Search Results (393)

Pulsed electric field (PEF) and high-pressure processing (HPP) are non-thermal treatments, developed to ensure preservation of food products whilst maintaining taste and valuable nutrients. In this study, we investigated their potential for the inactivation of 3 commercial exogenous pectinases (polygalacturonase, pectin transeliminase, pectin esterase) commonly used in juice processing for clarification of juices. The inactivation of these enzymes after processing is mandatory by European law. Clear apple juice was treated with both non-thermal processing methods, as well as with thermal pasteurization as the standard method. For HPP, 3 pressures (250, 450, and 600 MPa) and different holding times (from 2 to 12 min) were tested. For PEF, 3 electric field intensities (10, 13, and 15 kV/cm) and different specific energy values (from 121 to 417 kJ/kg). Standard thermal pasteurization resulted in a complete inactivation of all tested pectinases. HPP treatment only showed marginal effects on polygalacturonase and pectin transeliminase at the highest pressure and holding times, which are beyond levels used in industrial settings. For PEF, dependence upon high electric field strength and specific energy values was evident; however, here too, the effect was only moderate at the levels attainable within the scope of this study. Assuming a continued linear relationship, usable results could be achieved in an industrial setting, albeit under more extreme conditions. Full article

Rose hips are rich in polyphenols, making them a promising ingredient for the development of functional fruit-based beverages. This study aimed to evaluate the effect of Pulsed Electric Field (PEF) extraction treatment on rose hip (RH) pulp to enhance the extraction of polyphenols, carotenoids, and volatile compounds. Additionally, this study examined the impact of adding rose hip berries during different stages of carbohydrate fermentation on the resulting phenolic and aroma profiles. A control wort and four experimental formulations were prepared. Rose hip pulp—treated or untreated with PEF—was added either during fermentation or beforehand, and the volatiles produced were analyzed using GC-MS (in triplicate). Fermentation was carried out over 10 days at 20 °C using Saccharomyces cerevisiae and Torulaspora delbrueckii. At a 10:1 ratio, all beverage samples were subjected to physicochemical testing and HPLC analysis for polyphenols, organic acids, and carotenoids, as well as GC-MS analysis for aroma compounds. The results demonstrated that the use of PEF-treated rose hips significantly improved phenolic compound extraction. Moreover, the PEF treatment enhanced the aroma profile of the beverage, contributing to a more complex and appealing sensory experience. This research highlights the rich polyphenol content of rose hips and the potential of PEF-treated fruit as a natural ingredient to improve both the functional and sensory qualities of fruit-based beverages. Their application opens new possibilities for the development of innovative, health-promoting drinks in the brewing industry. Full article

This study used fresh (young) and old (mature) ginger tissues as model systems to investigate how plant maturity modulates the response to pulsed electric field (PEF), a non-thermal processing technology. Specifically, the influence of tissue maturity on dielectric behavior and its downstream effect on juice yield and bioactive compound extraction was systematically evaluated. At 2.5 kV/cm, old ginger exhibited a pronounced dielectric breakdown effect due to enhanced electrolyte content and cell wall lignification, resulting in a higher degree of cell disintegration (0.65) compared with fresh ginger (0.44). This translated into a significantly improved juice yield of 90.85% for old ginger, surpassing the 84.16% limit observed in fresh ginger. HPLC analysis revealed that the extraction efficiency of 6-gingerol and 6-shogaol increased from 1739.16 to 2233.60 µg/g and 310.31 to 339.63 µg/g, respectively, in old ginger after PEF treatment, while fresh ginger showed increases from 1257.88 to 1824.05 µg/g and 166.43 to 213.52 µg/g, respectively. Total phenolic content (TPC) and total flavonoid content (TFC) also increased in both tissues, with OG-2.5 reaching 789.57 µg GAE/mL and 336.49 µg RE/mL, compared with 738.19 µg GAE/mL and 329.62 µg RE/mL in FG-2.5. Antioxidant capacity, as measured by ABTS^•+ and DPPH^• inhibition, improved more markedly in OG-2.5 (37.8% and 18.7%, respectively) than in FG-2.5. Moreover, volatile compound concentrations increased by 177.9% in OG-2.5 and 137.0% in FG-2.5 compared with their respective controls, indicating differential aroma intensification and compound transformation. Structural characterization by SEM and FT-IR further corroborated enhanced cellular disruption and biochemical release in mature tissue. Collectively, these results reveal a maturity-dependent mechanism of electro-permeabilization in plant tissues, offering new insights into optimizing non-thermal processing for functional food production. Full article

