Pulsed electric field (PEF): Avant-garde extraction escalation technology in food industry

Extract toolkit for essential oils: State of the art, trends, and challenges

Plant essential oils have a wide range of applications including cosmetics, food, leather, and textiles. Traditional methods employed for essential oils extraction suffer from several drawbacks, which have escalated into a major bottleneck for industrial applications. To circumvent the limitations, various innovative and eco-friendly technologies have emerged for the extraction of essential oils, such as ultrasound-assisted extraction, pulsed electrical-assisted extraction, ohmic-assisted technology, supercritical fluid extraction, and solvent-free microwave extraction. These cutting-edge technologies provide notable advantages over traditional methods in terms of extraction efficiency, environmental safety, and product quality enhancement. This review highlights the advantage of these innovative techniques, with a particular focus on their ability to enhance the yield and antioxidant activity of essential oils while simultaneously reducing energy consumption. Additionally, the mechanisms of these new and eco-friendly extraction methods are thoroughly discussed. This review provides valuable insights into the advancements in essential oils extraction.

Electric fields as effective strategies for enhancing quality attributes of meat in cold chain logistics: A review

Meat quality (MQ) is unstable during cold chain logistics (CCL). Different technologies have been developed to enhance MQ during the CCL process, while most of them cannot cover all the links of the cold chain because of complex environment (especially transportation and distribution), compatibility issues, and their single effect. Electric fields (EFs) have been explored as a novel treatment for different food processing. The effects and potential advantages of EFs for biological cryopreservation have been reported in many publications and some commercial applications in CCL have been realized. However, there is still a lack of a systematic review on the effects of EFs on their quality attributes in meat and its applications in CCL. In this review, the potential mechanisms of EFs on meat physicochemical properties (heat and mass transfer and ice formation and melting) and MQ attributes during different CCL links (freezing, thawing, and refrigeration processes) were summarized. The current applications and limitations of EFs for cryopreserving meat were also discussed. Although high intensity EFs have some detrimental effects on the quality attributes in meat due to electroporation and electro-breakdown effect, EFs present good applicability opportunities in most CCL scenes that have been realized in some commercial applications. Future studies should focus on the biochemical reactions of meat to the different EFs parameters, and break the limitations on equipment, so as to make EFs techniques closer to usability in the production environment and realize cost-effective large-scale application of EFs on CCL.

Upgrading hazelnut skins: Green extraction of polyphenols from lab to semi-industrial scale

Hazelnut skins (HS) are usually managed as waste; however, this by-product is a source of bioactive compounds, with potential applications in feed and food sectors. Phenolic compounds can be extracted using green protocols combining enabling technologies and green solvents. This work investigates subcritical water extraction (SWE) of bioactive compounds from HS. A laboratory-scale study was performed on four different batches, with significant batch-to-batch heterogeneity. The evaluation of polyphenolic profiles and antioxidant activities afforded promising results compared to the benchmark of reflux maceration. To evaluate process effectiveness, the extraction protocol was replicated on a semi-industrial plant that processed 8 kg of matrix. Downstream processes have been optimized for scale-up, demonstrating the effectiveness of SWE in retaining product concentration and bioactivity avoiding excipients in spray-drying phase. Hazelnut extracts exhibited antibacterial properties against animal- and food-borne pathogens, supporting their potential use as sustainable feed ingredients for improved hazelnut production and animal farming practices.

Extraction of Bioactive Compounds from Wine Lees: A Systematic and Bibliometric Review

