1bc
0.5d
1.7a
0.2d
5.4
5.8
6.2
6.2
6.9
6.9
4.4
5.3
5.2
5.6
4.4
6.7
1.0bc
0.5d
0.9c
0.5d
1.7a
0.1d
*AC-9:strong acidic electrolyzed water washed for 9 min.
Mean values in column followed by different superscript letters are significantly different (p<0.05).
Reported values are mean values of duplicate.
(Lin et al. 2005)
Table 7-1. Effects of continuous changing of wash solution
on the reduction of aerobic plate count and colifroms
Treatment
Leafy vegetables
Chinjon
H2O-3333*
AC-333,AK-3†
AC-333,AK-3 ‡
Leafy cabbage
H2O-3333*
AC-333,AK-3†
AC-333,AK-3 ‡
Spinach
H2O-3333*
AC-333,AK-3†
AC-333,AK-3 ‡
Log reduction of micro-organisms
APC (log CFU/g)
Colifroms (log MPN)
0.1c
1.4b
2.1ab
0.6c
2.0ab
2.5a
0.2c
1.3b
1.6b
0.4c
1.7ab
2.2a
0.2c
2.2ab
2.4ab
0.4c
1.7ab
2.4a
* Water wash with shaking, changed water four or five times for every 3 min.
† Washed with shaking and changed AC water three or five times for every 3 min,then AK water for 3 or 5 min.
‡ Washed with ultrasonic and changed AC water three or five times for every 3 min, the AK water for 3 or 5 min.
Mean values in column followed by different superscript letters are significantly different (p<0.05). Reported values are
mean values of duplicate or triplicate.
(Lin et al. 2005)
Table 7-2. Effects of continuous changing of wash solution on
the reduction of aerobic plate count and colifroms
(continue)
Treatment
Fruit vegetables
Cucumber
H2O-33333*
AC-33333,AK-5†
AC-33333,AK-5 ‡
Green pepper
H2O-33333*
AC-33333,AK-5†
AC-33333,AK-5 ‡
Snap bean
H2O-33333*
AC-33333,AK-5†
AC-33333,AK-5 ‡
Log reduction of micro-organisms
APC (log CFU/g)
Colifroms (log MPN)
0.4c
1.7b
2.4ab
0.1c
1.9ab
2.5a
0.5c
1.3ab
2.2ab
0.3c
0.7ab
1.4a
0.6c
2.3ab
3.0a
0.2c
1.2ab
1.2a
(Lin et al. 2005)
Table 8.Effect of acidic, alkaline and electrolyzed
water washing on the dimethoate reduction
Reaction
time (min)
Percentage of dimethoate reduction
HCl
pH 2.8
NaOH
pH 11.2
AC
AK
8
0.75a
38.17a
96.01c
34.96a
10
5.54a
35.20a
99.21b
40.23a
12
6.34a
38.61a
99.75a
44.06a
14
4.38a
42.79a
99.87a
43.41a
16
5.01a
50.17a
99.94a
44.63a
a,b,c
Means in column followed by different letters are significantly different
(p<0.05)
(吳 2002)
Table 9. Effect of electrolyzed water washed on the
methamidophs reduction in leaf vegetables
Treatment
Percentage of methamidophos reduction
Spinach
Chinjon
Leaf
cabbage
H2O-3331
5.94d
17.96b
11.87c
AK-33332
17.19c
10.68c
33.77b
AC-333,AK-33
67.54a
40.44a
79.29a
AC-333,AK-3*
53.32b
42.20a
75.96a
*Washing by ultrasonic
1 Water washing, changed water 4 times for every 3 min.
2 AK washing, changed water 4 times for every 3 min.
3 AC washing, changed AC 3 times for every 3 min, then AK washing for 3 min.
a,b,c,d
Means in column followed by different letters are significantly different (p<0.05).
(吳 2002)
Percentage of pesticide reduction(%)
100
90
Methamidophos
80
Dimethoate
70
60
50
40
30
20
10
0
AC-333,AK-3
NaCl-9,H2O-3 NaOCl-9,H2O-3
Figure 3. Effect of electrolyzed water, saline and sodium
hypochlorite solution washing on the pesticide
reduction of Leaf cabbage.
(吳 2002)
Percentage of pesticide reduction(%)
45
40
Methamidophos
35
Dimethoate
30
25
20
15
10
5
0
AC-33333,AK-5 NaCl-15,H2O-5 NaOCl-15,H2O-5
Figure 4. Effect of electrolyzed water, saline and sodium
hypochlorite solution washing on the pesticide
reduction of cucumber.
