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Electrical stimulation therapy has attracted widespread attention for its advantages of promoting cell proliferation and tissue regeneration, accelerating skin barrier restoration, and reducing scars. Its effect on accelerating wound healing has been clinically proven. However, traditional electrical stimulation therapy requires large power supply devices, which are inconvenient to carry and use. Therefore, self-powered flexible nano-piezoelectric membranes were developed in this work, which can generate electric field under mechanical stimulation to effectively eliminate bacteria and accelerate wound healing. In this work, poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)) piezoelectric membranes were fabricated by electrospinning, and better piezoelectric properties were obtained by adding tetrabutylammonium chloride (TBAC), and their antibacterial and pro-healing effects were investigated with or without mechanical stimulation. Results showed that the output voltage of P(VDF-TrFE)/TBAC piezoelectric membrane was about 5.3 times higher than that of P(VDF-TrFE). Furthermore, the P(VDF-TrFE)/TBAC piezoelectric membrane had excellent antibacterial effect against both Escherichia coli and Staphylococcus aureus after mechanical stimulation, and the inhibition rates of Staphylococcus aureus and Escherichia coli were 71.43% and 97.25%, respectively. Meanwhile, the results of in vivo and in vitro healing promotion experiments showed that P(VDF-TrFE)/TBAC piezoelectric membrane was effective in promoting cell growth and wound healing after mechanical stimulation, the wound was almost completely healed on the 7th day, and the healing rate was increased by about 37% compared with the blank. The P(VDF-TrFE)/TBAC flexible piezoelectric membrane is effective in electrical stimulation for wound healing, and it has potential applications in wound treatment. [ABSTRACT FROM AUTHOR]

The continuous-flow pasteurization apparatus was presented, and the electric field within orange juice was produced via an oscillating magnetic field at 50 kHz, causing the volumetric heating of the juice with initial conductivity of 6.85 mS/cm and 8.76 mS/cm. The process principle, especially numerical relationships between excitation voltage, magnetic field, induced electric field (IEF), induced current density, and temperature profile were elaborated. When applying a rectangular wave of the voltage at 50–1000 V, the waveforms of the magnetic field and IEF in the juice were sine-like and sawtooth waves, respectively. Through electromagnetic simulation, the model was established, which indicated the indirect heating of orange juice via oscillating magnetic field was feasible. As the magnetic field increased, the outlet temperature and induced current density in the juice was improved. Notably, the 4–5 logs CFU/ml inactivation effects on aerobic bacteria, yeast and mold in orange juice could be achieved at 65 °C for 60 s after the treatment. • Engineering characteristics of induced electric field technology was elaborated. • Electromagnetic simulation model was conduced to verify its thermal effect. • Waveform of magnetic field and induced electric field was investigated. • Difference between experimental and predicted temperature was not significant. • Inactivation effects on aerobic bacteria, yeast and mold was achieved. [ABSTRACT FROM AUTHOR]

This study aimed to explore the effect of induced electric field (IEF) treatment on acid hydrolysis of corn starch by altering the connection modes of sample coils of a 4-reactor IEF system. Results suggested that IEF treatment could enhance the hydrolysis of corn starch and series connection (1. RRRR, η = 16 E Si 2 P in 4 Z Si + Z load ) exhibited higher energy efficiency than parallel (9. (RRRR), η = 4 E Si 2 P in Z Si + 4 Z load ), thus contributing to more extensive hydrolysis. Although no new functional group was formed, the starch granules were partially cracked into pieces and the crystallinity was slightly increased after IEF-assisted hydrolysis. Differential scanning calorimetry results indicated that IEF-assisted hydrolysis increased the gelatinization temperatures but decreased the enthalpy of starch, with a greatest variation was observed by series connection. Rapid visco-analysis showed that IEF-assisted hydrolysis greatly decreased the pasting viscosity of corn starch and also series connection showed the strongest reduction. The obtained results could provide a theoretical guide for the applications of IEF technology in biomaterial processing. [Display omitted] • Induced electric field (IEF) could enhance the acid hydrolysis of corn starch. • IEF-assisted hydrolysis highly depends on the energy efficiency of IEF system. • Series connection of IEF reactors showed the highest energy efficiency. • IEF-assisted hydrolysis largely decreased the pasting viscosity of corn starch. • IEF-assisted hydrolysis increased gelatinization temperatures but decreased enthalpy. [ABSTRACT FROM AUTHOR]

