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Chicken egg white (EW) proteins possess various useful techno-functionalities, including foaming, gelling or coagulating, and emulsifying. The gelling property is one of the most important functionalities of EW proteins, affecting their versatile applications in the food and pharmaceutical industries. However, it is challenging to develop high-quality gelled foods and innovative nutraceutical supplements using native EW and its proteins. This review describes the gelling properties of EW proteins. It discusses the development and action mechanism of the physical, chemical, and biological methods and exogenous substances used in the modification of EW gels. Two main applications of EW gels, i.e., gelling agents in foods and gel-type carriers for nutraceutical delivery, are systematically summarized and discussed. In addition, the research and technological gaps between modified EW gels and their applications are highlighted. By reviewing the new modification strategies and application trends of EW gels, this paper provides insights into the development of EW gel-derived products with new and functional features. [ABSTRACT FROM AUTHOR]

Egg white proteins (EWPs) are valuable ingredients in the food industry due to their unique functional properties, including gelling, foaming, and emulsifying. The gelation properties of EWPs are particularly important, as they serve as the foundation for many food applications. The denaturation and aggregation of EWPs lead to the formation of a dense three-dimensional gel network structure, which is influenced by both intrinsic and extrinsic factors. EWPs’ gels can be formed through physical and chemical methods, with heating being the most common approach. Researchers have recently explored novel processes to modify the gelation properties of EWPs, which have shown promising results. Importantly, EWPs are crucial components of various food formulations, including surimi and other meat- and plant-based food products. Previous studies have focused on the basic gelation properties of EWPs, but the effect of advanced technologies and intrinsic and extrinsic factors on their gelation potential have not been systematically reviewed. Hence, this review paper provides a systematic overview of the research around the gelation properties of EWPs and their application, serving as a guide for researchers and industry professionals to explore the versatility and value of EWPs as substantial food ingredients. [ABSTRACT FROM AUTHOR]

Chicken egg white (EW) proteins possess various useful techno-functionalities, including foaming, gelling or coagulating, and emulsifying. The gelling property is one of the most important functionalities of EW proteins, affecting their versatile applications in the food and pharmaceutical industries. However, it is challenging to develop high-quality gelled foods and innovative nutraceutical supplements using native EW and its proteins. This review describes the gelling properties of EW proteins. It discusses the development and action mechanism of the physical, chemical, and biological methods and exogenous substances used in the modification of EW gels. Two main applications of EW gels, i.e., gelling agents in foods and gel-type carriers for nutraceutical delivery, are systematically summarized and discussed. In addition, the research and technological gaps between modified EW gels and their applications are highlighted. By reviewing the new modification strategies and application trends of EW gels, this paper provides insights into the development of EW gel-derived products with new and functional features.

Glucose oxidase (GOx) is a typical model enzyme used to create biosensors. Exploring a strategy to prepare ready-to-use functional enzymatic microparticles combining GOx and food-based proteins offers compelling advantages. However, no reports exist on the integration of egg white materials to synthesize functional biorecognition particles with glucose oxidation catalytic functions for electrochemical biosensors. Here, we demonstrate functional microparticles combining egg white proteins, GOx, and 9,10-phenanthrenequinone (PQ). The egg white proteins crosslink to form three-dimensional scaffolds to accommodate GOx and redox molecules. The PQ mediator enhances electron transfer between the electrode surface and the GOx enzyme's flavin adenine dinucleotides. The functional microparticles are directly applied to the printed electrode. The performance of these microparticles is evaluated using a screen-printed carbon nanotube (CNT)-modified electrode coated with GOx/PQ/egg white protein microparticles. The analytical performance of the system exhibits a linear range of 0.125−40 mM, with a maximum current ( I m a x) and a Michaelis–Menten constant (K m) being 0.2 µA and 4.6 mM, respectively. Additionally, a decomposable electrode composed of CNTs and edible oil conjugated with functional enzyme microparticles is shown to undergo degradation under gastric conditions. Utilizing food-based proteins to accommodate enzymes and to create redox-active microparticles for catalyzing glucose oxidation offers advantages in developing affordable and degradable bioelectrodes. This concept holds promise for advancing biocompatible electrodes in biosensor and bioelectronics applications. [ABSTRACT FROM AUTHOR]

It has been estimated and demonstrated that the antioxidant capacity of proteins is increased as a result of digestion in the gastrointestinal tract, which can be contributed by denaturation and digestion. This study aimed to evaluate the effect of denaturation and proteolytic digestion on the antioxidant activity of bovine serum albumin (BSA) and chicken egg white proteins in model systems. Denaturation with an anionic detergent (sodium dodecyl sulfate) and digestion with papain and trypsin increased the antioxidant activity/capacity of the proteins, apparently due to the increased exposure of amino acid residues responsible for the antioxidant activity of proteins (tyrosine, tryptophan, cysteine, histidine, arginine, and cystine in the ABTS● decolorization assay; cysteine, tryptophan, tyrosine, and cystine in the FRAP assay). As the increase in the protein antioxidant activity/capacity was limited in extent, it does not invalidate the use of the antioxidant capacity of proteins to be consumed as a rough measure of their antioxidant capacity after modifications in the gastrointestinal tract. [ABSTRACT FROM AUTHOR]

