Egg White Protein Research Articles

Enhancement of emulsion pH stability by Ca2+ modulation: A novel approach for preparing egg white protein fibril cold emulsion gels

Egg white, a crucial ingredient in bulk food production with limited emulsifying properties, can be significantly improved by fibrillation modification. However, resulting emulsions may exhibit instability at critical food processing pH values. In this study, the egg white protein fibril (EWPF) emulsion gel was constructed by Ca2+, and the stability enhancement mechanism under different EWPF and Ca2+ concentrations was investigated. The results showed that higher EWPF concentrations led to improved stabilization of the oil-water interface. At 60 mg/mL EWPF concentration, water loss decreased by 13.86% and oil loss by 35.79%, while the firmness and viscosity of the emulsion gel system were enhanced. The ζ-potential was reduced by 67.98% and the ionic bond content was increased by 22 times with the addition of Ca2+, the droplets showed a uniform cross-linked structure, and the stability and plasticity of the system were improved. By adjusting EWPF concentration to 40 mg/mL and Ca2+ concentration to 30 mM, pH stability of the system was also enhanced. This study provided a reference for the high-value utilization of egg white and a possibility for the application of EWPF in food processing, such as low-fat foods.

Unveiling the presence of O-glycosylation in different glycoproteins present in chicken egg white

Chicken egg white contains hundreds of proteins that are widely used in the food, biological and pharmaceutical industries. Glycosylation provides additional structural diversity to the already specialized proteins. The array of glycans on protein surfaces and different glycosylation sites provide sophisticated structures essentials for the multiple functions that glycoproteins assume. Different types of analysis have been performed to determine N-glycosylation in chicken egg white. In different studies, up to 19 N-glycoproteins have been characterized. However, regarding O-glycosylation, there is insufficient knowledge of their structures and abundances. In fact, only ovomucin, a major component of chicken egg white, has been described as bearing O-glycans that consist of 2–6 sugar residues carrying sialic acid and/or sulfate groups. In the present work, the use of a reductive β-elimination reaction followed by a HPAEC-PAD analysis, showed released oligosaccharides suggesting the presence of different O-glycoproteins. Getting deeper into chicken egg white O-glycoproteomics, a nanoHPLC-ESI-Orbitrap-HCD analysis was performed and two different software tools were employed. Under these conditions, at least seven different O-glycosylated proteins were described. In addition, O–glycosylation of isolated ovalbumin was characterized for the first time and in a BEMAD analysis of the isolated glycoprotein, three O-glycosites were detected. Taking into account that glycosylation has been involved in the structure and properties of chicken egg white proteins such as allergenicity, antibacterial action and embryo protection, attention must be paid to explore new properties of this heterogeneous modification in relation to both the food and biopharmaceutical industries.

Improvement of antioxidant, emulsification properties and thermal stability of egg white protein by covalent binding to gallic acid/tannic acid and xanthan gum

This study aimed to improve the functional properties of egg white protein (EWP) by covalent modification of EWP with xanthan gum (XG) and gallic acid (GA)/tannic acid (TA) to form covalent complexes. The structure and functional properties of EWP before and after modification were explored. The results showed that the grafting degree of EWP-GA-XG and EWP-TA-XG reached 37.23% and 44.01% respectively measured by the OPA method. The secondary structure of EWP became loose after reaction with GA/TA and XG, with a decrease in the content of α-helix and an increase in the β-sheet content, thus contributing to the improvement of its functional properties. The DPPH and ABTS radical scavenging rate and iron reduction ability of EWP-GA-XG (44.94%, 56.38%, 18.29 mg VC/μmol) and EWP-TA-XG (85.45%, 88.39%, 39.26 mg VC/μmol) complexes were significantly improved compared with EWP (7.90%, 12.94%, 0.12 mg VC/μmol). The emulsion activity index and emulsion stability index of EWP-GA-XG (10.05 m2/g, 96.43%) and EWP-TA-XG (11.04 m2/g, 96.53%) complexes were also improved as compared to those of EWP (5.94 m2/g, 51.45%). Moreover, the peak transition temperatures of EWP-GA-XG (138.09 °C) and EWP-TA-XG (143.96 °C) complexes were higher than that of EWP (125.00 °C). This study may provide the theoretical basis for improving the functional properties of EWP and expanding its application in the field of food.