A novel electromagnetic heat extraction method was presented, whereby mandarin peels residue solution was located in a winding coil subjected to an oscillating magnetic field, and the pectin was extracted under appropriate conditions. Numerical relationships between applied magnetic field and induced electric field (IEF) in the extraction process were elaborated. The results showed that the induced current density, IEF and terminal temperature increased with increasing magnetic field. The maximum current density of 0.35 A/cm corresponds to the highest terminal temperature of 84.6 °C and IEF intensity of 26.6 V/cm. When magnetic field intensity was 1.39 T and the extraction time was 15 min, the maximum yield of pectin reached 9.16 %. In addition, all treatments impacted the ash content, protein content, water-holding capacity (WHC), and oil-holding capacity (OHC) of the obtained pectin. The pectin extracted by electromagnetic heat had the lowest DE value of 71.3 % with 126.55 kDa molecular weight, while the GalA content was at the highest level of 76.18 %. After different treatments, the composition of pectin monosaccharides changed, but there were slight differences in the composition of pectin polysaccharides. Moreover, the electromagnetic heat extracted pectin had light color and an obvious surface fragmentation of the peel residue. [Display omitted] • Novel electromagnetic heat method was presented for the extraction of pectin. • The maximum yield of pectin reached 9.16 % at 1.39 T and 15 min. • Electromagnetic heat extracted pectin had brighter color and highest GalA level. • There were slight differences in the composition of polysaccharides. [ABSTRACT FROM AUTHOR]

Induced electric field (IEF), as an alternative non-conventional processing technique, is utilized to sterilize liquid foods. In this study, the survival and sublethal injury of S. aureus under IEF were investigated in 0.85% normal saline, and the inactivation mechanism of IEF was expounded. The plate count results showed that the sublethal injury rates remained above 90% after IEF treatment for more than 8.4 s, and 7.1 log CFU/mL of S. aureus was completely inactivated after 14 s IEF treatment. Scanning electron microscopy and transmission electron microscope images showed that IEF caused the destruction of cell membrane and internal substructure, and the damage to intracellular substructure was more severe. Altered membrane integrity or permeability was demonstrated through flow cytometry and confocal laser scanning microscope analysis, and the different damage to cells was quantified by propidium iodide & 5-carboxy fluorescein diacetate single and double staining. In addition, IEF treatment also decreased the membrane potential and esterase activity of S. aureus cells. Putative inactivation mechanism of IEF against S. aureus is a complex process, and its apoptosis is the result of the combination of several factors, which provide a basis for understanding the inactivation mechanism of IEF. [Display omitted] • Germicidal efficacy and inactivation mechanism of IEF on S. aureus were explored. • Sublethal injury rates remained above 90% after IEF treatment for more than 8.4 s. • IEF caused the destruction of cell membrane, substructure, and permeability. • IEF decreased the membrane potential and esterase activity of S. aureus cells. • Putative inactivation mechanism of IEF against S. aureus is a complex process. [ABSTRACT FROM AUTHOR]

This study explored the effect of constant-current pulsed electric field thawing (CC-T) on the proteins and water-holding capacity of pork. Fresh meat (FM), and frozen meat after constant-voltage thawing (CV-T), air thawing (AT) and water immersion thawing (WT) were considered as controls. The results indicated that CC-T had a higher thawing rate than conventional thawing during ice-crystal melting stage (−5 to −1 °C). It also showed a lower water migration and thawing loss, maintaining pH and shear force closer to FM. Meanwhile, CC-T decreased myoglobin oxidation, resulting in a favorable surface color. The results of protein solubility, differential scanning calorimetry, total sulfhydryl, carbonyl and surface hydrophobicity demonstrated that CC-T reduced myofibrillar protein oxidative denaturation by suppressing the formation of disulfide and carbonyl bonds, thus enhancing solubility and thermal stability. Additionally, microstructural observation found that CC-T maintained a relatively intact muscle fiber structure by reducing muscle damage and myosin filament denaturation. [Display omitted] • CC-T reduced the conversion of immobilized water to free water in the meat. • CC-T resulted in higher protein solubility and thermal stability than AT and WT. • CC-T had a lower degree of myofibrillar protein oxidation compared to AT and WT. • CC-T resulted in less muscle tissue damage, making the fiber structure more complete. [ABSTRACT FROM AUTHOR]