In an effort to reduce greenhouse gas emission, reduce the consumption of natural resources, and increase the sustainability of biocomposite foams, the present study focuses on the recycling of cork processing waste for the production of lightweight, non-structural, fireproof thermal and acoustic insulating panels. Egg white proteins (EWP) were used as a matrix model to introduce an open cell structure via a simple and energy-efficient microwave foaming process. Samples with different compositions (ratio of EWP and cork) and additives (eggshells and inorganic intumescent fillers) were prepared with the aim of correlating composition, cellular structures, flame resistance, and mechanical properties. [ABSTRACT FROM AUTHOR]

Glucose oxidase (GOx)-based electrodes are important for bioelectronics, such as glucose sensors. It is challenging to effectively link GOx with nanomaterial-modified electrodes while preserving enzyme activity in a biocompatible environment. To date, no reports have used biocompatible food-based materials, such as egg white proteins, combined with GOx, redox molecules, and nanoparticles to create the biorecognition layer for biosensors and biofuel cells. This article demonstrates the interface of GOx integrated with egg white proteins on a 5 nm gold nanoparticle (AuNP) functionalized with a 1,4-naphthoquinone (NQ) and conjugated with a screen-printed flexible conductive carbon nanotube (CNT)-modified electrode. Egg white proteins containing ovalbumin can form three-dimensional scaffolds to accommodate immobilized enzymes and adjust the analytical performance. The structure of this biointerface prevents the escape of enzymes and provides a suitable microenvironment for the effective reaction. The bioelectrode's performance and kinetics were evaluated. Using redox-mediated molecules with the AuNPs and the three-dimensional matrix made of egg white proteins improves the transfer of electrons between the electrode and the redox center. By engineering the layer of egg white proteins on the GOx-NQ-AuNPs-mediated CNT-functionalized electrodes, we can modulate analytical performances such as sensitivity and linear range. The bioelectrodes demonstrate high sensitivity and can prolong the stability by more than 85% after 6 h of continuous operation. The use of food-based proteins with redox molecule-modified AuNPs and printed electrodes demonstrates advantages for biosensors and energy devices due to their small size, large surface area, and ease of modification. This concept holds a promise for creating biocompatible electrodes for biosensors and self-sustaining energy devices. [ABSTRACT FROM AUTHOR]

The application of unstable nutraceuticals in food formulation will be encouraged by designing delivery vehicles through the assembly of biopolymers at a variety of scales, from nanoscopic to macroscopic. Due to their high nutritional value and natural occurrence, egg white proteins (EWPs) have garnered interests recently for use as building blocks. In this review, the physicochemical properties of EWPs and the main techniques to promote their assembly were discussed at first. Following that, a thorough summary of current research was provided on the biopolymer- and emulsion-type carriers, which were created by assembling EWPs with or without the presence of exogenous proteins, polysaccharides, polyphenols, or functional groups. Furthermore, these carriers' stabilizing effects on curcumin, polyunsaturated fatty acids, vitamins, catechins, anthocyanins, carotenoids and resveratrol were categorized and emphasized. Lastly, we put forth the concerns and further perspectives of the EWPs-based delivery systems. A deeper comprehension of the relationship between structure and function clarifies the rational designation of EWPs-based carriers with desired properties. [Display omitted] • EWPs are suitable building blocks for edible biopolymer- and lipid-type vehicles. • EWPs are triggered to assemble with themselves or other compounds to create vehicles. • These carriers improved the stability, bioactivity and bioavailability of the loaded agent. • Mucopenetration, gut fermentation and allergenicity are top safety concerns. • EWP-based 3D/4D printing, fat substitutes and intelligent systems require more research. [ABSTRACT FROM AUTHOR]

Glucose oxidase (GOx) is a typical model enzyme used to create biosensors. Exploring a strategy to prepare ready-to-use functional enzymatic microparticles combining GOx and food-based proteins offers compelling advantages. However, no reports exist on the integration of egg white materials to synthesize functional biorecognition particles with glucose oxidation catalytic functions for electrochemical biosensors. Here, we demonstrate functional microparticles combining egg white proteins, GOx, and 9,10-phenanthrenequinone (PQ). The egg white proteins crosslink to form three-dimensional scaffolds to accommodate GOx and redox molecules. The PQ mediator enhances electron transfer between the electrode surface and the GOx enzyme’s flavin adenine dinucleotides. The functional microparticles are directly applied to the printed electrode. The performance of these microparticles is evaluated using a screen-printed carbon nanotube (CNT)-modified electrode coated with GOx/PQ/egg white protein microparticles. The analytical performance of the system exhibits a linear range of 0.125−40 mM, with a maximum current (Imax) and a Michaelis–Menten constant (Km) being 0.2 µA and 4.6 mM, respectively. Additionally, a decomposable electrode composed of CNTs and edible oil conjugated with functional enzyme microparticles is shown to undergo degradation under gastric conditions. Utilizing food-based proteins to accommodate enzymes and to create redox-active microparticles for catalyzing glucose oxidation offers advantages in developing affordable and degradable bioelectrodes. This concept holds promise for advancing biocompatible electrodes in biosensor and bioelectronics applications.

