Application Of Pulsed Electric Fields Research Articles

Prophylactic administration of glycopyrrolate prevents vasovagal responses induced by pulsed field ablation in patients with atrial fibrillation

Abstract Background The FarapulseTM system was the first pulsed field ablation device to receive regulatory approval. Vagal Responses (VR) during pulmonary vein isolation (PVI) with this pentaspline device are frequent and often require back-up pacing or the administration of parasympathetic drugs. Glycopirrolate (GLY) is a medication of the muscarinic anticholinergic group; its efficacy for VR prevention when administered prophylactically before PVI has never been reported. Objective To evaluate the effectiveness of prophylactic intravenous administration of GLY on VRs induced by PFA. Methods Consecutive AF patients undergoing first-time PVI with PFA via the FarapulseTM system between April and October 2023 were prospectively enrolled in 3 European centers. Prophylactic administration of GLY (0.2 mg intravenous administration before femoral vein puncture) [Group GLY(+)] was adopted based on operator’s preference. VR was defined as at least one of the following: sinus bradycardia (<40 beats/min), asystole (>6 sec), or atrioventricular block (AVB) occurring immediately after a pulsed electric field application. VRs and maximum pause duration (maximum RR interval) were determined for each PV. Temporary backup pacing was performed as per the operator's preference. Results We enrolled 141 patients [GLY(+): 64 patients; GLY(-): 77 patients] undergoing PVI with the pentaspline FarapulseTM system. Median age was 54.1 years (54.1- 70), and 76 (54%) patients were males with an average CHA2DS2-VASc Score of 1.0 (0 – 2). A total of 563 PVs, including 3 left common PVs and 2 accessory middle PVs, were successfully isolated with the FarapulseTM PFA system. There were no statistically significant differences in baseline and procedural characteristics between two groups. VRs during PVI occurred in a total of 53 (37.6%) patients. GLY administration reduced significantly the incidence of any VRs (4.7% vs 64.9%; p<0.001) (Figure 1A). Additionally, GLY resulted in a lower incidence of VRs during LSPV (4.7% vs 62.3%; p<0.001) and LIPV (1.6% vs 9.1%; p<0.001) (Figure 1B) isolation and the need for temporary backup pacing during LSPV (24.7% vs 1.6%; p<0.001) isolation. Maximum pause duration was significantly shorter in the GLY(+) group after PFA of LSPV (1195 vs 3459 sec; p<0.001), LIPV (1128 vs 1556 sec; p<0.001), RSPV (1138 vs 1607 sec; p<0.001) and RIPV (1103 vs 1343 sec; p<0.001) compared to GLY(-) group (Figure 1C). Conclusions Glycopyrrolate is highly effective in the prevention of VRs induced by PFA ablation in AF patients undergoing first-time PVI.Figure 1

Procedural characteristics, details on epicardial mapping-based lesion transmurality, and long-term success of posterior wall isolation with a pentaspline pulsed field ablation device