Compared to traditional heating methods by static immersion or stirring, induced electric field (IEF) treatment can significantly increase hydrolysis rate of potato starch. The aim of this study was to examine the characterization of acid hydrolysis of granular potato starch under IEF. Potato starch was hydrolyzed using 0.15 mol/L HCl combined with IEF (IEF-HCl) at an excitation voltage of 75 V from 4 h to 120 h. The changes in granular, crystal, and molecular structure of starch granules during IEF-HCl hydrolysis were investigated. Scanning electron microscope analysis showed the outer surface of potato starch was firstly attacked by free ions and then the inner structures was completely disrupted and broken into pieces. X-ray diffraction studies indicated that the crystallinity decreased from 38.92% to 34.9% after 4-h hydrolysis, and then gradually increased to 41.88% as hydrolysis time increased to 96 h, but decreased thereafter. The weight-average molecular weight dramatically decreased from 104.7 × 10 6 Da to 9.291 × 10 6 Da in the first 24 h and then decreased gradually. These results suggested that there were three steps in the catalytic process of IEF-HCl hydrolysis. Initially, hydrogen ions destroyed the external crystalline shell of granules. Next, hydrogen ions attacked the loose amorphous region and dense crystalline part within starch granules simultaneously. Finally, the remaining crystalline region was hydrolyzed slowly. [ABSTRACT FROM AUTHOR]

The induced electric field assisted hydrochloric acid (IEF-HCl) hydrolysis of potato starch was investigated in a fluidic system. The impact of various reaction parameters on the hydrolysis rate, including reactor number (1–4), salt type (KCl, MgCl 2 , FeCl 3 ), salt concentration (3–12%), temperature (40–55 °C), and hydrolysis time (0–60 h), were comprehensively assessed. Under optimal conditions, the maximum reducing sugar content in the hydrolysates was 10.59 g/L. X-ray diffraction suggested that the crystallinity of IEF-HCl-modified starches increased with the intensification of hydrolysis but was lower than that of native starch. Scanning electron microscopy indicated that the surface and interior regions of starch granules were disrupted by the hydrolysis. The solubility of IEF-HCl-modified starches increased compared to native starch while their swelling power decreased, contributing to a decline in paste viscosity. These results suggest that IEF is a notable potential electrotechnology to conventional hydrolysis under mild conditions without any electrode touching the subject. [ABSTRACT FROM AUTHOR]

Creating a fluidic system with an induced electrical field is regarded as an innovative, eco-friendly practice for the hydrolysis of lignocellulosic biomass at mild conditions. A multi-series, reconfigurable fluidic reactor was developed based on the transformer concept for the efficient hydrolysis of sugarcane bagasse via the interconversion of magnetic and electrical energy. A secondary coil comprised of a mixture of sulfuric acid (or other metal electrolyte) and the sample in continuous flow was exposed to an induced electric field at 400–700 Hz to accelerate the hydrolysis. The results showed that using an induced electric field to assist hydrolysis is indeed beneficial in the production of reducing sugar (RS). The total reducing sugar (TRS) yield is positively impacted by the excitation voltage but is negatively impacted by voltage frequency and the sample solution impedance. The hydrolysis efficiency improves as the number of reactors increases in both series and parallel modes of the system. The mode of connection of the reactors has varying effect on the TRS yield owing to differences in the equivalent impedance, output power, and load power factor. Increased number of secondary coil turns also improves hydrolysis efficiency under the same input power and primary coil turns and thus increasing the TRS yield. Induced-electric-field-assisted hydrolysis (IEFAH) substantially enhances the yield (by 756% approximately, at 300 V, 400 Hz in a 4-series reactors for 24 h) compared to continuous flow heating hydrolysis (CFHH) at mild conditions (50 °C and 1% H 2 SO 4 ). The proposed fluidic system combined with an induced electric field shows remarkable potential as a green technology for the efficient hydrolysis of lignocellulosic biomasses without the use of metal electrodes. [ABSTRACT FROM AUTHOR]