Crataegus monogyna, commonly known as hawthorn, is a valuable plant in pharmaceutical production. Its flowers, leaves, and fruits are rich in antioxidants. This study explores the application of pulsed electric field (PEF) for enhanced extraction of bioactive compounds from C. monogyna leaves. The liquid-to-solid ratio, solvent composition (ethanol, water, and 50% v/v aqueous ethanol), and key PEF parameters—including pulse duration, pulse period, electric field intensity, and treatment duration—were investigated during the optimization process. To determine the optimal extraction conditions and their impact on antioxidant activity, response surface methodology (RSM) with a six-factor design was employed. The total polyphenol content in the optimized extract was 244 mg gallic acid equivalents/g dry weight, while individual polyphenols were analyzed using high-performance liquid chromatography coupled with a diode array detector (HPLC-DAD). Furthermore, antioxidant activity was assessed using ferric-reducing antioxidant power (FRAP) and DPPH radical scavenging assays, yielding values of 3235 and 1850 μmol ascorbic acid equivalents/g dry weight, respectively. Additionally, correlation analyses were conducted to evaluate the interactions between bioactive compounds and antioxidant capacity. Compared to other extraction techniques, PEF stands out as an eco-friendly, non-thermal standalone method, offering a sustainable approach for the rapid production of health-promoting extracts from C. monogyna leaves. Full article

Microbial fermentation is a fundamental bioconversion mechanism widely used in diverse industrial sectors, notably in food processing and bioenergy production. Over the years, the wealth of information and scientific and technological advances in the field of fermentation have made considerable progress. Most recent research studies are currently devoted to the implementation of innovative technological processes in order to increase fermentation effectiveness while consuming less energy and processing time. The aim of the present review is to investigate the impact of innovative physical techniques (pulsed electric field, PEFs; cold atmospheric plasma, CAP; and magnetic fields, MFs) on fermentation processes. The bibliographic analysis will mainly focus on recent advances towards non-destructive methods (PEF, CAP, and MF) and their induced changes in fermentation dynamics, fermented product quality, metabolite synthesis, and microbial growth kinetics. Various databases, including PubMed, ScienceDirect, Google Scholar, ResearchGate, Scopus, and Web of Science, were used to collect pertinent scientific literature on the impact of innovative physical techniques on microorganisms and fermentation processes and to investigate the potential applications of these emerging technologies in the food and health sectors. According to the results, all techniques have the potential to optimize fermentation dynamics, boost metabolite synthesis, and enhance product quality. However, each technology displayed its own specific advantages and disadvantages. Full article

High-voltage unipolar square wave pulsed electric fields (PEFs) can cause cell membrane rupture and cell death during a process termed irreversible electroporation (IRE). PEF effects are influenced by pulse parameters like number of pulses (NP), voltage (PV), width (PW), and interval (PI). This study systematically evaluates their effects on the conductivity and relative conductivity changes between untreated and PEF-treated regions of potato tissue across a frequency range of 1 Hz to 5 MHz by means of electrochemical impedance spectroscopy (EIS), using a custom-made four-point EIS probe with RG58/U coaxial cables. Potatoes were chosen as a plant-based PEF model to reduce animal experiments and untreated tissue showed minimal conductivity variation across regions. Relative conductivity changes were maximal at 1000 Hz. At 1000 Hz, significant conductivity differences between untreated and PEF-treated regions were observed from PV = 200 V, NP = 10, PW = 10 µs, and PI = 50 ms onwards (most significant changes occurred for PV = 700 V; NP = 70; PW = 70 µs; PI = 250 ms and 500 ms). Our results may be beneficial for multiphysics modelling of IRE with specific electrical properties, conductivity mapping with optimal contrast—such as in electrical impedance tomography—and development of IRE procedures. Full article