Abstract Background Achieving durable posterior wall isolation (PWI) with thermal-based energies is challenging, as reconnection rates have been reported to be up to 60%. Additionally, PWI can significantly increase the risk of collateral thermal damage to the esophagus. Pulsed field ablation (PFA) is a non-thermal energy source with a remarkable safety profile due to its selectivity to cardiac tissue. Additionally, PWI durability was reported to be 100% in a recent phase-3 study enrolling persistent AF patients undergoing PFA via the FarapulseTM system. Purpose To report procedural details, acute lesion transmurality, and long-term success of PWI via the FarapulseTMsystem. Methods Consecutive persistent AF patients undergoing first-time ablation with the FarapulseTM system at four different centres were prospectively enrolled. All patients received first-time pulmonary vein isolation (PVI) and PWI. PFA was performed with either a 31mm or a 35mm device and an energy output of 2.0kV. At least 2 applications per position were delivered. Primary efficacy endpoint was freedom from any atrial tachyarrhythmia >30s after a 3month blanking period. PW lesion transmurality was assessed in a subpopulation of patients with an indication for hybrid AF ablation and left atrial appendage (LAA) clipping. The procedure was performed according to the following steps: 1) endocardial PVI plus PWI via the FarapulseTM system; 2) endocardial high-density mapping with RhythmiaTM plus Intellanav OrionTM; 3) thoracoscopy-assisted epicardial high-density mapping with Intellanav OrionTM 4) left atrial appendage clipping. Results 157 persistent AF patients (mean age: 62±11years; 75.5% males) were included. First-pass PVI was achieved in 100% of patients. On average, pulsed electric field applications for PWI were 16.3±2.4. Mean procedural time was 66±17min; left atrial dwelling and fluoroscopy times were 46±12min and 14±6min, respectively. SR restoration during PWI was observed in 8 (5.1%) cases. Minor and major periprocedural complications occurred in 2.5% (groin hematoma: 4pts) and 0.6% (diplopia with negative cerebral MRI) patients, respectively. During a mean follow-up of 353±58 days, arrhythmia-free survival was 78.3% (n=123). A redo ablation was performed in 23 patients, showing reconnection of 22.8% of PVs. Durable PWI was observed in 82.6% of patients. In the subpopulation of patients (n=3) undergoing hybrid ablation plus LAA clipping, thoracoscopy-guided epicardial mapping of the PW was performed between 57 and 72 minutes after the last endocardial PFA application. All patients showed transmural PWI (Figure1). Conclusions In a real-world multicenter registry, PWI by means of the FarapulseTM system was safe and feasible, contributing to approximately 80% success rate after 1 year. Endocardial PFA-based PWI led to 100% transmural lesions acutely, with a rate of reconnection <20% at redo procedures.

Ultrasound and pulsed electric field treatment effect on the thermal properties, oxidative stability and fatty acid profile of oils extracted from berry seeds

AbstractThe seeds of berry fruits which are considered as a by-product may be valorized by recovering the oil they content. Nevertheless, the conventional extraction methods are time, energy and organic solvents consuming. In order to make extraction more environmental-friendly, alternative methods, like ultrasound-assisted and pulsed electric field-assisted processes, are being developed. The procedure of extraction may however influence the quality of obtained oil. The following study aims to define the effects of ultrasound and pulsed electric field application in the extraction process on the thermal properties, i.e., oxidative stability, melting and cyclic heating/cooling profiles, thermal decomposition characteristics. Additionally, fatty acid profile assessment was included in the study. Seeds of blackberries, blackcurrants, chokeberries, raspberries and redcurrants were used to extract oil. Based on the results, it can be summarized that extraction method influenced the resistance of oils to oxidation. Ultrasound-assisted process resulted in oils with the highest oxidation induction times. Melting profile was slightly influenced by extraction method, with peak temperatures indicating the presence of low-melting and middle-melting triacylglycerol fractions. Differential scanning calorimetry with heat/cool/heat procedure let determine crystallization peak temperatures around − 60 °C, which could be associated with the specific triacylglycerol profile of berry seed oils. The courses of thermogravimetric analysis curves were comparable for all the tested samples. The fatty acid profile study revealed that all the studied thermal properties were affected by the unique fatty acid percentage share, with a great predominance of polyunsaturated fatty acids. Obtained results allowed to conclude that extraction method influenced oxidative stability, thermal properties and fatty acid profile only to some extent. The most promising extraction method among analyzed seems to be ultrasound-assisted extraction as it provided oil with high oxidative stability, typical thermal properties and unchanged fatty acid profile, without being harmful to natural environment due to possible reduction in solvent and time consumption.

Introduction to This Special Issue: Biomedical Applications of Pulsed Electric Fields

Introduction to This Special Issue: Biomedical Applications of Pulsed Electric Fields

Effect of Pulsed Electric Fields on the Shelf Stability and Sensory Acceptability of Osmotically Dehydrated Spinach: A Mathematical Modeling Approach.

This study focused on the osmotic dehydration (OD) of ready-to-eat spinach leaves combined with the pulsed electric field (PEF) pre-treatment. Untreated and PEF-treated (0.6 kV/cm, 0-200 pulses) spinach leaves were osmotically dehydrated at room temperature for up to 120 min. The application of PEF (0.6 kV/20 pulses) prior to OD (60% glycerol, 25 °C, 60 min) lowered water activity (aw = 0.891) while achieving satisfactory product acceptability (total sensory hedonic scoring of 8). During the storage of the product (at 4, 8, 12, and 20 °C for up to 30 d), a significant reduction in total microbial count evolution was observed (9.7 logCFU/g for the untreated samples vs. 5.1 logCFU/g for the PEF-OD-treated samples after 13 d of storage at 4 °C). The selection of these PEF and OD treatment conditions enabled the extension of the product shelf life by up to 33 d under chilled storage. Osmotically treated spinach could find application in ready-to-eat salad products with an extended shelf life, which is currently not possible due to the high perishability of the specific plant tissue.