A multi-series fluidic system based on the transformer concept was designed and built for the induced-electric-field-assisted extraction (IEFAE) of mulberry leaves polysaccharides (MLPs). Extraction was accelerated by exposing a secondary coil, made from a flowing mixture of sample grains and extractant, to a 20–80 kHz induced alternating electric field. The results indicate that this method benefits the release of polysaccharides without significantly affecting the quality of the products as evidenced by carbohydrate, protein, uronic acid, sulfuric radical and total polyphenol contents as well as average molecular weights and FT-IR . The polysaccharide yield improved as the excitation voltage increased, but the voltage frequency had a negative impact on the yield. At a solid-liquid ratio of 1:20 (g/mL), pH of 2.5, 60 °C temperature, 1000 V excitation voltage, and 20 kHz frequency, the 16-series system is performed optimally with a yield increased by 225.95% compared to the control (0 V). The relatively low environmental pH is conducive to extraction under the electric field, making the proposed system efficient for the extraction of valuable compounds without using metal electrode. [ABSTRACT FROM AUTHOR]

The effects of induced electric field (IEF) on the crystal structure and physicochemical properties of potato starch were investigated by subjecting identically treated control and electrically-modified samples to the same temperature history. Additionally, a method of combining IEF with heating for efficient modification of native polymer was also proposed. Results showed that the application of IEF at an electric voltage of 75 V has a statistically significant effect on starch gelatinization and pasting properties, especially when combined with heating at 50 °C. After treatment by the combination method for 96 h, the gelatinization temperatures increased, which can be explained by the slight increase in the ratio of 1044/1015 cm −1 and relative crystallinity. Furthermore, IEF reduced granular swelling and therefore contributed to decreasing the peak, breakdown, and setback viscosity of potato starch. This study explores the potential of IEF as innovative technology for starch modification. [ABSTRACT FROM AUTHOR]

Kiwifruit juice is a popular liquid food with a large consumption. It usually needs high temperature sterilization before packaging and selling. Alternating magnetic field can produce alternating induced electric field, then a thermal effect is triggered. This study aims to explore the inner heating of kiwifruit juice via induced electric field and its impact on the physicochemical properties. Meanwhile, ultra-high temperature instantaneous sterilization (121°C, 5 s), and conventional heat treatment (93°C, 2 min) were conducted as controls, then effects were compared between these treatments. The results showed that the bacterial, mold and yeast colonies were completely eliminated, polyphenol oxidase activity decreased by 94.8%, and peroxidase activity decreased by 92.7%, at 1800 V and 6 mL/min. The induced electric field treatment and ultra-high temperature instantaneous sterilization had no significant effect on pH and titratable acid (P ≥ 0.05). Conventional heat treatment increased soluble solid content by 5.3%. The induced electric field treatment resulted in the closest color and browning index to the fresh juice owing to moderate thermal effect. It also demonstrated minimal loss on total phenols and flavonoids contents after induced electric field treatment (7.1% and 2.7%, respectively). The heating effect caused by induced electric field has great application potential for the treatment of fruit juice. • Induced electric field was utilized for direct heating of kiwifruit juice. • Contact-less thermal effect and temperature rise on kiwifruit juice was evaluated. • The microbe and enzyme could be inactivated within 7.7 s via continuous-flow treatment. • The minimal loss of total phenols and flavonoid was achieved via induced electric field. [ABSTRACT FROM AUTHOR]

The novel, previous unreported induction heating technique developed here uses the inverse process of the existing induction heating techniques. The theoretical basis for developing this technique is to determine whether the induced current passing through a winding food coil would induce a magnetic flux or cause an increase in primary current. Therefore, to develop this technique and implement it in the food industry, it is necessary to understand its technical details and engineering characteristics. This study presents the design and development process of the technique, as well as the calculation formulas, including load voltage, induced electric field, induced current density, heating power and energy utilization rate during the heating process. The results reveal that although the application of this innovative inner heating technique has been achieved, the energy efficiency of the current system is low. The thermal effect and non-thermal effect of the induced electric field decreased the total bacterial counts in the samples of grapefruit juice and raw milk. Image 10083 • Innovative induction heating is a sister technology to ohmic heating in the food industry. • Liquid food can act as the secondary winding of a transformer for inner heating. • A thermal effect on liquid foods by an alternating magnetic field was observed. • The development and design process of this novel technique are presented. • Continuous-flow pasteurization of liquid food was achieved by an induced electric field. [ABSTRACT FROM AUTHOR]

