Potential Of Pulsed Electric Fields Research Articles

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.

Investigation of Xinomavro Red Wine Aging with Various Wood Chips Using Pulsed Electric Field

This study explored the potential of pulsed electric field (PEF) as an alternative wine-aging method in four Xinomavro red wines with the implementation of several wood chips (apricot, peach, apple, cherry, acacia, and oak trees). The evolution of total polyphenol content (TPC) and sensory properties of the wines were investigated. Sensory evaluation revealed that PEF treatment increased volatile compound extraction from each wood chip, thereby enhancing the overall quality of the wines. The utilization of acacia tree wood chips in Goumenissa wine led to a notable increase of 10.84% in TPC from the control sample, reaching 2334.74 mg gallic acid equivalents/L. A notable outcome was that PEF decreased TPC, a trend that was also verified through correlation analyses. The highest positive impact of PEF was observed in peach tree wood chips in Goumenissa wine, with a significant increase of 11.05% in TPC. The results from the volatile compound analysis revealed an increase in alcohols and esters from 0.24% to 23.82%, with the highest proportion found in 2-phenylethanol (16.92 mg/L) when utilizing peach tree wood chips in the production of Amyndeo wine. This study could provide a benchmark for rapid, efficient, and cost-effective wine aging through the implementation of the PEF process.

Antimicrobial Properties Related to Anti-Acne and Deodorant Efficacy of Hedychium coronarium J. Koenig Extracts from Pulsed Electric Field Extraction.

This study investigated the potential of pulsed electric field (PEF) extraction in enhancing the antimicrobial properties related to anti-acne and deodorant properties of Hedychium coronarium extract. The dried leaf and rhizome of H. coronarium were extracted using 95% v/v ethanol through both conventional solvent extraction and PEF extraction techniques (10, 14, and 20 kV/cm). The chemical composition of the extracts was analyzed. The antimicrobial activities, specifically in relation to acne treatment against Cutibacterium acnes and deodorant properties against Staphylococcus aureus, Bacillus subtilis, Micrococcus luteus, Pseudomonas aeruginosa, and Escherichia coli, were determined. The irritation profile of was evaluated using the hen's egg chorioallantoic membrane test. The results showed that PEF extraction increased the extract yield, particularly at an electric field strength of 20 kV/cm. Furthermore, PEF extraction significantly enhanced the ellagic acid content, particularly in the leaf extract. Furthermore, the leaf extract demonstrated stronger inhibitory effects against microorganisms associated with body odor and acne compared to the rhizome extract. Notably, all extracts exhibited no signs of irritation, indicating their safety. Overall, the findings suggest that PEF extraction from H. coronarium enhances yield, bioactive compound content, and antimicrobial effects. This indicates the potential of the extract for acne treatment and deodorant use.

Physico-chemical and structural modifications of caseins in micellar casein isolate induced by pulsed electric field

The potential of pulsed electric field (PEF) to modify the structure of caseins in micellar casein isolate (MCI) was investigated. MCI was PEF-treated at room (RT, 23 °C) and cold (CT, 4 °C) temperatures, using an electric field strength of 16 kV cm−1 for 6 or 31 μs. Conditions simulating elderly digestion, such as the peptide profile released after gastric digestion and bioactivity, were studied. Unfolding of the protein structure was observed in PEF-treated MCI at RT, which led to cleavage points that were more accessible to enzymes. By contrast, fluorescence emission of tyrosine and tryptophan and Raman spectra indicated a reorganization in the configuration of the micelle in PEF-processed at CT. Under these conditions was observed an increase in the number of peptides generated from gastric digestion compared with untreated MCI, especially the bioactive peptides FSDKIAK f(31–45) and MPFPKYPVEP f(124–133), despite a lower overall uptake of bioactive peptides by Caco-2 cells.Industrial relevance: Micellar casein isolate (MCI) is widely utilized for protein fortification (e.g., in fresh dairy products, smoothies, meat products, and clinical nutrition) and for the adjustment of functional properties in food (e.g., viscosity, foaming). The findings of this work provide valuable information about the potential of PEF processing to modify the properties of MCI.

Effects of pulsed electric fields on the conformation and gelation properties of myofibrillar proteins isolated from pale, soft, exudative (PSE)-like chicken breast meat: A molecular dynamics study

The potential of pulsed electric field (PEF) of different intensities (8, 18, and 28 kV/cm) on the conformation and gelation properties of myofibrillar proteins (MPs) extracted from pale, soft, and exudative-like (PSE-like) chicken meat was investigated. The results showed a positive correlation between gelation properties and PEF intensities in the range of 8–18 kV/cm; however, a further increase in intensity had a negative impact. Optimized PEF treatment (18 kV/cm) was capable of inducing MPs with a relatively small particle size, thus contributing to the production of a more homogeneous gel structure. The water distribution and mobility in the gel system significantly changed with increasing PEF intensities, the proportion of immobilized water (P21) increased, and that of free water (P22) decreased. Based on molecular dynamics simulations (MDS), an increasing trend in the number of hydrogen bonds and a reduction in the radius of gyration (Rg) after PEF treatment.

