Pulsed Field Ablation for Atrial Fibrillation: Mechanisms, Advantages, and Limitations.

Pulsed field ablation with irreversible electroporation for the treatment of atrial fibrillation involves tissue-specific and non-thermal energy-induced cell necrosis, which helps avoid complications, such as pulmonary vein stenosis, atrial collateral tissue damage, and extensive atrial structural damage, often encountered with traditional thermal ablation. In existing clinical trials, pulsed field ablation has shown excellent effects on pulmonary vein isolation in patients with paroxysmal and persistent atrial fibrillation. Pulsed field ablation is easy, simple, and quick and can reduce iatrogenic injury. Therefore, the application of pulsed field ablation technology in the treatment of atrial fibrillation has a promising future. Notably, the adjustment of parameters in pulsed field ablation with different ablation catheter systems can strongly affect the area and depth of the necrotic myocardium, which greatly affects the likelihood of atrial fibrillation recurrence and incidence of adverse complications after ablation. In this paper, we review the mechanisms, advantages, and limitations of pulsed field ablation based on the results of a series of previous studies and provide ideas and directions for future research.

Valorization of potato by-products as a source of plant proteins: novel extraction techniques and potential applications.

The potential of potato by-products as a protein source presents an exciting opportunity to explore new methods and technologies to extract, enhance, and incorporate this valuable protein source into a variety of food products. This article reviews the progress in research related to potato and other tuber plant protein extraction technology. It also explores some conventional and novel techniques for plant protein extraction that may be applicable to tuber protein extraction. For extraction from solid matter, conventional methods such as acid-base extraction with heat assistance often mean a waste of energy, solvent, and destruction of protein structure. Enzyme-assisted, ultrasound-assisted, and pulsed electric field extraction have their own advantages as novel processing methods. For liquid by-products of tuber plants, precipitation, membrane filtration and chromatography are applied to extract proteins. By combining protein extraction with various biomass extraction methods, every part of the potatoes can be fully utilized, minimizing waste. This approach offers the opportunity to optimize the utilization of all potatoes components, reduce waste, generate additional revenue streams and ultimately increase the sustainability and effectiveness of the process.

Pulsed electric field at resonance frequency combat Klebsiella pneumonia biofilms.

Healtcare-associated infections have increased due to the development of antimicrobial resistance (AMR) of Gram-negative pathogens (GNPs) and the development of outbreacks over the past two decades. In this work, we investigated how exposure to positive electric pulses affects the growth characteristics of Klebsiella pneumonia (K. pneumonia), a common cause of pneumonia. We explored the impact of varying exposure frequencies (0.2-2 Hz) and time (15-90 min, at resonance frequency) on bioelectric signals produced during cell division, biofilm formation, and bacterial antibiotic susceptibility. Our research found that an extremely low-frequency pulsed electric field (ELF-PEF) significantly inhibited K. pneumonia growth. Specifically, exposure to 0.8 Hz for one hour increased the antibiotic susceptibility of K. pneumonia to inhibitors of cell wall formation, proteins, ß-lactamase, DNA, and other substances. We also noticed a notable decrease in K. pneumonia biofilm development exposed to ELF-PEF. Our results suggest that the interaction of K. pneumonia cells with ELF-PEF at the specified frequency and time alters cellular activity and bacterial structure. This technique may be used in the future to treat K. pneumonia infections both in vitro and in vivo.

Optimization of Four Different Rosemary Extraction Techniques Using Plackett-Burman Design and Comparison of Their Antioxidant Compounds.