The mechanism of induced electric field (IEF)-assisted acid hydrolysis was investigated by using guar gum, chitosan, and pectin as model polysaccharides. Roles of thermal and non-thermal effects were explored by temperature determination, HPSEC-MALLS-RI, SEM, FT-IR, XRD, and a rheometer. Results suggested that IEF affected the hydrolysis of polysaccharides by inducing thermal and non-thermal effects. Thermal effect contributed to the hydrolysis. As the excitation voltage increased, the thermal effect enhanced, with a temperature increased by about 25 °C after IEF (75 V) treatment for 4 h. Non-thermal effect, induced by the rapid and directional migration of charged species, varied with the electrical properties of the polysaccharides. It enhanced the hydrolysis of guar gum and pectin but negatively impacted the chitosan due to their different migration directions under IEF. IEF-assisted hydrolysis damaged the structural compactness of polysaccharides and significantly decreased the viscosity of their solutions. This study clarified the hydrolysis mechanism of polysaccharides under IEF, providing a theoretical guide for the application of IEF in the chemical modification of biopolymers. Image 1 • IEF affected the hydrolysis of polysaccharides by thermal and non-thermal effects. • Thermal effect enhanced with increasing excitation voltage. • Non-thermal effect varied with the electrical properties of polysaccharides. • IEF-assisted hydrolysis damaged the structural compactness of polysaccharides. • IEF-assisted hydrolysis significantly decreased the viscosity of polysaccharides. [ABSTRACT FROM AUTHOR]

In this study, the air gap magnetic field characteristics of external rotor permanent magnet synchronous motors (PMSMs) under both the stator and rotor coordinate systems considering low‐order current harmonics and high‐order sideband current harmonics are analysed. A direct measurement technique (DMT) for air‐gap magnetic field is proposed. First, an analytical model of air gap magnetic field of external rotor PMSMs is established. The spatial order and frequency characteristics of stator/rotor air gap magnetic field are revealed. Then, a 24‐pole 27‐slot external rotor PMSM is taken as an example. The analytical and finite element (FE) results are compared and analysed. The difference of the spatial order and frequency characteristics between the stator and rotor air gap magnetic field are verified. Next, a new DMT is proposed, which can detect the precise distribution and local microscopic characteristics on the order of 10−1 mm with high resolution. The accuracy of analytical and FE model are verified by the DMT and an indirect experimental test of no‐load back electromotive force. Finally, the mechanical challenges of in‐wheel motors and the practicablility of DMT for eccentricity detection are further discussed. [ABSTRACT FROM AUTHOR]

Herein, a multistage induced electric field (IEF) combined with a continuous-flow reactor was utilized to assist the acid hydrolysis of corn, potato, and waxy corn starch for avoiding plate corrosion and heavy metal leakage. It was found that adding IEF stages was beneficial to improve the hydrolysis efficiency. Treating potato, corn, and waxy corn starch via continuous-flow IEF increased the reducing sugar contents up to 78.76 %, 57.86 %, and 66.18 %, respectively. The electrical conductivity of starch grew with the reaction stages, while starch yield demonstrated the opposite trend. Treated starch had higher solubility and gelatinization peak temperature than native starch, with the gelatinization enthalpy showing fluctuations. Meanwhile, the swelling power decreased as the number of IEF stages was increased. Observations of Fourier transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy indicated that the treated starch became more ordered, and crystalline regions were destroyed to various degrees with pores forming on particle surfaces. These variations could be attributed to acid hydrolysis and IEF. [ABSTRACT FROM AUTHOR]

