Effects of Slightly Acidic Electrolyzed Water on the Quality of Fresh-Cut Apple

Combined Effect of Low-Temperature Stress and Slightly Acidic Electrolyzed Water (SAEW) on the Microbial Control of Oat Sprout Production

Sprouts have many advantages, such as high nutritional value and simple cultivation conditions. In recent years, the loss rate of sprouts due to microbial contamination has been as high as 40%, and it is necessary to strengthen microbial control technology to reduce such losses. Current microbial control methods have issues such as a narrow bactericidal spectrum and high cost and contamination, whereas slightly acidic electrolyzed water (SAEW), as a new type of disinfectant, can solve these problems. In the present study, the efficacy of SAEW treatments in the disinfection of oat sprouts during germination and washing was evaluated at 25 °C and 4 °C compared to a TW control group. The results showed that compared to the TW control group, the Escherichia coli detection rates were significantly decreased by 2.32, 4.44 and 5.55 log10 CFU/g after soaking, undergoing germination for 60 h and washing with SAEW at 4 °C. This indicated that the 4 °C + SAEW treatment had a favorable bactericidal effect on the whole process of oat sprout washing. This result was demonstrated by scanning electron microscopy (SEM). In addition, for natural colony counts in oat sprouts, the 4 °C + SAEW treatment also showed strong bactericidal ability. Therefore, the application of SAEW combined with low temperature stress treatment in sprout production and processing has high potential.

Synergistic Bactericidal Efficiency of Slightly Acidic Electrolyzed Water-High-Pressure Parallel Processing on Escherichia coli in Freshly Cut Gastrodia elata Slices

The synergistic enhancement of bactericidal efficiencies on freshly cut Gastrodia elata slices by parallel processing using slightly acidic electrolyzed water (SAEW) and high-pressure (HP) technology was comprehensively investigated in this study. To this end, appropriate experimental conditions were determined through single-factor tests, which were ACCs (available chlorine concentrations) of 30, 38, and 49 mg/L; pressures of 100, 150, and 200 MPa; treatment times of 5, 7.5, and 10 min; and material-to-liquid ratios of 1:1, 1:3, and 1:5. Under these conditions, single and parallel bactericidal tests were conducted, and the corresponding synergistic enhancement values ΔI were calculated. Subsequently, using the lethal rate of Escherichia coli (E. coli) as the response value, we fitted multiple quadratic regression equations for SAEW, HP, and SAEW-HP with respect to ACC, pressure, pressure application time, and material-to-liquid ratio. The multiple quadratic regression equation for the synergistic enhancement term ΔI was then obtained through calculation. By analyzing this equation, the synergistic enhancement range was determined. Finally, experimental points were randomly selected within the synergistic enhancement range for validation. The results demonstrate that there was a synergistic bactericidal efficiency of the SAEW-HP parallel treatment of freshly cut G. elata slices. The synergistic enhancement range was pressure (xp) ∈ [52.18, 359.58] MPa; concentration of available chlorine (xc) ∈ [28.71, 46.27] mg/L; time (xt) ∈ [2.34, 12.38] min; and the material-to-solvent ratio (xr) ∈ ø g/mL. The validation experiments confirmed that within the respective ranges of p, c, and t, the SAEW-HP parallel treatment of freshly cut G. elata slices exhibited a '1 + 1 > 2' synergistic enhancement effect. These findings lay a theoretical foundation for the development of green bactericidal technologies for "adopting both minimum processing and dosage to achieve the optimal effect".

Advanced application of slightly acidic electrolyzed water for fresh-cut fruits and vegetables preservation

