Effects of acidic electrolyzed water treatment on storability, quality attributes and nutritive properties of longan fruit during storage

The role of respiration metabolism in dicyclohexylcarbodiimide and disodium succinate regulating the pulp breakdown occurrence of fresh longan (Dimocarpus longan Lour.) during storage

Compared to control longan, on day 6, DCC-treated longan presented 18 %, 2 %, 15 %, 34 %, 21 %, 26 % and 10 % higher levels of pulp breakdown index, fruit respiration rate, PGI, SDH, NAD, NADH and QH2, respectively. Meanwhile, DCC-treated longan displayed 25 %, 5 %, 8 % and 12 % higher activities of respiratory terminal oxidases including CCO, AOX, PPO and AAO, respectively. However, DCC-treated longan presented 9 %, 27 %, 24 %, 25 % and 16 % lower levels of NADK, G-6-PDH + 6-PGDH, NADP, NADPH and Q, respectively. These data indicate that DCC-hastened longan pulp breakdown occurrence was owing to the diminished PPP, and the elevated EMP, TCA cycle and CCP, thereby leading to an increased respiration rate. However, DS treatment displayed contrary effects, indicating DS restrained longan pulp breakdown occurrence through diminishing the respiration metabolism and depressing the respiration rate of fresh longan.

Melatonin treatment maintains the quality properties and storability of carambola fruit by modulating energy metabolism

The influences of 150 μmol/L melatonin treatment on the quality properties, storability, and energy metabolism in carambola fruit were explored. The results showed that, compared to the control, melatonin treatment significantly retained higher rate of commercially acceptable fruit, and retarded the development of fruit browning and yellowing. Additionally, melatonin treatment displayed higher levels of chromaticity L⁎ and h° values, titratable acid, total soluble solids, total soluble sugars, sucrose, and vitamin C, but lower respiration rate, chromaticity a⁎ and b⁎ values, and reducing sugar content. Moreover, melatonin treatment presented higher levels of ATP, ADP, and energy charge, as well as higher activities of H+-ATPase, Mg2+-ATPase, and Ca2+-ATPase in the membranes of vacuole, mitochondria, and plasma, thereby reducing the damage to cell membranes. These results will provide a scientific basis and practical guidance for melatonin to maintain the quality properties and storability, and to prolong the shelf life of postharvest carambola fruit.

Advances in antimicrobial techniques to reduce postharvest loss of fresh fruit by microbial reduction

This review will provide new ideas for preserving fruits and decreasing fruit waste. This review outlines and evaluates research concerning postharvest fruit preservation employing antimicrobial strategies, which involve the integration of biological control alongside physical or chemical methods. The concurrent deployment of two or three of these techniques, particularly biological approaches, has demonstrated enhanced and synergistic antimicrobial outcomes in practical scenarios.

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.

Effect of Different Postharvest Pre-Cooling Treatments on Quality of Water Bamboo Shoots (Zizania latifolia) during Refrigerated Storage

Post-harvest pre-cooling of water bamboo shoots (WBS) [Zizania latifolia] can effectively delay its quality deterioration. Six types of pre-cooling treatments were used to pre-cooling post-harvest WBS, including cold slightly acidic electrolytic water pre-cooling (CSAEW), cold water pre-cooling (CWPC), vacuum pre-cooling (VPC), strong wind pre-cooling (SWPC), refrigerator pre-cooling (RPC), and fluid ice pre-cooling (FIPC). The effects of different pre-cooling treatments on the quality of refrigerated WBS were investigated. The results showed that the FIPC treatment was harmful to the storage quality of WBS, while the other five pre-cooling treatments could extend the shelf life of WBS to some extent. These pre-cooling treatments can inhibit the respiration of WBS, slow down its weight loss and lignification process, and maintain its relatively high levels of nutrient content and antioxidant activity. The CSAEW treatment outperformed other treatments in terms of bactericidal action and microbiological content control for WBS during storage. The protective effect of CSAEW treatment on the storage quality of WBS was relatively the best, and extended the shelf life of WBS by 12 days compared to the control group. This study indicated that the CSAEW pre-cooling treatment offers a new choice for pre-cooling root vegetables.