Low-intensity pulsed electric fields pre-treatment on yogurt starter culture: Effects on fermentation time and quality attributes

Low-intensity pulsed electric fields (PEF) were applied to a starter culture mix (Streptococcus thermophilus, Lactobacillus bulgaricus, and partially skimmed milk) before the fermentation stage of natural yogurt. The impact of PEF processing conditions on yogurt fermentation time and quality characteristics was evaluated. PEF parameters were set based on a factorial experimental design; independent variables: electric field strength, pulse-frequency, and pulse-width, were explored, having fermentation time as a response. Most PEF treatments reduced fermentation time by 0.31–0.52 h compared to conventional yogurt processing (CY) (4.70 ± 0.23 h). The shortest time (4.18 ± 0.04 h) resulted from PEF pre-treatment with 8-μs monopolar pulses at 1 kV/cm and 150 Hz during 400 μs. The physicochemical and sensory characteristics of PEF-treated yogurt were similar to those of the CY immediately after processing and during refrigeration storage. Low-intensity PEF could be a promising alternative pre-treatment of yogurt production, reducing fermentation time while maintaining quality attributes of natural yogurt. Industrial relevanceConventional yogurt processing lasts around 4.5–6 h, representing high energy consumption and production costs. The application of pulsed electric fields (PEF) processing to the starter culture before yogurt fermentation represents a potential alternative to diminish production time by stimulating lactic acid bacteria and accelerating fermentation stage. This study demonstrated that low-intensity PEF (1–3 kV/ cm) reduced fermentation time by 0.31–0.52 h without compromising yogurt's quality properties, including physicochemical characteristics and sensory attributes. Obtained results suggest that this technology allows more efficient and sustainable yogurt production methods, positively impacting industry and consumers.

The Advancement and Utilization of Marx Electric Field Generator for Protein Extraction and Inducing Structural Alterations

This study introduces an innovative two-range, 12-stage Marx pulse generator employing thyristor switches designed specifically for the electroporation of biological cells. The generator consists of two module capacitors of different capacitances (1 μF and 0.25 μF), which enable the generation of electrical pulses with different durations and amplitudes of up to 25 kV. Safety aspects, including overcurrent and overvoltage protection mechanisms, are implemented in both the software and the hardware. In the experimental section, the tests of the Marx generator with resistive load are described in detail, and the results for the voltage fluctuations, pulse duration, and output characteristics of the generator are presented. The advantages of the design, including the high output voltage, the wide range of repetition rates, and the flexibility of the pulse parameters, are emphasized. Additionally, the research showcases the utilization of the devised generator for industrial purposes. Hence, an investigation into the efficiency of protein extraction from microalgae (Chlorella vulgaris) and the impacts of pulsed electric fields (PEFs) on the structural characteristics of casein micelles (CSMs) was chosen as an illustrative example. The obtained results provide valuable insights into the application of PEF in food processing and biotechnology and underline the potential of the developed generator for sustainable and environmentally friendly practices.

Biological autoluminescence enables effective monitoring of yeast cell electroporation.

The application of pulsed electric fields (PEFs) is becoming a promising tool for application in biotechnology, and the food industry. However, real-time monitoring of the efficiency of PEF treatment conditions is challenging, especially at the industrial scale and in continuous production conditions. To overcome this challenge, we have developed a straightforward setup capable of real-time detection of yeast biological autoluminescence (BAL) during pulsing. Saccharomyces cerevisiae culture was exposed to 8 pulses of 100 µs width with electric field strength magnitude 2-7kV cm-1. To assess the sensitivity of our method in detecting yeast electroporation, we conducted a comparison with established methods including impedance measurements, propidium iodide uptake, cell growth assay, and fluorescence microscopy. Our results demonstrate that yeast electroporation can be instantaneously monitored during pulsing, making it highly suitable for industrial applications. Furthermore, the simplicity of our setup facilitates its integration into continuous liquid flow systems. Additionally, we have established quantitative indicators based on a thorough statistical analysis of the data that can be implemented through a dedicated machine interface, providing efficiency indicators for analysis.