Fresh-cut fruits and vegetables (F&V) play a pivotal role in modern diets due to their convenience and nutritional value. However, their perishable nature renders them susceptible to rapid spoilage, causing quality deterioration, safety risks, and economic losses along the supply chain. Traditional preservation methods, while effective to some extent, often fall short in maintaining the quality and safety of fresh-cut F&V. This comprehensive review examines the utilization of slightly acidic electrolyzed water (SAEW) as a novel preservation technique for fresh-cut F&V. The review encompasses the production mechanisms, sterilization principles, classifications and application of SAEW. It explores the effects of SAEW on microbial inactivation, quality parameters, and metabolic pathways in fresh-cut F&V. Additionally, it assesses the synergistic effects of SAEW when combined with other preservation methods. SAEW demonstrates remarkable potential in extending the shelf life of fresh-cut F&V by effectively inhibiting microbial growth, suppressing browning, preserving chemical content, and influencing various metabolic processes. Moreover, its synergy with different treatments enhances its overall efficacy in maintaining fresh-cut F&V quality. The review highlights the promising role of SAEW as an innovative preservation approach for fresh-cut F&V. However, challenges regarding its widespread implementation and potential limitations require further exploration. Overall, SAEW stands as a significant contender in ensuring the safety and quality of fresh-cut F&V paving the way for future research and application in the food industry.

Slightly acidic electrolyzed water treatment enhances the quality attributes and the storability of postharvest litchis through regulating the metabolism of reactive oxygen species

Effects of slightly acidic electrolyzed water (SAEW) on the storability, quality attributes, and reactive oxygen species (ROS) metabolism of litchis were investigated. Results showed that SAEW-treated litchis presented better quality attributes and storability than control litchis. On storage day 5, the commercially acceptable fruit rate of control litchis was 42%, while SAEW-treated litchis displayed 59% higher rate of commercially acceptable fruit, 21% lower pericarp browning index, and 13% lower weight loss percentage than control litchis. Additionally, compared to control litchis, SAEW-treated litchis demonstrated higher activities of SOD, CAT and APX, higher levels of GSH, AsA, DPPH radical scavenging ability, and reducing power, but lower O2 -· generation rate, lower levels of H2O2 and MDA. These findings indicated that SAEW treatment could elevate antioxidant capacity and ROS scavenging ability, reduce ROS production and accumulation, and lower membrane lipid peroxidation, thereby retaining the quality attributes and storability of litchis.

Enhancing Fresh-Cut Apple Preservation: Impact of Slightly Acidic Electrolyzed Water and Chitosan-Apple Essence Microencapsulation Coating on Browning and Flavor

Fresh-cut apple preservation is a critical concern in the food industry due to the rapid deterioration of texture, color, and flavor. While our previous study introduced apple essence microencapsulation (AEM) to enhance flavor during storage, its impact on overall storage quality was minimal. Thus, this study explores the application of two preservation techniques, namely, slightly acidic electrolyzed water (SAEW) and chitosan-apple essence microencapsulation (CH-AEM) coating, to enhance the quality of fresh-cut apples. Our findings reveal that SAEW treatment significantly reduces the browning index (from 65.38 to 57.36) and respiratory rate (from 5.10% to 4.30% of CO2), and maintains a desirable aroma profile compared to uncoated treatment during 10 days of storage. Additionally, the CH-AEM coating acts as a protective barrier, further preserving the sensory characteristics of fresh-cut apples. Notably, the SAEW-CH-AEM group exhibits superior performance in firmness (8.14 N), respiratory rate (3.37% of CO2), ion leakage (34.86%), and juice yield (47.52%) after 10 days. Our research highlights the synergistic effect of combining these preservation strategies, providing a promising approach for extending the shelf life of fresh-cut apples while maintaining their visual appeal and aromatic quality. These results offer valuable insights for the fresh-cut produce industry, contributing to improved apple product preservation and consumer satisfaction.

Effects of the Combined Treatment of Trans-2-Hexenal, Ascorbic Acid, and Dimethyl Dicarbonate on the Quality in Fresh-Cut Potatoes (Solanum tuberosum L.) during Storage

