Pulsed Electric Field Pretreatment Research Articles

Accelerated pork salting using needle electrode-derived pulsed electric fields

This study aimed to evaluate the effects of pulsed electric field (PEF) pretreatment on the NaCl content, protein composition, and microstructure of pork during the marination process. The results showed that needle PEF could promote salt penetration into the center of pork pieces. Under optimal PEF conditions (3.0 kV/cm, 200 Hz, and 2400 pulses), the marination time could be reduced by almost 12 h. Protein characterization also revealed that PEF pretreatment changes myofibrillar protein properties by promoting salt penetration toward the center of pork. Furthermore, microstructural analysis demonstrated that the enhanced marination effect could be attributed to the PEF treatment-induced expansion of gaps between muscle bundles. Industrial relevanceIn this study, a PEF-assisted curing technique significantly (P < 0.05) improved salt penetration into the center of pork. Reducing the differences between internal and external salt concentrations can produce a more homogeneous marinade and reduce the marination time. Our findings suggest that PEF pretreatment is a promising and effective pretreatment technique for curing meat products.

Effect of Pulsed Electric Fields on the Shelf Stability and Sensory Acceptability of Osmotically Dehydrated Spinach: A Mathematical Modeling Approach.

This study focused on the osmotic dehydration (OD) of ready-to-eat spinach leaves combined with the pulsed electric field (PEF) pre-treatment. Untreated and PEF-treated (0.6 kV/cm, 0-200 pulses) spinach leaves were osmotically dehydrated at room temperature for up to 120 min. The application of PEF (0.6 kV/20 pulses) prior to OD (60% glycerol, 25 °C, 60 min) lowered water activity (aw = 0.891) while achieving satisfactory product acceptability (total sensory hedonic scoring of 8). During the storage of the product (at 4, 8, 12, and 20 °C for up to 30 d), a significant reduction in total microbial count evolution was observed (9.7 logCFU/g for the untreated samples vs. 5.1 logCFU/g for the PEF-OD-treated samples after 13 d of storage at 4 °C). The selection of these PEF and OD treatment conditions enabled the extension of the product shelf life by up to 33 d under chilled storage. Osmotically treated spinach could find application in ready-to-eat salad products with an extended shelf life, which is currently not possible due to the high perishability of the specific plant tissue.

Low-intensity pulsed electric fields pre-treatment on yogurt starter culture: Effects on fermentation time and quality attributes

Low-intensity pulsed electric fields (PEF) were applied to a starter culture mix (Streptococcus thermophilus, Lactobacillus bulgaricus, and partially skimmed milk) before the fermentation stage of natural yogurt. The impact of PEF processing conditions on yogurt fermentation time and quality characteristics was evaluated. PEF parameters were set based on a factorial experimental design; independent variables: electric field strength, pulse-frequency, and pulse-width, were explored, having fermentation time as a response. Most PEF treatments reduced fermentation time by 0.31–0.52 h compared to conventional yogurt processing (CY) (4.70 ± 0.23 h). The shortest time (4.18 ± 0.04 h) resulted from PEF pre-treatment with 8-μs monopolar pulses at 1 kV/cm and 150 Hz during 400 μs. The physicochemical and sensory characteristics of PEF-treated yogurt were similar to those of the CY immediately after processing and during refrigeration storage. Low-intensity PEF could be a promising alternative pre-treatment of yogurt production, reducing fermentation time while maintaining quality attributes of natural yogurt. Industrial relevanceConventional yogurt processing lasts around 4.5–6 h, representing high energy consumption and production costs. The application of pulsed electric fields (PEF) processing to the starter culture before yogurt fermentation represents a potential alternative to diminish production time by stimulating lactic acid bacteria and accelerating fermentation stage. This study demonstrated that low-intensity PEF (1–3 kV/ cm) reduced fermentation time by 0.31–0.52 h without compromising yogurt's quality properties, including physicochemical characteristics and sensory attributes. Obtained results suggest that this technology allows more efficient and sustainable yogurt production methods, positively impacting industry and consumers.