Rosemary has many medicinal and therapeutic properties and therefore it is important to study how to maximize the recovery of its bioactive compounds. In the present study, four different extraction techniques were used, namely stirring extraction (STE), pulsed electric field-assisted extraction (PEF), ultrasound probe-assisted extraction (UPAE), and ultrasound bath-assisted extraction (UBAE). First, some primary experiments were carried out in order to optimize each technique individually through the Plackett-Burman design. Then, each technique was applied under optimal conditions and the results were compared with each other. The optimal total polyphenol content (TPC) of STE is ~19 mg gallic acid equivalents per gram of dry weight (dw), while the antioxidant activity of the extract is 162 µmol ascorbic acid equivalents (AAEs) per gram of dw via FRAP and ~110 µmol AAE per gram of dw via DPPH. As for PEF, the optimal TPC is ~12 mg GAE/g dw, and the FRAP and DPPH values are ~102 and ~70 µmol AAE per gram of dw, respectively. When it comes to UPAE, the optimal TPC is ~16 mg GAE/g dw and the antioxidant capacity of the extract is ~128 µmol AAE/g dw through FRAP and ~98 µmol AAE/g dw through DPPH. UBAE optimal extract yielded ~17 mg GAE/g dw TPC, ~146 µmol AAE/g dw for FRAP, and ~143 µmol AAE/g dw for DPPH. The highest flavonoid content (~6.5 mg rutin equivalent/g dw) and DPPH (~143 µmol ascorbic acid equivalent/g dw) is obtained through UBAE. UPAE has been shown to be more efficient in recovering ascorbic acid (~20 mg/g dw). Additionally, the chlorophyll-to-carotenoid ratios of UPAE and UBAE were 2.98 and 2.96, respectively, indicating that the extracts had a generally positive impact on health. Considering the environmental impact of each extraction technique but also which antioxidant factor needs to be maximized, the most suitable extraction technique will be chosen.

Pulsed Electric Field-Assisted Extraction of Inulin from Ecuadorian Cabuya (Agave americana).

Inulin is a carbohydrate that belongs to fructans; due to its health benefits, it is widely used in the food and pharmaceutical industries. In this research, cabuya (Agave americana) was employed to obtain inulin by pulsed electric field-assisted extraction (PEFAE) and FTIR analysis confirmed its presence. The influence of PEFAE operating parameters, namely, electric field strength (1, 3 and 5 kV/cm), pulse duration (0.1, 0.2 and 0.5 ms), number of pulses (10,000, 20,000 and 40,000) and work cycle (20, 50 and 80%) on the permeabilization index and energy expenditure were tested. Also, once the operating conditions for PEFAE were set, the temperature for conventional extraction (CE) and PEFAE were defined by comparing extraction kinetics. The cabuya meristem slices were exposed to PEFAE to obtain extracts that were quantified, purified and concentrated. The inulin was isolated by fractional precipitation with ethanol to be characterized. The highest permeabilization index and the lowest energy consumption were reached at 5 kV/cm, 0.5 ms, 10,000 pulses and 20%. The same extraction yield and approximately the same amount of inulin were obtained by PEFAE at 60 °C compared to CE at 80 °C. Despite, the lower amount of inulin obtained by PEFAE in comparison to CE, its quality was better because it is mainly constituted of inulin of high average polymerization degree with more than 38 fructose units. In addition, TGA analyses showed that inulin obtained by PEFAE has a lower thermal degradation rate than the obtained by CE and to the standard.

Effect of Novel Processing Techniques on the Carotenoid Release during the Production of Red Guava Juice.

Red guava, distinguished by its elevated lycopene content, emerges as a promising natural source of carotenoids. This study systematically evaluates the impact of diverse processing techniques on the efficient release of carotenoids. The primary objective is to facilitate the transfer of carotenoids into the juice fraction, yielding carotenoid-enriched juice seamlessly integrable into aqueous-based food matrices. The untreated guava puree exhibited a modest release of carotenoids, with only 66.26% of ß-carotene and 57.08% of lycopene reaching the juice. Contrastly, both high-pressure homogenization (HPH) at 25 MPa and enzyme (EM) treatment significantly enhanced carotenoid release efficiency (p < 0.05), while high hydrostatic pressure (HHP) at 400 MPa and pulsed electric field (PEF) of 4 kV/cm did not (p > 0.05). Notably, HPH demonstrated the most substantial release effect, with ß-carotene and lycopene reaching 90.78% and 73.85%, respectively. However, the stability of EM-treated samples was relatively poor, evident in a zeta-potential value of -6.51 mV observed in the juice. Correlation analysis highlighted the interactions between pectin and carotenoids likely a key factor influencing the stable dissolution or dispersion of carotenoids in the aqueous phase. The findings underscore HPH as a potent tool for obtaining carotenoid-enriched guava juice, positioning it as a desirable ingredient for clean-label foods.

