The effect of electrolyzed water on fresh-cut eggplant in storage period

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.

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.

Biochemistry behind firmness retention of jujube fruit by combined treatment of acidic electrolyzed water and high-voltage electrostatic field

Harvested jujube (Zizyphus jujuba Mill) is prone to softening due to active metabolism. This study investigated the effects of acidic electrolyzed water (AEW), high-voltage electrostatic field (HVEF) and their combination (AEW + HVEF) on softening and associated cell wall degrading enzymes (CWDEs), cell membrane integrity and antioxidant system of 'Huping' jujube during storage at 0 ± 1 °C. The results indicated that fruit subjected to AEW + HVEF, AEW or HVEF treatments maintained firmness 15.7%, 10.7%, and 5.3% higher than that of untreated control fruit at the end of 90 days cool storage. Fruit treated with AEW + HVEF could better maintain cell membrane integrity and exhibit lower activities of CWDEs and higher antioxidant capacity than that treated with either AEW or HVEF. Correlation analysis suggested that inhibition of softening was associated with reduction of CWDEs activities, and maintenance of membrane integrity and antioxidant system.

Proposing Signaling Molecules as Key Optimization Targets for Intensifying the Phytochemical Biosynthesis Induced by Emerging Nonthermal Stress Pretreatments of Plant-Based Foods: A Focus on γ-Aminobutyric Acid

Emerging evidence has confirmed the role of emerging nonthermal stressors (e.g., electromagnetic fields, ultrasonication, plasma) in accumulating bioactive metabolites in plant-based food. However, the signal decoding mechanisms behind NonTt-driven phytochemical production remain unclear, hindering postharvest bioactive component intensification. This study aims to summarize the association between signaling molecules and bioactive secondary metabolite production under nonthermal conditions, demonstrating the feasibility of enhancing phytochemical accumulation through signaling molecule crosstalk manipulation. Nonthermal elicitors were found to be capable of inducing stress metabolisms and activating various signaling molecules, similar to conventional abiotic stress. A simplified pathway model for nonthermally induced γ-aminobutyric acid accumulation was proposed with reactive oxygen species and calcium signaling being versatile pathways responsive to nonthermal elicitors. Manipulating signal molecules/pathways under nonthermal conditions can intensify phytochemical biosynthesis. Further research is needed to integrate signaling molecule responses and metabolic network shifts in nonthermally stressed plant-based matrices, balancing quality modifications and intensification of food functionality potential.

The influences of acidic electrolyzed water on quality and bacteria community of fresh-cut jackfruit in storage

This study evaluated the effects of acidic electrolyzed oxidizing water (AEW) on the quality and bacterial communities of fresh-cut jackfruit during storage. The result showed that AEW treatment, as compared to the CK group (without AEW treatment), could effectively inhibit the browning, maintain higher firmness and higher amounts of total titratable acidity (TTA) (0.21%), sugars (58.30 g/kg), ascorbic acids (28.72 mg/kg) and total phenolics (35.47 mg/kg) of fresh-cut jackfruits, and suppress the decrease of antioxidant ability during 4–8 days of storage. Additionally, the bacterial communities were significantly affected by AEW during storage. In particular, the AEW treated samples showed lower abundance of Pseudomonas and Lactobacillus than the CK group after storage of 8 day. And energy metabolism, nucleotide metabolism has the significantly lower (p < 0.05) relative abundance in the AEW group than in CK group. These results suggested that AEW (pH: 4.2–4.5, ACC: 35–38 mg/L) treatment could maintain the quality of fresh-cut jackfruit during storage. It could be attributed to that AEW treatment affect the growth and metabolism of bacterial communities, resulting in the decrease of nutrients consumption.

Hydrogen-Rich Water Treatment of Fresh-Cut Kiwifruit with Slightly Acidic Electrolytic Water: Influence on Antioxidant Metabolism and Cell Wall Stability

The synergistic impact of hydrogen-rich water (HRW, 394 ppb) and slightly acidic electrolyzed water (SAEW, pH of 6.25 ± 0.19) on the antioxidant metabolism of fresh-cut kiwifruit during storage was investigated (temperature: (3 ± 1) °C, humidity: 80%-85%). Compared with control group, H+S treatment increased the contents of active oxygen-scavenging enzymes (SOD, CAT, POD, and APX) and inhibited the increase of O₂^•- and H₂O₂ contents during the storage of fresh-cut kiwifruit. Meanwhile, H+S treatment could reduce the activities of the cell wall-degrading enzymes PG, PME, PL, Cx, and β-Gal, inhibit the formation of soluble pectin, delay the degradation rate of propectin, cellulose, and pseudocellulose, and maintain higher fruit hardness and chewability. The results showed that H+S treatment could enhance free radical scavenging ability and reduce the cell wall metabolism of fresh-cut kiwifruit, maintaining the good texture found in fresh-cut fruit.

Slightly acidic electrolyzed water treatment improves the quality and storage properties of carambola fruit

This study aimed to explore the impacts of slightly acidic electrolyzed water (SAEW) treatment on the physiology, quality, and storage properties of postharvest carambola. The carambolas were immersed in SAEW with a pH value of 6.0, ORP of 1340 mV and ACC of 80 mg/L. Results demonstrated that SAEW could significantly reduce the respiration rate, inhibit the increase in cell membrane permeability, and delay apparent color change. Relatively higher contents of bioactive compounds and nutritional components, such as flavonoids, polyphenols, reducing sugars, sucrose, vitamin C, total soluble sugar, and total soluble solid, as well as higher titratable acidity were maintained in SAEW-treated carambola. In addition, SAEW-treated carambola exhibited a higher commercial acceptability rate and a higher firmness, but lower weight loss and peel browning index than control fruits. Our results indicated that SAEW treatment achieved high fruit quality and nutritional values, potentially contributing to improve storage properties of harvested carambola.

Recent trends and applications of electrolyzed oxidizing water in fresh foodstuff preservation and safety control

With the growing demand for safe and nutritious foods, some novel food nonthermal sterilization technologies were developed in recent years. Electrolyzed oxidizing water (EOW) has the characteristics of strong antimicrobial ability, wide sterilization range, and posing no threat to the humans and environment. Furthermore, EOW can be used as a green disinfectant to replace conventional production water used in the food industry since it can be converted to the ordinary water after sterilization. This review summarizes recent developments of the EOW technology in food industry. It also reviews the preparation principles, physical and chemical characteristics, antimicrobial mechanisms of EOW, and inactivation of toxins using EOW. In addition, this study highlights the applications of EOW in food preservation and safety control, as well as the future prospects of this novel technology. EOW is a promising nonthermal sterilization technology that has great potential for applications in the food industry.