Effects of PEF pretreatment, combined with different drying methods, on the physicochemical properties, bioactive components, antioxidant potential as well as structural and thermal properties of dried yams

This work investigated the effects of pulsed electric field (PEF) pretreatment, combined with different drying methods, on the quality of dried yams. The results showed that the pretreatment resulted in the formation of large pores in the yam tissues, thereby affecting the rehydration capability and hardness of the dried yam slices. The type of drying method after treatment did not alter the free radical stretching bands of yam. Additionally, the pretreated samples had a higher peak viscosity, through viscosity, final viscosity and break down, alongside lower pasting temperatures, To, Tp, Tc, and △H. Rheological measurements further indicated that all doughs exhibited solid-like behavior to different extents. The pretreatment also decreased the amount of allantoin and polysaccharides in dried yam slices, while negatively influencing their antioxidant activity. Finally, the choice of drying methods significantly affected the quality of the dried yams. In highlighting the effects of PEF pretreatment, combined with different drying methods, on dried yam, the results can help to expand their application within the food industry.

Sustainable Valorization of Industrial Cherry Pomace: A Novel Cascade Approach Using Pulsed Electric Fields and Ultrasound Assisted-Extraction.

In this study, a two-stage cascade extraction process utilizing pulsed electric fields (PEF) (3 kV/cm, 10 kJ/kg) for initial extraction, followed by ultrasound (US) (200 W, 20 min)-assisted extraction (UAE) in a 50% (v/v) ethanol-water mixture (T = 50 °C, t = 60 min), was designed for the efficient release of valuable intracellular compounds from industrial cherry pomace. The extracted compounds were evaluated for total phenolic content (TPC), flavonoid content (FC), total anthocyanin content (TAC), and antioxidant activity (FRAP), and were compared with conventional solid-liquid extraction (SLE). Results showed that the highest release of bioactive compounds occurred in the first stage, which was attributed to the impact of PEF pre-treatment, resulting in significant increases in TPC (79%), FC (79%), TAC (83%), and FRAP values (80%) of the total content observed in the post-cascade PEF-UAE process. The integration of UAE into the cascade process further augmented the extraction efficiency, yielding 21%, 49%, 56%, and 26% increases for TPC, FC, TAC, and FRAP, respectively, as compared to extracts obtained through a second-stage conventional SLE. HPLC analysis identified neochlorogenic acid, 4-p-coumaroylquinic, and cyanidin-3-O-rutinoside as the predominant phenolic compounds in both untreated and cascade-treated cherry pomace extracts, and no degradation of the specific compounds occurred upon PEF and US application. SEM analysis revealed microstructural changes in cherry pomace induced by PEF and UAE treatments, enhancing the porosity and facilitating the extraction process. The study suggests the efficiency of the proposed cascade PEF-UAE extraction approach for phenolic compounds from industrial cherry pomace with potential applications to other plant-based biomasses.

Improving the Composition and Bioactivity of Cocoa (Theobroma cacao L.) Bean Shell Extract by Choline Chloride-Lactic Acid Natural Deep Eutectic Solvent Extraction Assisted by Pulsed Electric Field Pre-Treatment.

An environmentally friendly method for the release of cocoa bean shell (CBS) extracts is proposed in this paper. This work aims to investigate the effect of pulsed electric field (PEF) pre-treatment on subsequent solid-liquid extraction (SLE) of metabolites with choline chloride-lactic acid natural deep eutectic solvent (NaDES) and bioactivity of cocoa bean shell (CBS) extract. Two different media for PEF application were evaluated: water and chlorine chloride-lactic acid. Total polyphenols (TPC), total flavonoids (TFC), individual major compounds, and antioxidant and antibacterial activity of CBS extracts were assessed. The performance of PEF-assisted extraction was compared with SLE and ultrasound-assisted extraction (UAE). The proposed method improved the release of TPC up to 45% and TFC up to 48% compared with the conventional extraction. The CBS extract showed medium growth inhibition of Escherichia coli and high growth inhibition of Salmonella sp, Listeria monocytogenes, and Staphylococcus aureus. Thus, an extract with enhanced antioxidant and antibacterial properties was obtained.

Promoting the Aging Process and Enhancing the Production of Antioxidant Components of Garlic through Pulsed Electric Field Treatments.

Shortening the aging duration and enhancing the functional components of garlic present significant technical challenges that need to be addressed. Thus, this study aimed to evaluate the potential role of pulsed electric field (PEF) treatment, a novel nonthermal food processing method, in promoting and enhancing the functional attributes of aged garlic. Our results showed that 2-4 kV/cm PEF pretreatment increased S-allyl cysteine (SAC), total polyphenol (TPC), and flavonoid contents (TFC) compared with un-pretreated garlic during aging. The browning and texture-softening were also significantly improved during processing time, though the latter showed no significant difference from the eighth day to the end of the aging process. The principal component analysis results showed that PEF positively affects the SAC and TFC formations without adverse effects. Among the PEF pretreatments, 3 kV/cm is the most effective in enhancing functional component production compared with the other PEF pretreatments. Therefore, PEF pretreatment is a time-saving process that promotes and enhances the functionality of aged garlic.