Fresh-cut potatoes (Solanum tuberosum L.) are susceptible to browning and microbial contamination during storage. In this study, the effects of trans-2-hexenal (E2H), ascorbic acid (VC), dimethyl dicarbonate (DMDC), and the combined treatment of E2H, VC, and DMDC on quality deterioration in fresh-cut potatoes were investigated. The response surface methodology (RSM) demonstrated that E2H, VC, and DMDC concentrations of 0.010%, 0.65%, and 240 mg/L, respectively, were the optimum conditions for fresh-cut potato preservation. Further analysis showed that the combined treatment of E2H, VC, and DMDC was the most effective method of reducing quality deterioration in potatoes compared to the control and individual treatments. Furthermore, the combined treatment of E2H, VC, and DMDC could decrease the accumulation of reactive oxygen species (ROS) via improving antioxidant enzyme activities. Meanwhile, energy-metabolism-related enzyme activities and glutamate decarboxylase (GAD) activity were enhanced, while γ-aminobutyric acid transaminase (GABA-T) activity was reduced via the combined treatment of E2H, VC, and DMDC, which contributed to maintaining high energy levels and GABA content in potatoes. These findings suggested that the combined treatment of E2H, VC, and DMDC could protect membrane integrity through enhancing antioxidant capacity, energy levels, and GABA content to maintain quality in fresh-cut potatoes.

Recent advances in activated water systems for the postharvest management of quality and safety of fresh fruits and vegetables

Over the last three decades, decontamination management of fresh fruits and vegetables (FFVs) in the packhouses and along the supply chains has been heavily dependent on chemical-based wash. This has resulted in the emergence of resistant foodborne pathogens and often the deposition of disinfectant byproducts on FFVs, rendering them unacceptable to consumers. The management of foodborne pathogens, microbial contaminants, and quality of FFVs are a major concern for the horticultural industries and public health. Activated water systems (AWS), such as electrolyzed water, plasma-activated water, and micro-nano bubbles, have gained significant attention from researchers over the last decade due to their nonthermal and nontoxic mode of action for microbial inactivation and preservation of FFVs quality. The aim of this review is to provide a comprehensive summary of recent progress on the application of AWS and their effects on quality attributes and microbial safety of FFVs. An overview of the different types of AWS and their properties is provided. Furthermore, the review highlights the chemistry behind generation of reactive species and the impact of AWS on the quality attributes of FFVs and on the inactivation/reduction of spoilage and pathogenic microbes (in vivo or in vitro). The mechanisms of action of microorganism inactivation are discussed. Finally, this work highlights challenges and limitations for commercialization and safety and regulation issues of AWS. The synergistic prospect on combining AWS for maximum microorganism inactivation effectiveness is also considered. AWS offers a potential alternative as nonchemical interventions to maintain quality attributes, inactivate spoilage and pathogenic microorganisms, and extend the shelf-life for FFVs.

Nisin and ε-polylysine combined treatment enhances quality of fresh-cut jackfruit at refrigerated storage

This study investigated the effects of nisin combined with ε-polylysine on microorganisms and the refrigerated quality of fresh-cut jackfruit. After being treated with distilled water (control), nisin (0.5 g/L), ε-polylysine (0.5 g/L), and the combination of nisin (0.1 g/L) and ε-polylysine (0.4 g/L), microporous modified atmosphere packaging (MMAP) was carried out and stored at 10 ± 1°C for 8 days. The microorganisms and physicochemical indexes were measured every 2 days during storage. The results indicated that combined treatment (0.1 g/L nisin, 0.4 g/L ε-polylysine) had the best preservation on fresh-cut jackfruit. Compared with the control, combined treatment inhibited microbial growth (total bacterial count, mold and yeast), reduced the weight loss rate, respiratory intensity, polyphenol oxidase and peroxidase activities, and maintained higher sugar acid content, firmness, and color. Furthermore, it preserved higher levels of antioxidant compounds, reduced the accumulation of malondialdehyde and hydrogen peroxide, thereby reducing oxidative damage and maintaining high nutritional and sensory qualities. As a safe application of natural preservatives, nisin combined with ε-polylysine treatment has great application potential in the fresh-cut jackfruit industry.