The extraction of bioactive compounds from wine lees involves a variety of methods, the selection of which is crucial to ensure optimal yields. This systematic review, following PRISMA guidelines and utilizing the Web of Science database, aimed to examine the current state of this field, providing insights for future investigations. The search employed strategies with truncation techniques and Boolean operators, followed by a three-step screening using well-defined eligibility criteria. A bibliometric analysis was conducted to identify authors, affiliations, countries/regions, and research trends. Thirty references were selected for analysis, with Spain standing out as the main source of research on the topic. The majority of studies (66%) focused on the extraction of bioactive compounds from alcoholic fermentation lees, while 33% were directed towards malolactic fermentation lees. Binary mixtures (ethanol-water) were the predominant solvents, with ultrasound being the most used extraction method (31.3%), providing the highest average yields (288.6%) for the various evaluated compounds, especially flavonoids. The potential of wine lees as a source of bioactive compounds is highlighted, along with the need for further research exploring alternative extraction technologies and the combination of methods. Additionally, the importance of "in vitro" and "in vivo" tests to assess the bioactive potential of lees, as well as the use of computational tools to optimize extraction and identify the molecules responsible for bioactive activity, is emphasized.

Pulsed Electric Field Technology for the Extraction of Glutathione from Saccharomyces cerevisiae

Glutathione is a potent antioxidant that has shown promise in enhancing the processing of various foods and drinks such as bread and wine. Saccharomyces cerevisiae stands as a primary microorganism for glutathione production. This study sought to assess the potential of pulsed electric fields (PEFs) in extracting glutathione from S. cerevisiae cells. Yeast cells were subjected to PEF treatment (12 kV/cm, 150 µs) followed by incubation at varying pH values (4.0, 6.0, and 8.0) and temperatures (4 °C and 25 °C). Glutathione and protein extraction were assessed at different incubation times. Within one hour of incubation, PEF-treated yeast cells released over 60% of their total glutathione content, irrespective of pH and temperature. Notably, the antioxidant activity of the resulting extract surpassed that obtained through complete mechanical cell destruction and hot water, which form the conventional industrial extraction method in the glutathione industry. These results suggest that PEF could offer a rapid and more selective procedure, improving the extraction of this bioactive compound.

Effects of Pulsed Electric Field and High-Pressure Processing Treatments on the Juice Yield and Quality of Sea Buckthorn

Sea buckthorn juice has high nutritional value and a rich flavor that consumers enjoy. Traditional sea buckthorn thermal processing (TP) technology has problems such as low juice yield, poor quality, and poor flavor. Sea buckthorn berries are processed using a technique combining pulsed electric field (PEF) and high-pressure processing (HPP) to increase juice yield and study its impact on the quality and volatile aroma of sea buckthorn juice. Results have show that, compared with TP, under the condition of PEF-HPP, the juice yield of sea buckthorn significantly increased by 11.37% (p > 0.05); TP and PEF-HPP treatments could effectively kill microorganisms in sea buckthorn juice, but the quality of sea buckthorn juice decreased significantly after TP treatment (p > 0.05), whereas PEF-HPP coupling technology could maximally retain the nutrients of sea buckthorn juice while inhibiting enzymatic browning to improve color, viscosity, and particle size. The flavor of sea buckthorn juice is analyzed using electronic nose (E-nose) and gas chromatography-ion mobility spectrometer (GC-IMS) techniques, and it has been shown that PEF-HPP retains more characteristic volatile organic compounds (VOCs) of sea buckthorn while avoiding the acrid and pungent flavors produced by TP, such as benzaldehyde, (E)-2-heptenal, and pentanoic acid, among others, which improves the sensory quality of sea buckthorn juice. PEF-HPP technology is environmentally friendly and efficient, with significant economic benefits. Research data provide information and a theoretical basis for the sea buckthorn juice processing industry.

Nonconventional Technologies in Lipid Modifications

Lipid modifications play a crucial role in various fields, including food science, pharmaceuticals, and biofuel production. Traditional methods for lipid modifications involve physical and chemical approaches or enzymatic reactions, which often have limitations in terms of specificity, efficiency, and environmental impact. In recent years, nonconventional technologies have emerged as promising alternatives for lipid modifications. This review provides a comprehensive overview of nonconventional technologies for lipid modifications, including high-pressure processing, pulsed electric fields, ultrasound, ozonation, and cold plasma technology. The principles,mechanisms, and advantages of these technologies are discussed, along with their applications in lipid modification processes. Additionally, the challenges and future perspectives of nonconventional technologies in lipid modifications are addressed, highlighting the potential and challenges for further advancements in this field. The integration of nonconventional technologies with traditional methods has the potential to revolutionize lipid modifications, enabling the development of novel lipid-based products with enhanced functional properties and improved sustainability profiles.