Combined effect of pulse electric field and probe ultrasound technologies for obtaining phenolic compounds from orange by-product

Orange peel by-product is a known source of bioactive compounds with several health benefits. This study focuses on optimizing the conditions for pulsed electric field (PEF) technology as a pretreatment to obtain extracts rich in phenolic compounds from the orange peel. A Box-Behnken design of 15 experiments with 3 independent factors (field energy, number of pulses and pulse width) was performed. The phenolic content was extracted by ultrasound technology and analyzed by HPLC-ESI-TOF-MS. Optimum conditions were 1.4 kV/cm and 30 pulses of 110 μs achieving a recovery of 40.8 mg/g dry weight of phenolic compounds, 27.5% higher than obtained without PEF. Besides, hesperidin and narirutin content increased by 29.4 and 38.9%, respectively. For the antioxidant assays also significative increments (≥ 53%) were achieved. The combination of optimized PEF pre-treatment with ultrasound extraction has let to obtain orange peel enriched extracts in polyphenols with higher antioxidant activity.

PEF pre-treatment and ultrasound-assisted drying at different temperatures as a stabilizing method for the up-cycling of kiwifruit: Effect on drying kinetics and final quality

The drying of food by-products, such as kiwifruit discards and surpluses, constitutes an interesting option as a means of stabilizing them for later use. This study assesses the combined influence of the drying temperature (40–70 °C), pulsed electric field (PEF) pretreatment (0–5000 V) and ultrasound (US; 0–50 W) application during the drying of kiwifruit. The increase in temperature, the use of PEF pretreatment or the US application during drying accelerated the process, but it was the combination of the three which led to the highest values of the effective diffusivity and the mass transfer coefficient. Over the range of different conditions studied, the functional and antioxidant properties of dried kiwifruit were not significantly affected, while the color presented some differences, mainly related to the L* and a* coordinates. Therefore, the combination of temperature, PEF and US allowed the processing time to be shortened without significantly affecting the final quality of kiwifruit. Industrial relevance textKiwifruit is one of the most globally popular fruits. Its high moisture content makes its by-products susceptible to chemical and microbiological degradation, so a drying step is needed to prolong its shelf-life and make up-cycling possible. To this end, hot air drying is one of the most widely-used techniques in the food industry, whose main drawback is a large amount of energy consumed. Therefore, there is a need to look for alternatives to reduce its economic and environmental impact and achieve a quality dried product. This study points out the combination of drying temperature, PEF pretreatments and ultrasound-assisted drying for the purposes of shortening the drying process while preserving the quality of the final product. These results, therefore, underline the promising nature of these techniques not only as regards their application in kiwifruit drying but also in the drying of other fruits and vegetables.

Nutritional Value and Microbiological Aspects of Dried Yellow Mealworm (Tenebrio molitor L.) Larvae Pretreated with a Pulsed Electric Field

Complete protein, which includes all the essential amino acids, and bioactive compounds needed in human nutrition, can be found in edible insects. Bioactive compounds play a crucial role in protecting cells from the damage caused by free radicals. Therefore, in this study, fat extraction yield, protein content, amino acid profile, total polyphenol content, antioxidant properties, crustacean and mollusk content, and microbiological quality have been assessed to evaluate the influence of the drying method and pulsed electric field (PEF) pretreatment. To this end, the sample was processed by the PEF at varied specific energy intakes (5, 20, and 40 kJ/kg) and dried by means of two methods: convective (CD) and infrared-convective (IR-CD). A comparable protein content (47.5–48.7 g/100 g d.m.) was determined for most of the samples tested. A significantly higher lysine and methionine content was detected in the CD insects, especially for samples treated by the PEF at 40 kJ/kg. The IR-CD samples exhibited a significantly higher content of polyphenols as compared to those obtained by means of the CD method, whereas the PEF apparently had a significant impact to the extent of increasing their content. Taking into account allergenicity, the crustacean content was approximately 10 times higher than the mollusk content. The study has shown that the PEF treatment prior to infrared-convective drying resulted in the assurance of the microbiological quality of dried insects for food use. Furthermore, a dose of the PEF at 20 and 40 kJ/kg demonstrated the antimicrobial effect. The results have proven that, in this case, a high temperature during the CD method did not cause the undesirable changes that had been expected. Therefore, PEF-assisted convective drying may conceivably be considered to obtain highly nutritionally valuable insects; however, it is crucial to utilize appropriate parameters in the course of the PEF processing.

