Electrostatic Field Treatment Research Articles

Utilizing Nano-Adsorbents and Electrostatic Field Treatment for Sustainable Refinement of Crude Canola Oil.

Removal of polar impurities, such as phospholipids, free fatty acids (FFA), and peroxides, can be challenging during the refining of crude canola oil. Current conventional refining methods are energy-intensive (e.g., hot water washes) and can generate significant waste (e.g., wastewater effluent) and neutral oil loss. This study investigated the joint use of nano-adsorbents and electrostatic field (E-field) treatment as a potential and sustainable alternative in removing these impurities during the oil refining process. Specifically, aluminum oxide (Al2O3) nanoparticles were employed to neutralize FFAs, achieving a 62.4% reduction in acid value while preserving the fatty acid profile of the oil. After refining, E-field treatment was successful in removing the spent nano-adsorbent from solution (up to 72.3% by weight), demonstrating enhanced efficiency compared to conventional methods (e.g., gravitational settling, filtration, and centrifugation). The neutral oil loss using Al2O3 nano-adsorbents was also comparable to conventional refining methods, with a 4.38% (by weight) loss. After E-field treatment, the Al2O3 nano-adsorbent was then calcined to assess reusability. The Al2O3 nano-adsorbent was effectively recycled for three refining cycles. the methods do not use of large amounts of water and generate minimal waste byproducts (e.g., effluent). Nonetheless, while the nano-adsorbents demonstrated promising results in FFA removal, they were less effective in eliminating peroxides and pigments. E-field techniques were also effective in removing spent nano-adsorbent; although, optimization of E-field parameters could further improve its binding capacity. Finally, future studies could potentially focus on the physicochemical modifications of the nano-adsorbent material to enhance their refining capacity and reusability. Overall, this study presents a sustainable alternative or addition to conventional refining methods and lays the groundwork for future research.

Novel Post-Harvest Preservation Techniques for Edible Fungi: A Review.

Edible fungi are well known for their rich nutrition and unique flavor. However, their post-harvest shelf-life is relatively short, and effective post-harvest preservation techniques are crucial for maintaining their quality. In recent years, many new technologies have been used for the preservation of edible fungi. These technologies include cold plasma treatment, electrostatic field treatment, active packaging, edible coatings, antimicrobial photodynamic therapy, and genetic editing, among others. This paper reviews the new methods for post-harvest preservation of mainstream edible fungi. By comprehensively evaluating the relative advantages and limitations of these new technologies, their potential and challenges in practical applications are inferred. The paper also proposes directions and suggestions for the future development of edible fungi preservation, aiming to provide reference and guidance for improving the quality of edible fungi products and extending their shelf-life.

Effects of different electrostatic field intensities assisted controlled freezing point storage on water holding capacity of fresh meat during the early postmortem period

In this study, the effect of different intensity electrostatic fields on the water holding capacity (WHC) of fresh meat during the early postmortem period in controlled freezing point storage (CFPS) were investigated. Significantly lower cooking loss were found in low voltage electrostatic field (LVEF) and high voltage electrostatic field (HVEF) compared to the control group (CK) (p < 0.05). The myofibril fragmentation index and microstructure results suggested that the sample under HVEF treatment remained relatively intact. It has been revealed that the changes in actomyosin properties under electrostatic field treatment groups were due to the combination and dissociation of actomyosin binding into myofilament concentration, which consequently affects the muscle WHC. The study further demonstrated that the electrostatic field, especially HVEF, might increase the WHC of fresh meat by affecting the distribution of water molecules and physiochemical properties of actomyosin during the early postmortem period.

Effects of electrostatic field-assisted freezing on the functional properties and aggregation behavior of gluten

Changes in gluten during the freezing process could cause a deterioration in dough quality, which would be solved by electrostatic field treatment. This paper investigated the effects of electrostatic field assisted freezing (EFAF) on the functional properties, structural characteristics and aggregation behavior of gluten. The results showed that EFAF improved the functional properties of gluten with enhanced water holding, emulsifying and foaming properties. When the electrostatic field was applied, the α-helix content and g-g-g conformation of gluten proteins increased with a maximum of 27.50 % and 40.05 %, respectively, which were significantly different from the control (P < 0.05). The degree of depolymerization of gluten macromolecules decreased when the electrostatic field was applied, and was obtained to be the lowest at 600 V with 5.71 %, which was significantly different from that without applied electrostatic field (P < 0.05). After EFAF, AFM analysis showed a more intact glutenin chain structure and smaller particle size of the gliadin. These results indicated that EFAF improved the functional properties of gluten proteins by the mechanism of slowing down the depolymerization of gluten macromolecules, maintaining the chain structure of gluten, stabilizing the intramolecular disulfide bonds of gliadin, and stabilizing the microstructure of gluten.