Non-thermal processing encompasses a range of emerging food technologies, including high-pressure processing (HPP), pulsed electric field (PEF), cold atmospheric plasma (CAP), high-pressure carbon dioxide (HPCD), and ultrasound (US). Unlike traditional thermal processing or chemical preservatives, these methods offer advantages such as lower energy consumption, enhanced environmental sustainability, and effective microbial inactivation, thereby extending food shelf life. Moreover, they can better preserve the nutritional integrity, color, flavor, and texture of food products. However, a critical concern associated with non-thermal processing is its potential to induce microorganisms into a viable but nonculturable (VBNC) state. These VBNC cells evade detection via conventional culturing techniques and may remain metabolically active and retain virulence, posing hidden food safety risks. Despite these implications, comprehensive reviews addressing the induction of a VBNC state by non-thermal treatments remain limited. This review systematically summarizes the microbial inactivation effects and mechanisms of non-thermal processing techniques, the VBNC state, and their associated hazards. This review aims to support technological innovation and sustainable advancement in non-thermal food processing. Full article

The use of astaxanthin (AST) is expanding from its origins as a food coloring to health-related applications. This paper evaluates the efficiency of its extraction from dried Xanthophyllomyces dendrorhous using two combined and consecutive techniques. First, cell membrane permeation is achieved with the application of pulsed electric fields (PEFs). Solid–liquid extraction is then performed with hydrophobic eutectic solvents (hESs) prepared by mixing components of essential oils (linalool, l-menthol, eugenol, geraniol, cinnamyl alcohol, or thymol) and oleic acid. The hESs were characterized by measuring of several thermophysical properties at 25 °C and 0.1 MPa. An initial screening was performed to choose the best solvent and the extraction conditions (composition, extraction time, and temperature) were evaluated using the response surface methodology. The results showed the importance of the electroporation as a preliminary step to the extraction. The more hydrophobic and less compact the hES, the more effective the solvent. Thus, the equimolar mixture of l-menthol and oleic acid achieved an efficiency of 77% for untreated biomass, 83% for that treated with PEF, and 92% for that treated with PEF and later incubated. Molecular dynamics simulations demonstrated the importance of the hydrophobic interactions between AST and the components of the best solvent. Full article

This study aimed to evaluate the drying kinetics, microstructural features, moisture content, color, pH, aw, texture, acidity, rehydration capacity, and sensorial attributes of strawberry slices processed by different drying methodologies. Strawberry samples were processed by hot air-drying (HA, 60 °C, 0.5 m/s), freeze-drying (FD, 0.055 mbar), and pulsed electric field (PEF)-assisted freeze-drying (PEFFD, 1 kV/cm and 3.2 kJ/kg). PEF pre-treatment significantly increased cell membrane permeability by forming micropores, which led to a significant reduction in the moisture content of up to 8.87% and improved the drying efficiency. Nonetheless, this pre-treatment did not significantly alter the drying rate due to the inherent constraints of the freeze-drying process. PEFFD samples better retained their shape, volume, and visual quality, and exhibited a maximum rehydration capacity of 64.90%. The ascorbic acid retention was found to be higher in the FD and PEFFD when compared to HA. FD and PEFFD samples had an increase in both red and yellow hue. PEF shows promise as a pre-treatment technique, improving both the drying efficiency and strawberry quality. Further studies are needed to assess PEFFD’s industrial scalability and economic feasibility. Full article

