Determination of Plasmalogen Molecular Species in Hen Eggs.

(1) Background: Plasmalogens are vinyl ether-type glycerophospholipids that are characteristically distributed in neural tissues and are significantly reduced in the brains of individuals with dementia compared to those in healthy subjects, suggesting a link between plasmalogen deficiency and cognitive decline. Hen eggs are expected to be a potential source of dietary plasmalogens, but the details remain unclear. (2) Methods: We evaluated the fresh weight, dry weight, total lipid, neutral lipids, glycolipids, and phospholipids in the egg yolk and egg white of hen egg. Then, the molecular species of plasmalogens were quantified using HPLC-ESI-MS/MS. (3) Results: In egg yolk, the total plasmalogen content was 1292.1 µg/100 g fresh weight and predominantly ethanolamine plasmalogens (PE-Pls), specifically 18:0/22:6-PE-Pls, which made up 75.6 wt% of the total plasmalogen. In egg white, the plasmalogen content was 31.4 µg/100 g fresh weight and predominantly PE-Pls, specifically 18:0/20:4-PE-Pls, which made up 49.6 wt% of the total plasmalogen. (4) Conclusions: Plasmalogens were found to be more enriched in egg yolk than in egg white. It was found that humans are likely to ingest almost 0.3 mg of total plasmalogens from one hen egg. These findings highlight the importance of plasmalogens in the daily diet, and it is recommended to explore the impact of long-term dietary plasmalogen intake to assess its effect on human health. This provides a viewpoint for the development of new food products.

Egg White Diet Induces Severe Allergic Enteritis in an Animal Model Driven by Caspase-3 and Gasdermin C-Mediated Mucosal Alarmin Secretion.

Allergic enteritis is an important phenotype of food allergies. However, there is not a suitable animal model for deeply exploring the natural progression and mechanism of allergic enteritis. In our study, we successfully developed an allergic enteritis animal model by feeding mice with an egg white diet. Following the dietary challenge, allergic mice displayed typical food allergy manifestations, including decreased core temperature, aversion to the allergenic diet, and elevated levels of serum sIgE and mMCP-1. Notably, these dietary challenged mice exhibited severe gut damage, characterized by disrupted intestinal microstructure, tissue inflammation, and edema that were evident morphologically. Moreover, upon exposure to food allergens, we observed a marked increase in caspase-3 and GSDMC levels in allergic mice. These two active proteins were found to be colocalized in damaged mucosal enterocytes and were associated with the secretion of epithelial sourced alarmins, such as IL25 and TSLP. Further data on the cellular and molecular levels suggest that such severe food-induced enteritis is mediated by the caspase-3-GSDMC pathway. We believe that this established animal model provides a valuable tool for advancing research on the mechanisms of food allergies.

Moisture sorption isotherm and thermodynamic analysis of egg powders dried by foam-mat-assisted refractance window drying.

BACKGROUND: In the designed study, the moisture sorption isotherm and thermodynamic properties of refractance-window-dried egg white powder (EWP), egg yolk powder (EYP) and whole egg powder (WEP) were determined. RESULTS: The adsorption isotherm of egg powders was classified as type II, giving a sigmoidal shape. Peleg showed the highest goodness of fitting for egg powder. The monolayer moisture content of egg powders varied between 0.02 and 0.09 g g-1. According to the thermodynamic analysis, an increase in moisture content led to a decrease in net isosteric heat of sorption (qst), and the highest decrease was observed in EWP. The qst of EWP was calculated as 18 637 kJ mol-1, while it decreased to 3104 kJ mol-1 at 0.2 g g-1 moisture content. Like qst, sorption entropy decreased from 52.07 to 7.14 J mol-1 K-1 with increasing water activity (aw) for EWP. Increasing temperature caused a decrease in spreading pressure and was higher in EWP samples. Increasing moisture content and temperature also decreased Gibbs free energy level. CONCLUSION: Moisture sorption isotherm (MSI) is used to predict the amount of bound water in a material at a specific relative humidity and temperature. To inhibit chemical and microbiological spoilage, the drying process must continue until the monolayer moisture content is reached. In this study, the monolayer moisture content of powdered eggs for safe storage was demonstrated by MSI. Additionally, by determining the thermodynamic functions of egg powder, valuable information was obtained related to predicting the energy requirement in drying processes. © 2024 Society of Chemical Industry.

Formation mechanism and stability of egg white fluid gels under ultrahigh-pressure homogenization pretreatment and synergistic heating effect.

