Multistage aqueous and non-aqueous extraction of bio-molecules from microalga Phaeodactylum tricornutum

A multi-step aqueous and non-aqueous extraction procedure was applied to recovery bio-molecules from Phaeodactylum tricornutum. The process include that physical pre-treatments (high voltage electrical discharges (HVED, 40 kV/cm, 1–8 ms, HVED samples) or high pressure homogenization (HPH, 1200 bar, 10 passes, P samples)) (1st step); aqueous extraction (2nd step); pigments extraction in ethanol (3rd step); and lipids extraction in CHCl₃/MeOH (4th step). The extractability of ionics, carbohydrates, proteins, pigments and lipids for untreated, HVED and P samples were evaluated. The results evidenced that HVED allowed selective extraction of water soluble ionic products at 1st and 2nd steps. The maximum ionic concentrations were found for HVED samples. However, P samples resulted in higher contents of extracted components as compared to HVED samples (≈1.5-fold of carbohydrates, ≈2.5-fold of proteins, ≈5-fold of carotenoids, and ≈3-fold of chlorophylls). Moreover, the non-aqueous extraction (3rd and 4th steps) allowed supplementary extraction of pigments and lipids.Industrial relevancePre-treatments by high voltage electrical discharge (HVED) or high pressure homogenization (HPH) allowed effective extraction of different bio-molecules from microalga biomass. The combination of HVED/HPH, aqueous and non-aqueous extraction allowed selective recovery of target molecules. The paper also presents a multistage extraction procedure allowed reducing the amount of toxic solvents, increasing the extraction efficiency, and reducing the energy consumption. These approaches opened the doors to high-efficiency recovery of valuable compounds from microalgae relevant for industrial application.     

Effect of pulsed electric fields and high pressure on improved recovery of high-added-value compounds from olive pomace

Olive pomace is considered a solid by-product and a rich source of valuable compounds such as polyphenols, flavonoids with antioxidant properties, and proteins. Nonthermal technologies, which cause alterations to cell permeability, are being explored to assist conventional recovery techniques. The aim of this study was to assess the effect of pulsed electric fields (PEF) and high pressure (HP) on improved recovery yield of the high-added-value compounds or to shorten the extraction time of these compounds. Olive pomace (Tsounati cv) was pretreated with PEF (1.0 to 6.5 kV/cm, 0.9 to 51.1 kJ/kg, and 15 µs pulse width) or HP (200 to 600 MPa and 0 to 40 min). Evaluation of the intracellular compounds extracted via solid–liquid extraction (50% ethanol–water solution) was performed. More intense PEF and HP conditions resulted in a significant increase of the phenolic concentration up to 91.6% and 71.8%, respectively. The increased antioxidant capacity of each extract was correlated to phenolic compound concentration. The protein concentration that was achieved with PEF pretreatment was doubled; however, HP-pretreated extracts reached 88.1% higher yield than untreated for pressures up to 200 MPa. HP and PEF pretreatment decreased extraction completion time t₉₈ (needed time to recover the equal amount of phenolics and proteins of untreated after 60 min of conventional extraction) to 12 min and lower than 1 min, respectively. To conclude, both pretreatments are effective in improving the conventional extraction process for increased yield recovery of high-added-value compounds from olive pomace.     

Comparison of aqueous extraction efficiency and biological activities of polyphenols from pomegranate peels assisted by infrared,ultrasound, pulsed electric fields and high-voltage electrical discharges

The effects of aqueous extraction of bioactive compounds from pomegranate peels using conventional extraction (CE) and extraction assisted by infrared irradiation (IR), ultrasound (US), pulsed electric fields (PEF), and high-voltage electrical discharges (HVED) have been compared. For the extractions assisted by US, PEF and HVED, the saturation in extraction was observed approximately at the same specific energy input in the order of W ≈ 90–100 kJ/kg. HVED assisted extraction enhanced the recovery of polyphenols by ≈3 and ≈1.3 times as compared to US and PEF assisted extractions, respectively. Scanning electron microscopy (SEM) data evidenced that the highest yield of total polyphenols after the HVED treatment can reflect the presence of a strong damage of the microstructure of pomegranate skins. The obtained data on inhibition of growth of A. flavus and biosynthesis of aflatoxin B1 were explained accounting for the presence of different synergetic effects of phenolic compounds on inhibition of different bioactivities. All the studied extracts (0.2 mg/mL) demonstrated the higher inhibition efficiency for S. aureus (up to ≈80%) as compared to E. coli (up to ≈33%). PEF selectively extracted and enhanced the recovery of ellagic acid (≈740 μg/g DM), whereas HVED (≈345 μg/g DM) intensified gallic acid extraction compared to US, IR, HVED and WB.     