Physicochemical and microbiological evaluation of treated Gastrodia elata with combination of slightly acidic electrolyzed water and lithium magnesium silicate under certain temperatures and different storage periods

This study aimed to investigate the impact of slightly acidic electrolyzed water combined with lithium magnesium silicate hydrosol on the quality of fresh slices of Gastrodia elata under varying storage temperatures, including room temperature fresh slices of Gastrodia elata 25 °C and 37 °C. Fresh slices of Gastrodia elata 25 and 37 samples were stored for 13 days and extensively analyzed for color, weight loss, decay index, bacterial count, vitamin C, and polysaccharide contents during different storage periods. The findings revealed that the slightly acidic electrolyzed water + hydrosol treatment notably decreased weight loss and decay index compared to distilled water and slightly acidic electrolyzed water treatments. Moreover, fresh slices of Gastrodia elata treated with slightly acidic electrolyzed water  + hydrosol exhibited untraceable bacterial counts after 3 days, with counts starting to increase after 7 days of storage. The bacterial counts rose from 3.25 to 5.36 and from 4.13 to 5.79 log CFU/g under both storage conditions. The application of slightly acidic electrolyzed water + hydrosol resulted in reduced chromaticity values of L*, a*, and b* on the Gastrodia elata surface, along with a lower percentage loss of polysaccharide contents and vitamin C compared to distilled water and slightly acidic electrolyzed water treatments. These results suggested that Gastrodia elata treated with slightly acidic electrolyzed water + hydrosol maintained its quality characteristics and nutritional attributes, exhibiting greater stability during storage.

Isolation and Identification of Postharvest Rot Pathogens in Citrus × tangelo and Their Potential Inhibition with Acidic Electrolyzed Water

This study focused on the identification of rot-causing fungi in Citrus × tangelo (tangelo) with a particular emphasis on investigating the inhibitory effects of acidic electrolyzed water on the identified pathogens. The dominant strains responsible for postharvest decay were isolated from infected tangelo fruits and characterized through morphological observation, molecular identification, and pathogenicity detection. Two strains were isolated from postharvest diseased tangelo fruits, cultured and morphologically characterized, and had their gene fragments amplified using primers ITS1 and ITS4. The results revealed the rDNA-ITS sequence of two dominant pathogens were 100% homologous with those of Penicillium citrinum and Aspergillus sydowii. These isolated fungi were confirmed to induce tangelo disease, and subsequent re-isolation validated their consistency with the inoculum. Antifungal tests demonstrated that acidic electrolyzed water (AEW) exhibited a potent inhibitory effect on P. citrinum and A. sydowii, with EC50 values of 85.4 μg/mL and 60.12 μg/mL, respectively. The inhibition zones of 150 μg/mL AEW to 2 kinds of pathogenic fungi were over 75 mm in diameter. Furthermore, treatment with AEW resulted in morphological changes such as bending and shrinking of the fungal hyphae surface. In addition, extracellular pH, conductivity, and absorbance at 260 nm of the fungi hypha significantly increased post-treatment with AEW. Pathogenic morphology and IST sequencing analysis confirmed P. citrinum and A. sydowii as the primary pathogenic fungi, with their growth effectively inhibited by AEW.

Effect of different types of electrolyzed water on drying characteristics and quality of Spondias dulcis in oven drying

Due to its less adverse impact on the environment as well as human health, electrolyzed water, a non-thermal method, has been recognized to be a promising alternative as a new disinfectant for the food industry, which does not change odor, texture, and flavor of foods. Spondias dulcis fruit is rich in bioactive compounds, vitamins and minerals, which are known to have many beneficial effects on health. Fresh S. dulcis has a short shelf life and drying is an option to preserve the fruit. In this study, the effects of electrolyzed water treatment on the quality characteristics of dried S. dulcis were investigated. Slices of fruit treated with four different electrolyzed waters (Anolyte NaCl, Catholyte NaCl, Anolyte Na2CO3, and Catholyte Na2CO3) were dried in a conventional oven at 70 °C. Color, Browning index, antioxidant characteristics, texture profile, rehydration capacity, pH, and Fourier transform infrared spectroscopy analyzes of dried S. dulcis were performed. The samples treated with electrolyzed water prior to drying showed higher antioxidant activity (59.46 ± 0.09), total phenolic content (287.00 ± 1.76), and rehydration capacity (4.52 ± 0.05) compared to the control samples. The findings of the current study showed that electrolyzed water treatment could prevent the browning of dried S. dulcis fruits and preserve bioactive compounds as well as chemical properties.