EFFECT OF EGG WHITE PROTEIN AND WATER CONTENT ON THE STABILIZATION MECHANISMS OF NATURAL RUBBER LATEX FOAMS OBTAINED FROM MICROWAVE RADIATION

The global plastic consumption, as one of the paramount concerns of our society, open new paths of investigation in green materials. This study presents our contribution to the field with the obtention of natural rubber latex foams using egg white powder as bio stabilizing agent. The route followed to develop these samples is based on a two‐step process, a previous aeration, followed by microwave dehydration. This synthesis route is greener and eco‐friendlier than conventional ones due to the use of biobased bulk materials, the utilisation of microwave radiation which reduces the energy consumption in comparison with conventional heating methods and the elimination of the vulcanization process typically used when producing latex foams. In this work a deep study of the effect of egg white protein on natural rubber latex foams obtained at three water content levels (i.e. 40, 70, 90 phr) is carried out. The density and cellular structure parameters are measured for the formulations of liquid and solid foams which led to stable final samples in order to comprehend the stabilization mechanisms due to the presence of the egg white and the effect of water content in these systems. With the route developed in this research it has been possible to produce open cell natural rubber latex foams with densities as low as 53 kg/m3 and cell sizes as low as 114 µm.This article is protected by copyright. All rights reserved.

Heat-induced aggregation and gelation of egg white protein

Heat-induced aggregation and gelation of egg white protein

DRYING OF CHERRY LAUREL JUICE USING FOAM MAT DRYING TECHNIQUE AND INVESTIGATING THE EFFECT OF DRYING TEMPERATURE ON DRYING CHARACTERISTICS AND BIOACTIVE COMPONENTS

This study aimed to optimize the foam properties for the foam mat drying (FMD) process and investigate the effect of drying temperatures (60, 70, and 80 °C) on the cherry laurel juice's drying characteristics and bioactive properties. Egg white protein (EWP), carboxymethyl cellulose (CMC), and mixing time (MT) variables were optimized using the Taguchi method to achieve the juice foam with maximum foam capacity and stability. The optimal conditions determined were 10% EWP, 0.3% CMC, and 12 min of MT. The drying times and effective moisture diffusivities (Deff) for 60, 70, and 80 °C were recorded as 160, 120 and 90 min and 6.09×10-9, 7.74×10-9 and 11.33×10-9 m2/s, respectively. As the drying temperature increased, the total phenolic and total monomeric anthocyanin contents, and antioxidant activity values increased, but ascorbic acid content decreased. This research demonstrates that the FMD process can successfully be applied to dry juices with pronounced bioactive properties.

Foaming and structural properties of egg yolk components microgel particles and their adsorption characteristics at the air-water interface

In this study, microgel particles of egg yolk and its components were constructed by inducing and modifying their structure via the high-pressure homogenization (HPH). In order to compare their structural characterization and reveal their adsorption mechanism at the air-water interface, yolk components were also combined with egg white protein (EWP) to achieve their microgels for investigation. Results suggested that after HPH, foam stabilities of egg yolk protein microgel (EYM) and egg yolk plasma microgel (EPM) were significantly improved, whereas no significance occurred on egg yolk granules microgel (EGM). Interestingly, after HPH, the adsorption capacity of the microgels from combination of yolk components and EWP exhibited a significant increasing trend. However, their interfacial adsorption stability was poor. Fluorescence spectrum and surface tension revealed that more hydrophilic groups and lower surface tension would occur on EY and EP after HPH, whilst no significant effects would happen on EG, which was consistent with the results of foaming characteristics. SDS-PAGE exhibited that there was no obvious change in the protein bands of egg yolk and its components, indicating that egg yolk and component proteins did not undergo covalent crosslinking or degradation with HPH treatment. In summary, our study prepares for the first time of the microgel particles from egg yolk components for stabilizing the air-water interface. In addition, we have revealed the relationship between the physicochemical properties, microstructures and interfacial adsorption properties of the microgel particles from egg yolk components, and have explored their mechanisms in depth.