A comparative study of physical pretreatments for the extraction of polyphenols and proteins from vine shoots

This work examined the potential of valorization of vine shoots through their polyphenol and protein contents. However the choice of the experimental conditions targeted polyphenol extraction at the expense of proteins for further simplification of the purification process. The intensification of polyphenol and protein extraction by physical treatments (pulsed electric fields (PEF), high-voltage electrical discharges (HVED) and ultrasound (US)) was studied. A significant enhancement of polyphenol extraction was noticed with HVED, PEF and US. However, and for each treatment, the improvement of the extraction process started beyond a specific energetic threshold (HVED (10 kJ/kg), PEF (50 kJ/kg) and US (1010 kJ/kg)). HVED had the highest polyphenol and protein extraction yields with the lowest energetic prerequisite. Extracts of high polyphenol yield (34.5 mg of gallic acid equivalent (GAE) per g of dry matter (DM)) and high purity (89%) were obtained with HVED. Polyphenol and protein diffusion coefficients (m²/s) demonstrated HVED to better enhance the extraction process of those biomolecules. Similarly, the calculation of the electrical conductivity disintegration index, Z, showed the highest tissue damage for HVED and a rising cellular damage with the increased energetic requirement of each treatment.     

Combined densification and pulsed electric field treatment for selective polyphenols recovery from fermented grape pomace

The aim of this study is to assess a new process for the valorization of fermented grape pomace using pulsed electric fields (PEF). The combination of densification and PEF treatment was applied on grape pomace of low relative humidity, without any addition of conductive liquid. The kinetics of extraction and the composition of polyphenols were evaluated throughout the subsequent hydro-alcoholic extraction at different temperatures.Optimal parameters of PEF treatment (field strength E = 1.2 kV·cm^− 1; energy input W = 18 kJ·kg^− 1; density ρ = 1.0 g·cm^− 3) increased the content of total polyphenols regardless of the temperature of extraction. The ratio of total anthocyanins to total flavan-3-ols at 20 °C was equal to 7.1 and 9.0 for control and PEF treated modalities, respectively. These results demonstrate the selective nature of PEF treatment in anthocyanin extraction, and thus reveal new possibilities to produce extracts with different biochemical compositions.Industrial relevanceThis study examines the feasibility of densification combined with PEF pre-treatment of relatively low humidity grape pomace for the enhancement of bioactive compounds extraction. The concentration of total phenolic compounds obtained after PEF treatment showed that the use of this technique is relevant for an industrial use, since solvent amount and extraction time can be reduced. Moreover, the selective nature of PEF opens the opportunity to produce extracts of different biochemical compositions. This process is an alternative to conventional pre-treatments of raw material (e.g. dehydration and grinding), which have impacts on product quality and are more energy consuming.     

Valorisation of grape pomace by the extraction of phenolic antioxidants: Application of high voltage electrical discharges

The aim of this study was to optimise the electrically assisted extraction in order to obtain grape pomace extracts with high polyphenols content, which would be potentially interesting for applications as natural antioxidants. High voltage electrical discharges (HVED) were applied for intensification of the extraction. The effects of the energy input, the electrodes distance gap and the liquid-to-solid ratio were studied. Diffusion was then carried out in different mixtures of water and ethanol for one hour at 20, 30, 40 and 60 °C. The most efficient extraction was (i) an HVED pre-treatment at 80 kJ/kg with an electrodes distance of 5 mm in a liquid-to-solid ratio of 5 followed by (ii) a diffusion with 30% ethanol in water at 60 °C for 30 min. The highest total polyphenols content reached 2.8 ± 0.4 gGAE/100gDM with a corresponding antioxidant activity of 66.8 ± 3.1 gTEAC/kgDM. The polyphenols extraction rate increased with temperature in accordance to an Arrhenius type of relationship: activation energy of 21.5 ± 1.1 kJ/mol for HVED treated systems against 0.5 ± 0.2 kJ/mol for untreated ones.     