Pulsed electric field-assisted extraction of hesperidin from tangerine peel and its technological optimization through response surface methodology.

BACKGROUND: Tangerine peel is rich in flavonoids, particularly hesperidin, which has anti-inflammatory, antioxidant and anticancer biological activities. However, it is often wasted during citrus processing. The current common extraction method for hesperidin is solvent extraction, which has the characteristics of low extraction rate and high contamination. The aim of this study was to investigate the effect of pulsed electric field-assisted alkali dissolution extraction, followed by an acidification precipitation method, on the extraction rate and structure of hesperidin from tangerine peel. RESULTS: The results showed that the selected factors (material/liquid ratio, electric field intensity and pulse number) had a significant effect on the extraction yield. An optimum condition of 66.00 mL g-1, 4.00 kV cm-1 and 35.00 pulses gave the maximum amount (669.38 µg mL-1), which was consistent with the theoretically predicted value by software (672.10 µg mL-1), indicating that the extraction process was feasible. In addition, the purified extract was further identified as hesperidin from UV and NMR spectra. CONCLUSION: An appropriate strength of pulsed electric field-assisted alkali dissolution extraction followed by an acidification precipitation method can effectively improve the extraction rate of orange peel, and the purity of the extracted orange peel is higher. Compared with the traditional extraction, the pulsed electric field-assisted extraction method may be a potential technology for hesperidin extraction, which is beneficial for the high-value utilization of citrus resources. © 2024 Society of Chemical Industry.

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.

Enhancing enzymatic production efficiency of crude pectic oligosaccharides by pulsed electric field and study of prebiotic potential.

Orange juice by-products, including peel, segments, and seeds, account for more than 50% of the total mass. This study aims to valorize the peel and segments of Sai Nam Phueng (Citrus reticulata Blanco 'Sai Nam Phueng') orange juice by-products by producing crude pectic oligosaccharides (POS) with prebiotic potential using pulsed electric field (PEF)-assisted enzymatic treatment. PEF was performed for 5 min at field strengths of 10 and 7.5 kV/cm for orange peel powder (OPP) and orange segment powder (OSP), respectively, combined with Cellulase XL-531 at a concentration of 1.75%, pH 5.5, 40 °C for 2 h. The crude OPP-POS and OSP-POS yields were 19.16% and 17.51%, respectively, significantly higher than values obtained with PEF or enzymic hydrolysis singly. Thin layer chromatography results showed that the crude POS consisted of oligogalacturonic acids with various degrees of polymerization. Both POS products could enhance the growth of target probiotic bacteria and simultaneously produce short-chain fatty acids, especially propionic acid. Furthermore, the crude POS products also showed more than 90% resistance to simulated gastrointestinal digestion. These findings support the utilization of by-products from Sai Nam Phueng orange juice as a potential source for prebiotic production using PEF. Supplementary Information: The online version contains supplementary material available at 10.1007/s13197-023-05843-8.

[Development and Application of Catheter Electrodes for Rat Airway High-Voltage Pulsed Electric Field Ablation].

High-voltage pulsed electric field (HV-PEF) ablation technology has demonstrated promising applications in the clinical treatment of chronic obstructive pulmonary disease (COPD). However, its use has been limited to exploratory applications in a small number of cases, and the underlying mechanisms remain largely undefined. To facilitate broader clinical implementation, comprehensive molecular mechanism studies via extensive animal experimentation are essential. Rats, due to their ease of modeling COPD and the availability of comprehensive molecular reagents, serve as an optimal model for such studies. Consequently, the development of electrodes specifically designed for HV-PEF respiratory ablation in SD rats is of significant importance. In this study, we meticulously examined the anatomical structure of rat airways and investigated various equipment parameters, including material composition, rigidity, diameter, electrode ring dimensions, spacing between positive and negative poles, insulation coating for the catheters, welding techniques between the guidewire and electrode ring, and the design of vent holes in the catheter. Based on these considerations, we fabricated PVC ablation electrode catheters with integrated ventilation functionality. Subsequently, we employed finite element simulation to estimate the field strengths that could be applied by these electrodes. The simulation results were then validated in normal rats to assess the electrical safety and efficacy of the electrodes. These findings laid the groundwork for further investigation into the mechanisms of HV-PEF treatment for COPD.