Egg white proteins (EWP) were prone to thermal aggregation under heat sterilization conditions, thereby limiting their application in the field of protein beverages. In this study, EWP were microgel particleized via polysaccharide-protein phase separation to enhance their resistance to thermal aggregation during processing. Results indicated that the charge characteristics of polysaccharides were crucial factors influencing their interaction with EWP. Microstructural and physicochemical properties indicated that egg white protein microgel particles (EMGP) with the bilayer structure formation (polysaccharide shell layer and dense protein core) could only be formed in the phase separation system of EWP and anionic polysaccharides (carboxymethyl cellulose sodium salt (low viscosity), carboxymethyl cellulose sodium salt (high viscosity), High-methoxyl pectin). Additionally, the EMGP exhibited uniform size, high denaturation extent and dense structure that effectively prevented structural unfolding and exposure of active sites upon reheating of the EWP. The thermal denaturation temperatures of the EMGP were significantly higher (up to 155.8 °C, 163.5 °C, 165.7 °C), compared to natural proteins (88.8 °C). Thermal stability experiments confirmed that the suspension of 5% w/v microgel particles maintained good flow ability after heating at 100 °C for 30 min, demonstrating excellent thermal stability suitable for high-temperature pasteurization conditions. Moreover, its uniform particle size and adsorption of polysaccharides improved storage stability. In contrast, groups other than anionic polysaccharides exhibited aggregation and gelation upon heating. Overall, this study demonstrated that preparing heat-stable EMGP effectively reduces aggregation in EWP beverages during heat-pasteurization, enhanced product sensory attributes, extended shelf-life, and expanded the application scope of EWP. [Display omitted] • Proteins and anionic polysaccharides phase separated to form microgel particles. • Microgel particles had uniform size, high denaturation extent and dense structure. • Microgel particleization contributed to the thermal stability of proteins. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the mechanism of NaCl perturbed preheat–treated egg white proteins' (EWPs) physicochemical and structural properties to modulate the foaming property (FP). The results revealed that NaCl regulated the salinolysis (5 mM) – salt precipitation (50 mM) – gradual or complete coverage with hydrated Na+ of the hydration layer (100–300 mM) – enhanced Cl− hydration repulsion (500 mM) of EWP, showing a gradual decrease in aggregates particle size, and reversibility of structural freedom, including moleculer flexibility and surface hydrophobicity. Whereas preheating temperature affected the secondary structure rearrangement and tertiary conformation exposure, and excessive temperature reduced foaming capacity while enhanced foam stability, with a tight correlation between NaCl–mediated EWPs' FP and the extent of Na+ covering the hydration layer. The findings provide a theoretical basis for processing factors to modulate the protein hydration layer to influence the functional properties. [Display omitted] • NaCl enhanced solubility of aggregates along with reversible surface structure. • FTIR reflected the changes of protein water molecule layer. • Preheating at 66 °C greatly improving foam stability. • 500 mM Na+ completely occupied the hydration layer of EWPs. • 5 mM NaCl promoted the foaming capacity of 60 °C preheated treated EWPs. [ABSTRACT FROM AUTHOR]

[Display omitted] • Glycosylation tuned structural and interfacial properties of egg white proteins. • EWPG exhibited better interactions with aliphatic amino acids. • EWPG-stabilized HIPPEs demonstrated superior physical stability. • EWPG-stabilized HIPPEs could co-deliver anthocyanins and melatonin. • The FFA release of HIPPEs followed the first-order kinetic model. This study was oriented towards the impacts of unique interfacial networks, formed by glycosylated and non-glycosylated egg white proteins, on the characteristics of high internal phase Pickering emulsions (HIPPEs). Glycosylated egg white protein particles (EWPG) manifested a more compact protein tertiary structure and amplified surface hydrophobicity, forming durable coral-like networks at the oil-water interface. The non-glycosylated egg white protein particles (EWP) could form spherical cluster interfacial networks. Raman spectroscopy analysis illuminated that EWPG could exhibit better interactions with aliphatic amino acids via hydrogen bonds and hydrophobic interactions. The release of free fatty acid (FFA) from both HIPPEs followed the first-order kinetic model with a combination of diffusion. EWPG-stabilized HIPPEs demonstrated superior physical stability and cellular antioxidant activity. This research shed light on the promising prospects of HIPPEs as promising amphiphilic delivery systems with capabilities to co-deliver hydrophilic and hydrophobic nutraceuticals and amplify their intracellular biological potency. [ABSTRACT FROM AUTHOR]

In an effort to reduce greenhouse gas emission, reduce the consumption of natural resources, and increase the sustainability of biocomposite foams, the present study focuses on the recycling of cork processing waste for the production of lightweight, non-structural, fireproof thermal and acoustic insulating panels. Egg white proteins (EWP) were used as a matrix model to introduce an open cell structure via a simple and energy-efficient microwave foaming process. Samples with different compositions (ratio of EWP and cork) and additives (eggshells and inorganic intumescent fillers) were prepared with the aim of correlating composition, cellular structures, flame resistance, and mechanical properties.

Glucose oxidase (GOx)-based electrodes are important for bioelectronics, such as glucose sensors. It is challenging to effectively link GOx with nanomaterial-modified electrodes while preserving enzyme activity in a biocompatible environment. To date, no reports have used biocompatible food-based materials, such as egg white proteins, combined with GOx, redox molecules, and nanoparticles to create the biorecognition layer for biosensors and biofuel cells. This article demonstrates the interface of GOx integrated with egg white proteins on a 5 nm gold nanoparticle (AuNP) functionalized with a 1,4-naphthoquinone (NQ) and conjugated with a screen-printed flexible conductive carbon nanotube (CNT)-modified electrode. Egg white proteins containing ovalbumin can form three-dimensional scaffolds to accommodate immobilized enzymes and adjust the analytical performance. The structure of this biointerface prevents the escape of enzymes and provides a suitable microenvironment for the effective reaction. The bioelectrode’s performance and kinetics were evaluated. Using redox-mediated molecules with the AuNPs and the three-dimensional matrix made of egg white proteins improves the transfer of electrons between the electrode and the redox center. By engineering the layer of egg white proteins on the GOx-NQ-AuNPs-mediated CNT-functionalized electrodes, we can modulate analytical performances such as sensitivity and linear range. The bioelectrodes demonstrate high sensitivity and can prolong the stability by more than 85% after 6 h of continuous operation. The use of food-based proteins with redox molecule-modified AuNPs and printed electrodes demonstrates advantages for biosensors and energy devices due to their small size, large surface area, and ease of modification. This concept holds a promise for creating biocompatible electrodes for biosensors and self-sustaining energy devices.