(吳 2002)
Table 10. The effect of 50mg/L electrolyzed water populations and
a copper hydroxide /mancozed mixture on leaf surface
populations of three bacterial pathogens of vegetables X
Crop
X
Lettuce
Tomato
Pepper
X
Y
Z
Treatment
Y
Control (water)
EO water
Copper hydroxide/mancozed
Control (water)
EO water
Copper hydroxide/mancozed
Control (water)
EO water
Copper hydroxide/mancozed
Population
(log10CFU/g fresh weight)
Exp.1
5.04a Z
4.18a
0b
4.95a
4.45b
4.89a
5.43a
4.93a
0b
Exp.2
4.41a
5.0a
0b
7.5a
7.8a
6.8a
6.4a
6.3a
5.8b
Crop and pathogens tested were cos lettuce /Xanthomonas campestris pv. vitians; and tomato and pepper/ Xanthomonas
campestris pv. vesicatoria.
Leaf surfaces were sprayed with sprayed with bactericides or water control ca. 15 min before misting leaves with 1×107
CFU/ml suspensions of homologous bacteria resistant to 50 mg/L rifampicin. Leaf washing (1h at 150 rpm)were used to
estimate populations based on bacteria colony counts on glucose-nutrients agar amended with 50 mg/L rifampicin.
Means for treatment comparisons for a given crop followed by the same letter are not significantly different, p≦
0.05 ,according to Waller-Duncan’s κ-ratio t-test mean separation procedure. Zero values reflect no turbidity in broth
cultures after48-h shaker incobation.
(Pernezny et al. 2005)
Table 11. Number of fungi and bacteria CFU present in soil extracts
after treatment with acidic electrolyzed water or sodium
hypochlorite and spread onto antibiotic water agar a
Solid
lot b
Untreated
Fungi c
AEW
Bacteriac Fungi c
Bacteriac
0.4%NaOCl
Reduction
(%)d
Fungi c
Bacteriac Reduction
(%)d
Arizona
6.3
1.3
33
0.0
99.57
29.0
0.0
99.62
Georgia
1.0
0.3
5.0
0.0
99.59
6.7
0.0
99.46
Kansas
1.6
1.6
5.7
0.0
99.82
12.0
0.0
99.63
Maryland
0.4
2.5
7.3
0.0
99.75
6.7
0.0
99.77
Average
2.3
1.4
12.8
0.0
99.68
13.6
0.0
99.62
a
Nine separate 3-g samples for each of four soil lots were extracted by a modification of the sieving and sucrose
centrifugation technique of Babadoost and Mathre. Three samples were treatment (control). Serial dilutions of 10 -1 to
10-4 of control samples were made and undiluted and diluted samples were spread onto AWA.
b Soil lot designated by state from where obtained.
c Each figure represents the average number of CFU × 103 of fungi and bacteria present 6 days after seeding petri dishes
with extracts from three soil samples from a soil lot.
d Percent reduction is average percent decrease in colony numbers for three replicate samples treated with AEW or
NaOCl compared with the control (no treatment) samples.
(Bonde et al. 2003)
Table 12. Percent reduction in population of E. Coli O157:H7
on alfalfa seeds treated with various Amp of acidic
electrolyzed water for up to 64 min
Contact
time (min)
2
Percent reduction in population X,Y
Control Z
b
48.1 AB
6 Amp
cd
65.3 A
59.7 AB
14 Amp
19 Amp
b
b
52.8 AB
4
b
50.4 B
d
8
a
78.2 A
bcd
69. 3 A
a
89.0 A
a
80.2 A
16
a
89.3 A
abc
88.5 A
a
89.5 A
a
90.0 A
32
a
90.3 A
ab
90.6 A
a
89.5 A
a
91.6 A
64
a
90.6 A
a
97.10 A
a
96.9 A
95.6 A
ab
a
76.4 A
38.2 B
b 39.7 B
X
Whithin the same row, Values not followed by the same letter are significantly different (p<0.05).
Y
Whithin the same column, values not preceded by the same letter are significantly different (p<0.05).
Z
Control is sterilized deionized water.
(Sharma et al. 2003)
Table 13. Percent reduction in population of E. Coli O157:H7
on alfalfa sprouts treated with 19 Amp of acidic
electrolyzed water for up to 64 min
Contact time (min)
Percent reduction in population X,Y
Control Z
Treatment
sprouts
2
ab
85.4 A
b 91.1 A
4
ab
85.0 B
b
91.5 A
8
ab
88.2 B
a
98.4 A
16
b
82.4 B
a
99.0 A
32
a
88.9 B
a
99.6 A
64
ab
87.1 B
a
99.8 A
X
Whithin the same row, Values not followed by the same letter are significantly different (p<0.05).
Y
Whithin the same column, values not preceded by the same letter are significantly different (p<0.05).
Z
Control is sterilized deionized water.
(Sharma et al. 2003)
Conclusions




Acidic electrolyzed water has strong antibacterial activity by
unique ORP and HOCl.
Alkaline electrolyzed water possess reducing power than
NaOH solution which ?. When alkaline electrolyzed water is
combining with food materials may effect food material’s
physico-chemical properties.
Electrolyzed water washing with shaking method showed
significant effects in reducing the microbial load in vegetable
washing application.
Finally, electrolyzed water might be used for organic
vegetable application by bacterial inactivity characteristic and
other beneficial effect.