Pulsed electric field treatment of seeds altered the endophytic bacterial community and promotes early growth of roots in buckwheat.

BACKGROUND: Endophytic bacteria provide nutrients and stimulate systemic resistance during seed germination and plant growth and development, and their functional properties in combating various stresses make them a powerful tool in green agricultural production. In this paper we explored the function of the endophyte community in buckwheat seeds in order to provide a theoretical basis for the application and scientific research of endophytes in buckwheat cultivation. We used pulsed electric field (PEF) technology to treat buckwheat seeds, monitored the effect of high-voltage pulse treatment on buckwheat seed germination, and analyzed the diversity of endophytic bacteria in buckwheat seeds using the amplicon sequencing method. RESULTS: PEF treatment promoted root development during buckwheat seed germination. A total of 350 Operational taxonomic units (OTUs) that were assigned into 103 genera were obtained from control and treatment groups using 16SrRNA amplicon sequencing technology. Additionally, PEF treatment also caused a significant decrease in the abundance of Actinobacteria, Proteobacteria, and Bacteroidetes. The abundance of 28 genera changed significantly as well: 11 genera were more abundant, and 17 were less abundant. The number of associated network edges was reduced from 980 to 117, the number of positive correlations decreased by 89.1%, and the number of negative correlations decreased by 86.6%. CONCLUSION: PEF treatment promoted early root development in buckwheat and was able to alter the seed endophytic bacterial community. This study thus makes a significant contribution to the field of endophyte research and to the application of PEF technology in plant cultivation.

Non-thermal techniques as an approach to modify the structure of milk proteins and improve their functionalities: a review of novel preparation.

BACKGROUND: Milk proteins (MPs) have been widely used in the food industry due to their excellent functionalities. However, MPs are thermal-unstable substances and their functional properties are easily affected by heat treatment. Emerging non-thermal approaches (i.e., high-pressure homogenization (HPH), ultrasound (US), pulsed electric field (PEF)) have been increasingly popular. A detailed understanding of these approaches' impacts on the structure and functionalities of MPs can provide theoretical guidance for further development to accelerate their industrialization. SCOPE AND APPROACH: This review assesses the mechanisms of HPH, US and PEF technologies on the structure and functionalities of MPs from molecular, mesoscopic and macroscopic levels, elucidates the modifications of MPs by these theologies combined with other methods, and further discusses their existing issues and the development in the food filed. KEY FINDINGS AND CONCLUSIONS: The structure of MPs changed after HPH, US and PEF treatment, affecting their functionalities. The changes in these properties of MPs are related to treated-parameters of used-technologies, the concentration of MPs, as well as molecular properties. Additionally, these technologies combined with other methods could obtain some outstanding functional properties for MPs. If properly managed, these theologies can be tailored for manufacturing superior functional MPs for various processing fields.

Recent developments in the use of cold plasma, high hydrostatic pressure, and pulsed electric fields on microorganisms and viruses in seafood.

Non-thermal processing methods, such as cold plasma (CP), high pressure processing (HPP) and pulsed electric fields (PEF), have been proposed for natural and fresh-like foods to inactivate microorganisms at nearly-ambient or moderate temperature. Since natural, safe, and healthy foods with longer shelf-life are increasingly demanded, these requests are challenging to fulfill by using current thermal processing technologies. Thus, novel preservation technologies based on non-thermal processing methods are required. The aim of this article is to provide recent developments in maintaining seafood safety via CP, HHP, and PEF technologies, as well as their mechanisms of action regarding contamination with food-borne microorganisms. Their application to control parasites, spores and the possibility to eradicate the hazard of SARS-CoV-2 transmission through seafood products are also discussed. CP, HHP, and PEF have been applied to inactivate food-borne microorganisms in the seafood industry. However, the drawbacks for each emerging technology have also been reported. To ensure safety and maintain quality of seafood products, the combination of these processing techniques with natural antimicrobial agents or existing thermal methods may be more applicable in the case of the seafood industry. Further studies are required to examine the effects of these methods on viruses, parasites, and SARS-CoV-2 in seafood.

