Antioxidant Activity Enhancement Effect of Silver-Ionized Water: Silver Cation Prepared by Electrolysis.

In the present study, tap water, alkaline electrolyzed water (AlEW) and tourmaline water (TMW) were used as the electrolytes to generated the silver-ionized water (SIW), AlEW-SIW and TMW-SIW, respectively. The antioxidant properties of the samples containing ascorbic acid (AsA) were investigated by WST-kit method. The results showed that the SOD activity of AsA (2 mmol/L) dissolved in SIW (66.0%) was enhanced by about 8% compared to that of the tap water (57.9%). The SOD activity of the AlEW-SIW solution (77.3%), which was higher than that of the SIW solution, and lower than that of the AlEW solution (83.6%). The SOD activity of the TMW-SIW solution (83.0%) was similar to that of the TMW solution (82.5%). Furthermore, to classify the sample solutions, discriminant analyses were performed based on near infrared (NIR) spectral data, which was consistent with the results of the WST-kit method. The SOD activity of the AlEW-SIW and TMW-SIW solutions decreased slowly with storage time, and their SOD activities were higher than that of AlEW, TMW and the tap water solutions at storage time of 14 days. In summary, AlEW-SIW and TMW-SIW showed similar antioxidant activity enhancement as AlEW and TMW, and they also maintained the stability of the antioxidant activity of AsA during storage.

Effect of Functional Water on the Antioxidant Property of Concentrated Reconstituted Juice.

People often consume juice to easily ingest antioxidants, which can scavenge free radicals and reduce the risk of lifestyle-related diseases. In this study, the SOD assay kit-WST method was used to evaluate the antioxidant activity of two types of functional water, alkaline electrolyzed water (AlEW) and tourmaline water (TMW), reconstituted commercially available (Tropicana) and freshly squeezed concentrated juices and the effect of functional waters on physicochemical parameters and sensory evaluation of reconstituted juices was also analyzed. The reconstituted juice exhibited the highest antioxidant activity when the electrolysis current of AlEW was 8A or the tourmaline stone treatment temperature of TMW was 75 °C. Compared with the control group (69.4%), SOD activity of the reconstituted orange juice in the 8A-AlEW (77.2%) and 75 °C-TMW (84.5%) groups increased by 7.8 and 15.1%, respectively. Furthermore, the color and pH of the functional water reconstituted juice were not significantly different from the juice before concentration, and the taste was better. In summary, functional water could enhance the antioxidant activity of concentrated juice as a formula which could provide novel ideas for the development of functional beverages with antioxidant properties.

Microbial Community Analysis of Digested Liquids Exhibiting Different Methane Production Potential in Methane Fermentation of Swine Feces.

Batch methane fermentation was conducted using seed sludge collected from six methane fermentation facilities. Swine feces were centrifuged and autoclaved, followed by its use as a substrate for methanogenesis. This "swine feces supernatant medium" facilitates the cultivation of the microbes of the seed sludge, sampling of the digested liquid using a syringe, and subculturing of the digested liquid in a subsequent medium using a syringe. Through 15 subcultures, digested liquids with high and low methane production potential were obtained, which were named "H-DS" and "L-DS," respectively. On the day 10 of cultivation, chemical oxygen demand (COD) of H-DS significantly decreased by 31% and that of L-DS did not differ significantly compared with that on the day 0 of cultivation. Acetic acid concentration of H-DS (1009 mg/L) was significantly lower than that of L-DS (2686 mg/L). These chemical characteristics indicate that organics decomposition in L-DS was not successful and suggest that H-DS has high relative abundance of bacteria decomposing organic matter and methanogen utilizing acetic acid compared with those in L-DS. Microbial community analysis revealed that Shannon index of H-DS was significantly higher than that of L-DS, and the relative abundance of acetogenic bacteria (e.g., Syntrophomonas) and acetic acid-utilizing methanogen (Methanosarcina) in H-DS was significantly higher than that in L-DS. Thus, the high methane production potential of H-DS might be attributable to the smooth flow from acetogenesis to methanogenesis step in the methane fermentation, compared with the case of L-DS.

In vitro inactivation of Escherichia coli, Staphylococcus aureus and Salmonella spp. using slightly acidic electrolyzed water.