Exploring the potential of alternative current electric field treatment for preservation and the tissue softening mechanism in Pleurotus ostreatus

Pleurotus ostreatus (P. ostreatus) is one of the common edible fungi; however, enzyme reactions during the storage period destroys its texture, resulting in a short shelf life (<10 days) and eventually resulting in wastes. Previous studies have demonstrated that the application of high electrostatic field treatment effectively suppresses the browning of P. ostreatus during storage by inhibiting oxidase activity. In the present study, P. ostreatus was employed as a model to explore cell wall decomposition alleviation by treatment with direct current electric field (DCEF) and alternative current electric field (ACEF). The results indicated that ACEF (400 kV m−1, 90–120 min) led to lower weight loss, lower firmness loss (400 kV m−1, 120 min), and reduced moisture migration during storage. Further research confirmed that ACEF (600 kV m−1, 120 min) treatment inhibited chitinase and β-1,3-glucanase activities by 72% ± 6% and 53% ± 3%, respectively, thereby delaying the disintegration of P. ostreatus during storage. In addition, as a noncompetitive inhibitor, ACEF reduced the Km and Vmax of chitinase and β-1,3-glucanase in P. ostreatus. In conclusion, ACEF treatment significantly alleviated texture loss in P. ostreatus, with a preservation rate of 9.3% ± 0.3%. These findings highlight the potential of ACEF treatment as a promising strategy for enhancing the preservation and commercialization of edible fungi.

Preparation of sodium-containing coacervates via high-voltage electrostatic field treatment: Saltiness perception of prefabricated chicken patties

Sodium-containing soy protein isolates (SPI)/apple pectin (AP) coacervate dispersion were prepared via high-voltage electrostatic field (HVEF) application to inhomogeneous spatial distribution of sodium as a strategy for reduction of salt content and enhancing the saltiness of prefabricated chicken patties. SPI/AP coacervates were prepared by HVEF processing at pH of 4.0, HVEF voltage of 32 kV, and ratio of SPI: AP to 5:1 which was optimized according to Artificial neural network (ANN)-coupled with genetic algorithm. Fluorescence intensity and FTIR analysis demonstrated that the HVEF treatment caused alteration of protein conformation, improved hydrogen bonding and electrostatic interactions between SPI and AP. At the NaCl concentration of 100 mM, HVEF treated sodium-containing SPI/AP coacervates achieved maximum phase separation as well as coacervate yield (85.23 ± 0.51%). HVEF treated sodium-containing SPI/AP coacervates displayed increased sodium fluorescence intensities, higher sodium concentration difference between coacervate phase and supernatant, and smaller particle sizes. Furthermore, HVEF treated coacervate dispersion showed higher sodium release in vitro during oral digestion. The saltiness of prefabricated chicken patties prepared using HVEF treated coacervates dispersion allowed a reduction in the sodium content of 43.59%. The increase of saltiness perception and sodium release in prefabricated chicken patties is attributed to enhanced water mobility in the matrix and distribution of inhomogeneous sodium.

Low voltage electrostatic field treatment of fresh-cut pineapples with slightly acidic electrolytic water: Influence on physicochemical changes and membrane stability

The synergistic impact of slightly acidic electrolyzed water (SAEW, pH 6.7; ACC 30 mg/L) and low voltage electrostatic field (LVEF, 150 V 1000 Hz) on the membrane stability and quality of fresh-cut pineapples during 12 d cold storage were investigated. The results show that LVEF+SAEW treatment decreased by 0.25–4.38% moisture loss compared with other groups, inhibited the decline in hardness and maintained good sensory quality. The oxidation and decomposition of ascorbic acid could be effectively suppressed, and the total phenol content was maintained at a high level by adjusting the phenol metabolic enzyme (such as PAL and PPO). The retardation of browning effectively suppressed the decrease of L* value. The LVEF+SAEW treatment weakened the breathing intensity cause by cutting injury, increased ROS clearance enzyme activity (such as SOD, CAT), and reduced the H2O2 content. The increase rate of ROS and LOX activity was inhibited, the final product MDA content of membrane lipid oxidation was decreased, which could maintain the stability of the membrane. SAEW pre-washing combined with LVEF storage could be used commercially as cost-effective method for extending the shelf-life of fresh-cut pineapples.