Heat-induced gelation of egg white proteins depending on heating temperature: Insights into protein structure and digestive behaviors in the elderly in vitro digestion model

This study investigated the effects of heating temperature of egg white gels (EWGs) on the digestive characteristics by heating egg white (EW) to reach 75 °C (EWG-75) and 95 °C (EWG-95). The gel protein structure showed a decrease in the maximum tryptophan fluorescence intensity and a significant increase in the surface hydrophobicity of EWGs compared to EW (P < 0.05). The total and reactive free sulfhydryl groups were higher in the EWGs than in the EW (P < 0.05). While the proportions of α-helical and β-sheet structures remained similar in EW and EWG-75 (P > 0.05), EWG-95 exhibited a notable decrease in α-helix content (P < 0.05) and an increase in β-sheet content (P < 0.05). Furthermore, EWG-95 displayed higher hardness and cohesiveness than EWG-75 (P < 0.05). In the adult and elderly in vitro digestion models, EWG-95 exhibited the highest protein digestibility (50.44 % and 54.65 % in the models of elderly and adult subjects, respectively) after GI digestion (P < 0.05), followed by EWG-75 and EW. The electrophoretogram of the digesta revealed more intense protein bands in the elderly digestion model, particularly in the gastric digesta of EW, indicating slower digestion compared to the adult model. Therefore, EW should be appropriately heated before consumption, especially for elderly individuals, to facilitate efficient protein digestion and absorption.

Egg White Protein-Proanthocyanin Complexes Stabilized Emulsions: Investigation of Physical Stability, Digestion Kinetics, and Free Fatty Acid Release Dynamics.

Egg white proteins pose notable limitations in emulsion applications due to their inadequate wettability and interfacial instability. Polyphenol-driven alterations in proteins serve as an effective strategy for optimizing their properties. Herein, covalent and non-covalent complexes of egg white proteins-proanthocyanins were synthesized. The analysis of structural alterations, amino acid side chains and wettability was performed. The superior wettability (80.00° ± 2.23°) and rigid structure (2.95 GPa) of covalent complexes established favorable conditions for their utilization in emulsions. Furthermore, stability evaluation, digestion kinetics, free fatty acid (FFA) release kinetics, and correlation analysis were explored to unravel the impact of covalent and non-covalent modification on emulsion stability, dynamic digestion process, and interlinkages. Emulsion stabilized by covalent complex exhibited exceptional stabilization properties, and FFA release kinetics followed both first-order and Korsmeyer-Peppas models. This study offers valuable insights into the application of complexes of proteins-polyphenols in emulsion systems and introduces an innovative approach for analyzing the dynamics of the emulsion digestion process.

Effect of Egg-White Protein Alone or Combined With Niacin on Nutritional Status, and Phosphorus Control in Maintenance Hemodialysis Patients: A Randomized Controlled Trial

BackgroundNiacin is reported to decrease phosphorus concentration in Maintenance Hemodialysis (MHD) patients. Egg white is one of the main substitutable proteins in MHD patients due to its low phosphorus content. Therefore, we aimed to evaluate the effects of combined egg white and niacin supplementation on dialysis patients' serum phosphorus and nutritional biomarkers. MethodsIn this randomized controlled clinical trial, 98 patients on MHD were randomly allocated to four groups for eight weeks: 24 g egg white (n=25), 600 g niacin daily (n=24), egg white combined with niacin (n=24), and control (n=24). Calcium, phosphorus, fibroblast growth factor-23, and other nutritional markers were assessed. ResultsThere was a significant difference among the groups only in phosphorus at the end of the trial, which was significantly lower in the niacin group (4.38+0.812 mg/dl) than in both the egg white (5.07+0.49 mg/dl) and egg white with niacin supplementation (5.41+0.662 mg/dl) groups. In this regard, albumin increased in egg white and egg white with niacin supplementation, while albumin did not change significantly in the niacin group. Urea reduction ratio and Kt/V rose only in the egg-white group, while aspartate aminotransferase increased only in the niacin and control groups. ConclusionNiacin decreases serum phosphorus concentration more than egg-white protein or a combined intervention. Egg white protein supplementation has beneficial effects on some nutritional statuses other than phosphorus control without the side effects of niacin.

The influence of unique interfacial networks based on egg white proteins for the stabilization of high internal phase Pickering emulsions: Physical stability and free fatty acid release kinetics

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.