Food allergy has become an important food safety concern affecting people's health and quality of life. As one of the most common allergic foods, egg poses a safety hazard to susceptible individuals. Therefore, it is crucial to develop rapid and sensitive detection methods for allergen monitoring. Sandwich ELISA detection method was developed based on two polyclonal antibodies for the detection of egg white allergens in this study. Goat antisera and rabbit antisera are used as capture antibodies and detection antibodies, respectively. The detection limit of this ELISA detection method is 0.105 ng/mL with high specificity to egg white proteins, and the linear range is between 1 and 20 ng/mL. The mean recovery rate ranges from 70.27 to 101.95% and the mean coefficients of variation of intra-assay and inter-assay are within 2.73% and 9.19%, respectively. The sandwich ELISA detection method can be effectively used for the detection of egg proteins in foods on the market and will help reduce the incidence of egg allergy. [ABSTRACT FROM AUTHOR]

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In the present study, the fresh egg white was employed as a carrier for enhancing the aqueous solubility and antioxidant activity of the curcumin as a bioactive hydrophobic ingredient. The curcumin-egg white protein complexes were prepared at pH values of 7.0 and 3.0. The results indicated that the binding of curcumin to egg white proteins at pH values of 7.0 and 3.0 drastically improved its water solubility. The fluorescence measurements showed that the hydrophobic interactions were generated between the curcumin and proteins. The curcumin-loaded egg white prepared at pH 7.0 and 3.0 also had a good antioxidant activity that was measured by radical (ABTS and DPPH) scavenging activity and reducing power test. In general, the findings of this study suggested that the egg white can be considered as an efficient system for increasing the aqueous solubility and antioxidant activity of curcumin which enhances its applications in different fields including food, cosmetic, and pharmaceutical industries.

Background: Hen's egg white (HEW) is the most common cause of food allergy in children which induces mild to fatal reactions. The consultation for a proper restriction is important in HEW allergy. We aimed to identify the changes in HEW allergenicity using diverse cooking methods commonly used in Korean dishes., Methods: Crude extract of raw and 4 types of cooked HEW extracts were produced and used for sodium dodecyl-sulfate polyacrylamide gel electrophoresis (SDS-PAGE), enzyme-linked immunosorbent assay (ELISA), and ELISA inhibition assays using 45 serum samples from HEW allergic and tolerant children. Extracts were prepared; scrambled without oil for 20-30 seconds in frying pan without oil, boiled at 100°C for 15 minutes, short-baked at 180°C for 20 minutes, and long-baked at 45°C for 12 hours with a gradual increase in temperature up to 110°C for additional 12 hours, respectively., Results: In SDS-PAGE, the intensity of bands of 50-54 kDa decreased by boiling and baking. All bands almost disappeared in long-baked eggs. The intensity of the ovalbumin (OVA) immunoglobulin E (IgE) bands did not change after scrambling; however, an evident decrease was observed in boiled egg white (EW). In contrast, ovomucoid (OM) IgE bands were darker and wider after scrambling and boiling. The IgE binding reactivity to all EW allergens were weakened in short-baked EW and considerably diminished in long-baked EW. In individual ELISA analysis using OVA + OM + serum samples, the median of specific IgE optical density values was 0.435 in raw EW, 0.476 in scrambled EW, and 0.487 in boiled EW. Conversely, it was significantly decreased in short-baked (0.406) and long-baked EW (0.012). Significant inhibition was observed by four inhibitors such as raw, scrambled, boiled and short-baked HEW, but there was no significant inhibition by long-baked HEW (IC 50 > 100 mg/mL)., Conclusion: We identified minimally reduced allergenicity in scrambled EW and extensively decreased allergenicity in long-baked EW comparing to boiled and short-baked EW as well as raw EW. By applying the results of this study, we would be able to provide safer dietary guidence with higher quality to egg allergic children., Competing Interests: The authors have no potential conflicts of interest to disclose., (© 2024 The Korean Academy of Medical Sciences.)

Electrospun polyacrylonitrile (PAN) nanofiber membrane was functionalized with chitosan and proteins for use in the treatment of dye-containing wastewater. The PAN nanofiber membrane was subjected to alkaline hydrolysis, before being grafted with chitosan and subsequently the proteins from chicken egg white. The resultant nanofiber membrane (P-COOH-CS-CEW) was comprehensively characterized using thermogravimetric analysis, Fourier-transform infrared spectroscopy, and scanning electron microscopy. The efficiency of P-COOH-CS-CEW in removing cationic dye toluidine blue O (TBO) and anionic dye acid orange 7 (AO7) in aqueous solution was evaluated. Based on the performance of model fitting, Langmuir and pseudo-second-order kinetic model could be used to describe the performance of P-COOH-CS-CEW in the removal of TBO (pH 10) and AO7 (pH 2) from the dye solutions. The adsorbed TBO and AO7 dyes can be completely desorbed by an elution solution made of 50% (v/v) ethanol and 1 M sodium chloride. After five consecutive adsorption-desorption cycles, the efficiency of dye removal by P-COOH-CS-CEW was maintained above 97%.