Potential of pulsed electric field to control Aspergillus parasiticus, aflatoxin and mutagenicity levels: Sesame seed quality

AbstractSeed processing technologies are essential for seed safety and functionality through protection of physicochemical quality, pathogen inactivation, aflatoxin detoxification and alleviation of mutagenicity. Design of a pilot‐scale unit of pulsed electric fields (PEF) to treat sesame seeds with respect to quality parameters, Aspergillus parasiticus inactivation and aflatoxin reduction as well as alleviation of aflatoxin mutagenicity were prompted in this study. PEF energy ranged from 0.97 to 17.28 J achieved maximum reductions of peroxide value and acidity number of 67.4 and 85.7%, respectively, and did not change color L*, a*, b* and hue values. A 60% reduction of A. parasiticus counts occurred at the maximum PEF energy. Aflatoxins G1, G2, B1, and B2 contents decreased by 94.7, 92.7, 86.9, and 98.7%, respectively. Except for the samples treated by 2.16 J with 100 μg/plate and by 6.80 J with 10 μg/plate, PEF treatment provided elimination of aflatoxin mutagenity. It is concluded that PEF treatment can be used to treat sesame seeds with preservation of physicochemical properties, inactivation of A. parasiticus and decomposition of aflatoxins with reduced mutagenicity.

Enzymatic Processes Triggered by PEF for Astaxanthin Extraction From Xanthophyllomyces dendrorhous.

The aim of this study was to evaluate the potential of pulsed electric fields (PEF) to improve the extraction of the lipid-soluble astaxanthin from fresh biomass of a wild-type (CECT 11028) and mutant (ATCC 74219) Xanthophyllomyces dendrorhous strain using ethanol as solvent. Inactivation and propidium uptake studies revealed that inactivation is a good index for estimated the proportion of irreversible permeabilized cells when inactivation is higher than 70% in the two strains. Ethanol was ineffective for extracting carotenoids from the PEF-treated cells (20 kV/cm, 135 μs) of the two strains. However, after aqueous incubation of PEF-treated X. dendrorhous ATCC 74219 cells for 12 h, up to 2.4 ± 0.05 mg/g dried weight (d.w.) of carotenoids were extracted in ethanol. From total carotenoid extracted, around 84% corresponded to all-trans astaxanthin. The detection and quantification of esterase activity in the supernatant and the relationship between the percentage of esterase activity quantified and the amount of carotenoids extracted indicate that the extraction of astaxanthin was mediated by enzymatic esterase activity triggered by PEF during incubation. On the other hand, the formation of a large lipid globule into the cytoplasm of PEF-treated X. dendrorhous CECT 11028 cells during aqueous incubation prevented carotenoid extraction. The process developed in this investigation represents a more sustainable and greener method that those previously used for extracting astaxanthin from yeast.

Sustainable extraction of valuable components from Spirulina assisted by pulsed electric fields technology

The study investigated the potential of pulsed electric fields (PEF) technology application for the improvement of cell disintegration and subsequent extraction/fractionation of cyanobacteria Arthrospira maxima into valuable components (phycocyanin, proteins, oils and carbohydrates). Pulsed electric fields were applied to fresh A. maxima suspension, dried powder and dried sticks in combination with water as extraction solvent and freeze-thawing. Pulsed electric fields application for cell disruption reached approximately 90% increase of C-phycocyanin extraction compared to bead milling. Obtained fractions of phycocyanin and bulk proteins were also of higher purity and had twice lower environmental impact than similar fractions obtained without Pulsed electric fields treatment. Extracts with improved purity can be directly applied in pharma and food industry without any further processing and purification steps.

The application of pulsed electric field as a sodium reducing strategy for meat products

This study investigated the potential of pulsed electric field (PEF) as a sodium-reduction strategy for processed meat. Beef jerky was used as a model and prepared using different levels of NaCl, viz. 2.0% (control), 1.2% (T1) and 1.2% along with PEF processing (T2). A significant (p < 0.05) effect of PEF was observed on shear force (N) and toughness (N/mm s) of the products, which was also reflected in sensory scores. No effects for PEF were observed on colour, yield (%) and oxidative and microbial stability. PEF-treated samples (T2) had significantly (p < 0.05) lower sodium content than the control, however, the sensory scores were comparable (p > 0.05) with control and >84% of the panellists preferred T2 samples over T1 for saltiness. Results suggest that PEF treatment improved saltiness by influencing the salt diffusion and sodium delivery that led to better perception during chewing. PEF could be a novel method to produce healthier reduced-sodium meat products.