In the current study, the effectiveness of slightly acidic electrolyzed water (SAEW) on an in vitro inactivation of Escherichia coli (E. coli), Staphylococcus aureus (S. aureus) and Salmonella spp. was evaluated and compared with other sanitizers. SAEW (pH 5.6, 23mg/l available chlorine concentration; ACC; and 940mV oxidation reduction potential; ORP) was generated by electrolysis of dilute solution of HCl (2%) in a chamber of a non-membrane electrolytic cell. One milliliter of bacteria suspension (ca. 10-11 log(10)CFU/ml) was mixed with 9ml of SAEW, strong acidic electrolyzed water (StAEW; ca. 50mg/l ACC), sodium hypochlorite solution (NaOCl; ca.120mg/l ACC) and distilled water (DW) as control and treated for 60s. SAEW effectively reduced the population of E. coli, S. aureus and Salmonella spp. by 5.1, 4.8, and 5.2 log(10)CFU/ml. Although, ACC of SAEW was more than 5 times lower than that of NaOCl solution, they showed no significant bactericidal difference (p>0.05). However, the bactericidal effect of StAEW was significantly higher (p<0.05) than SAEW and NaOCl solution in all cases. When tested with each individual test solution, E. coli, S. aureus and Salmonella spp. reductions were not significantly different (p>0.05). These findings indicate that SAEW with low available chlorine concentration can equally inactivate E. coli, S. aureus and Salmonella spp. as NaOCl solution and therefore SAEW shows a high potential of application in agriculture and food industry as an environmentally friendly disinfection agent.

The mechanism of the enhanced antioxidant effects against superoxide anion radicals of reduced water produced by electrolysis.

We reported that reduced water produced by electrolysis enhanced the antioxidant effects of proton donors such as ascorbic acid (AsA) in a previous paper. We also demonstrated that reduced water produced by electrolysis of 2 mM NaCl solutions did not show antioxidant effects by itself. We reasoned that the enhancement of antioxidant effects may be due to the increase of the ionic product of water as solvent. The ionic product of water (pKw) was estimated by measurements of pH and by a neutralization titration method. As an indicator of oxidative damage, Reactive Oxygen Species- (ROS) mediated DNA strand breaks were measured by the conversion of supercoiled phiX-174 RF I double-strand DNA to open and linear forms. Reduced water had a tendency to suppress single-strand breakage of DNA induced by reactive oxygen species produced by H2O2/Cu (II) and HQ/Cu (II) systems. The enhancement of superoxide anion radical dismutation activity can be explained by changes in the ionic product of water in the reduced water.

Influence of inoculation method, spot inoculation site, and inoculation size on the efficacy of acidic electrolyzed water against pathogens on lettuce.

The influence of bacterial inoculation methods on the efficacy of sanitizers against pathogens was examined. Dip and spot inoculation methods were employed in this study to evaluate the effectiveness of acidic electrolyzed water (AcEW) and chlorinated water (200 ppm free available chlorine) against Escherichia coli O157:H7 and Salmonella spp. Ten pieces of lettuce leaf (5 by 5 cm) were inoculated by each method then immersed in 1.5 liters of AcEW, chlorinated water, or sterile distilled water for 1 min with agitation (150 rpm) at room temperature. The outer (abaxial) and inner (adaxial) surfaces of the lettuce leaf were distinguished in the spot inoculation. Initial inoculated pathogen population was in the range 7.3 to 7.8 log CFU/g. Treatment with AcEW and chlorinated water resulted in a 1 log CFU/g or less reduction of E. coli O157:H7 and Salmonella populations inoculated with the dip method. Spot inoculation of the inner surface of the lettuce leaf with AcEW and chlorinated water reduced the number of E. coli O157:H7 and Salmonella by approximately 2.7 and 2.5 log CFU/g, respectively. Spot inoculation of the outer surface of the lettuce leaf with both sanitizers resulted in approximately 4.6 and 4.4 log CFU/g reductions of E. coli O157:H7 and Salmonella, respectively. The influence of inoculation population size was also examined. Each sanitizer could not completely eliminate the pathogens when E. coli O157:H7 and Salmonella cells inoculated on the lettuce were of low population size (10(3) to 10(4) CFU/g), regardless of the inoculation technique.