This study evaluates the feasibility of integrating pulsed electric field (PEF) technology with heat recovery for fruit juice pasteurization, comparing it to conventional high-temperature short-time (HTST) pasteurization. Three preheating temperature conditions (35 °C, 45 °C, and 55 °C) and varying heat recovery efficiencies have been assessed to analyze energy consumption, economic feasibility, and environmental impact. The results indicate that, while PEF pasteurization requires a higher initial investment, it improves energy efficiency, leading to significant reductions in utility costs. Across the tested configurations, PEF technology achieved reductions in electricity consumption by up to 20%, fuel gas usage by over 60%, greenhouse gas emissions by approximately 30%, and water consumption by 25%, compared to HTST. The optimal configuration of the PEF process, featuring a 35% waste heat recovery efficiency and a pre-heating temperature of 55 °C, has been identified as the most energy-efficient and sustainable solution, effectively reducing both water consumption and CO₂ emissions. A life cycle assessment has confirmed these environmental benefits, demonstrating reductions in global warming potential, fossil fuel consumption, and other impact categories. This study suggests that PEF technology can significantly contribute to more sustainable food processing by reducing environmental impacts, optimizing resource usage, and enhancing energy efficiency. Full article

The microbiological safety of milk can be ensured through heat processing; however, this method has a negative effect on the sensory profile of this food product. Emerging technologies could be used as an alternative process for guaranteeing innocuity and maintaining sensory changes. An alternative is to evaluate pulsed electric field (PEF) electroporation, which is a method of processing cells using short pulses of a strong electric field. PEF has the potential to be a type of alternative low-temperature pasteurization process that consists of high-frequency voltage pulsations. Specifically, the presented work is a proof of concept for the design of a converter capable of generating a PEF to feed a load that meets the impedance characteristics of milk. The proposed converter is simulated using PLECS software (4.9.6 version) under impedance change scenarios that emulate variations in milk throughout the entire process. This research proposes the modification of a classic Vienna rectifier (adding an MBC—Multilevel Boost Converter structure) to supply a pulsating signal that could be used for low-temperature processes of milk to guarantee proper pasteurization. The characteristics of the generated high-voltage pulse make it feasible to quickly process the real sample. The control law design considers a regulation loop to achieve a voltage in the range of kV and a switching-type control law that activates switches in MMC arrays. These switches are activated randomly to avoid transients that cause significant stress on them. Full article

This study investigates the effects of electric field pretreatment parameters such as electric field strength (0.1–0.2 kV/cm), waveform (sinusoidal vs. square), and application mode (continuous vs. pulsed) on the quality attributes of dried Fuji apple slices, including ascorbic acid (vitamin C) retention, β-carotene content, and hydroxymethylfurfural (HMF) formation. Electric-field-treated samples were compared to untreated controls after convective drying at 75 °C. Results revealed that vitamin C was significantly influenced by waveform, with sinusoidal waves preserving about 27% more vitamin C than square waves, likely due to reduced oxidative degradation from gentler electroporation. Conversely, square waves caused the highest β-carotene losses (25% vs. control), attributed to prolonged peak voltage destabilizing carotenoids. HMF formation was reduced by 10–23% in electric-field-treated samples compared to controls, linked to accelerated drying rates limiting Maillard reaction time. Low electric field strengths (0.1–0.15 kV/cm) enhanced antioxidant activity; however, higher intensities showed a potential decline. The square waveform had a more detrimental effect on phenolic compounds than the sinusoidal waveform. These findings suggest that low electric field pretreatment, particularly with sinusoidal waveforms at 0.2 kV/cm, enhances drying efficiency while balancing nutrient retention and HMF mitigation, offering a promising strategy for producing high-quality dried fruits. Full article