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.

Quality evaluation of house cricket flour processed by electrohydrodynamic drying and pulsed electric fields treatment

House crickets are expected to play a significant role in the future food sector. Electrohydrodynamic (EHD) drying offers an environmentally friendly alternative to conventional drying methods. Pulsed electric fields (PEF) is a non-thermal process that facilitates conventional processes. EHD was applied to house crickets with and without PEF pretreatment, and the effect of PEF and EHD on the quality of the insects was evaluated. PEF pretreatment positively affected the oven drying at 60 °C by reducing its duration and thus decreasing the energy consumption by 14.22%. Moisture removal of EHD was not sufficient to replace oven drying, but when combined with oven drying, the overall energy consumption was reduced by >50%. PEF processing also increased the protein solubility (53.07% higher than the respective control) and antioxidant activity (24.05% higher than the respective control) of the oven-dried samples and reduced the histamine content of the EHD-dried samples (25.87% lower than the respective control).

Effect of Pulsed Electric Field Technology on the Composition and Bioactive Compounds of Black Soldier Fly Larvae Dried with Convective and Infrared-Convective Methods.

In recent years, an increasing interest has been shown in alternative food sources. Many studies are focused on the use of insects. The aim of this study was to investigate the changes in the chemical and thermal properties of black soldier fly larvae influenced by the pulsed electric field (PEF) and convective (CD) or infrared-convective (IR-CD) drying techniques. Examinations of the basic chemical composition, properties of extracted fat (fatty acid composition, acid and peroxide values, and oxidative stability), total polyphenol content, antioxidant activity, allergen content, and thermogravimetric analysis (TGA) were performed. Generally, the results showed that dried black soldier fly larvae are a good source of protein and fat, up to 33% and 44%, respectively. The fat extracted from the dried insects consisted mainly of saturated fatty acids (above 75%), in particular lauric acid (C12:0). A good oxidative stability of the fat was also observed, especially from samples dried with the IR-CD method. The convective drying technique allowed for better preservation of protein content compared to samples dried with the IR-CD method. Nevertheless, samples treated with PEF were characterized by significantly lower protein content. The samples after PEF pretreatment, with an intensity of 20 and 40 kJ/kg and dried with the IR-CD method, were represented by a significantly higher total polyphenol content and antioxidant activity. Furthermore, in most cases, the convectively dried samples were characterized by a higher allergen content, both crustaceans and mollusks. Taking into account all of the investigated properties, it can be stated that the samples without treatment and those that were PEF-treated with an intensity of 40 kJ/kg and dried with the infrared-convective method (IR-CD) were the most rewarding from the nutritional point of view.

Optimizing the solvent extraction process for high-value compounds from sweet cherry press cake treated with pulsed electric fields using response surface methodology

Introduction: Cherry juice production generates substantial cherry processing by-products, presenting a significant environmental challenge. The valorization of these by-products can not only reduce management costs but also enhance profitability by recovering valuable intracellular compounds.Methods: This study aimed at the extraction of bioactive compounds with potent antioxidant activity from sweet cherry press cake using Pulsed Electric Fields (PEF)-assisted extraction. PEF pre-treatment, carried out using a predetermined field strength (E = 3 kV/cm) and total specific energy input (WT = 10 kJ/kg), was applied to the cherry press cake prior to the subsequent solid-liquid extraction (SLE) stage. To optimize the SLE process for both untreated and PEF-treated samples, Response Surface Methodology (RSM) was employed to determine the most effective extraction parameters, including extraction temperature (20–50°C), solvent concentration (0–50% ethanol in water), solid-liquid ratio (0.05–0.2 g/mL), and diffusion time (30–360 min). The objective was to maximize key response variables: total phenolic content (TPC), flavonoid content (FC), total anthocyanin content (TAC), and antioxidant activity (FRAP). The extracts obtained from both untreated and PEF-treated samples under optimal conditions underwent HPLC-DAD analysis.Results and discussion: The results revealed that, under optimized SLE conditions (50°C, 50% ethanol-water mixture, 0.2 g/mL solid-liquid ratio, and 360 min extraction time), PEF pre-treatment significantly enhanced the extractability of high-value compounds. This resulted in notable increases in TPC (+26%), FC (+27%), TAC (+42%), and antioxidant activity (+44%) compared to conventional SLE. Additionally, the application of PEF reduced extraction time (by 5–18 min) and solvent usage (by 2%). HPLC analysis identified cyanidin-3-O-rutinoside as the predominant phenolic compound in both untreated and PEF-treated extracts, with a remarkable increase (+2.3-fold) after PEF application. These findings underscore the potential of PEF-assisted extraction as a promising approach to maximize the recovery of valuable compounds from sweet cherry press cake, contributing to food waste reduction and enhanced value generation from by-products.