Sustainable Valorization of Industrial Cherry Pomace: A Novel Cascade Approach Using Pulsed Electric Fields and Ultrasound Assisted-Extraction.

In this study, a two-stage cascade extraction process utilizing pulsed electric fields (PEF) (3 kV/cm, 10 kJ/kg) for initial extraction, followed by ultrasound (US) (200 W, 20 min)-assisted extraction (UAE) in a 50% (v/v) ethanol-water mixture (T = 50 °C, t = 60 min), was designed for the efficient release of valuable intracellular compounds from industrial cherry pomace. The extracted compounds were evaluated for total phenolic content (TPC), flavonoid content (FC), total anthocyanin content (TAC), and antioxidant activity (FRAP), and were compared with conventional solid-liquid extraction (SLE). Results showed that the highest release of bioactive compounds occurred in the first stage, which was attributed to the impact of PEF pre-treatment, resulting in significant increases in TPC (79%), FC (79%), TAC (83%), and FRAP values (80%) of the total content observed in the post-cascade PEF-UAE process. The integration of UAE into the cascade process further augmented the extraction efficiency, yielding 21%, 49%, 56%, and 26% increases for TPC, FC, TAC, and FRAP, respectively, as compared to extracts obtained through a second-stage conventional SLE. HPLC analysis identified neochlorogenic acid, 4-p-coumaroylquinic, and cyanidin-3-O-rutinoside as the predominant phenolic compounds in both untreated and cascade-treated cherry pomace extracts, and no degradation of the specific compounds occurred upon PEF and US application. SEM analysis revealed microstructural changes in cherry pomace induced by PEF and UAE treatments, enhancing the porosity and facilitating the extraction process. The study suggests the efficiency of the proposed cascade PEF-UAE extraction approach for phenolic compounds from industrial cherry pomace with potential applications to other plant-based biomasses.

Improving the Composition and Bioactivity of Cocoa (Theobroma cacao L.) Bean Shell Extract by Choline Chloride-Lactic Acid Natural Deep Eutectic Solvent Extraction Assisted by Pulsed Electric Field Pre-Treatment.

An environmentally friendly method for the release of cocoa bean shell (CBS) extracts is proposed in this paper. This work aims to investigate the effect of pulsed electric field (PEF) pre-treatment on subsequent solid-liquid extraction (SLE) of metabolites with choline chloride-lactic acid natural deep eutectic solvent (NaDES) and bioactivity of cocoa bean shell (CBS) extract. Two different media for PEF application were evaluated: water and chlorine chloride-lactic acid. Total polyphenols (TPC), total flavonoids (TFC), individual major compounds, and antioxidant and antibacterial activity of CBS extracts were assessed. The performance of PEF-assisted extraction was compared with SLE and ultrasound-assisted extraction (UAE). The proposed method improved the release of TPC up to 45% and TFC up to 48% compared with the conventional extraction. The CBS extract showed medium growth inhibition of Escherichia coli and high growth inhibition of Salmonella sp, Listeria monocytogenes, and Staphylococcus aureus. Thus, an extract with enhanced antioxidant and antibacterial properties was obtained.

Germination and stress tolerance of oats treated with pulsed electric field at different phases of seedling growth

This study explores the impact of pulsed electric field (PEF) application on oat seedling growth and stress tolerance. PEF treatment (99 monopolar, rectangular pulses lasting 10 µs each, with a frequency of 13 Hz and a nominal electric field strength of 2250 V/cm) was applied at two growth stages: (i) when the seedlings had 0.2 cm roots emerging from the kernel, and (ii) when they had a 0.4 cm shoot emerging from the kernel. Post-treatment, the seedlings were hydroponically grown for 8 days. To induce stress, the hydroponic medium was augmented with PEG (15 %) to induce drought stress and NaCl (150 mM) to induce salinity stress. Results demonstrate that applying PEF improved the growth of the root and shoot of oat seedlings. This effect was more pronounced when applied to more developed seedlings. When PEF was applied during the later stage of germination, seedlings exposed to salinity stress showed enhanced shoot growth compared to the control. Under the studied conditions, the application of PEF had no impact on the growth of seedlings under drought stress.