Cryptosporidium spp. oocysts are highly resistant to conventional disinfection methods and have been associated with foodborne outbreaks linked to unpasteurized fruit and vegetable juices. This study aimed to evaluate the effectiveness of Pulsed Electric Fields (PEF) in permeabilizing Cryptosporidium oocysts in water, apple juice, and carrot juice. Oocysts were exposed to monopolar square-wave pulses (3 µs) at electric field strengths ranging from 15 to 35 kV/cm, with treatment times up to 180 µs, and application temperatures between 25 °C and 60 °C. Membrane permeabilization was assessed using propidium iodide uptake via fluorescence microscopy and flow cytometry. Results showed that oocyst permeabilization increased with electric field strength, treatment time, and temperature, with up to 90% permeabilization achieved at 35 kV/cm and 45 °C. Carrot juice treatments yielded higher permeabilization levels than apple juice, attributed to greater electrical conductivity and energy input. Temperatures below 60 °C alone had negligible effects, but synergistically enhanced PEF efficacy. These findings demonstrate that PEF, particularly when combined with mild heat, is a promising non-thermal technology for reducing Cryptosporidium viability in beverages, offering an effective alternative for improving the microbiological safety of minimally processed juices while preserving sensory and nutritional quality. Full article

Seed quality is vital for agricultural productivity, as it directly influences the crop yield and resilience to environmental stressors. This study evaluated the effectiveness of a pulsed electric field (PEF) treatment in enhancing the tomato (Solanum lycopersicum) seed quality, seedling growth, and microbial safety. Tomato seeds were treated with PEFs at energy levels ranging from 1.07 to 17.28 J, and several parameters were assessed, including the germination rate, normal seedling development, tolerance to cold and salinity stress, electrical conductivity, and microbial inactivation. The highest germination rate (72.81%) was observed at 15.36 J on the seventh day of germination, whereas the highest normal seedling rate (94.62%) was recorded at 17.28 J (p ≤ 0.05). The germination under cold stress (5 days at 24 °C) was highest, with a 46.67% germination observed at both 1.92 and 10.88 J. PEF-treated seeds exposed to 100 and 200 mM of NaCl exhibited significantly improved germination compared to the controls (p ≤ 0.05). The electrical conductivity (EC) was more influenced by the incubation time than by the PEF intensity, as the EC of all samples showed a significant increase from 4 to 8 h. The samples treated with 17.28 J exhibited the highest germination rates under salt stress, reaching 62.00 ± 0.90% and 50.00 ± 0.60% under 100 mM and 200 mM of NaCl, respectively (p ≤ 0.05). The initial mean counts of the total mesophilic aerobic bacteria and the total mold and yeast—4.00 ± 0.03 and 3.06 ± 0.03 log cfu/g, respectively—were reduced to undetectable levels by the application of 17.28 J, with higher energy levels yielding greater inactivation. These findings demonstrate that the PEF is a promising technique for enhancing seed quality, promoting seedling vigor, and reducing microbial contamination, supporting its application in sustainable agriculture. Full article

Meat is a vital source of high-quality proteins, amino acids, vitamins, and minerals essential for human health. Growing demand for healthier lifestyles and technological advancements has heightened the focus on meat products, whose quality depends on meat protein properties, such as texture, water holding capacity (WHC), and structural integrity. Non-thermal processing technologies are gaining attention for enhancing the gelation properties of meat protein gels (MPGs) by optimizing solubilization, denaturation, and aggregation while preserving nutritional and sensory qualities and avoiding the drawbacks of thermal treatments. This review focuses on advanced non-thermal processing techniques, including high-pressure processing (HPP), pulsed electric fields (PEFs), ultrasound, and cold plasma, and their impact on MPGs. It also examines vibrational spectroscopy methods, such as Fourier Transform Infrared (FTIR) and Raman spectroscopy, for non-invasive analysis of MPGs. The integration of these approaches with hyperspectral imaging and machine learning is also explored as a tool to improve quality control and assessment. Full article