Application of pulsed electric fields for improving the maceration process during vinification of red wine: influence of grape variety

The effect of the application of pulsed electric fields (PEF) treatments (2, 5 and 10 kV/cm) to the grape skin on the evolution of colour intensity, anthocyanins and index of total polyphenols along the vinification process of three grape varieties (Garnacha, Mazuelo and Graciano) has been investigated. It has been demonstrated that the ability of PEF to permeabilize cellular tissues is an effective treatment to improve the extraction of phenolic compounds. The influence of the intensity of the PEF treatment on colour intensity, anthocyanins and index of total polyphenols depended on the grape variety investigated. As compared with the control, the application of a PEF treatment was more effective in Mazuelo than in Garnacha and Graciano varieties. Increasing the electric field strength from 2 to 10 kV/cm led to a significant increment in treatment efficiency in Mazuelo but not in Garnacha and Graciano. The low energy consumption for cell permeabilization of grape skins (0.4–6.7 kJ/kg) and the short processing time required are key advantages of PEF technology to reduce the duration of the maceration during vinification or to increase the quantity of phenolic compounds in the final wine.     

Impact of Electric Pulse Treatment on Selective Extraction of Intracellular Compounds from Saccharomyces cerevisiae Yeasts

Treatments by high-voltage electrical discharges (HVED, needle-plate electrode geometry, U?=?40 kV, t _p?≈?0.5 μs) and pulsed electric field (PEF, plate–plate electrode geometry, E?=?5–40 kV/cm, t _p?≈?8.3 μs) were evaluated as tools for selective extraction of different intracellular components from the wine Saccharomyces cerevisiae (bayanus) yeasts in a 0.5% (w/w) aqueous suspension. The pulses in the form of damped oscillations and exponential decay were applied in HVED and PEF modes of treatment, respectively. The extraction efficiency results obtained using HVED and PEF techniques were compared with those for high-pressure homogenization technique. The HVED and PEF treatments always resulted in incomplete damage of yeast cells, though efficiency of HVED was higher than that of PEF. The high selectivity of extraction of ionic substances, proteins, and nucleic acids was demonstrated; e.g., electric pulse treatments at E?=?40 kV/cm and N?=?500 allowed extraction of ≈80% and ≈70% of ionic substances, ≈4% and ≈1% of proteins and ≈30% and ≈16% of nucleic acids in cases of HVED and PEF modes, respectively.     

High voltage electric discharges assisted extraction of phenolic compounds from grape stems: Effect of processing parameters on flavan-3-ols,flavonols and stilbenes recovery

This work aimed at providing some novel aspects pertaining to flavan-3-ols, flavonols and stilbenes extraction from grape stems using high voltage electrical discharges (HVED). Treatment time, pH and ethanol concentration affecting the extractability of these compounds were optimized through response surface methodology. The results from the optimized extraction technique (pH = 2.5; Time = 4.0 ms: Ethanol = 50%) were compared to a conventional hydro-alcoholic extraction.HVED improved significantly the extraction of flavan-3-ols and flavonols but was less efficient on stilbenes. The efficiency of HVED is directly correlated with the other processing conditions (pH, ethanol concentration). Prolonged HVED treatment at low pH value was a positive combination for flavan-3-ols. The proposed procedure (pH = 2.5; Time = 4.0 ms; Ethanol = 50%) allowed the release of almost 35% of additional phenolic compounds, which can be attributed to a better extractability of flavan-3-ols (+ 21%) and of flavonols (+ 12%), compared to conventional hydro-alcoholic extraction.     

New approaches for the effective valorization of papaya seeds: Extraction of proteins,phenolic compounds,carbohydrates, and isothiocyanates assisted by pulsed electric energy

The study compares the efficiency of common aqueous extraction (CE) at different pH (2.5–11) and temperatures (20–60 °C) and extraction assisted by pulsed electric energy (pulsed electric fields, PEF or high voltage electrical discharges, HVED) of nutritionally valuable and antioxidant compounds from papaya seeds. The exponential decay pulses with initial electric field strengths of ≈ 13.3 kV/cm and ≈ 40 kV/cm for PEF and HVED treatments, respectively, were used. The number of pulses n was changed within 1–2000. The impacts of temperature and pH on extraction efficiency of different components (proteins, total phenolic compounds, carbohydrates, isothiocyanates) and antioxidant capacity were ambiguous. The highest values of nutritionally valuable and antioxidant compounds were obtained for HVED-assisted extraction. However, the application of HVED-treatment may produce undesirable contaminants (chemical products of electrolysis, free reactive radicals, etc.) and extracts were unstable and cloudy. On the other hand, the application of the two-stage procedure PEF + supplementary aqueous extraction (+ SAE) that include PEF-assisted extraction as the first step, and + SAE at 50 °C, pH = 7 during 3 h as the second step, allowed noticeable enhancement of the yields (+ 200%) and antioxidant capacities (+ 20%) even at neutral pH. This method has high prospects of industrial applications for release of valuable components from papaya seeds.     

