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This research study examines the effect of electrolyzed water on the quality of fruits and vegetables during the washing process. It explores the use of alkaline and acidic electrolyzed water for washing produce, eliminating pesticides, and modifying soil. The study reviews relevant literature and provides conclusions based on experimental findings.
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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.
( I ) Figure 1. Preparation of electrolyzed water. Tap water + Diluted 0.1% NaCl solution Cathode : Alkaline electrolyzed water pH 12, 2H2O+2e- = 2OH-+H2 ORP -880 mV Anode : Acidic electrolyzed Water pH 2.8, H2O = 2H++1/2O2+2e- ORP +1100 mV HOCl,Cl2 diaphragm + -
Figure 1-2. Preparation of electrolyzed water. Tap water Cathode : Alkaline electrolyzed water pH 12, 2H2O+2e- = 2OH-+H2 ORP -880 mV Anode : Acidic electrolyzed Water pH 2.8, H2O = 2H++1/2O2+2e- ORP +1100 mV diaphragm + -
Table 1. Physicochemical parameters of electrolyzed NaCl solutions
(II) Figure 2. Effect of various alkaline electrolyzed water on the hydrogen peroxide and DPPH radical scavenging activity of L-ascorbic acid. A B C a D Scavenging activity(%) a E b b b (柯 2005)
Table 3.Effect of two types alkaline electrolyzed water used in bread making on color and textural properties of bread 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 ℃ (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 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) (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) (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 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) ND=Not detectable. (Izumi 1999)
Table 6. Effects of acidic or alkaline electrolyzed water wash with shaking on different vegetables *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 washsolution on the reduction of aerobic plate count and colifroms * 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 washsolution on the reduction of aerobic plate count and colifroms (continue) (Lin et al. 2005)
Table 8.Effect of acidic, alkaline and electrolyzed water washing on the dimethoate reduction 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 *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(%) 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)
Figure 4. Effect of electrolyzed water, saline and sodium hypochlorite solution washing on the pesticide reduction of cucumber. Percentage of pesticide reduction(%) AC-33333,AK-5 NaCl-15,H2O-5 NaOCl-15,H2O-5 (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 vegetablesX X Crop and pathogens tested were cos lettuce /Xanthomonas campestris pv. vitians; and tomato and pepper/ Xanthomonas campestris pv. vesicatoria. Y 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. Z 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 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 XWhithin 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 XWhithin 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.