Egg white proteins are one of the major allergens. The objective of this study was to investigate the effect of Aspergillus oryzae cultivation on IgE binding ability of egg white proteins. Effect of A. oryzae on egg white proteins was determined using ninhydrin method, SDS-PAGE, ELISA, fluorescence FITC labeling, MALDI-TOF-MS and LC-MS/MS analysis. Adding mycelium of A. oryzae ATCC 1011 and 16868 substantially reduced the IgE binding ability of acidified egg white after 24 h incubation. The binding capacity of egg white proteins to IgE in plasma from four egg allergy patients was almost completely lost after incubation with mycelium of ATCC 16868. Results from SDS-PAGE, free amino acid analysis, MALDI-TOF-MS and LC-MS/MS indicated that there was no substantial protein degradation during incubation. Therefore, the reduction of IgE binding ability of egg white proteins during A. oryzae treatment was probably due to a loss of ~1700 Da mass including a fragment of the ovomucoid N terminus.

Quality protein maize (QPM) is nutritionally improved maize which has twice the amount of lysine and tryptophan than normal maize. The present study evaluated the effect of different proteins namely egg white proteins (EWP), casein, whey protein isolate, soy protein isolate (SPI) on characteristics of gluten free QPM based muffins. QPM muffins without any added protein served as control and muffins prepared using wheat and EWP served as reference. Effect of addition of different proteins on pasting properties revealed that the thermal stability of QPM flour increased as indicated by decrease in breakdown viscosity. The effect of added proteins on QPM muffin-making properties was evaluated for rheology of batter and physicochemical, texture, color and sensory characteristics of muffins. Dynamic rheology showed that storage modulus (G′) and loss modulus (G″) of batter with SPI was the highest while batter with EWP showed lowest value. QPM-EWP muffins were softer, chewy and springier and had more specific volume than control muffins and were comparable to reference muffins. Inclusion of all proteins increased L* values (lightness) and decreased a* (redness/greenness) and b* (yellow/blueness) values of QPM based muffins. Sensory analysis revealed that gluten free QPM muffin prepared from EWP were acceptable with a sensory score of 7.97 which was comparable to reference muffins (8.03). [ABSTRACT FROM AUTHOR]

Antigen detection during Western blotting commonly utilizes a horseradish peroxidase-coupled secondary antibody and enhanced chemiluminescent substrate. We utilized this technique to examine the impact of green tea-derived polyphenols on the binding of egg white protein-specific IgE antibodies from allergic human plasma to their cognate antigens. Our experiments unexpectedly showed that green tea-derived polyphenols, when stably complexed with egg white proteins, caused “ghost” band formation in the presence of horseradish peroxide. This study suggests that caution should be taken when evaluating polyphenol-bound proteins by enhanced chemiluminescence Western blotting using horseradish peroxidase and demonstrates that protein-bound polyphenols can be a source of “ghost” band artifacts on Western blots.

Antigen detection during Western blotting commonly utilizes a horseradish peroxidase-coupled secondary antibody and enhanced chemiluminescent substrate. We utilized this technique to examine the impact of green tea-derived polyphenols on the binding of egg white protein-specific IgE antibodies from allergic human plasma to their cognate antigens. Our experiments unexpectedly showed that green tea-derived polyphenols, when stably complexed with egg white proteins, caused hyperactivation of horseradish peroxidase resulting in the appearance of white “ghost” bands. This study suggests that caution should be taken when evaluating polyphenol-bound proteins by enhanced chemiluminescence Western blotting using horseradish peroxidase and demonstrates that protein-bound polyphenols can be a source of “ghost” band artifacts on Western blots.

Egg proteins are a good source of bioactive peptides. Previous work from our research group has demonstrated the potential of egg white hydrolysate (EWH) for enhancing adipogenic differentiation and insulin signalling in 3T3-F442A pre-adipocytes. EWH was prepared by a combination of thermolysin and pepsin. Here, in this study, we aimed to identify the responsible peptide(s) in EWH. EWH was fractionated stepwise by ultrafiltration, C18 Sep-Pack cartridge, cation-exchange chromatography, and reverse-phase chromatography. The two most active fractions were analyzed by LC–MS/MS and 42 peptides were identified. Eleven peptides were synthesized and WEKAFKDED, QAMPFRVTEQE, ERYPIL, and VFKGL from ovalbumin were validated with peroxisome proliferator-associated receptor gamma stimulatory activity in adipocytes. For the first time, adipogenic differentiating peptides were characterized from egg white proteins. This data is pivotal for future structure–function studies of adipogenic peptides. [ABSTRACT FROM AUTHOR]