Time-dependent model of temperature distribution in continuous flow pulsed electric field treatment chambers

A key component of a continuous flow pulsed electric field (PEF) system is the treatment chamber, where the product is exposed to electric pulses. Determination of the temperature distribution in the chamber during PEF treatment is important since high local increases in temperatures can affect the quality of the product. Coupled simulations of electric field, fluid flow, and heating in the existing literature do not model each individual electric pulse, but rather employ a “duty cycle” approach, which does not account for transient variations in treatment intensity and temperature changes in the medium. We present a time-dependent approach to modelling PEF treatment in continuous flow treatment chambers, which can model each pulse separately, and thus enables a more accurate study of temporal and spatial distributions of electric field and temperature. The model has been validated on laboratory scale treatment chambers of parallel plate or colinear design and using realistic protocols. Industrial relevance textThe paper is relevant to all pulsed electric field (PEF) applications either on laboratory or industrial scale that implement a continuous flow treatment chamber. It presents an improved modelling approach which allows for an analysis of the electrical current, electric field, and temperature distribution in the chamber during, at the end, and in between application of electrical pulses. The model can be used to predict the peak temperature at the end of each pulse in the hot spots, which if large enough could potentially lead to thermal damage of the product or in extreme cases even potential local boiling of the medium, resulting not only in degradation of the treated product, but also in accelerated electrode fouling, oxidation, and dissolution (etching), as well as arcing. This would not only affect the quality of the treated product but would also affect the wear and lifetime of electrodes/chambers, and of the pulse generator. The model can also be used to avoid expensive trial-and-error optimization of the PEF protocols and chamber geometries in situ.

Pulsed Electric Fields Induce STING Palmitoylation and Polymerization Independently of Plasmid DNA Electrotransfer.

Gene therapy approaches may target skeletal muscle due to its high protein-expressing nature and vascularization. Intramuscular plasmid DNA (pDNA) delivery via pulsed electric fields (PEFs) can be termed electroporation or electrotransfer. Nonviral delivery of plasmids to cells and tissues activates DNA-sensing pathways. The central signaling complex in cytosolic DNA sensing is the cyclic GMP-AMP synthase-stimulator of interferon genes (cGAS-STING). The effects of pDNA electrotransfer on the signaling of STING, a key adapter protein, remain incompletely characterized. STING undergoes several post-translational modifications which modulate its function, including palmitoylation. This study demonstrated that in mouse skeletal muscle, STING was constitutively palmitoylated at two sites, while an additional site was modified following electroporation independent of the presence of pDNA. This third palmitoylation site correlated with STING polymerization but not with STING activation. Expression of several palmitoyl acyltransferases, including zinc finger and DHHC motif containing 1 (zDHHC1), coincided with STING activation. Expression of several depalmitoylases, including palmitoyl protein thioesterase 2 (PPT2), was diminished in all PEF application groups. Therefore, STING may not be regulated by active modification by palmitate after electroporation but inversely by the downregulation of palmitate removal. These findings unveil intricate molecular changes induced by PEF application.

Impact of pulsed electric fields on membrane disintegration, drying, and osmotic dehydration of foods

AbstractDrying is one of the oldest and most conventional methods used to preserve foods. Unique traditional methods have been applied for the drying of plant‐based food products. However, the disadvantage of this approach is the low drying rate, high energy, and processing costs accompanied by the loss of nutritional quality in food products. As a substitute, pulsed electric field (PEF) is a modern and promising technique that has various advantages over thermal treatments. Nowadays, it has become an area of innovation to meet increasing industrial demands. Application of PEF during drying and osmotic dehydration has beneficial impacts on the extension of shelf‐life, increases in storage stability, and improvement of nutritional quality. Upscaling the use of PEF from laboratory to industrial scale while maintaining productivity is an area for further research and development. The aim of this commentary review is to give an overview of a newly proposed PEF process, which improves drying rate, mass‐energy transfer, retention of bioactive compounds, and osmotic dehydration in food. PEF processing led to achieving the innovative development of a wide range of foods and was extended to solve environmental issues. Drying food products is the most promising area in the food industry which needs improvement in terms of achieving energy efficiency and cost‐effectiveness to dry food products with the maintenance of nutritional properties to adequate levels. In this regard, PEF could be a suitable and novel drying method to overcome the limitations of conventional drying methods which might open new horizons for valuable research in manufacturing dried fruits and vegetables on an industrial scale.