Acidic electrolyzed-oxidizing water treatment mitigated the disease progression in Phomopsis longanae Chi-infected longans by modulating ROS and membrane lipid metabolism

Postharvest harmful pathogenic infestation leads to rapid decay in longan fruit. Compared with P. longanae-infected longans, AEOW alleviated fruit disease severity and diminished the O2-. production rate and MDA content. It also increased APX, CAT, and SOD activities, delayed the decrease in the levels of GSH and AsA, as well as the reducing power and DPPH radical scavenging ability, which resulted in a decline in membrane lipid peroxidation in P. longanae-infected longans. Additionally, AEOW reduced LOX, lipase, PI-PLC, PC-PLC, and PLD activities, maintained higher levels of PC, PI, IUFA, USFAs, and U/S, while reducing levels of PA, DAG, SFAs, and CMP. These effects alleviated membrane lipid degradation and peroxidation in P. longanae-infected longans. Consequently, AEOW effectively maintained membrane integrity via improving antioxidant capacity and suppressing membrane lipid peroxidation. This comprehensive coordination of ROS and membrane lipid metabolisms improved fruit resistance and delayed disease development in longans.

Comparative transcriptome and metabolome reveal the role of acidic electrolyzed oxidizing water in improving postharvest disease resistance of longan fruit

Acidic electrolyzed oxidizing water (AEOW) was applied to suppress disease development and maintain good quality of fresh fruit. However, the involvement of AEOW in improving disease resistance of fresh longan remains unknown. Here, transcriptomic and metabolic analyses were performed to compare non-treated and AEOW-treated longan during storage. The transcriptome analysis showed AEOW-induced genes associated with phenylpropanoid and flavonoid biosynthesis. The metabolome analysis found the contents of coumarin, phenolic acid, and tannin maintained higher levels in AEOW-treated longan than non-treated longan. Moreover, the weighted correlation network analysis (WGCNA) was performed to identify hub genes, and a gene-metabolite correlation network associated with AEOW-improved disease resistance in longan was constructed by the co-analysis of transcriptomics and metabolomics. These findings identified a series of important genes and metabolites involving in AEOW-induced disease resistance of longan fruit, expanding our knowledges on fruit disease resistance and quality maintenance at the transcript and metabolic levels.

Extraction, characterization, and utilization of mung bean starch as an edible coating material for papaya fruit shelf-life enhancement

This research was aimed to investigate the utilization of mung bean starch as an innovative edible coating material to enhance the shelf-life of cut papaya fruits. The study focused on the extraction process of mung bean starch and its subsequent characterization through various analyses. Particle size (142.3 ± 1.24 nm), zeta potential (-25.52 ± 1.02 mV), morphological images, Fourier transform infrared (FTIR) spectra, and thermal stability (68.36 ± 0.15°C) were assessed to determine the mung bean starch properties. The functional properties, such as bulk density (0.51 ± 0.004 g/cm3) and tapped density (0.62 ± 0.010 g/cm3), angle of repose (21.61°), swelling power (12.26 ± 0.25%), and minimum gelation concentration (4.01 ± 1.25%), were examined to detect its potential as a coating base material. Subsequently, the prepared mung bean starch coating solution (1%, 2%, 3%, 4%, and 5%) was applied to papaya fruits and the coated fruits' physicochemical characteristics evaluated during storage. These characteristics encompassed color, weight loss, pH shifts, total soluble solids, titratable acidity, vitamin C content, fruit firmness, microbial analysis, and sensory attributes. The results revealed that starch coating on papaya maintained its color, reduced weight loss, preserved vitamin C, and delayed firmness loss, enhancing shelf-life when compared to control sample. These findings demonstrated the effectiveness of mung bean starch coatings in preserving papaya fruits. The research made a significant contribution to the use of mung bean starch as a potential coating material for improving the shelf-life of papaya fruits. This finding has great promise for the field of food preservation and quality control.

Effects of slightly acidic electrolyzed water on the quality and antioxidant capacity of fresh red waxy corn during postharvest cold storage

Fresh red waxy corn is consumed worldwide because of its unique flavor and rich nutrients, but it is susceptible to deterioration with a short shelf life. This study explored the effect of slightly acidic electrolyzed water (SAEW) treatment on the quality and antioxidant capacity of fresh red waxy corn during postharvest cold storage up to 40 d. The SAEW treatment exhibited lower weight loss, softer firmness, and higher total soluble solids (TSS) and moisture content than the control group. Correspondingly, the SAEW maintained the microstructure of endosperm cell wall and starch granules of fresh red waxy corn kernels well, contributing to good sensory quality. Furthermore, SAEW effectively reduced the accumulation of H2O2 content, elevated the O2 -· scavenging ability, maintained higher CAT and APX activities, and decreased the decline of the flavonoids and anthocyanin during the storage. These results revealed that the SAEW treatment could be a promising preservation method to maintain higher-quality attributes and the antioxidant capacity of fresh red waxy corn during postharvest cold storage.