Ultrasound synergistic slightly acidic electrolyzed water treatment of grapes: Impacts on microbial loads, wettability, and postharvest storage quality

Microbial contamination is the principal factor in the deterioration of postharvest storage quality in grapes. To mitigate this issue, we explored a synergistic treatment which combines ultrasound (US) and slightly acidic electrolyzed water (SAEW), and rigorously compared with conventional water cleaning (CW), exclusive US treatment, and standalone SAEW treatment. The US + SAEW treatment proved to be markedly superior in reducing total bacterial, mold & yeast counts on grapes. Specifically, it achieved reductions of 2.23 log CFU/g and 2.76 log CFU/g, respectively, exceeding the efficiencies of SAEW (0.78, 0.75), US (0.58, 0.65), and CW (0.24, 0.46). The efficacy of this synergistic treatment is attributed to the ultrasound removal of the wax layer on grape skins, which transitions the skin from hydrophobic to hydrophilic. This alteration increases the contact area between the grape surface and SAEW, thereby enhancing the antimicrobial efficacy of SAEW. From a physicochemical quality standpoint, the US + SAEW treatment exhibited multiple advantages. It not only minimized weight loss, color deviations, polyphenol oxidase activity and malondialdehyde synthesis in comparison to CW-treated samples but also preserved firmness, sugar-acid ratio and the activities of key enzymes including phenylalanine ammonia-lyase, superoxide dismutase and catalase, and thus maintaining high levels of total phenolics, total ascorbic acid, total anthocyanins, and antioxidants. Consequently, US + SAEW treatment put off the times of decay onset in grapes by 12 days, outperforming both SAEW (8) and US (4) in comparison to CW. These results highlight the potential of US + SAEW as an effective strategy for maintaining grape quality during their postharvest storage period.

Kinetics of sterilization of atomized slightly acidic electrolyzed water on tableware

The aim of this study was to elucidate the kinetics of atomization of slightly acidic electrolyzed water (SAEW) for use in sterilization of secondary contaminated tableware surfaces. The sterilization efficacy of SAEW was assessed on the basis of the change in the total number of colonies with different contamination levels (101 CFU/mL and 102 CFU/mL), atomization time (10, 20, 30, 40, and 50 s), atomizing distance (5, 10, 15, 20, 25, and 30 cm), and available chlorine concentration (ACC; 25.2, 30.2, 34.9, 40.5, 44.8, and 53.3 mg/L) as the main influencing factors. According to the relationship among flux, atomization area, and time, a kinetic model of SAEW atomization for the sterilization of tableware surfaces was established. The results indicated that the sterilization efficacy of SAEW gradually improved with decreased contamination levels (12.69 %-15.74 %), extended atomization time (13.68 %-46.58 %), and increased ACC (36.89 %-95.14 %). Based on the kinetics analysis, the change law of the kinetic model of SAEW atomization and sterilization of tableware surfaces with secondary pollution was found to be consistent with the change law of sterilization (r2 > 0.8). The results of this study provide a theoretical basis for SAEW atomization for sterilization of secondary contaminated tableware surfaces and also contributes to the improvement of technological theory of SAEW sterilization.

Ultrasonic synergistic slightly acidic electrolyzed water processing to improve postharvest storage quality of Chinese bayberry

In the postharvest storage of Chinese bayberry, microbial loads and exogenous contaminants pose significant challenges, leading to rapid decay and deterioration in quality. This study introduced a synergistic approach, combining ultrasonics and slightly acidic electrolyzed water (US + SAEW), to enhance the postharvest storage quality of Chinese bayberry. This approach was benchmarked against conventional water washing (CW), standalone ultrasonic (US), and slightly acidic electrolyzed water (SAEW) processing. Notably, compared to CW, the US + SAEW method enhanced iprodione and procymidone removal rates by 69.62 % and 72.45 % respectively, improved dirt removal efficiency by 122.87 %, repelled drosophila melanogaster larvae by 58.33 %, and curtailed total bacterial, mold & yeast growth by 78.18 % and 83.09 %. Furthermore, it postponed the appearance of sample decay by 6 days, compared to 4 days for both US and SAEW alone. From a physicochemical perspective, compared to CW-treated samples, US + SAEW processing mitigated weight loss and color deviations, retained hardness, amplified the sugar-acid ratio, augmented activities of phenylalanine ammonia-lyase, superoxide dismutase, and catalase enzymes, suppressed polyphenol oxidase activity and malondialdehyde synthesis, and preserved total phenolic, anthocyanin, and antioxidant levels. These findings underscore the potential of US + SAEW as a strategic tool to preserve the quality of Chinese bayberry during postharvest storage.