Abstract: There is a growing interest in substituting animal proteins with plant protein sources in food systems. A notable example is the replacement of hen egg white (EW) protein, which is used in a wide range of food products because of its excellent foaming characteristics. Here, enzymatically hydrolyzed wheat gluten, which has greater solubility and better foaming properties than wheat gluten itself, was prepared and incorporated in a classical meringue recipe to investigate its potential as a foaming agent. Meringues based on gluten hydrolysates (GHs) had batters with lower density and greater apparent viscosity than those based solely on EW protein. Furthermore, after baking, these GH containing meringues had greater specific volume than those based on EW protein alone and no notable differences in color or texture between the different samples were noted. These outcomes were related to basic insights in the air–water interfacial behavior of GHs obtained in earlier studies. More specifically, the greater foaming capacity of GH than of EW protein solutions was related to their superior meringue batter (density and apparent viscosity) and product (specific volume) properties. While EW protein solutions had better foam stability than GH solutions (in the absence of sugar), this was apparently less relevant for meringue properties, probably due to the very high viscosity of the sugar rich batter, which could obscure differences in the intrinsic foam stabilizing ability of the samples. Practical Application: Replacing animal proteins with plant protein sources in the food industry is desirable from an economic and environmental perspective. Enzymatic hydrolysis serves as a tool to improve the foaming properties of water‐insoluble wheat gluten proteins. We conclude that wheat gluten hydrolysates can be a valid functional alternative for egg white proteins in meringues, and possibly other food systems. [ABSTRACT FROM AUTHOR]

Background Egg is one of the most nutritious foods that is easily available and it has become a favorite source of major nutrients like lipids and proteins around the world. However, eggs can trigger severe allergic reactions, especially in infants and children. The reactions are mostly IgE-mediated with a range of symptoms related to nose and throat and further can lead to life-threatening anaphylaxis. A total of ten allergens have been recognized to date and researchers are actively working on understanding their structure-function relationship which could help reduce the allergy incidences. Major egg allergens are abundant in egg white which include ovalbumin (OA), ovomucoid (OVM), ovotransferrin (OVT) and lysozyme (Lys). In addition to allergens, avidin present in egg white is also extensively studied due to its anti-nutritional properties. Avidin is known to form a complex with biotin which makes it unavailable for absorption. Scope and approach This review focuses on the effects of thermal and non-thermal processing methods on the structure and functional properties of various egg proteins including a wide range of allergens and anti-nutrients. Key findings and conclusions Novel processing techniques including various non-thermal techniques show promising results in reducing the allergic reactions of egg. Anti-nutrients like avidin can be partly inactivated under combined high-pressure processing and heat treatment. [ABSTRACT FROM AUTHOR]

Enzymatically hydrolyzed wheat gluten can be a viable alternative for traditional animal-based foam stabilizing proteins in food systems. Gluten hydrolysates (GHs) can be considered for (partially) replacing surface-active food proteins such as those of egg white (EW). We here studied the foaming and air-water (A-W) interfacial characteristics of mixed GH + EW protein solutions. GH solutions had much higher (P < 0.05) foaming capacities than EW solutions, while the latter had much higher (P < 0.05) foam stability than the former. When only one sixth of EW proteins was replaced by GHs, the foaming capacity of the mixtures was as high as or higher than that of the GH solutions. Furthermore, when half of the EW protein was replaced by GH, the mixtures still had high foam stability. It thus seems that both GH and EW proteins contribute positively to the foaming characteristics of the mixtures. However, measurements of the early stages of diffusion to and adsorption at the interface, plus measurements of surface dilatational moduli at the interface, both suggested that the adsorbed protein film consists primarily of GHs rather than of EW proteins. Nonetheless, FS was higher when EW proteins were present. Mixed GH + EW solutions have a higher resistance to coalescence than GH solutions. Therefore, it is hypothesized that EW proteins form a secondary protein layer below the A-W interface which is maintained by interactions with adsorbed GH constituents, thereby providing bubbles with an additional resistance to coalescence. [ABSTRACT FROM AUTHOR]

Egg white contains many functionally important proteins: ovalbumin (54%), ovotransferrin (12%), ovomucoid (11%), ovoglobulin (G2 and G3, 8%), ovomucin (3.5%), and lysozyme (3.5%) are major proteins, while ovoinhibitors, ovomacroglobulin, ovoglycoprotein, ovoflavoprotein, thiamine-binding proteins, and avidin are minor proteins present in egg white. These proteins, as well as the peptides derived from the proteins, have been recognized for their functional importance as antioxidant, antimicrobial, metal-chelating, anti-viral, anti-tumour, and angiotensin-converting enzyme (ACE)-inhibitory activities. Among the functional properties of the peptides, antioxidant and antimicrobial activities are important characteristics for food processing while other properties such as ACE-inhibitory activity of the peptides can have important health-related functionalities. Bioactive peptides can be produced from egg white proteins by enzyme hydrolysis, chemical treatments, or thermal treatments at different pH conditions. The effective functional peptides produced from egg white proteins are usually smaller than 2 kDa in molecular size. However, these peptides are known for their beneficial activities in vitro only, and little work has been done to prove their beneficial effects in vivo. Therefore, further studies are needed to see if the bioactive peptides derived from egg white proteins are helpful for humans in the future. [ABSTRACT FROM AUTHOR]

In the present study, protein complexes emerged in high molecular weight (MW) region (95-170 kDa) were observed in fertilised chicken egg white after 7 days of incubation. Investigations were performed to reveal the possible proteins involved in these complexes. The emerged 10 protein bands from SDS-PAGE gel were confirmed to be ovalbumin through matrix-assisted laser desorption/ionisation time-of-flight tandem mass spectrometry (MALDI-TOF MS/MS) followed by Western blot analysis. To reveal the possible interactions among ovalbumin and other egg white proteins, LC connected to LTQ-Orbitrap mass spectrometer was used. Besides ovalbumin, 11 egg white proteins were identified including ovotransferrin, lysozyme, ovalbumin-related protein X, ovalbumin-related protein Y, hep21, alpha-enolase, ovoinhibitor, and a protein similar to ryanodine receptor 1. These results indicated widespread thermal-induced protein interactions among ovalbumin and other egg white proteins. [ABSTRACT FROM AUTHOR]