Health Benefits of High Voltage Electrostatic Field Processing of Fruits and Vegetables

High voltage electrostatic field processing (HVEF) is a food preservation procedure frequently used to produce healthy minimally processed fruits and vegetables (F&V) as it reduces the growth of microorganisms and activates or inhibits various enzymes, thus retarding their natural ripening while preserving and even enhancing native nutritional quality and sensory characteristics. HVEF is one of the various nonthermal processing technology (NTPT) regarded as abiotic stress that can activate the antioxidant system of F&V and can also inhibith spoilage enzymes as, polyphenol oxidase (PPO), lipoxygenase (LOX), pectin methylesterase (PME), polygalacturonase (PG), cellulase (Cel), β-xylosidase, xyloglucan and endotransglycosylase/hydrolase, bringing positive effect on hardness, firmness, colour attributes, electric conductivity, antioxidant compounds, microstructure and decreasing electrolyte leakage (EL), malondialdehyde (MDA) contents and browning degree. This technique can also increase the contents of fructose, glucose, and sucrose and decrease the production of CO2 and H2O2. Additionally, it has been reported that HVEF could be used with other treatments, such as modified atmosphere packaging (MAP) and acidic electrolyzed water (AEW) treatment, to enhance its effects. Future works should deepen on elucidating the activation of the antioxidant systems by applying HVEF of critical enzymes related to the synthesis pathways of phenolic compounds (PC) and carotenoids (Car). Holistic approaches to the effects of HVEF on metabolism based on systems biology also need to be studied by considering the overall biochemical, physical, and process engineering related aspects of this technique.

Acidic Electrolyzed Water Maintains the Storage Quality of Postharvest Wampee Fruit by Activating the Disease Resistance

Harvested wampee fruit is susceptible to disease, resulting in postharvest losses. Acidic electrolyzed water (AEW), a safe and innovative sterilization technology, plays a role in enhancing disease resistance in harvested produce. In this study, the efficacy of AEW in delaying wampee disease development was assessed, along with its association with disease resistance metabolism. Wampee fruit was treated with AEW (pH 2.5) at different available chlorine concentrations (ACCs) (20, 40, 60, and 80 mg/L) and subsequently stored at 25 °C for 8 days. Results revealed that 40 mg/L ACC in AEW (pH 2.5) was most effective in improving the postharvest quality of wampee fruit. Compared with control wampee fruit, those treated with 40 mg/L ACC in AEW exhibited lower incidence of fruit disease, higher pericarp lignin content, and higher activities of pericarp disease resistance enzymes (DREs), such as cinnamate-4-hydroxylase, phenylalanine ammonia-lyase, chitinase, β-1,3-glucanase, polyphenol oxidase, 4-coumarate CoA ligase, and cinnamyl alcohol dehydrogenase. These results suggested that AEW elevated DRE activities, promoted lignin accumulation, and ultimately enhanced disease resistance, suppressed disease development, and improved storage quality in harvested wampee fruit. Consequently, AEW emerged as a safe technology to mitigate the disease development and enhance the storage quality of harvested wampee fruit.

Synergistic improvement of antioxidant and antibacterial properties of carbon quantum complexes with zinc doping and chlorogenic acid for longan preservation

The deterioration of fruit could reduce the shelf life, decreased marketability and substantial economic value. Thus, a safe, simple, economical and environmentally friendly preservation technology for fruit is of great significance. Here, the postharvest preservation technology was investigated with zinc-doped carbon quantum dots and chlorogenic acid (Zn-CQDs/CGA) composite. Zn-CQDs/CGA composite were synthesized, which exhibits superior antioxidant and antibacterial activities. The binding mechanism of the Zn-CQDs/CGA composite was investigated, which revealed that the bindings of two components were mainly driven by hydrogen bonding and van der Waals forces to create a novel composite. The Zn-CQDs/CGA composite was applied to longan preservation and was found to significantly reduce the incidence of mildew spot, browning of fruit endocarp and pulp, as well as the degree of degradation of quality indexes. These results suggest that the Zn-CQDs/CGA composite has the potential for inhibiting browning and preserving the quality of longan during storage.

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.