Selective extraction of recombinant membrane proteins from Hansenula polymorpha by pulsed electric field and lytic enzyme pretreatment.

BACKGROUND: In yeast, recombinant membrane proteins including viral scaffold proteins used for the formation of enveloped Virus-like particles (eVLPs) typically accumulate intracellularly. Their recovery is carried out by mechanical disruption of the cells, often in combination with detergent treatment. Cell permeabilization is an attractive alternative to mechanical lysis because it allows for milder and more selective recovery of different intracellular products. RESULTS: Here, we present a novel approach for extraction of integral membrane proteins from yeast based on cell envelope permeabilization through a combination of pulsed electric field and lytic enzyme pretreatment of the cells. Our primary experiments focused on Hansenula polymorpha strain #25-5 co-expressing the integral membrane small surface protein (dS) of the duck hepatitis B virus and a fusion protein of dS with a trimer of a Human papillomavirus (HPV) L2-peptide (3xL2-dS). Irreversible plasma membrane permeabilization was induced by treating the cell suspension with monopolar rectangular pulses using a continuous flow system. The permeabilized cells were incubated with lyticase and dithiothreitol. This treatment increased the cell wall permeability, resulting in the release of over 50% of the soluble host proteins without causing significant cell lysis. The subsequent incubation with Triton X-100 resulted in the solubilization and release of a significant portion of 3xL2-dS and dS from the cells. By applying two steps: (i) brief heating of the cells before detergent treatment, and (ii) incubation of the extracts with KSCN, an 80% purity on the protein level has been achieved. Experiments performed with H. polymorpha strain T#3-3, co-expressing dS and the fusion protein EDIIIWNV-dS consisting of dS and the antigen from the West Nile virus (WSV), confirmed the applicability of this approach for recovering dS. The treatment, optimal for solubilization of 3xL2-dS and a significant part of dS, was not effective in isolating the fused protein EDIIIWNV-dS from the membranes, resulting in its retention within the cells. CONCLUSIONS: This study presents an alternative approach for the recovery and partial purification of viral membrane proteins expressed in H. polymorpha. The factors influencing the effectiveness of this procedure and its potential use for the recovery of other integral membrane proteins are discussed.

The latest research progress on minimally invasive treatments for hepatocellular carcinoma.

BACKGROUND: Hepatocellular carcinoma (HCC) is the fourth leading cause of cancer-related death worldwide. Due to the high prevalence of hepatitis B virus (HBV) infection in China, the incidence of HCC in China is high, and liver cirrhosis caused by chronic hepatitis also brings great challenges to treatment. This paper reviewed the latest research progress on minimally invasive treatments for HCC, including percutaneous thermal ablation and new nonthermal ablation techniques, and introduced the principles, advantages, and clinical applications of various therapeutic methods in detail. DATA SOURCES: The data of treatments for HCC were systematically collected from the PubMed, ScienceDirect, American Chemical Society and Web of Science databases published in English, using "minimally invasive" and "hepatocellular carcinoma" or "liver cancer" as the keywords. RESULTS: Percutaneous thermal ablation is still a first-line strategy for the minimally invasive treatment of HCC. The effect of microwave ablation (MWA) on downgrading treatment before liver transplantation is better than that of radiofrequency ablation (RFA), while RFA is more widely used in the clinical practice. High-intensity focused ultrasound (HIFU) is mainly used for the palliative treatment of advanced liver cancer. Electrochemotherapy (ECT) delivers chemotherapeutic drugs to the target cells while reducing the blood supply around HCC. Irreversible electroporation (IRE) uses a microsecond-pulsed electric field that induces apoptosis and necrosis and triggers a systemic immune response. The nanosecond pulsed electric field (nsPEF) has achieved a good response in the ablation of mice with HCC, but it has not been reported in China for the treatment of human HCC. CONCLUSIONS: A variety of minimally invasive treatments provide a sufficient survival advantage for HCC patients. Nonthermal ablation will lead to a new wave with its unique advantage of antitumor recurrence and metastasis.