Tailoring an egg white protein double network emulsion gel as a novel fat substitute for improving freeze-thaw stability of minced meat gel

This work aimed to investigate the effect of double network emulsion gel (DNEG) as a substitute for pork back fat (PBF) on the freeze-thaw stability of minced meat gel (MMG). We used slow acidification with glucono-δ-lactone (GDL) to induce egg white protein (EWP) gelation, while CaCO3 was affected by acidification to release Ca2+ to cross-link sodium alginate (SA), resulting in the gradual formation of DNEG networks. The MMG prepared using DNEG substitute for PBF had fine hardness and color after 5 freeze-thaw cycles (FTCs). This was due to the excellent plasticity of DNEG, which made it more capable of filling the voids of minced meat products, thus reducing the space for ice crystal growth. As a result, MMG prepared with DNEG could pass through the maximum ice crystal formation zone faster and avoid damage due to the formation of larger ice crystals. Notably, DNEG provided a barrier for the migration of immobilized water to bulk water in the sample. After several freeze-thaw treatments, the water holding capacity of samples prepared with DNEG decreased significantly slower, which slowed down the oxidation and decomposition of meat proteins. In summary, this study revealed the role of fat substitute DNEG as a favorable filling material for improving the freeze-thaw stability of minced meat products, and provided a technical reference for the development of healthy and storable meat products.

The Effect of Ionic Strength on the Formation and Stability of Ovalbumin-Xanthan Gum Complex Emulsions.

Protein-polysaccharide complexes have been widely used to stabilize emulsions, but the effect of NaCl on ovalbumin-xanthan gum (OVA-XG) complex emulsions is unclear. Therefore, OVA-XG complex emulsions with different XG concentrations at pH 5.5 were prepared, and the effects of NaCl on them were explored. The results indicated that the NaCl significantly affected the interaction force between OVA-XG complexes. The NaCl improved the adsorption of proteins at the oil-water interface and significantly enhanced emulsion stability, and the droplet size and zeta potential of the emulsion gradually decreased with increasing NaCl concentrations (0-0.08 M). In particular, 0.08 M NaCl was added to the OVA-0.2% XG emulsion, which had a minimum droplet size of 18.3 μm. Additionally, XG as a stabilizer could improve the stability of the emulsions, and the OVA-0.3% XG emulsion also exhibited good stability, even without NaCl. This study further revealed the effects of NaCl on emulsions, which has positive implications for the application of egg white proteins in food processing.

In silico identification and molecular mechanism of novel egg white-derived tyrosinase inhibitory peptides

This study aimed to identify novel tyrosinase inhibitory peptides from egg white proteins including ovalbumin, ovotransferrin and ovomucoid. Peptides GDVA and DEK were identified using computer-aided virtual screening and in vitro tyrosinase inhibition experiments. Especially, peptide DEK exhibited the strongest tyrosinase inhibitory capacity with IC50 value of 0.205 ± 0.07 mmol L−1. Molecular docking and isothermal titration calorimetry analysis (ITC) were performed to explore the molecular mechanism. The results revealed that two peptides interacted with key residues of tyrosinase mainly by hydrogen bonding and hydrophobic interaction. The binding reactions of these peptides with tyrosinase were spontaneous, endothermic and entropy driven. Furthermore, the structure of two peptide-tyrosinase complexes was compact and stable during the molecular dynamic simulation. These findings indicated that egg white-derived peptide DEK had potential as tyrosinase inhibitory peptide.

Synergistic effect of egg white protein particles and rhamnolipid on improving the bioavailability of curcumin carried in high internal phase emulsions