Optimization of Pulsed Electric Field-Based Extraction of Bioactive Compounds from Cannabis sativa Leaves

The current investigation examines the application of pulsed electric fields (PEFs) for isolating polyphenols from Cannabis sativa var. Futura 75 leaves. Firstly, the solvent composition, which included ethanol, water, and various mixtures of the two, was explored, along with the liquid-to-solid ratio. Subsequently, the primary parameters associated with PEFs (namely, pulse duration, pulse period, electric field intensity, and treatment duration) were optimized. The extracted samples were analyzed to determine their total polyphenol content (TPC), and individual polyphenols were also evaluated through high-performance liquid chromatography. In addition, the antioxidant activity of the extracts was assessed through ferric-reducing antioxidant power (FRAP) and DPPH assays. The extracts prepared utilizing PEFs were compared to the extracts obtained without PEFs in terms of their TPC, FRAP values, and DPPH activity. The results indicate that the most effective extraction parameters were a pulse duration of 10 μs, a pulse period of 1000 μs, and an electric field strength of 0.9 kV/cm after 25 min of extraction. The most efficient solvent was determined to be a 50% (v/v) mixture of ethanol and water in a 20:1 liquid-to-solid ratio. The extract obtained under the optimal conditions exhibited a ~75% increase in TPC compared to the extract obtained without any application of PEFs, while some individual polyphenols exhibited an increase of up to ~300%. Furthermore, significant increases of ~74% and ~71% were observed in FRAP and DPPH assays. From the information provided, it was observed that the tested variables had an impact on the recovery of polyphenols from C. sativa leaves.

Pilot Scale Continuous Pulsed Electric Fields Treatments for Vinification and Stabilization of Arinto and Moscatel Graúdo (Vitis vinifera L.) White Grape Varieties: Effects on Sensory and Physico-Chemical Quality of Wines

Pulsed electric field (PEF) processing of white grapes (Arinto, Moscatel Graúdo also known as Moscatel de Setúbal) before pressing for must extraction (1.2 and 1.6 kV/cm) and before bottling for finished wine physical stabilization (10 kV/cm) was implemented in a pilot-scale winery to produce about 540 L of wine for each variety. PEF was applied at these two different stages of wine production, and its effects on the sensory and physico-chemical quality of the wines were investigated. The sensory triangle tests revealed no significant change in both wine varieties’ colour, odour, and taste with PEF extraction and PEF stabilization treatments. However, for colour coordinates assessed with a spectrophotometer, a significant increase in CIE b* colour coordinate was registered for PEF-extracted Arinto and Moscatel wine samples, showing a development of a more intense yellow colour. Concerning physico-chemical quality parameters, the PEF extraction increased both wine varieties’ turbidity and pH, although total acidity was not affected. The total phenols also increased in Arinto with extraction. The second PEF treatment applied for wine stabilization did not affect any of the quality parameters, except total phenols, which decreased in Moscatel wine. The results encourage the application of PEF in the wineries at different stages of vinification of white wine grape varieties.

Cascaded boost converter-based high-voltage pulse generator for pulsed electric field applications

Cascaded boost converter-based high-voltage pulse generator for pulsed electric field applications

Accelerating Xinomavro Red Wine Flavor Aging Using a Pulsed Electric Field and Various Wood Chips