Mung bean protein isolate treated with high-intensity pulsed electric field: characteristics and its use for encapsulation of Asian seabass oil.

AIM: To modify the techno-functional properties of mung bean protein isolate (MBPI) by high-intensity pulsed electric field (HIPEF) treatment and to apply the treated MBPI for encapsulation of Asian seabass oil (ASO). METHODS: MBPI was prepared using isoelectric precipitation. HIPEF was applied to MBPI solutions at 25 kV/cm with varying pulse numbers (0-400). Physicochemical properties and structure of MBPI were assessed. ASO microcapsules prepared using HIPEF-treated protein as wall material was characterised and tested for storage stability. RESULTS: Solubility, surface hydrophobicity, total sulfhydryl content, and emulsifying property of MBPI increased and ß-sheets and α-helix were altered after HIPEF treatment at pulse number of 300. ASO microcapsules possessing spherical shape with surface indentations had EE of 72.07 ± 5.08%. ASO capsules had lower lipid oxidation than the control during storage. CONCLUSION: HIPEF improved techno-functional properties of treated MBPI. Treated MBPI could be used as wall material for encapsulation of fish oils.

Effects of Nanosecond Pulsed Electric Field (nsPEF) on a Multicellular Spheroid Tumor Model: Influence of Pulse Duration, Pulse Repetition Rate, Absorbed Energy, and Temperature.

Cellular response upon nsPEF exposure depends on different parameters, such as pulse number and duration, the intensity of the electric field, pulse repetition rate (PRR), pulsing buffer composition, absorbed energy, and local temperature increase. Therefore, a deep insight into the impact of such parameters on cellular response is paramount to adaptively optimize nsPEF treatment. Herein, we examined the effects of nsPEF ≤ 10 ns on long-term cellular viability and growth as a function of pulse duration (2-10 ns), PRR (20 and 200 Hz), cumulative time duration (1-5 µs), and absorbed electrical energy density (up to 81 mJ/mm3 in sucrose-containing low-conductivity buffer and up to 700 mJ/mm3 in high-conductivity HBSS buffer). Our results show that the effectiveness of nsPEFs in ablating 3D-grown cancer cells depends on the medium to which the cells are exposed and the PRR. When a medium with low-conductivity is used, the pulses do not result in cell ablation. Conversely, when the same pulse parameters are applied in a high-conductivity HBSS buffer and high PRRs are applied, the local temperature rises and yields either cell sensitization to nsPEFs or thermal damage.

The Influence of Pulsed Electric Field and Air Temperature on the Course of Hot-Air Drying and the Bioactive Compounds of Apple Tissue.

Drying is one of the oldest methods of obtaining a product with a long shelf-life. Recently, this process has been modified and accelerated by the application of pulsed electric field (PEF); however, PEF pretreatment has an effect on different properties-physical as well as chemical. Thus, the aim of this study was to investigate the effect of pulsed electric field pretreatment and air temperature on the course of hot air drying and selected chemical properties of the apple tissue of Gloster variety apples. The dried apple tissue samples were obtained using a combination of PEF pretreatment with electric field intensity levels of 1, 3.5, and 6 kJ/kg and subsequent hot air drying at 60, 70, and 80 °C. It was found that a higher pulsed electric field intensity facilitated the removal of water from the apple tissue while reducing the drying time. The study results showed that PEF pretreatment influenced the degradation of bioactive compounds such as polyphenols, flavonoids, and ascorbic acid. The degradation of vitamin C was higher with an increase in PEF pretreatment intensity level. PEF pretreatment did not influence the total sugar and sorbitol contents of the dried apple tissue as well as the FTIR spectra. According to the optimization process and statistical profiles of approximated values, the optimal parameters to achieve high-quality dried apple tissue in a short drying time are PEF pretreatment application with an intensity of 3.5 kJ/kg and hot air drying at a temperature of 70 °C.