Pulsed electric field technology in vegetable and fruit juice processing: A review

The worldwide market for vegetable and fruit juices stands as a thriving sector with projected revenues reaching to $81.4 billion by 2024 and an anticipated annual growth rate of 5.27% until 2028. Juices offer a convenient means of consuming bioactive compounds and essential nutrients crucial for human health. However, conventional thermal treatments employed in the juice and beverage industry to inactivate spoilage and pathogenic microorganisms, as well as endogenous enzymes, can lead to the degradation of bioactive compounds and vitamins. In response, non-thermal technologies have emerged as promising alternatives to traditional heat processing, with pulsed electric field (PEF) technology standing out as an innovative and sustainable choice. In this context, this comprehensive review investigated the impact of PEF on the microbiological, physicochemical, functional, nutritional, and sensory qualities of vegetable and fruit juices. PEF induces electroporation phenomena in cell membranes, resulting in reversible or irreversible changes. Consequently, a detailed examination of the effects of PEF process variables on juice properties is essential. Monitoring factors such as electric field strength, frequency, pulse width, total treatment time, and specific energy is important to ensure the production of a safe and chemically/kinetically stable product. PEF technology proves effective in microbial and enzymatic inactivation within vegetable and fruit juices, mitigating factors contributing to deterioration while maintaining the physicochemical characteristics of these products. Furthermore, PEF treatment does not compromise the content of substances with functional, nutritional, and sensory properties, such as phenolic compounds and vitamins. When compared to alternative processing methods, such as mild thermal treatments and other non-thermal technologies, PEF treatment consistently demonstrates comparable outcomes in terms of physicochemical attributes, functional properties, nutritional quality, and overall safety.

Oilseed meal proteins: From novel extraction methods to nanocarriers of bioactive compounds

The global demand for animal proteins is predicted to increase twofold by 2050. This has led to growing environmental and health apprehensions, thereby prompting the appraisal of alternative protein sources. Oilseed meals present a promising alternative due to their abundance in global production and inherent dietary protein content. The alkaline extraction remains the preferred technique for protein extraction from oilseed meals in commercial processes. However, the combination of innovative techniques has proven to be more effective in the recovery and functional modification of oilseed meal proteins (OMPs), resulting in improved protein quality and reduced allergenicity and environmental hazards. This manuscript explores the extraction of valuable proteins from sustainable sources, specifically by-products from the oil processing industry, using emerging technologies. Chemical structure, nutritional value, and functional properties of the main OMPs are evaluated with a particular focus on their potential application as nanocarriers for bioactive compounds.

Synergistic ultrasound pulsed electric field extraction of litchi peel polyphenols and determination of their properties

The effects of pulsed electric field combined with ultrasound (PEF-US) on the recovery of polyphenols from litchi peels were investigated. In addition, the optimal purification parameters for polyphenol extracts and their biological activities were also explored in this study. Single-factor and orthogonal experiments were used to optimize the extraction conditions of polyphenols. After optimization, the total phenol content (TPC) of the sample extracted by PEF-US was 2.30 times higher than that of the sample extracted by traditional hot-water extraction. The mechanism of PEF-US enhancing polyphenol recovery was also revealed by morphological analysis of the powder surface. LX-7 was the best resin by comparing the purification effect of nine macroporous resins. The optimum conditions for purification of litchi peel polyphenols by LX-7 resin were also optimized through adsorption and desorption experiments. UHPLC-MS and HPLC results revealed that gentisic acid, catechin, procyanidin A2 and procyanidin B1 are four main substances in purified samples. The results of bioactivity experiments showed that the purified polyphenol samples had strong antioxidant and antibacterial activity. Overall, PEF-US is an efficient method for recovering polyphenols from litchi peels. Our study also provides a strategy for the comprehensive utilization of fruit processing waste.