Pulsed Electric Field Applications for the Extraction of Bioactive Compounds from Food Waste and By-Products: A Critical Review

The food processing industry is a continuously developing sector that uses innovative technologies to efficiently process food products. During processing, food industries generate substantial amounts of by-products in the form of waste materials. This food waste consists of organic matter rich in bioactive compounds, such as polyphenols, carotenoids, and flavonoids. Improper management of food waste can adversely affect both the environment and human health, leading to environmental pollution and the release of greenhouse gas emissions. Thus, proper food waste management has become an urgent global issue. The presence of bioactive compounds (mainly polyphenols, flavonoids, and anthocyanins, but also carotenoids, alkaloids, proteins, lipids, and carbohydrates) in food waste holds the potential to transform them into valuable resources. Several sectors, including food and energy, have recognized food waste as an innovative source. Recently, much emphasis has been placed on optimizing the extraction yield of such bioactive compounds through the utilization of environmentally friendly and sustainable methodologies and solvents. Pulsed electric field (PEF)-assisted extraction is an emerging technique that holds promise for the utilization of waste materials. PEF technology can efficiently optimize the extraction of valuable compounds within a shorter time while minimizing solvent and energy consumption. In this review, we provide a comprehensive overview of the current state of PEF technology and its implications for recovering bioactive compounds from food waste. The integration of innovative technologies like PEF in the food processing industry can play a crucial role in managing food waste sustainably, reducing environmental impact, and harnessing the full potential of bioactive compounds contained in these waste materials. The objective of this critical review is to provide an overview of the utilization of PEF pretreatment for food by-products and to conduct a comparative analysis with other extraction techniques.

Pulsed electric field for shalgam juice: effects on fermentation, shelf-life, and sensory quality.

Pulsed electric field (PEF) has become a reality in the food industry as a non-thermal application. PEF is used due to its benefits such as increasing the extraction of anthocyanin or other bioactive substances, shortening the fermentation time, and reducing the microbiological load by electroporation. This study aimed to determine the effect of PEF pretreatment on the fermentation, chemical, microbiological, and sensory properties of shalgam juice. For this purpose, PEF with 1 kV cm-1 of field strength was used as a pretreatment for shalgam juice and changes in control and PEF-treated samples were monitored during fermentation and 70 days of cold storage (4 °C). The pH and lactic acid content during fermentation were similar for both samples. The effect of PEF on pH (3.15-3.39), titratable acidity (4.35-5.49 g L-1 ), total phenolic content (279-766 mg mL-1 GAE) and antioxidant activity (694-2091 μmol Trolox mL-1 ) during storage was insignificant. PEF-treated samples had lower total aerobic mesophilic bacteria (~9%) and lactic acid bacteria (~3%) counts than the control samples at the end of 70 days. Sensory analyses performed at 30th and 60th days of storage with 74 panelists revealed that the color, taste, sourness, saltiness, bitterness, and general acceptability were not inversely affected by PEF. Our results could be a basis to produce shalgam juice commercially by PEF treatment. Although more studies with new experimental designs should be carried out, preliminary results indicated that the use of PEF might have a potential for fermented products such as shalgam juices. © 2023 Society of Chemical Industry.

Modelling and Evaluation of the Effect of Pulsed Electric Fields and High Pressure Processing Conditions on the Quality Parameters of Osmotically Dehydrated Tomatoes

This study explores the osmotic dehydration (OD) of fresh-cut cherry tomatoes through the application of Pulsed Electric Fields (PEF) and High-Pressure (HP) pre-treatments. Untreated, PEF-treated (1.8 kV/cm, 0–300 pulses), and HP-treated (0–600 MPa, 5 min) tomatoes were subjected to osmotic dehydration at 35 °C for up to 3 h. The results reveal that a 100-pulse PEF treatment and HP treatment at 600 MPa yielded optimal outcomes in terms of both OD enhancement (with effective moisture diffusion coefficients of 7.91 · 10−10 m2/s for PEF and 7.40 · 10−10 m2/s for HP-treated tomatoes compared to 5.17 · 10−10 m2/s for untreated samples) and product acceptability (achieving overall acceptance scores between 7 and 8). Applying PEF (100 pulses) and HP (600 MPa) pre-treatments reduced the water activity (aw) to 0.887 and 0.760, respectively, after 3 h of OD, compared to aw = 0.923 for untreated OD samples. The selection of these pre-treatment conditions enabled effective dehydration and quality retention, extending the shelf life by up to 40 days under chilled storage.