Comparison of the effect of pulsed electric field or high voltage electrical discharge for the control of sweet white must fermentation process with the conventional addition of sulfur dioxide

The present work discusses the efficiency of pulsed electrical treatments for the inactivation of yeasts. The application of pulsed electric fields (PEFs) and high voltage electrical discharges (HVEDs) as alternatives to sulfites, which are used as anti-microbial to stop the fermentation of sweet white wine, was investigated. The influence of sulfite concentration (from 0 mg·L^− 1 to 500 mg·L^− 1), PEF (from 4 kV·cm^− 1 to 20 kV·cm^− 1; from 0.25 ms to 6 ms) and HVED (40 kV/cm; 1 ms or 4 ms) treatments on the inactivation of total yeasts and non-Saccharomyces yeasts was determined. The addition of SO₂ (250 mg·L^− 1) resulted in 8 log total yeast reduction. The maximum yeast inactivation obtained with PEF and HVED was respectively 3 and 4 logs. The use of SO₂, HVED and PEF allows decreasing the non-Saccharomyces yeast level by 7, 5 and 4 logs respectively. However, the wine browning was less pronounced for the samples treated by PEF in comparison with HVED and SO₂ treatments. PEF seems to be the most suitable alternative technique to sulfite addition.     

High voltage electrical discharges followed by deep eutectic solvents extraction for the valorization of pomegranate seeds (Punica granatum L.)

This work proposes a sustainable methodology based on the use of high voltage electrical discharges (HVED) and deep eutectic solvents (DES) for the simultaneous extraction of proteins and polyphenols from pomegranate seeds. Pomegranate seeds were firstly pretreated with HVED and, next, submitted to a solid-liquid extraction using DES. HVED pretreatment was compared with ultrasounds observing a better performance of HVED that promoted the disintegration of 86% of cells at 160 kJ/kg energy input and, consequently, the release of 70% of proteins and 78% of polyphenols. Extraction/solubilization of proteins and polyphenols was carried out using 5 different DES and results were compared with the obtained using NaOH. DES improved the diffusivity of both proteins and polyphenols, although the highest rates were observed for proteins, while NaOH extracted higher amounts of both. Application of RP-HPLC-ESI-Q-TOF to the analysis of extracts enabled to identify 30 different phenolic compounds among extracts, most of them ellagitannins. Proteomics enabled to identity a total of 11 different proteins among pomegranate seed extracts that were mainly assigned to globulins and albumins, with nutrient reservoir activity.     

Microwave and pulsed electric field assisted extractions of polyphenols from defatted canola seed cake

The incorporation of microwave and pulsed electric field (PEF) technologies in optimising the extraction of polyphenols from defatted canola seed cake was determined by Box‐Behnken response surface methodology, using three parameters of microwave treatment (power, time and liquid: solid (L:S) ratio) and four parameters of PEF (ethanol concentration, time, frequency and voltage). After microwave and PEF pretreatments, the polyphenols of defatted canola seed cake were extracted by ultrasound treatment under fixed variables (200 W of ultrasonic power, 70 °C of water bath and 20 min of extraction time). The measured responses were total phenolics, total flavonoids, the DPPH˙ scavenging activity and ferric reducing antioxidant power (FRAP). The maximum yields of all responses were achieved under optimum conditions of microwave processing (5 min, L:S ratio of 6.0 and 633.3 W) and PEF‐assisted extraction (30 V, 30 Hz, 10% ethanol concentration and 10 s).     

Pulsed electric field, ultrasound, and thermal pretreatments for better phenolic extraction during red fermentation

The moderate thermal (MT), ultrasound (US), and pulsed electric field (PEF) pretreatments are studied to enhance the phenolics extraction from Cabernet Franc (CF) grapes. The next pretreatment conditions are investigated: MT (50 °C, 15 min, 125 kJ/kg), US1 (24 kHz, 5 min, 121 kJ/kg), US2 (24 kHz, 10 min, 242 kJ/kg), US3 (24 kHz, 15 min, 363 kJ/kg), PEF1 (0.8 kV/cm, 100 ms, 42 kJ/kg), and PEF2 (5 kV/cm, 1 ms, 53 kJ/kg). The qualitative parameters of extracts (pH, °Brix, and color intensity), their total polyphenols content, anthocyanins, tannins, and free radical scavenging activity were determined during the whole period of alcoholic fermentation. The results show that all studied pretreatments improve phenolics extraction (anthocyanins and tannins content), color intensity, and scavenging activity of the samples during red fermentation. However, the moderate (0.8 kV/cm) and high (5 kV/cm) PEF were the most effective pretreatments and increased the phenolics extraction yield, respectively, on 51 and 62 %, while the MT and US3 pretreatments increased the phenolics extraction yield, respectively, on 20 and 7 %. The anthocyanin and tannins were also better extracted, and the color intensity was highest after the PEF pretreatments in comparison with the MT and US pretreatments.     