Effects of Pulsed Electric Field on Meat Tenderization and Microbial Decontamination: A Review

This review sought to categorize studies on meat tenderization and safety through pulsed electric field (PEF) treatment, with a particular focus on reconciling conflicting findings regarding the tenderization effect (i.e., the primary outcome of PEF treatment) and to discuss the underlying mechanisms of these effects. While the tenderization effect may vary depending on the homogeneity of PEF treatment and variations in the conditions of texture measurements, the protein associated with tenderization was degraded by PEF treatment in most studies. PEF technology enables the delivery of a high voltage for a brief duration, typically in the microsecond range, making it a non-thermal technology. One of the distinct advantages of PEF is its ability to preserve the freshness of meat due to its exceptionally short treatment time. While PEF studies have traditionally centered on pasteurizing liquid foods, research on its application to meat is steadily expanding. Therefore, this review aims to elucidate the mechanisms of PEF and provide current insights into the applications of this technology for meat tenderization and microbial inactivation.

The Structure, Functions and Potential Medicinal Effects of Chlorophylls Derived from Microalgae

Microalgae are considered to be natural producers of bioactive pigments, with the production of pigments from microalgae being a sustainable and economical strategy that promises to alleviate growing demand. Chlorophyll, as the main pigment of photosynthesis, has been widely studied, but its medicinal applications as an antioxidant, antibacterial, and antitumor reagent are still poorly understood. Chlorophyll is the most important pigment in plants and algae, which not only provides food for organisms throughout the biosphere, but also plays an important role in a variety of human and man-made applications. The biological activity of chlorophyll is closely related to its chemical structure; its specific structure offers the possibility for its medicinal applications. This paper reviews the structural and functional roles of microalgal chlorophylls, commonly used extraction methods, and recent advances in medicine, to provide a theoretical basis for the standardization and commercial production and application of chlorophylls.

Effects of Pulsed Electric Field Pretreatment on Black Tea Processing and Its Impact on Cold-Brewed Tea

This study applied pulsed electric fields (PEFs) to accelerate the withering and drying processes during cold-brewed black tea production. PEF pretreatment was administered at 1.0, 1.5, and 2.0 kV/cm electric field strengths, combined with varying withering times from 8 to 12 hr. During the 12-hour withering process, the redness value (a*) and total color change (∆E) of PEF-treated leaves significantly increased (p < 0.05). Furthermore, the homogenous redness of tea leaves during fermentation depended on the PEF strength applied. In addition, PEF pretreatment remarkably reduced the drying time, up to a 50% reduction at a 2.0 kV/cm field strength. Additionally, the 2.0 kV/cm PEF-pretreated black tea exhibited a notable 42% increase in theaflavin (TF) content and a 54% increase in thearubigin (TR) content. Sensory evaluation scores were highest for black tea that received PEF pretreatment at 2.0 kV/cm. These findings highlight the significant potential of PEFs in enhancing the efficiency of withering and drying processes while positively impacting the physicochemical and sensory properties of cold-brewed black tea.

Polyphenol Extraction from Food (by) Products by Pulsed Electric Field: A Review

Nowadays, more and more researchers engage in studies regarding the extraction of bioactive compounds from natural sources. To this end, plenty of studies have been published on this topic, with the interest in the field growing exponentially. One major aim of such studies is to maximize the extraction yield and, simultaneously, to use procedures that adhere to the principles of green chemistry, as much as possible. It was not until recently that pulsed electric field (PEF) technology has been put to good use to achieve this goal. This new technique exhibits many advantages, compared to other techniques, and they have successfully been reaped for the production of extracts with enhanced concentrations in bioactive compounds. In this advancing field of research, a good understanding of the existing literature is mandatory to develop more advanced concepts in the future. The aim of this review is to provide a thorough discussion of the most important applications of PEF for the enhancement of polyphenols extraction from fresh food products and by-products, as well as to discuss the current limitations and the prospects of the field.