Influence of pulsed electric fields on aroma and polyphenolic compounds of Garnacha wine

The potential of pulsed electric fields (PEF) for improving polyphenol extraction, decreasing maceration and increasing aroma compounds in the course of the winemaking process were investigated. Twelve tons of Garnacha grapes were processed at a flow rate of 2500kgh−1, and wines obtained from untreated and PEF-treated (4.0kVcm−1) grapes after 3 and 6days of maceration were compared. The highest values of total anthocyanin, total polyphenolic, tannin content, and color intensity were obtained with PEF-treated grapes as well as when the maceration period was extended. The higher tannin concentration observed in PEF-treated wines was a consequence of a higher degree of extraction of tannins located in the grape skins rather than in the seeds. Finally, PEF contributed to the extraction of some individual precursors positive for aroma.These results, obtained at conditions very close to requirements at industrial scale, may encourage the adoption of PEF technology by wineries.

Implementation of PEF Treatment at Real-Scale Tomatoes Processing Considering LCA Methodology as an Innovation Strategy in the Agri-Food Sector

In Europe, science and innovation are boosting the agri-food sector and, in parallel, are helping to decrease greenhouse gas emissions (GHG) and European dependency on non-renewable resources. Currently, it is well-known that this sector contributes to the consumption of energy and material resources, causing significant environmental impacts that require a complex and comprehensive environmental evaluation in order to manage them effectively. This becomes even more complicated when new technologies are reaching the level of technological maturity needed to be installed in the production lines. To address this scientific challenge, the life cycle assessment (LCA) has been used in this paper to evaluate the potential of pulsed electric fields (PEF) technology at an industrial scale to facilitate the steam peeling of tomato fruits. Considering the thermo-physical peeling stage, the LCA has shown that PEF technology is environmentally friendly, because when PEF technology is applied, all the considered environmental indicators improve between 17% and 20%.

Improving the Extraction Yield of Juice and Bioactive Compounds from Sweet Cherries and Their By-products by Pulsed Electric Fields

The influence of pulsed electric fields (PEF) pre-treatment of sweet cherry (Prunus Avium) fruits of “Duroni Nero” variety both on the extraction yield and antioxidant properties of juice obtained by pressing, and on the subsequent extraction with solvent of bioactive compounds from cherry by-products (press-cake) was investigated. PEF pre-treatments were performed at constant specific energy input (WT = 10 kJ/kg) and different electric field strength (E= 0.5-3 kV/cm) before applying a pressure of 1.64 bar for 5 min. PEF-assisted pressing (E = 1 kV/cm) led to a significant increase of juice yield (+40%), anthocyanins (+80%), and antioxidant power (+27%) with respect to untreated samples. However, PEF treatment intensity higher than 1 kV/cm did not significantly improved the quantitative and qualitative characteristics of juice. Compared to the untreated samples, the extracts from electroporated press-cakes achieved after PEF-assisted pressing of cherry fruits at 0.5 kV/cm showed the highest increases in anthocyanins (+38%) and antioxidant activity (+21%). No evidence of selective release or degradation of individual anthocyanins in juice and press cake extracts due to PEF application was observed. Overall, the results of this investigation demonstrated the potential of PEF as a mild technology to improve the efficiency of industrial processing of cherry fruits.

Pulsed electric field and pH assisted selective extraction of intracellular components from microalgae Nannochloropsis

The study was aimed at investigation of the potential of pulsed electric field (PEF) pre-treatment as a preliminary step of pH-assisted aqueous extraction of algae components from microalgae Nannochloropsis suspensions. The PEF and sonication (S) were compared as pretreatment methods. They were applied at normal (pH=8.5) and basic (pH=11) conditions, and supplementary basic extraction (at pH=11) was done. The extracts were analyzed for content of pigments, proteins, carbohydrates, total phenolic compounds and antioxidant capacity. The colloidal stability of PEF- and S-pretreated suspensions was also evaluated. The data evidence that PEF technique allows selective extraction of a portion of pure proteins that are different from proteins extracted from S-pretreated suspensions. The discovered effects have shown the advantages of PEF-pretreatment at normal conditions (pH=8.5) and supplementary extraction at basic conditions (pH=11) for selective extraction of different intracellular components.

Winery Trial on Application of Pulsed Electric Fields for Improving Vinification of Garnacha Grapes

The potential of pulsed electric fields (PEF) to improve polyphenol extraction during winemaking was investigated in a winery trial. Four thousand five hundred kilograms of Garnacha grapes were treated with PEF (4.3 kV/cm, 60 μs) at a flow of 1,900 kg/h using a collinear treatment chamber. Wine obtained from PEF-treated grapes with a maceration time of 7 days was compared with wines obtained from untreated and PEF-treated grapes with the current maceration time (14 days) used by the winery. After 7 days of maceration, the color intensity, anthocyanin content, and polyphenol index in the tank containing grapes treated by PEF were 12.5, 25, and 23.5 % higher, respectively, than in the tank containing untreated grapes. However, after 14 days of maceration, no significant differences were observed between the control wine and the wine obtained from grapes treated by PEF for these three indices. An HPLC analysis indicated that the concentrations of major individual phenolic compounds were similar among the three wines at bottling. A sensory analysis revealed that the wine obtained from PEF-treated grapes macerated for 7 days was significantly preferable to the other two wines.