Electrostatic field treatment as a novel and efficient method for refining crude canola oil

Traditional vegetable oil refining strategies are energy-intensive and can result in substantial oil loss. In metalworking and machine shops, electrostatic “oil cleaners” are used to remove particulate matter (e.g., wear particles, soot, vanish, and dust) from non-polar working fluids with low dielectric constants (e.g., lubricating oil and hydraulic oil). Vegetable oils are also non-polar fluids. Polar contaminants (e.g., phospholipids, free fatty acids, peroxides) can be present in unrefined vegetable oils. The effects of electrostatic field (E-field) applied using a commercial electrostatic “oil cleaner” on crude canola oils were studied. E-field treatments of crude canola oils reduced suspended particles and the contents of phospholipids (reduction of 74.9%), free fatty acids (reduction of 53.2%), and peroxides (reduction of 47.0%). These treatments did not significantly alter either carotenoid content or fatty acid composition. Furthermore, oil loss was negligible (0.37%) during E-field treatment. Therefore, E-field can provide an economical, sustainable, and environmentally friendly alternative to conventional refining methods with minimal oil loss.

Comparative freezing study of broccoli and cauliflower: Effects of electrostatic field and static magnetic field

The effects of 1, 3, 5 kV/cm electrostatic field (EF) and 2, 5, 8 mT static magnetic field (MF) on the quality of frozen broccoli and cauliflower (B and C) were studied. The freezing parameters were significantly improved by 3, 5 kV/cm EF or 8 mT MF treatment (P < 0.05), a maximum reduction of nucleation time and phase transition time by 20.14 % and 32.09 % was found in 5 kV/cm EF treated cauliflower. EF or MF treatment improved sample quality to some extent, the overall effect of 3 kV/cm EF was the best, which led to a maximum drip loss reduction of 64.3 % in cauliflower, accompanied by lower relative conductivity, higher ascorbic acid and less cell rupture. EF or MF did not significantly reduce the damage of the flavor. MF was less effective than EF in improving the quality of frozen B and C.

Cell wall and reactive oxygen metabolism responses of strawberry fruit during storage to low voltage electrostatic field treatment

Low voltage electrostatic field (LVEF) is a new, non-thermal and low-cost fresh-keeping technology. However, there are few studies to evaluate the effects of LVEF on cell wall metabolism and reactive oxygen metabolism of strawberries. In this investigation, strawberries were stored in LVEF at 4 ± 1 °C for 10 d to explore the mechanism of cell wall metabolism and the effect of reactive oxygen on fruit quality. After 10 d of storage, strawberries were of better qualities compared to control group, with fruit firmness increased by 17 %, decay incidence decreased by 38%, weight loss reduced by 25 % and relative conductivity reduced by 38 %. Meanwhile, LVEF treatment significantly inhibited the accumulation of malondialdehyde, hydrogen peroxide and superoxide anion, and induced an increase of superoxide dismutase, catalase and ascorbate peroxidase activities. LVEF treatment also retained antioxidant components such as ascorbic acid and reduced glutathione. In addition, LVEF treatment slowed down the degradation of protopectin to water-soluble pectin and inhibited the activities of cellular degradation enzymes, including pectin methylesterase, polygalacturonase, cellulase, β-xylosidase and Xyloglucan endotransglycosylase/hydrolase. These results demonstrated that LVEF treatment might be an effective method for extending strawberries shelf life.