Pulsed electric field (PEF) treatment has gained significant attention within the food industry. This study examines the application of PEF combined with wood chips of diverse species to expedite the flavor aging process of Xinomavro red wine. Various wood chip species, including black locust, common juniper, apricot, sweet chestnut, cherry, apple, peach, and European oak, sourced from pruning residues were immersed in the wine prior to subjecting it to PEF treatment. The samples underwent a range of pulse durations and intervals during treatment. Comparative preparations encompassing wine without chips and wine infused with each wood type left at ambient temperature for 5 days were also examined. The sensory attributes and the volatile compounds (VC) were assessed through the utilization of headspace solid-phase microextraction and GC-MS. In the control sample, 12 VCs were identified, whereas in the samples, 22 distinct VCs were identified. Favorable sensory attributes across all PEF conditions were associated with the incorporation of cherry wood chips. These findings highlight the potential of PEF treatment to enhance the quality parameters of the aging process in Xinomavro red wine, capitalizing on the synergistic interaction between PEF and various wood chip species. This innovative approach holds promise for augmenting crucial oenological parameters of red wine, strengthening the use of PEF as an efficient technique to enhance the overall quality.

Optimizing the solvent extraction process for high-value compounds from sweet cherry press cake treated with pulsed electric fields using response surface methodology

Introduction: Cherry juice production generates substantial cherry processing by-products, presenting a significant environmental challenge. The valorization of these by-products can not only reduce management costs but also enhance profitability by recovering valuable intracellular compounds.Methods: This study aimed at the extraction of bioactive compounds with potent antioxidant activity from sweet cherry press cake using Pulsed Electric Fields (PEF)-assisted extraction. PEF pre-treatment, carried out using a predetermined field strength (E = 3 kV/cm) and total specific energy input (WT = 10 kJ/kg), was applied to the cherry press cake prior to the subsequent solid-liquid extraction (SLE) stage. To optimize the SLE process for both untreated and PEF-treated samples, Response Surface Methodology (RSM) was employed to determine the most effective extraction parameters, including extraction temperature (20–50°C), solvent concentration (0–50% ethanol in water), solid-liquid ratio (0.05–0.2 g/mL), and diffusion time (30–360 min). The objective was to maximize key response variables: total phenolic content (TPC), flavonoid content (FC), total anthocyanin content (TAC), and antioxidant activity (FRAP). The extracts obtained from both untreated and PEF-treated samples under optimal conditions underwent HPLC-DAD analysis.Results and discussion: The results revealed that, under optimized SLE conditions (50°C, 50% ethanol-water mixture, 0.2 g/mL solid-liquid ratio, and 360 min extraction time), PEF pre-treatment significantly enhanced the extractability of high-value compounds. This resulted in notable increases in TPC (+26%), FC (+27%), TAC (+42%), and antioxidant activity (+44%) compared to conventional SLE. Additionally, the application of PEF reduced extraction time (by 5–18 min) and solvent usage (by 2%). HPLC analysis identified cyanidin-3-O-rutinoside as the predominant phenolic compound in both untreated and PEF-treated extracts, with a remarkable increase (+2.3-fold) after PEF application. These findings underscore the potential of PEF-assisted extraction as a promising approach to maximize the recovery of valuable compounds from sweet cherry press cake, contributing to food waste reduction and enhanced value generation from by-products.

Mode and mechanism of water droplet breakup in oil under high-voltage and high-frequency pulsed electric fields

In industrial processes, the application of pulsed electric fields for electrostatic demulsification may cause droplet breakup, reducing demulsification efficiency. In this paper, a comprehensive approach combining microscopic experiment, theoretical derivation, and molecular dynamics simulation, were employed to explore the water droplet breakup in water-in-oil (W/O) under high-voltage and high-frequency pulsed electric fields. The results showed that droplet breakup would occur when the electrostatic tensile stress of the droplet surpassed the additional compressive stress. Three main modes of droplet breakup were observed: breakup at one end, breakup at both ends, and breakup in the middle part. By applying Maxwell stress equation, critical field strengths were derived to predict breakup locations. In the pulsed electric field, the droplets underwent a sequence of stretching, retraction, and eventual breakup. The formation and migration of hydrated ions was of crucial importance in the droplet breakup. A decrease in electrostatic attraction between H2O and an increase in dispersion attraction effect between H2O and C6H14 promoted the droplet breakup. The number of hydrogen bond inside the droplet was reduced, weakening the stability of droplet. The energy of electric field was transformed into the deflection of dipole moment and the velocity of water molecules. The time required for droplet breakup decreased when the pulsed electric field strength increased. The research findings in this paper uncovered the mechanism behind the breakup of water droplets in pulsed electric fields, and offered theoretical guidance for optimizing demulsification processes.