Valorization of sage extracts (Salvia officinalis L.) obtained by high voltage electrical discharges: Process control and antioxidant properties

Study explored high voltage electrical discharge (HVED) for recovery of bioactive compounds from Dalmatian sage. HVED parameters were: treatment time (3, 9 min), ethanol content (0, 25, 50%, v/v), voltage for argon (15, 20 kV) and nitrogen (20, 25 kV). Findings were compared to conventional extraction (CE) with assessment of total phenolic content (TPC), antioxidant activity (EPR), NIR spectroscopy, colorimetric parameters, Fourier-transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC). Raw sage was analyzed for pesticide residues and heavy metals. The optimal HVED extraction expressed as TPC 57.21 mg GAE/g was obtained with nitrogen/9 min/25 kV/33% of ethanol. Sage is safe for extraction in terms of pesticide residues and heavy metals. HVED electroporation facilitated the extraction of bioactive compounds and produced extracts with high antioxidant potential, thus confirmed HVED as “green” extraction for sustainable functional food production.     

A study of mechanisms involved during the extraction of polyphenols from grape seeds by pulsed electrical discharges

This paper presents an experimental study of the influence of pulsed electrical discharges of low energy (3 to 10 J) on the extraction of polyphenols from grape seeds. To obtain a better understanding, three basic phenomena involved in the whole discharge process are studied separately: pulsed electric field (PEF), pre-breakdown phase (streamer), and breakdown phase (arc). The polyphenol extraction is much more efficient with arcs, compared to streamers and PEF. Therefore, during the discharge process, the enhancement of polyphenol extraction can be mainly ascribed to the final arc phase. The total energy per unit mass CW_p required to extract 5000 mg GAE/100 g DM with the arc (CW_p = 16 kJ/kg) is 27 times lower compared to streamers alone, and 47 times lower compared to PEF. An optical study shows that the mechanical effects of arcs (shock waves, expanding cavity, and strong turbulence) are much more pronounced compared to streamers. These mechanical effects are responsible for the fragmentation of grape seeds, and strongly promote the release of polyphenols. Other parameters such as the test cell shape and the inter-electrode distance also show that the polyphenol extraction is further enhanced when grape seeds are in close proximity with the breakdown arc. In optimized conditions, the extraction efficiency with low energy discharges can be significantly higher than previous measurements with high energy discharges.Industrial relevanceThis paper presents relevant information for the design of generating electrical discharges treatment. The study also addresses a specific case of use of by-products and shows the effectiveness of such technology.     

Pulsed-electric-field-assisted extraction of anthocyanins from purple-fleshed potato

The influence of pulsed electric field (PEF) treatment on the anthocyanin extraction yield (AEY) from purple-fleshed potato (PFP) at different extraction times (60–480 min) and temperatures (10–40 °C) using water and ethanol (48% and 96%) as solvents has been investigated. Response surface methodology was used to determine optimal PEF treatment and optimise anthocyanin extraction. A PEF treatment of 3.4 kV/cm and 105 μs (35 pulses of 3 μs) resulted in the highest cell disintegration index (Z_p = 1) at the lowest specific energy requirements (8.92 kJ/kg). This PEF treatment increased the AEY, the effect being higher at lower extraction temperature with water as solvent. After 480 min at 40 °C, the AEY obtained for the untreated sample using 96% ethanol as the solvent (63.9 mg/100 g fw) was similar to that obtained in the PEF-treated sample using water (65.8 mg/100 g fw). Therefore, PEF was possible with water, a more environmental-friendly solvent than ethanol, without decreasing the AEY from PFP.     