The Effect of Nonthermal Pretreatment on the Drying Kinetics and Quality of Black Garlic.

Black garlic is obtained from regular garlic (Allium sativum L.) through the aging process and consequently gains many health-promoting properties, including antidiabetic and antioxidant. However, the material is still prone to microbiological deterioration and requires a long time to dry due to its properties. Therefore, this study aimed to investigate the effect of various drying methods on the quality of black garlic as well as determine the influence of selected nonthermal pretreatments on the drying kinetics and quality of black garlic, which is especially important in the case of the materials that are difficult to dry. The Weibull model was chosen to describe drying kinetics. Additionally, color, water activity together with antioxidant activity, phenolic compounds, and antidiabetic potential were determined. This study found that the application of a pulsed electric field (PEF), a constant electric field (CEF) as well as a magnetic field (MF) significantly reduced the time of drying (by 32, 40, and 24 min for a PEF, a CEF, and a MF, respectively, compared to combined drying without the pretreatment), and resulted in high antidiabetic potential. However, the highest content of phenolic compounds (1123.54 and 1125.36 mg/100 g dm for VMD125 and CD3h-VMD, respectively) and antioxidant capacity (ABTS = 6.05 and 5.06 mmol Trolox/100 g dm for VMD500 and CD6h-VMD, respectively) were reported for black garlic treated by vacuum-microwave drying and combined convective pre-drying followed by vacuum-microwave drying. Overall, the nonthermal pretreatment decreased the time of drying and showed very good efficiency in maintaining the antidiabetic potential of black garlic, especially in the case of the materials pretreated by a constant electric field (IC50 = 99 and 56 mg/mL, for α-amylase and α-glucosidase, respectively).

Recent processing of fruits and vegetables using emerging thermal and non-thermal technologies. A critical review of their potentialities and limitations on bioactives, structure, and drying performance.

Fruits and vegetables have rich bioactive compounds and antioxidants that are vital for the human body and prevent the cell from disease-causing free radicals. Therefore, there is a growing demand for high-quality fruits and vegetables. Nevertheless, fruits and vegetables deteriorate due to their high moisture content, resulting in a 40-50% loss. Drying is a common food preservation technique in the food industry to increase fruits and vegetables' shelf-life. However, drying causes chemical modifications, changes in microstructure, and bioactives, thus, lowering the final product's quality as a considerable amount of bioactives compounds and antioxidants are lost. Conventional pretreatments such as hot water blanching, and osmotic pretreatment have improved fruit and vegetable drying performance. However, these conventional pretreatments affect fruits' bioactive compounds retention and microstructure. Hence, emerging thermal (infrared blanching, microwave blanching, and high-humidity hot-air impingement blanching) and non-thermal pretreatments (cold plasma, ultrasound, pulsed electric field, and edible films and coatings) have been researched. So the question is; (1) what are the mechanisms behind emerging non-thermal and thermal technologies' ability to improve fruits and vegetables' microstructure, texture, and drying performance? (2) how do emerging thermal and non-thermal technologies affect fruits and vegetables' bioactive compounds and antioxidant activity? and (3) what are preventing the large-scale commercialization of these emerging thermal and non-thermal technologies' for fruits and vegetables, and what are the future recommendations? Hence, this article reviewed emerging thermal blanching and non-thermal pretreatment technologies, emphasizing their efficacy in improving dried fruits and vegetables' bioactive compounds, structural properties, and drying performance. The fundamental mechanisms in emerging thermal and non-thermal blanching pretreatment methods on the fruits and vegetables' microstructure and drying performance were delved in, as well as what are preventing the large-scale commercialization of these emerging thermal and non-thermal blanching for fruits and vegetables, and the future recommendations. Emerging pretreatment approaches not only improve the drying performance but further significantly improve the retention of bioactive compounds and antioxidants and enhance the microstructure of the dried fruits and vegetables.