• Alkaline salts promote the formation of elastic egg white gel with low lightness. • Ionic strength and pH act differently in modulating the protein aggregation state. • The extent of protein aggregates cross-linking affected digestibility of the gel. In this study, the thermal gelation and digestion properties of hen egg white (hen EW) proteins with different salts were investigated. Results show that the addition of neutral salt - sodium chloride (NaCl) decreased the gel hardness/resilience, increased gel lightness, aggregated particle size and digestibility of hen EW proteins significantly. In contrast, alkaline salts – phosphate and carbonate addition increased the gel resilience and strain tolerance as well as reduced the aggregated particle size and gel lightness of hen EW proteins due to the increase of solution pH and negative charge. Correlation analysis shows that the digestibility of hen EW gels was affected by gel viscoelasticity, molecule forces and texture. In conclusion, thermal gelation properties of hen EW proteins could be modulated by salts with different pH/ionic strength, and thus affected the protein digestion and peptide released. [ABSTRACT FROM AUTHOR]

Effect of salts (Sodium chloride (NaCl), Sodium sulfate (Na 2 SO 4 ), Ammonium sulfate ((NH 4 ) 2 SO 4 ), and nonionic surfactants (glycerol, tween20, tween80) on thermal properties of egg white proteins as a whole were investigated. Egg white solutions with additive (0, 0.5 and 1%) were collected after 0, 1 and 2 min heat treatment. Physico-chemical properties of egg white proteins were evaluated by measuring heat coagulation time, solubility and turbidity of solution. Adding glycerol caused the most significant decrease in turbidity and increase in heat coagulation time and solubility of egg white, although Sodium Chloride had the least positive impact on physico-chemical properties of egg white under heat treatment. The Fourier transform infrared (FT-IR) spectroscopy analysis of heat treated egg white proteins as a whole with additives demonstrated changes in secondary protein structure, which are presented regarding the shape, intensity and position of FT-IR band. Meanwhile, it showed a good correlation with the physico-chemical properties consequences. Generally, the effect of nonionic surfactants were more noticeable than that of salts in preventing of egg white proteins aggregation under heat treatment. By improving thermal stability of egg white proteins, its usage in thermal processing industry can be evolved. [ABSTRACT FROM AUTHOR]

The objective of this research was to investigate the impact of high-intensity ultrasound (HIU) generated by a probe-type sonicator (frequency 20 ± 0.2 kHz and an amplitude of 40%) for 2-20 min on the selected functional and structural properties of egg white proteins (EWPs) and their susceptibility to hydrolysis by alcalase. The protein solubility, foaming, and emulsifying properties were studied as a function of ultrasonication time and related to protein particle and structural properties. The length of ultrasonication exhibited important effect on EWP particle size, uniformity, and charge, affecting also the protein conformation and susceptibility to alcalase hydrolysis and determining functional properties. There was a linear correlation between the particle size decrease and the solubility while a two-step linear correlation between the foam capacity (FC)/foam stability (FS) and particle size was apparent. Specifically, FC and FS sharply increased with decreasing particle size for range from ∼370 to ∼260 nm, and below this range from 260.6 to 68.4 nm, the changes were not that substantial. Besides, the solubility, FC, and FS were directly and linearly related with the absolute value of the particle zeta potential. The overall emulsifying properties were also improved with an increase of sonication time, through both the decrease of the mean particle diameter and the increase of zeta potential, but there was no direct correlation between the emulsion activity/stability index and protein particle size and/or charge. Analysis of EWP structure by Raman spectroscopy revealed that the HIU leads to changes in the secondary structure, while heat and ultrasound generated by the ultrasound bath were not sufficient to exhibit this effect. [ABSTRACT FROM AUTHOR]

Due to the unsatisfactory physicochemical properties of egg white proteins (EWPs), which limit their widespread application in wound dressings, we modified EWPs with graphene oxide (GO) due to excellent material properties. Egg white protein (EWP)/polyvinyl alcohol (PVA)/graphene oxide (GO) fibrous wound dressings with different GO concentrations (0, 0.5, 1, and 2 mg/ml) were produced by electrospinning, and their application potential in skin tissue repair was studied. The fabricated fibrous wound dressing was cross-linked and characterised, and hydrophilicity, degradation, water vapour transmission rate (WVTR), mechanical properties, antibacterial activity, cell compatibility and wound healing effect in vivo were measured. As the GO content increased, the spinnability of the mixed solution was reduced. FTIR and XRD confirmed that the GO, EWPs and PVA fibres were successfully combined. The addition of GO improved the antibacterial activity of the wound dressings. The overall performance of the EWP/PVA/GO wound dressing containing 1 mg/ml GO was optimal, displaying good hydrophilicity, degradation, WVTR, thermal stability, tensile mechanical properties, cell survival, and enhancing the proliferation, adhesion and migration of human dermal fibroblasts (HDFs) and human umbilical vein endothelial cells (HUVECs). In vivo healing experiments showed that the wound dressing containing 1 mg/ml GO promoted skin wound healing and tissue regeneration (type I collagen, vascularisation and hair follicle) the best. EWP/PVA/GO electrospun fibres with 1 mg/ml GO have great potential in wound dressing applications. [Display omitted] [ABSTRACT FROM AUTHOR]