Vesicle-enhanced liquid-phase pulsed discharge extraction of polyphenols from green tea leaves

A vesicle-enhanced liquid-phase pulsed discharge (V-LPD) was proposed to extract polyphenols from green tea leaves. The optimal extraction conditions obtained by the process optimization were 3% (w/v) dodecyl trimethy lammonium bromide (DTAB)/sodium dodecyl sulfate (SDS) vesicle, 10% (v/v) ethanol/vesicle, 66 mL/g liquid-to-solid ratio, 5 kV discharge voltage, and 2.5 min extraction time. Under these optimal conditions, the polyphenols yield was 124.650 ± 1.197 mg/g, which was observably higher than that by heat reflux extraction (HRE) (108.156 ± 1.437 mg/g) for 45 min and that by ethanol-enhanced LPD (116.123 ± 1.164 mg/g) for 4 min. The energy consumptions of V-LDP and ethanol-enhanced LPD were far lower than that by HRE. Similar chemical constituents were observed by HPLC analysis in three extraction methods, and the extracts obtained by V-LPD had the highest antioxidant capacity. Therefore, the V-LPD is a time-saving and energy-saving method for the extraction of polyphenols.Industrial relevanceGreen tea is considered to be an important source of polyphenols. The potential of V-LPD has been demonstrated as a time-saving and energy-saving alternative using vesicle solvents for the simultaneous cell disruption and strengthening diffusion of polyphenols from green tea leaves. The polyphenols obtained with V-LPD process can be used in an array of pharmaceutical, cosmetic and food applications.     

Impact of an integrated process of hot pressurised liquid extraction–macroporous resin purification over the polyphenols,hydroxymethylfurfural and reducing sugars content of Vitis vinifera ‘Carménère’ pomace extracts

Thermal degradation and generation of objectionable compounds such as hydroxymethylfurfural have been observed in hot pressurised water extraction of polyphenols. Addition of small amounts of ethanol can reduce process temperatures and retain extraction efficiencies. However, ethanol may reduce the recovery of polyphenols in the subsequent purification stage. The overall effect of increasing amounts of ethanol (0–15%) and reduced temperatures (90, 75, 60 °C) in the extraction stage, as well as increasing amounts of ethanol in the desorption eluent (60–80%) were analysed in a combined hot pressurised liquid extraction–resin purification grape pomace polyphenols process for the first time. Without decreasing the polyphenols recovery (~24 mg GAE g^?1), ethanol addition (15%) reduced the extraction temperature (from 130 to 90 °C) which not only decreased the reducing sugar extraction (~25%) but also avoided the hydroxymethylfurfural generation in the extraction stage. Additionally, the combined hot pressurised liquid extraction–resin purification process preserved the proanthocyanidin oligomeric distribution and was selective to polyphenols. The operating conditions found for the combined process, efficiently produced purified polyphenols extracts (11 mg GAE g^?1), free of hydroxymethylfurfural and reducing sugars.     

Improving the pressing extraction of polyphenols of orange peel by pulsed electric fields

The influence of pulsed electric field (PEF) treatment on the extraction by pressing of total polyphenols and flavonoids (naringin and hesperin) from orange peel was investigated. A treatment time of 60 μs (20 pulses of 3 μs) achieved the highest cell disintegration index (Zp) at the different electric field strengths tested. After 30 min of pressurization at 5 bars, the total polyphenol extraction yield (TPEY) increased 20%, 129%, 153% and 159% for orange peel PEF treated at 1, 3, 5 and 7 kV/cm, respectively. A PEF treatment of 5 kV/cm to the orange peels increased the quantity of naringin and hesperidin in the extract of 100 g of orange peels from 1 to 3.1 mg/100 g of fresh weigh (fw) orange peel and from 1.3 to 4.6 mg100 g fw orange peel respectively. Compared to the untreated sample, PEF treatments of 1, 3, 5 and 7 kV/cm increased the antioxidant activity of the extract 51%, 94%, 148% and 192%, respectively.The results of this investigation demonstrate the potential of PEF as a gentle technology to improve the extraction by pressing of polyphenols from fresh orange peel. This procedure enhances the antioxidant capacity of the extracts, reduces extraction times and does not require using organic solvents.Industrial relevanceProcessing of orange fruits to obtain fresh juice or citrus-based drinks generates very large amounts of byproduct wastes, such as peels that are a rich source of polyphenols mainly flavonoids. Extraction of these compounds from orange peels is a crucial step for use of these compounds in the food and pharmaceutical industries as antioxidants. PEF-assisted extraction by pressing of polyphenols from fresh orange peels stands as an economical and environmentally friendly alternative to conventional extraction methods which require the product to be dried, use large amounts of organic solvents and need long extraction times.