Combined effect of electrolyzed water (EW) and sonication with equilibrium modified atmosphere packaging for prolonging storage stability of fresh strawberry

This research focuses on the effectiveness of electrolyzed water (50 and 100 ppm for 3 min), ultrasonication (80 W for 3 min), and their combinations on fresh strawberries, which are then packaged using microperforated film to enhance their storage stability. The gas composition in the headspace, pH, soluble solids, color (L*, a*, b*, and ΔE* values), anthocyanins, total phenolics, and texture profile was evaluated for the 35 days of storage at +4 °C. The lowest weight loss was measured at about 100 ppm electrolyzed water (EW; 0.47%), and the highest one was in the control group (0.57%) after storage. At the end of the storage, O2 in the headspace decreased from 20.90% to 10.50-8.10% and CO2 was accumulated from 0.03% to 16.4-14.34%. The results showed that soluble solids decreased (9.95 to 8.48-7.85 °Bx) and pH values increased (3.34 to 3.79-3.91) during storage. At the end of the storage, the total phenolics in the control group decreased by the most during storage (from 1209.09 ppm to 808.00 ppm), whereas the 50 ppm EW group had the highest (931.66 ppm). Further, the significantly highest anthocyanin amount was found to be 143.86 ppm in the 100 ppm EW group at the end of 28 days of storage. The EW can significantly delay the degradation of anthocyanin over the storage period. The sonication at 100 ppm EW damages strawberry tissues, reducing their hardness. The lowest decay rate was found in fruits treated with 100 ppm EW (41.67%), followed by 50 ppm EW (58.33%), compared to the control (75.00%). This study reveals that applications of the 50 ppm EW and also 50 pm EW combined with ultrasonication have great potential in the extending storage stability of the fresh strawberries.

Hydrogen peroxide induced changes in the levels of disease-resistant substances and activities of disease-resistant enzymes in relation to the storability of longan fruit

The influences of hydrogen peroxide (H2O2) on the storability and metabolism of disease-resistant substances in fresh longan were investigated. Compared to the control samples, H2O2-treated longan exhibited a higher index of fruit disease, pericarp browning, and pulp breakdown, a higher rate of fruit weight loss, but lower chromaticity values (L*, a* and b*) in pericarp appearance, and a lower commercially acceptable fruit rate. Additionally, H2O2-treated longan showed a lower lignin content, lower activities of enzymes including phenylalnine ammonia lyase (PAL), cinnamate 4-hydroxylase (C4H), 4-coumaryl coenzyme A ligase (4-CL), cinnamate dehydrogenase (CAD), peroxidase (POD), chitinase (CHI), and β-1,3-glucanase (GLU). These data collectively suggest that H2O2 negatively impacted the storability of fresh longan. This can be attributed to H2O2's role in reducing the levels of disease-resistant substances and suppressing the activities of disease-resistant enzymes, implying that H2O2 reduced the postharvest storability of longan by compromising its disease resistance.

Critical assessment of the delivery methods of chemical and natural postharvest preservatives for fruits and vegetables: a review

Through a comprehensive review on preservative delivery methods in fruits and vegetables preservation, it becomes evident that majority of existing studies concentrate on the development and mechanisms of preservatives. However, a notable gap lies in comparative analysis of different delivery methods, despite the direct impact of delivery methods on preservation outcomes. Additionally, emerging delivery techniques have displayed promising potential in enhancing delivery efficiency and likewise preservation effectiveness.

Electrolyzed Hypochlorous Acid (HOCl) Aqueous Solution as Low-Impact and Eco-Friendly Agent for Floor Cleaning and Sanitation

Recently, the use of disinfectants has been becoming a diffused and sometimes indiscriminate practice of paramount importance to limit the spreading of infections. The control of microbial contamination has now been concentrated on the use of traditional agents (i.e., hypochlorite, ozone). However, their prolonged use can cause potential treats, for both human health and environment. Currently, low-impact but effective biocides that are prepared in a way that avoids waste, with a very low toxicity, and safe and easy to handle and store are strongly needed. In this study, produced electrochemically activated hypochlorous (HOCl) acid solutions are investigated and proposed, integrated in a scrubbing machine for floor cleaning treatment. Such an innovative machine has been used for floor cleaning and sanitation in order to evaluate the microbial charge and organic dirt removal capacity of HOCl in comparison with a machine charged with traditional Ecolabel standard detergent. The potential damage on floor materials has also been investigated by means of Scanning Electron Microscope (SEM). A comparative Life Cycle Assessment (LCA) analysis has been carried out for evaluating the sustainability of the use of the HOCl-based and detergent-based machine.