Hierarchical structural modification of starch via non-thermal plasma: A state-of-the-art review

The hierarchical architecture of natural and processed starches with different surface and internal structures determines their final physicochemical properties. However, the oriented control of starch structure presents a significant challenge, and non-thermal plasma (cold plasma, CP) has gradually been used to design and tailor starch macromolecules, though without clear illustration. In this review, the multi-scale structure (i.e., chain-length distribution, crystal structure, lamellar structure, and particle surface) of starch is summarized by CP treatment. The plasma type, mode, medium gas and mechanism are also illustrated, as well as their sustainable food applications, such as in food taste, safety, and packaging. The effects of CP on the chain-length distribution, lamellar structure, amorphous zone, and particle surface/core of starch includes irregularity due to the complex of CP types, action modes, and reactive conditions. CP-induced chain breaks lead to short-chain distributions in starch, but this rule is no longer useful when CP is combined with other physical treatments. The degree but not type of starch crystals is indirectly influenced by CP through attacking the amorphous region. Furthermore, the CP-induced surface corrosion and channel disintegration of starch cause changes in functional properties for starch-related applications.

Non-thermal emerging processing Technologies: Mitigation of microorganisms and mycotoxins, sensory and nutritional properties maintenance in clean label fruit juices

The increase in the fruit juice consumption and the interest in clean label products boosted the development and evaluation of new processing technologies. The impact of some emerging non-thermal technologies in food safety and sensory properties has been evaluated. The main technologies applied in the studies are ultrasound, high pressure, supercritical carbon dioxide, ultraviolet, pulsed electric field, cold plasma, ozone and pulsed light. Since there is no single technique that presents high potential for all the evaluated requirements (food safety, sensory, nutritional and the feasibility of implementation in the industry), the search for new technologies to overcome the limitations is fundamental. The high pressure seems to be the most promising technology regarding all the aspects mentioned. Some of the outstanding results are 5 log reduction of E. coli, Listeria and Salmonella, 98.2% of polyphenol oxidase inactivation and 96% PME reduction. However its cost can be a limitation for industrial implementation. The combination of pulsed light and ultrasound could overcome this limitation and provide higher quality fruit juices. The combination was able to achieve 5.8-6.4 log cycles reduction of S. Cerevisiae, and pulsed light is able to obtain PME inactivation around 90%, 61.0 % more antioxidants, 38.8% more phenolics and 68.2% more vitamin C comparing to conventional processing, and similar sensory scores after 45 days at 4 °C comparing to fresh fruit juice. This review aims to update the information related to the application of non-thermal technologies in the fruit juice processing through systematic and updated data to assist in industrial implementation strategies.

The Role of Emergent Processing Technologies in Beer Production

The brewing industry is regarded as a fiercely competitive and insatiable sector of activity, driven by the significant technological improvements observed in recent years and the most recent consumer trends pointing to a sharp demand for sensory enhanced beers. Some emergent and sustainable technologies regarding food processing such as pulsed electric fields (PEF), ultrasound (US), thermosonication (TS), high-pressure processing (HPP), and ohmic heating (OH) have shown the potential to contribute to the development of currently employed brewing methodologies by both enhancing the quality of beer and contributing to processing efficiency with a promise of being more environmentally friendly. Some of these technologies have not yet found their way into the industrial brewing process but already show potential to be embedded in continuous thermal and non-thermal unit operations such as pasteurization, boiling and sterilization, resulting in beer with improved organoleptic properties. This review article aims to explore the potential of different advanced processing technologies for industrial application in several key stages of brewing, with particular emphasis on continuous beer production.