Assessment of the effect of air humidity and temperature on convective drying of apple with pulsed electric field pretreatment

This research aims at assessing the impact of pulsed electric field (PEF) pretreatment and various properties of drying agent (absolute humidity, temperature) on the course of convective drying (CD) of apples. Moreover, the selected quality indicators of obtained dried materials (dry matter content, water activity, hygroscopicity, rehydration, color, total phenolic content, antioxidant activity) have been evaluated. As a result of increased permeabilization of cells, PEF reduced time of CD of apples even by 20%. However, lower total phenolic content and antioxidant activity in PEF-pretreated dried samples were observed. With the use of PEF, the release of phenolic compounds from the cellular structures of the apple tissue could occur, making them more susceptible to thermal degradation. After introducing the dehumidification system, an increase in the drying time of apples was observed. It could be so due to case hardening, which further deteriorated the reconstitution properties of the obtained dried materials.

High-intensity pulsed electric field-assisted acidic extraction of pectin from citrus peel: Physicochemical characteristics and emulsifying properties

Sustainable innovation seeks more energy-efficient processes for producing highly demanded products from industrial by-products. This study follows this endeavor. Comparisons were made on two processes for producing pectins from citrus peel as well as the two derived pectin products: a high-intensity pulsed electric field (HIPEF) pretreatment of citrus peel powder followed by a milder acidic extraction (pH 2, heating at 70 °C for 1 h; pectin termed HIPEF-CP), and a conventional direct hot-acid extraction (pH 2, heating at 90 °C for 2 h; pectin termed CP). HIPEF-assisted extraction significantly improved pectin yield (by 8.48%) and production efficiency (by 100.23%) while reducing energy consumption. Both were low-methoxyl pectins with similar branching degrees and contents of rhamnogalacturonan-I (RG-I), protein, phenolic compounds, total alkaloids and vitamin C. Compared with CP, HIPEF-CP contained higher homogalacturonan content, higher galactose content, higher galacturonic acid content, lower arabinose content, lower xylose content, slightly lower degree of methyl esterification, higher linearity, lower side chain size, higher molecular weight, and wider molecular weight distribution. The antioxidant, emulsifying and emulsion-stabilizing abilities of HIPEF-CP were superior to those of CP, though both pectins were satisfactory emulsifiers, exhibiting good antioxidant activities and emulsifying capacities at pectin concentrations not lower than 1.0%. The HIPEF pretreatment of citrus peel made the subsequent acidic pectin extraction feasible under milder conditions, to produce pectin with desired antioxidant and emulsifying capacities.

Pulsed Electric Field-Assisted Enzymatic and Alcoholic-Alkaline Production of Porous Granular Cold-Water-Soluble Starch: A Carrier with Efficient Zeaxanthin-Loading Capacity.

In this study, porous starch was modified using pulsed electric field (PEF) pretreatment and alcoholic-alkaline treatment to prepare porous granular cold-water-soluble starch (P-GCWSS). The soluble porous starch has high adsorption capability and high cold water solubility, allowing effective encapsulation of zeaxanthin and improving zeaxanthin's water solubility, stability, and bioavailability. The physical and chemical properties of GCWSS and complex were investigated using scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray diffraction. The results showed that the cold water solubility of the pulsed electric field-treated porous granular cold-water-soluble starch (PEF-P-GCWSS) increased by 12.81% compared to granular cold-water-soluble starch (GCWSS). The pulsed electric field treatment also increased the oil absorption of PEF-P-GCWSS was improved by 15.32% compared to porous granular cold-water-soluble starch (P-GCWSS). PEF-P-GCWSS was effective in encapsulating zeaxanthin, which provided a good protection for zeaxanthin. The zeaxanthin-saturated solubility in water of PPG-Z was increased by 56.72% compared with free zeaxanthin. The zeaxanthin embedded in PEF-P-GCWSS was able to be released slowly during gastric digestion and released rapidly during intestinal digestion.