High-voltage electrostatic field-assisted modified atmosphere packaging for long-term storage of pakchoi and avoidance of off-flavors

Pakchoi is an important source of many essential nutrients for humans, but the leaves are prone to yellowing and rotting. This study aimed to maintain the quality of post-harvest pakchoi by using non-thermal high-voltage electrostatic field (HVEF) treatment in combination with modified atmosphere packaging (MAP) to compensate for each other's technical shortcomings and extend the shelf life of pakchoi. After 40 days of storage, HVEF at 4 kV/cm effectively degraded the volatile flavor components within the package, maintaining the chlorophyll and ascorbic acid content. It also reduced the microbial count by 1.82 ± log CFU g−1 (at 25 days) compared to the single MAP treatment (p < 0.05). The combined treatment of pakchoi has been verified by low-field nuclear magnetic resonance to have relatively low water mobility as well as lower electrolyte permeability and better texture than the single treatment. So, it has a higher sensory score. The HVEF assisted treatment resulted in lower respiration rates in the modified atmosphere packed pakchoi and changes in polyphenol oxidase (PPO) and superoxide dismutase (SOD) activities by affecting metal ion valence and enzyme conformation in favor of long-term storage. Principal component analysis (PCA) showed that the sensory and nutritional qualities of pakchoi treated with MAP and HVEF at 4 kV/cm in concert were closest to those of fresh samples. As a result, the shelf life of the pakchoi was successfully extended to 40 days while the pakchoi with a single MAP treatment lost its edible value at 25 days. HVEF assisted modified atmosphere packaging is expected to be an environmentally friendly, efficient and promising preservation technology. Industrial relevanceThis research provides new ideas for reducing the production of off-flavors vegetables in modified atmosphere packaging and extending the shelf life of vegetables. After modified atmosphere packaging the vegetables receive a high-voltage electrostatic field treatment at five-day intervals. This intermittent post-treatment is both low energy and efficient; and the antibiotic effect on microorganisms is unmatched by other integrated treatments. This opens up new possibilities for the transportation of fresh vegetables by fleets on long sea voyages and for the marketing of off seasonable fruit and vegetables in extreme weather.

Carrot (Daucus carota L.) Seed Germination Was Promoted by Hydro-Electro Hybrid Priming Through Regulating the Accumulation of Proteins Involved in Carbohydrate and Protein Metabolism.

Asynchronized and non-uniform seed germination is causing obstacles to the large-scale cultivation of carrot (Daucus carota L.). In the present study, the combination of high voltage electrostatic field treatment (EF) with hydropriming (HYD), namely hydro-electro hybrid priming (HEHP), significantly improved all germination indicators of carrot seeds, and the promoting effect was superior to that of the HYD treatment. A tandem mass tags (TMT)-based proteomic analysis identified 4,936 proteins from the seeds, and the maximum number of differentially abundant proteins (DAPs) appeared between CK and HEHP. KEGG analysis revealed that the upregulated DAPs were mainly enriched in the pathways related to protein synthesis and degradation such as “ribosome” and “proteasome,” while the downregulated DAPs were mainly enriched in photosynthesis-related pathways. Furthermore, the maximum DAPs were annotated in carbohydrate metabolism. Some proteins identified as key enzymes of the glyoxylate cycle, the tricarboxylate cycle, glycolysis and the pentose phosphate pathway showed enhanced abundance in priming treatments. The activities of several key enzymes involved in carbohydrate metabolism were also enhanced by the priming treatments, especially the HEHP treatment. Real-time quantitative PCR (qRT-PCR) analysis revealed that the effect of priming is mainly reflected before sowing. In conclusion, the optimal effect of HEHP is to regulate the synthesis and degradation of proteins in seeds to meet the requirements of germination and initiate the utilization of seed storage reserves and respiratory metabolism. The present work expanded the understanding of the response mechanism of carrot seed germination to priming and the biological effects of high voltage electrostatic field.

Hydro-Electro Hybrid Priming Promotes Carrot (Daucus carota L.) Seed Germination by Activating Lipid Utilization and Respiratory Metabolism.