Egg white proteins (EWPs), in addition to their nutritional values, possess excellent functional properties that facilitate their use in the food industry. This review collates the published information concerning the major functional properties of EWPs such as gelling, foaming, and emulsifying. Gelation of EWPs has several applications in various food products such as puddings and desserts. Foaming is an important element in the manufacture of the foods such as cakes, bread, meringues, and cookies. However, the application of EWPs as an emulsifier in food products is limited, and thus, various techniques and methods for improving the emulsifying ability of these proteins have been investigated. The effect of various parameters on the functional properties of EWPs and possible correlations between structure and function, with a focus on practical performance in food systems, are discussed in this paper. These findings can lead to enriching the research systems on the functional properties of EWPs and providing information for the development of new EWPs -derived/enriched food products. [Display omitted] • Environmental conditions change hydrophilic/hydrophobic ratio of egg white proteins. • Heat treatments potentially denature egg white proteins (EWPs) and change their structure. • Emulsifying stability of egg white proteins under neutral and alkaline conditions is poor. • Electrostatic and hydrophobic interactions are important during gel formation of EWPs. • EWPs have considerable applications in foods such as meringues and cake batters. [ABSTRACT FROM AUTHOR]

The objectives of this study were to examine the effect of sonication and high-pressure carbon dioxide processing on proteolytic hydrolysis of egg white proteins and antioxidant activity of the obtained hydrolysates. It appeared that the ultrasound pretreatment resulted in an increase in the degree of hydrolysis of the enzymatic reaction while the high-pressure carbon dioxide processing showed an inhibition effect on the enzymatic hydrolysis of egg white proteins to some extent. The antioxidant activity of the obtained hydrolysates was improved by ultrasound pretreatment of egg white proteins at the pH 8.3. Thus, the combination of ultrasound pretreatment at the pH 8.3 and subsequent enzymatic hydrolysis with alcalase at 50°C and pH 8.0 could offer a new approach to the improvement of the functional properties of egg white proteins and their biological activity. [Projekat Ministarstva nauke Republike Srbije, br. E!6750]

The impacts of hydrodynamic cavitation (HC) (orifice plate-2 mm) and acoustic cavitation/ultrasound (US) (probe sonicator- 50% amplitude; 20 kHz frequency) on the functional (foaming, gelling, emulsifying), physicochemical (solubility), rheological and structural properties of egg white proteins (EWP) were evaluated. The egg white solutions were treated for 5, 10 and 15 min for both HC and US. The results suggested that HC-treated samples had higher impact on physiochemical and functional properties when compared to US-treated samples. The best foaming, emulsifying and gelling property was obtained for HC-treated samples (15 min treatment time). Both cavitation treatments exhibited shear thinning behavior, among which US-treated samples had the lowest viscosity. HC-treatment applied for 15 min provided the highest in vitro digestibility (75.51 ± 0.126%) among all the samples. The FTIR spectra of EWP exhibited similar backbone structure for all the samples, while the secondary structure obtained from deconvolution of Amide-I peak differed significantly. Moreover, for product development with EWP, HC -treated samples were more appropriate in gelling and emulsifying applications, which can ensure quality products with higher in vitro digestibility. Overall, this study indicated that HC treatment (for 15 min) improved the functional, rheological, and structural properties of EWP. • The effect of hydrodynamic cavitation (HC) and ultrasonication (US) on egg white proteins (EWP) was investigated. • HC provided beneficial improvements in EWP functionality compared to US. • The solubility and digestibility improved; viscosity reduced with treatment time. • Cavitation led to conformational changes in EWP. • HC is more promising for large-scale processing of EWP than US. [ABSTRACT FROM AUTHOR]

The study analyzed the influence of the degree of apple pectin methylation and the concentration of xanthan gum on physicochemical properties of fresh wet egg white protein based foams. Molecular characterization of applied hydrocolloids was performed and amino acid composition of proteins was established. First, essential physicochemical properties of the starting solutions, i.e. density, surface tension and hydrophobicity, were analyzed, and electrophoretic analysis of the solutions was carried out. Density and content of the gaseous phase in the continuous phase were determined. The image analysis allowed assessment of the size distributions of gas bubbles and, subsequently, cross compliance of the population of obtained bubbles was performed using the Kolmogorov–Smirnov test. Next, using the maximum likelihood method, three distributions, i.e. Weibull, log-normal and gamma distributions, were matched to one another. The results showed that the log-normal distribution provided the best description of the bubble distribution. [ABSTRACT FROM AUTHOR]

Highlights: [•] The risk due to fining agent residues for allergic subjects is considered. [•] Wines fined with egg white with/without bentonites were analysed. [•] The amount of egg white protein residues in wine was investigated by an ELISA test. [•] Immunoblotting technique was used to confirm data obtained by ELISA test. [•] All wines analysed contained an undetectable amount of egg white proteins. [Copyright &y& Elsevier]

Highlights: [•] A mixture of hydrocolloids stabilizes the rheological properties of egg white protein based foams. [•] Xanthan gum clearly strengthens the foam structure and enhances native viscoelastic properties. [•] Addition of carrageenan causes degradation of the relaxation spectrum. [ABSTRACT FROM AUTHOR]