Comprehensive analyses of membrane lipids and phenolics metabolisms reveal the developments of chilling injury and browning in Chinese olives during cold storage

The impacts of chilling injury (CI) temperature (2 °C) and non-CI temperature (8 °C) on the CI development, browning occurrence, and its underlying mechanism in Chinese olives were investigated. The results showed that, 2 °C induced higher levels of CI index, browning degree, chromaticity a* and b* values, but lower values of h°, chlorophyll and carotenoid contents in Chinese olives as compared to 8 °C. Furthermore, 2 °C raised cell membrane permeability, increased the activities of phospholipase D, lipase and lipoxygenase, accelerated the hydrolyses of phosphatidylcholine and phosphatidylinositol to phosphatidic acid, and promoted the conversions of unsaturated fatty acids to saturated fatty acids in Chinese olives. Moreover, 2 °C-stored Chinese olives showed higher activities of peroxidase and polyphenol oxidase, but lower contents of tanin, flavonoid and phenolics. These findings demonstrated that the CI and browning developments in Chinese olives were closely associated with the metabolisms of membrane lipid and phenolics.

Combined Treatment of Acidic Electrolyzed Water and High-Voltage Electrostatic Field Improves the Storage Quality of Huping Jujube (Ziziphus jujuba Mill. cv. Huping)

Fresh jujube is prone to rapid deterioration after harvest due to its active metabolism and rich nutrients. This study aimed to investigate the effects of acidic electrolyzed water (AEW), a high-voltage electrostatic field (HVEF) and a combination of AEW and HVEF (AEW + HVEF) treatments on the storage quality of Huping jujube (Ziziphus jujuba Mill. cv. Huping) stored at 0 ± 1 °C for 90 days. The results showed that the fruits treated with AEW + HVEF exhibited better storage quality than those treated with either AEW or HVEF alone. Specifically, the fruits treated with AEW + HVEF maintained higher levels of nutrients and taste compounds, including total soluble solid (TSS), total soluble sugar, reducing sugar and titratable acidity (TA), as well as lower respiration rate, weight loss, decay index and TSS/TA ratio. Additionally, the AEW + HVEF treatment could delay the increase in reddening index, a* and color change (ΔE) values, and the decrease in L* and b* values, by retarding the degradation of chlorophyll and accumulation of carotenoids and flavonoids, thereby preserving the more desirable appearance color. Furthermore, the combined treatment could enhance the glutathione reductase (GR) activity and 2,2'-azino-bis-(3-ethylbenzothizoline)-6-sulfonic acid (ABTS) +-scavenging ability. Thus, the AEW + HVEF treatment is a potential method for Huping jujube preservation.

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.

UV-C delays senescence in 'Lingwu long' jujube fruit by regulating ROS and phenylpropanoid metabolism

Ultraviolet (UV-C), a no residual environmentally friendly physical treatment, plays an important role in delaying the senescence in fruit. In this study, 'Lingwu long' jujubes were treated with UV-C (5 kJ m^-2) to investigate the impacts of cell wall degrading enzymes (CWDEs) activities, reactive oxygen species (ROS) metabolism, and phenylpropanoid metabolism under storage at 4 ± 1 °C for 30 d. UV-C treatment reduced respiration rate and decay index. Treated fruit exhibited lower polygalacturonase (PG), pectinate lyases (PL), cellulase (Cel), and β-galactosidase (β-gal) activities which ultimately delayed the reduction of firmness. UV-C treatment increased hydrogen peroxide (H₂O₂), free radical scavenging ability, and superoxide dismutase (SOD) and catalase (CAT) activities, reduced superoxide anion (O₂^-) and malondialdehyde (MDA) content. In addition, ascorbate peroxidase (APX), glutathione reductase (GR), dehydroascorbate reductase (DHAR), and monodehydroascorbate reductase (MDHAR) activities were activated by UV-C treatment, leading to glutathione (GSH) and ascorbic acid (AsA) increased. Besides, phenolic compounds of jujube fruit treated with UV-C were also increased, which might be due to the enhanced phenylalanine ammonia-lyase (PAL), cinnamate-4-hydroxylase (C4H), and 4-coumarate-CoA ligase (4CL) activities. In conclusion, UV-C was recommended for improving overall quality and alleviating senescence in jujube 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.

Extraction, purification, structural features and biological activities of longan fruit pulp (Longyan) polysaccharides: A review

Dimocarpus longan Lour. (also called as longan) is a subtropical and tropical evergreen tree belonging to the Sapindaceae family and is widely distributed in China, Southeast Asia and South Asia. The pulp of longan fruit is a time-honored traditional medicinal and edible raw material in China and some Asian countries. With the advancement of food therapy in modern medicine, longan fruit pulp as an edible medicinal material is expected to usher in its rapid development as a functional nutrient. As one of the main constituents of longan fruit pulp, longan fruit pulp polysaccharides (LPs) play an indispensable role in longan fruit pulp-based functional utilization. This review aims to outline the extraction and purification methods, structural characteristics and biological activities (such as immunoregulatory, anti-tumor, prebiotic, anti-oxidant, anti-inflammatory and inhibition of AChE activity) of LPs. Besides, the structure-activity relationship, application prospect and patent application of LPs were analyzed and summarized. Through the systematic summary, this review attempts to provide a theoretical basis for further research of LPs, and promote the industrial development of this class of polysaccharides.