Carrot (Daucus carota L.) is widely cultivated as one of the most important root crops, and developing an effective presowing treatment method can promote the development of modern mechanized precision sowing. In the present study, a novel seed priming technology, named hydro-electro hybrid priming (HEHP), was used to promote the germination of carrot seeds. Seed germination experiments showed that HEHP was able to increase the germination index (GI) and vigor index (VI) by 3.1-fold and 6.8-fold, respectively, and the effect was significantly superior to that of hydro-priming (HYD) and electrostatic field treatment (EF). The consumption and utilization rate of seed storage reserves were also greatly improved. Meanwhile, both glyoxysomes and mitochondria were found to appear ahead of time in the endosperm cells of HEHP through observations of the subcellular structure of the endosperm. Activities of isocitrate lyase (ICL), NAD-dependent malate dehydrogenase (MDH), pyruvate kinase (PK), and alcohol dehydrogenase (ADH) were significantly increased by HEHP. From transcriptome results, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways related to the glyoxylate cycle, glycolysis, gluconeogenesis, and the citrate cycle were significantly enriched and real-time quantitative PCR (qRT-PCR) analysis confirmed the expression pattern of 15 critical differentially expressed genes (DEGs) in these pathways. All DEGs encoding MDH, phosphoenolpyruvate carboxykinase (PEPCK), and PK were upregulated in HEHP; thus, it is reasonable to infer that the transformation of malate, oxalacetate, phosphoenolpyruvate, and pyruvate in the cytoplasm may be pivotal for the energy supply during early germination. The results suggest that the optimal effect of HEHP is achieved by initiating stored lipid utilization and respiratory metabolism pathways related to germination.

Effects of electrostatic field treatment on the maturation characteristics of rum and its mechanism

Effects of electrostatic field treatment on the maturation characteristics of rum and its mechanism

Combined impacts of low voltage electrostatic field and high humidity assisted-thawing on quality of pork steaks

The present study investigated the synergistic effects of low voltage electrostatic field combined with high humidity thawing (LHT) on the quality of pork steaks. Results indicated that LHT effectively maintained the colour stability of pork steaks by inhibiting the formation of metmyoglobin. Meanwhile, the thawing loss and centrifuging loss of pork steaks were significantly reduced (P < 0.05) in LHT group and low-field nuclear magnetic resonance (LF-NMR) results confirmed its improved WHC of muscle. Additionally, LHT samples displayed significantly lower hardness with higher springiness (P < 0.05) owing to its integrated muscle microstructure. Based on the thaw curve and PCA results, it can be concluded that the low voltage electrostatic field treatment could effectively shorten the thawing time and promote the WHC of muscle, while the high humidity seemed to play an important role in maintaining the colour stability of thawed pork. These results evidenced a potential application of the LHT method for meat thawing.

Robust and durable bonding performance of bamboo induced by high voltage electrostatic field treatment

To enhance the bonding performance of bamboo, the high voltage electrostatic field (HVEF) treatment was used for flattened moso bamboo (Phyllostachys pubescens). Three bonding types including bamboo skin-bamboo skin (BS-BS), bamboo skin-bamboo pith (BS-BP) and bamboo pith-bamboo pith (BP-BP) were tested. Surface characteristics of HVEF-treated bamboo composites were analyzed by the electron spin resonance (ESR), X-ray photoelectron spectra (XPS), Fourier transform infrared spectroscopy (FTIR), fluorescence microscopy and vertical density profile (VDP). Mechanical properties, including bonding strength, modulus of rupture (MOR), modulus of elasticity (MOE) and boiling peeling rate of treated-bamboo composites were tested as well. The results of ESR, XPS and FTIR showed that significantly increased free radicals, broken chemical bonds and oxygen-containing groups (OH, CO and CO) were obtained. These variations were attributed to the fact that triggered electrons were able to break oxygen and water molecules in the atmosphere under HVEF treatment and more broken chemical bonds (oxygen atoms and ions) appeared and reacted with bamboo surface. Higher change ratios involved in BS compared with BP were due to higher components of cellulose and lignin. HVEF treatment induced a significant decrease on adhesive penetration depth and an increment on density at bonding interphase. The highest decrease of adhesive penetration depth and increment of density at bamboo interphase were obtained in BS-BS while the least was BP-BP. All the bonding performance significantly enhanced after HVEF-treatment. The most robust and durable bonding performances were obtained in BS-BS type, and BP-BP showed the most increment extents of bamboo failure ratio. Results of this study revealed that: HVEF treatment was an effective approach for enhancing bonding properties of both bamboo skin and pith.