SummaryHigh internal phase emulsions (HIPEs) are potential carriers of fat‐soluble nutrients due to their high loading capacity. In this study, egg white protein particles (EWPP) and rhamnolipid (Rha) were used to co‐emulsify oil/water HIPEs to carry curcumin (Cur). The results showed that the Cur loading efficiency, microstructure, protein composition, molecular distribution of protein hydrolysates, protein interfacial adsorption rate and Cur bioavailability were measured. The results showed that, incorporation with Rha was unhelpful for improving loading efficiency of Cur, which decreased from 80.8% to 73.7% at pH 3.8 after incorporation with Rha, due to the decreased viscosity and destroyed continuous interface membrane, while beneficial for restricting coalescence of oil droplets. As studied, Rha could effectively reduce the droplet size to slow down the speed of coalescence and form EWPP–Rha complex to inhibit proteolysis. Finally, Cur bioavailability in EWPP–Rha co‐emulsified HIPE was the highest (40.3%), indicating the synergistic effect of EWPP and Rha promoting the effective adsorption of Cur, related to the increased coalescence stability during digestion and participation of Rha in the micellisation reaction. In comparison, fibrous (pH 3.8) and granular (pH 7.0) EWPP stabilised HIPEs, showed no obvious difference in Cur bioavailability, due to the balance between the interfacial adsorption ability and the digestion resistance of EWPP with various morphologies. This study has important significance for the construction of lipid soluble nutrient ‘carriers’ with high load and high bioavailability.

From biomass to batteries: the contribution of silicon–carbon composites prepared from high-nitrogen egg whites and micron-sized silica powder to lithium-ion battery performance

This research uses egg white proteins as a carbon source to create silicon/nitrogen-doped composites, addressing silicon electrode volume expansion in lithium-ion batteries.

Ovomukoid (najvažniji alergen belanca) kao uzrok teške alergije na jaja

Hypersensitivity, or an allergy to highly valuable chicken egg proteins, is a prevalent symptomatic condition. It occurs when the immune system of a hypersensitive or allergic individual overreacts upon contact with egg allergens (egg proteins), triggering a complex immune response. Among these allergens, ovomucoid is the most allergenic, making up 11% of egg white. Ovomucoid is both thermostable and resistant to digestion, distinguishing it from other egg white proteins. While ovalbumin is the most abundant protein in egg white, ovomucoid is responsible for the majority of its allergic properties. Humans generally lack tolerance to both raw and cooked eggs due to the presence of this allergenic protein. Given the significance of ovomucoid in egg allergy , it has a direct impact on the quality of life of affected individuals. A better understanding of the role of various drug classes is essential for managing and treating egg allergy. Additionally, insights into embryogenesis may be critical in understanding the efficacy of these treatments in alleviating egg allergies. This knowledge could not only benefit individuals with egg allergies but also the egg production industry and society as a whole. Maintaining good health is one of the most crucial factors in serving our community, and addressing egg allergy is an important part of that.

Potential of cold plasma in enhancing egg white protein for sustainable food applications: a comprehensive review

The objective of this review is to explore recent insights into the impact of cold plasma treatment on the structural and functional properties of egg white protein and to assess its potential for sustainable food applications.

Variation in the Allergenicity of Scrambled, Boiled, Short-Baked and Long-Baked Egg White Proteins.

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. 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. 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 (IC50 > 100 mg/mL). 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.

Ovomucin and its hydrolysates differentially influenced colitis severity in Citrobacter rodentium-infected mice.

Egg white protein ovomucin and its hydrolysates were previously reported to exhibit anti-inflammatory and anti-adhesive activities. However, their potential to regulate pathogen colonization and disease severity has not been fully characterized. To investigate the effects of ovomucin (OVM) and its hydrolysates including ovomucin-Protex 26L (OP) and -pepsin/pancreatin (OPP) on host resistance to pathogen infection, a well-documented colitis model in mice for attaching and effacing E. coli pathogens, Citrobacter rodentium, was used in the current study. C57Bl/6J female mice were fed on a basal diet supplemented with OVM or its hydrolysates for 3 weeks prior to the C. rodentium challenge, with the dietary treatments continued for seven days. Body weight was not affected throughout the experimental period. OP supplementation resulted in lower (P < 0.05) pathogen loads at 7 dpi. Attenuated colitis severity was observed in mice that received OVM and OP, as indicated by reduced colonic pathological scores and pro-inflammatory responses compared with the infected control group. In contrast, OPP consumption resulted in enhanced C. rodentium colonization and disease severity. Notably, reduced microbial diversity indices of the gut microbiota were observed in the OPP-supplemented mice compared with the OVM- and OP-supplemented groups. This study showed the potential of OVM and OP to alleviate the severity of colitis induced by infection while also suggesting the opposite outcome of OPP in mitigating enteric infection.