Amelioration of chilling injury and enhancement of quality maintenance in cold-stored guava fruit by melatonin treatment

The influence of melatonin treatment on the quality and chilling injury of guavas during storage at 4 ± 1 °C were evaluated. Compared with control group, fruit of guava cv. Xiguahong exposed to various concentrations (50, 100, 150, and 200 μmol/L) of melatonin showed a significantly lower fruit respiration rate, weight loss, cell membrane permeability, and chilling injury index, but a higher commercially acceptable fruit rate, higher peel L*, h° value, and chlorophyll content. Melatonin treatment also delayed the decreases of fruit firmness, sucrose, total soluble sugar, vitamin C, titratable acidity, and total soluble solids. These data indicate that melatonin treatment could increase chilling tolerance and retain quality of cold-stored guavas. Among various concentrations of melatonin treatment, 100 μmol/L melatonin-treated guavas showed the preferable quality properties and lowest chilling injury index. Thus, melatonin may be a novel method of postharvest handling to enhance cold resistance and extend storage-life of cold-stored guava fruit.

The Influence of a Novel Chitosan-Based Coating with Natural Antimicrobial Agents on the Storage Properties and Reactive Oxygen Species Metabolism of Harvested Tangelo Fruit

This study investigated the effects of a novel antibacterial film based on chitosan, carboxymethyl cellulose, sodium alginate, tea polyphenols, ascorbic acid, and tangelo peel extract on the postharvest quality and reactive oxygen species metabolism of tangelo fruit during storage. The composite film significantly reduced the fruit decay rate and weight loss, delayed the reduction in total soluble solids and titratable acidity, and retained fruit firmness and the appearance of tangelo fruit during storage. Furthermore, the composite film effectively reduced the fruit respiration rate, inhibited the increase in cell-membrane permeability, markedly reduced the generation of superoxide anion, hydrogen peroxide, and malondialdehyde, and enhanced the activity of the antioxidant enzymes superoxide dismutase, catalase, and ascorbate peroxidase. The composite film also reduced losses of the nonenzymatic antioxidants ascorbic acid and glutathione. Overall, the chitosan-based composite antibacterial film effectively maintained the quality of tangelo fruit during storage, enhanced ROS scavenging capacity and antioxidant properties, and then reduced the rot rate of postharvest tangelo.

Acidic electrolyzed water treatment retards softening and retains cell wall polysaccharides in pulp of postharvest fresh longans and its possible mechanism

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AEW delayed pulp softening of longans via suppressing cell wall disassembly.

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AEW down-regulated expression levels of longan pulp cell wall degrading-related genes.

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AEW decreased activities of cell wall degrading enzymes in pulp of harvested longans.

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AEW retained higher levels of longan pulp CWM, CSP, ISP, cellulose, and hemicellulose.

Effects of acidic electrolyzed water (AEW) treatment (pH = 2.5, ACC = 80 mg L⁻¹, 10 min) on pulp firmness, amounts of CWM and CWP, activities and expression of relevant genes of CWDEs in pulp of Fuyan longan during storage at 25 °C were evaluated. Compared to control samples, during storage, AEW-treated fruit retained a higher pulp firmness, prevented WSP formation, reduced the degradation of CSP, cellulose and hemicellulose, and lowered CWDEs activities and their corresponding gene expression. When stored for 5 d, pulp firmness (113.6 g mm⁻¹), CWM (13.9 g kg⁻¹), and CSP (1.4 g kg⁻¹) in AEW-treated fruit displayed the clearly higher contents than those in control samples. These data suggest that AEW treatment can slow down the pulp softening and retain higher pulp CWP levels in postharvest fresh longans, which was because AEW lowered activities of CWDEs and its gene expression levels, and maintained the cell wall structure's integrity.