Plant Extraction in Water: Towards Highly Efficient Industrial Applications

Since the beginning of this century, the world has experienced a growing need for enabling techniques and more environmentally friendly protocols that can facilitate more rational industrial production. Scientists are faced with the major challenges of global warming and safeguarding water and food quality. Organic solvents are still widely used and seem to be hard to replace, despite their enormous environmental and toxicological impact. The development of water-based strategies for the extraction of primary and secondary metabolites from plants on a laboratory scale is well documented, with several intensified processes being able to maximize the extraction power of water. Technologies, such as ultrasound, hydrodynamic cavitation, microwaves and pressurized reactors that achieve subcritical water conditions can dramatically increase extraction rates and yields. In addition, significant synergistic effects have been observed when using combined techniques. Due to the limited penetration depth of microwaves and ultrasonic waves, scaling up entails changes to reactor design. Nevertheless, the rich academic literature from laboratory-scale investigations may contribute to the engineering work involved in maximizing mass/energy transfer. In this article, we provide an overview of current and innovative techniques for solid-liquid extraction in water for industrial applications, where continuous and semi-continuous processes can meet the high demands for productivity, profitability and quality.

Investigation on the Effects of a Pulsed Electric Field (PEF) Continuous System Implemented in an Industrial Olive Oil Plant

The aim of this study was to investigate how the treatment of olive paste of the Picholine variety with pulsed electric fields (PEF) under real operating conditions in a large-scale olive oil extraction plant affects the extractability, chemical composition and sensory profile of the oils. The application of pulsed electric fields (PEF) as a non-thermal food processing technology is interesting for many food extraction processes. The results of this study show that pulsed electric fields can be used as a pretreatment before oil separation to increase the extractability of the process and improve the content of functional components. The application of pulsed electric field (PEF) treatment (2.4 kV/cm, 4 kJ/kg, 6 µs pulse width) to olive paste through a continuous system significantly increased the extractability and total concentration of phenols (especially oleuropein derivatives) compared to the control. In addition, the volatile compounds, α-tocopherol, the fatty acid profile and the main legal quality parameters of extra virgin olive oil (EVOO), including free acidity, peroxide values, extinction indices and sensory analysis, were evaluated. The pulsed electric fields (PEF) treatment did not modify these EVOO quality parameters, neither the α-tocopherol content nor the volatile profile. The sensory properties of EVOO were not affected as well as the PEF treatment showed a similar intensity of fruity and pungent attributes without any off-flavor according to the European Union legal standards. An increase in the bitter taste attribute was observed in the PEF oils. Consequently, this study demonstrates that pulsed electric fields (PEF) processing could be implemented in olive oil processing as pretreatment for improving the efficiency of the process.

Cross-Comparison of the Impact of Grass Silage Pulsed Electric Field and Microwave-Induced Disintegration on Biogas Production Efficiency

Lignocellulosic biomass is included in the group of renewable energy sources. Its calorific value is high, owing to which it can be successfully used in the production of second-generation fuels, e.g., biogas. However, its complex structure makes it necessary to apply a pretreatment in order to increase the biogas output. This study presents the usability of a pulsed electric field in grass silage pretreatment in methane fermentation and compares it with microwave-induced disintegration. The experiment shows that substrate disintegration with a pulsed electric field (PEF) results in an increase in methane output. The productivity of methane from PEF pretreatment silage increased by 20.1% compared to the untreated control. The application of microwave disintegration, with the assumption that the same energy is used for the pretreatment, resulted in a methane output increase of 6% compared to the control. The highest biogas production output in PEF-pretreated samples was 535.57 NL/kg VS, while the highest biogas output from substrates pretreated with microwaves was 487.18 NL/kg VS.

Strategy for anthocyanins production: From efficient green extraction to novel microbial biosynthesis

Anthocyanins are widely distributed in nature and exhibit brilliant colors and multiple health-promoting effects; therefore, they are extensively incorporated into foods, pharmaceuticals, and cosmetic industries. Anthocyanins have been traditionally produced by plant extraction, which is characterized by high expenditure, low production rates, and rather complex processes, and hence cannot meet the increasing market demand. In addition, the emerging environmental issues resulting from traditional solvent extraction technologies necessitate a more efficient and eco-friendly alternative strategy for producing anthocyanins. This review summarizes the efficient approach for green extraction and introduces a novel strategy for microbial biosynthesis of anthocyanins, emphasizing the technological changes in production.