Effect of high voltage electrostatic field treatment on thawing characteristics and post-thawing quality of lightly salted, frozen pork tenderloin

The thawing characteristics, initial thawing mechanism and post-thawing quality of lightly salted, frozen pork tenderloin following the use of high-voltage electrostatic fields (HVEFs) were investigated in this study. The thawing rate increased with increasing salt concentrations for pork thawed by a −10 kV or −15 kV HVEF. Thermal property values of pork changed with increasing salt concentration (0–6%). HVEFs could enhance salt diffusion during the thawing process. The pork tenderloin thawed using HVEFs had significantly less drip loss (P < 0.05) than occurred during air thawing, which was also proven by the myosin denaturation enthalpy (−0.05 ± 0.03 J/g for the air-thawed samples and −0.24 ± 0.03 for the −10 kV HVEF-thawed samples). Additionally, there is apparent sample grouping with respect to the thawing methods between 30 ms–100 ms after PCA analysis. Thawing with −10 kV and −15 kV HVEFs resulted in a 0.5 log reduction in the number of Pseudomonas in the pork tenderloin compared with the number in the air-thawed group at day 0.

Effects of high-voltage electrostatic field treatment on the thawing rate and post-thawing quality of frozen rabbit meat

Abstract The thawing rate and post-thawing quality of frozen rabbit meat after the use of high-voltage electrostatic fields (HVEFs) were investigated in this study. The thawing efficiency could be significantly improved at voltages of − 15, − 20 or − 25 kV, and HVEF treatment resulted in 0.5–1.7log reductions in the number of microorganisms. The rabbit meat thawed at − 20 kV had optimal qualities, including a high water-holding capacity (WHC) and good texture quality. Although there were structural alterations of the myoglobin treated at − 20 kV HVEF, the sarcoplasmic protein solubility was not reduced. Additionally, the − 20 kV HVEF treatment led to less denaturation of the myofibrillar proteins than with still air thawing, as demonstrated by the actin denaturation enthalpy (− 0.26 ± 0.085 and − 0.12 ± 0.040 J/g, respectively). Finally, thawing at − 20 kV HVEF had little influence on the relaxation of water, including the water mobility, in rabbit meat. Industrial relevance This study found that HVEF thawing could shorten thawing time by 60%. Moreover, compared with air thawing, − 20 kV HVEF thawing led to less denaturation of the myofibrillar proteins, which is very important for further processing in the rabbit meat industry.

Effect of freezing under electrostatic field on the quality of lamb meat

Abstract The objective of this study was to investigate the effects of electrostatic field treatment on the quality attributes of frozen lamb meat. The static external electric field was applied at the intensities of E = 0–5.8 × 104 V/m during freezing at − 20 °C. Following freezing under electrostatic field, meat samples were thawed and their quality characteristics such as drip loss, texture, and colour were assessed by instrumental methods. Light microscopy technique was used to investigate the microstructure of meat. Results showed that electrostatic field application during freezing led to the significant microstructural changes in meat tissue. The average ice crystal size in the meat samples frozen under 5.8 × 104 V/m electric field decreased up to 60% in comparison to the conventional freezing process. It was also found that the drip loss decreased with increasing the electrostatic field strength. The colour and hardness of the meat were not significantly influenced by electric field. Industrial relevance This study gives significant information about the effect of electrostatic freezing on the quality of meat. It shows the effectiveness of electrostatic for decreasing the size of ice crystals and helps maintain the quality of meat during freezing. Since this method requires less energy and causes less damage to food the industrial application of this technology is growing.

Study of the defect evolution of the GH4169 superalloy under electrostatic field

An electrostatic field was applied to the GH4169 alloy during ageing, and the defect evolution process and mechanism were investigated using positron annihilation spectroscopy and vacuum inverted pendulum mechanical spectrometer. The results indicated that atomic thermal vibration and vacancy mobility can be increased by the electrostatic field treatment (EFT), resulting in the enhancement of vacancy formation. Under EFT, the relationship between atomic thermal vibration energy and the ageing temperature gives the E index, and there are more vacancies in the matrix with an increase in the ageing temperature. As the alloy was aged at 1073 K, the atomic thermal vibration energy displays the exponential growth with electric field intensity, contributing to an increase in the vacancy size and amount.