Impacts of exogenous ROS scavenger ascorbic acid on the storability and quality attributes of fresh longan fruit

The impacts of reactive oxygen species (ROS) scavenger ascorbic acid (AsA) treatment on the storability and quality attributes of 'Fuyan' longan fruit were explored. Compared to control samples, the treatment of 4 g L^-1 AsA solution clearly reduced fruit weight loss, indexes of fruit disease and pericarp browning, retained higher percentage of commercially acceptable fruit, higher values of chromaticity a^∗, chromaticity b^∗ , and chromaticity L^∗ , delayed pigment degradation in longan pericarp, and retarded the decreases of nutritive ingredients in longan pulp. When stored for 6 d, vitamin C (0.08 g kg^-1), sucrose (20.70 g kg^-1), total soluble sugar (56.32 g kg^-1), and total soluble solids (12.4%) in AsA-treated fruit displayed the clearly higher contents than those in control samples. These data suggested that the treatment of exogenous ROS scavenger AsA could effectively enhance the quality attributes and storability of postharvest longan fruit, thereby lengthen their postharvest shelf-life.

Alternative postharvest pre-treatment strategies for quality and microbial safety of 'Granny Smith' apple

Over the years, chemical pre-treatments have been used intensively to maintain apple quality and reduce decay during postharvest. This conduct has been reported to have a negative impact on environment and human health. This study aimed to investigate alternative approaches such as hot water (HW) and electrolyzed water (WE) treatments for decay management of 'Granny Smith' apples. Two different sets of experiments were set up for this study. In experiment 1, the effects of HW treatment (45 °C) under varying dipping durations (5, 10 and 15 min) on physicochemical quality of apple were investigated. In experiment 2, the curative efficacy of slightly alkaline electrolyzed water (SAl-EW) (50, 100, 200, 300, 400 and 500 mg L^-1) against Botrytis cinerea was investigated. Hot water treatment duration (15 min) had beneficial effects on flesh firmness, fruit colour, total soluble solid (TSS) and titritable acidity (TA) by the end of the storage. In contrast, a significant reduction in fruit weight and TA values (p < 0.05) were observed in control fruit. The SAl-EW treatments against B. cinerea resulted in a significant reduction in lesion zones compared to the untreated control fruit. Curative efficacy was most effective at concentrations of 200-500 mg L^-1 for 5 °C and 300-500 mg L^-1 for 24 °C. These findings suggest the potential of combining lower concentrations of SAl-EW with other hurdle techniques for better preservation of fresh apples.

Electrolyzed Oxidizing Water and Its Applications as Sanitation and Cleaning Agent

Electrolyzed oxidizing water (EOW) is one of the promising novel antimicrobial agents that have recently been proposed as the alternative to conventional decontamination methods such as heat and chemical sanitizers. Acidic EOW with pH ranging from 2 to 5 is regarded most applicable in the antimicrobial treatment of vegetables and meats. Neutral and alkaline electrolyzed water have also been explored in few studies for their applications in the food industry. Neutral electrolyzed water is proposed to solve the problems related to the storage and corrosion effect of acidic EOW. Recently, the research focus has been shifted toward the application of slightly acidic EOW as more effective with some supplemental physical and chemical treatment methods such as ultrasound and UV radiations. The different applications of electrolyzed water range from drinking water and wastewater to food, utensil, and hard surfaces. The recent studies also conclude that electrolyzed water is more effective in suspensions as compared with the food surfaces where longer retention times are required. The commercialization of EOW instruments is not adopted frequently in many countries due to the potential corrosion problems associated with acidic electrolyzed water. This review article summarizes the EOW types and possible mechanism of action as well as highlights the most recent research studies in the field of antimicrobial applications and cleaning. Electrolyzed water can replace conventional chemical decontamination methods in the industry and household. However, more research is needed to know its actual mechanism of antimicrobial action along with the primary concerns related to EOW in the processing of different food products.

Acidic electrolyzed water potently inactivates SARS-CoV-2 depending on the amount of free available chlorine contacting with the virus

Alcohol-based disinfectant shortage is a serious concern in the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic. Acidic electrolyzed water (EW) with a high concentration of free available chlorine (FAC) shows strong antimicrobial activity against bacteria, fungi, and viruses. Here, we assessed the SARS-CoV-2-inactivating efficacy of acidic EW for use as an alternative disinfectant. The quick virucidal effect of acidic EW depended on the concentrations of contained-FAC. The effect completely disappeared in acidic EW in which FAC was lost owing to long-time storage after generation. In addition, the virucidal activity increased proportionately with the volume of acidic EW mixed with the virus solution when the FAC concentration in EW was same. These findings suggest that the virucidal activity of acidic EW against SARS-CoV-2 depends on the amount of FAC contacting the virus.

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Acidic electrolyzed water (EW) shows virucidal activity against SARS-CoV-2.

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Virucidal activity of acidic EW depends on free available chlorine (FAC).

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Acidic solution without FAC does not inactivate SARS-CoV-2 in a 1-min reaction.

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Large amounts of FAC are required to inactivate virus containing many proteins.