Non-conventional heating technology based on electric fields can be utilized to process liquid foods. In this study, the induced electric field (IEF) was investigated to clarify its inactivation mechanism on E.coli. Staining results show that inactivation of E.coli by IEF can be attributed to the reversible destruction of the cell membrane, followed by the denaturation of intracellular enzymes, and finally the irreversible rupture of the cell membrane. The increased levels of extracellular proteins and nucleic acids were also observed. IEF treatment at 400 Hz and 800 V (or 53 V/cm) results in a reduction of 4.5 log CFU·mL−1 in the number of E.coli. Storage life analysis shows that IEF treatment can improve the stability of apple juice and the content of bioactive components. Thus, IEF is a potential technique for liquid food processing. • The inactivation mechanism of induced electric field on E.coli was investigated. • A reduction of 4.5 log CFU·mL−1 of E.coli was realized by applying the IEF. • IEF treatment retains bio-active components in fresh apple juice. • The storage stability of apple juice was improved through IEF treatment. [ABSTRACT FROM AUTHOR]

• Innovative contactless thermal effect on starch hydrolysis was investigated. • Starch acidolysis solution acts as the coils of a transformer for heating treatment. • Innovative inner heating method accelerated corn starch acid hydrolysis. • The treated starch had increased solubility and swelling power. • Thermal effect of induced electric field altered the physicochemical properties of starch. Growing attention has been focused on modifications of starch using electric field, but electrode corrosion and metal contamination remain unavoidable during the process. To solve these problems, the magneto-induced electric field was used to assist corn starch hydrolysis due to its thermal effect. Results indicated that the method accelerated corn starch acid hydrolysis and decreased the treatment time. The reducing sugar content increased to 0.59 g/L after a 60 s treatment, which was 353.44 % higher than the 20 s treatment, while the average degree of polymerization reached a minimum. The treated starch showed increased solubility and swelling power, as well as decreased freeze-thaw stability. X-ray diffraction, fourier transform infrared spectroscopy, and scanning electron microscopy results suggested that the physicochemical changes of corn starch were due to the thermal effect of the induced electric field. This study is expected to provide an important basis for applying new electric field hydrolysis technology to starch modification. [ABSTRACT FROM AUTHOR]

This study aimed to efficiently and selectively hydrolyze maize starch via induced electric field (IEF). The role of electrical conductivity in regulating hydrolysis efficiency and selectivity was investigated, and the structural and physicochemical properties of hydrolyzed products were characterized. Compared with water-bath heating, IEF induced the rapid and ordered migration of charged species, thus increasing the hydrolysis rate and narrowing the molecular weight distribution of hydrolyzed starch. The addition of KCl enhanced IEF-assisted hydrolysis due to the absorption of additional electrical energy into the reaction system. After hydrolysis, the molecular chains of maize starch exhibited cleavage, the granular surface became rough, the crystallinity increased, the gelatinization enthalpy slightly increased, the viscosity of starch paste reduced, the hardness of starch gel declined, and the re-crystallization showed no significant improvement. Overall, this study extends the potential applications of electro-techniques in preparing hydrolyzed starch with narrow molecular weight distribution in food and material fields. [Display omitted] • Induced electric field (IEF) improved the hydrolysis efficiency of maize starch. • IEF increased the hydrolysis selectivity of maize starch. • The efficiency and selectivity enhanced with the increasing conductivity. • IEF-assisted hydrolysis roughened granular surface and increased crystallinity. • IEF-assisted hydrolysis decreased viscosity but showed no effect on re-crystallization. [ABSTRACT FROM AUTHOR]

• IEF-assisted hydrolysis enhanced with increasing DD of chitosan. • Electrical properties of chitosan showed no significant effect on the hydrolysis. • Structural compactness determined the hydrolysis behavior of different-DD chitosan. This study explored the impact of re-acetylation on induced electric field (IEF)-assisted hydrolysis of chitosan. Chitosan with different degree of deacetylation (DD) exhibited different charge content but similar electrical conductivity and output voltage of the electrolyte system, thus theoretically resulting in equivalent electro-processing efficiency. However, molecular and rheological measurements suggested that the hydrolysis rate decreased with an increase of DD. Re-acetylation had no significant effect on the molecular weight and viscosity of chitosan but damaged its granular and crystal structure, making chitosan chains more susceptible to the acid. The IEF-assisted hydrolysis of dissolved chitosan confirmed that the structural compactness of chitosan played a more important role on the hydrolysis than the charge content. This study extended current knowledge regarding the effect of charge content and structural compactness on IEF-assisted hydrolysis process, which contributed to the applications of IEF in biopolymer modification. [ABSTRACT FROM AUTHOR]