The thermal sterilization process of protein beverages inevitably leads to the formation of insoluble thermal aggregates, greatly reducing the texture and taste of protein beverages. In this study, homogenized egg white (HEW) was obtained by ultrahigh-high-pressure (UHP) homogenization pretreatment of egg white (EW), and then a special egg white fluid gel (EWFG) was prepared by water bath heating. The results showed that the optimal conditions for preparing EWFG were three cycles at 20 MPa homogenizing pressure and heating in a water bath at 72℃ for 10 min. Under these conditions, the EWFG was a milky-white homogeneous liquid with an average particle size of about 560 nm. Measurements of the physicochemical properties of HEW and EWFG showed that the UHP homogenization treatment reduced the viscosity of HEW, decreased the particle size of protein aggregates, and increased the zeta potential, which altered the interactions of proteins during the subsequent heating process and facilitated the formation of homogeneous and dispersed EWFG. EWFG showed good stability at pH 6-10 and in low-concentration saline and medium-concentration sucrose solutions. The EWFG obtained by the present treatment is more suitable for factory-scale production and has great potential for protein beverage applications.

Unveiling the emerging trends of egg components-based biodegradable food packaging development: A comprehensive review.

Food packaging plays a crucial role in the food supply chain by aiding in food preservation and reducing food losses throughout the distribution process. The extensive, unregulated utilization, and waste mismanagement of food packaging materials made up of conventional petroleum-based plastics has led to a significant environmental crisis. Egg components-based food packaging has attracted considerable attention from the global packaging industry as a viable alternative to synthetic polymers due to its biodegradability, sustainability, and health-related benefits. This comprehensive review explores the composition and properties of egg components (eggshell, eggshell membrane, egg white, and egg yolk), and recent advancements in biodegradable packaging films derived from them. Additionally, it introduces the characteristics of these films and their applications in food, highlighting their biodegradability, sustainability, and suitable mechanical, barrier, thermal, optical, antioxidant, and antimicrobial properties as substitutes for traditional synthetic polymers. The utilization of various egg components in the packaging industry is a safe, non-toxic, cost-effective, and economical approach. However, it was found that incorporating active compounds from natural sources into packaging films, as well as composite films composed of egg components combined with other biopolymers, resulted in superior properties, compared to single component films. Moreover, the application of novel technologies in film development has proven to be more effective than conventional methods. These innovative egg components-based packaging films can be optimized and commercialized for use as packaging materials for food products.

Lipidomics combined with random forest machine learning algorithms to reveal freshness markers for duck eggs during storage in different rearing systems.

The differences in lipids in duck eggs between the 2 rearing systems during storage have not been fully studied. Herein, we propose untargeted lipidomics combined with a random forest (RF) algorithm to identify potential marker lipids based on ultra-performance liquid chromatography‒mass spectrometry (UPLPC-MS/MS). A total of 106 and 16 differential lipids (DL) were screened in egg yolk and white, respectively. In yolk, metabolic pathway analysis of DLs revealed that glycerophospholipid metabolism and sphingolipid metabolism were the key metabolic pathways in the traditional free-range system (TFS) during storage, glycosylphosphatidylinositol-anchored biosynthesis and glyceride metabolism were the key pathways in the floor-rearing system (FRS). In egg white, the key pathway in both systems is the biosynthesis of unsaturated fatty acids. Combined with RF algorithm, 12 marker lipids were screened during storage. Therefore, this study elucidates the changes in lipids in duck eggs during storage in 2 rearing systems and provides new ideas for screening marker lipids during storage. This approach is highly important for evaluating the quality of egg and egg products and provides guidance for duck egg production.

Crucial effect of ovomucin on alkali-induced egg white gel formation: Properties, structure and facilitation mechanism.

Alkali-induced preserved egg gel formation is a dynamic process that involves complex protein changes. Ovomucin (OVM) is closely associated with the gel properties of egg white. In this study, the effect of OVM in alkali-induced egg white gel (AEWG) formation was investigated. The results suggested that OVM reduced the gel formation time by 15 %. The mechanical properties of the fully formed gel were also improved by OVM. Specifically, OVM increased the storage modulus (G') of the gel by 1.5-fold, while the hardness significantly increased from 78.90 ± 4.24 g to 99.80 ± 9.23 g. Low-field nuclear magnetic resonance (LF-NMR) demonstrated that OVM significantly shortened T23 relaxation time and reduced the water mobility, thus increasing the water holding capacity (WHC). Meanwhile, the presence of OVM resulted in a more homogeneous and denser microscopic morphology of the gel. Selective solubility experiments revealed that disulfide bonds are the primary force in gel formation. OVM promoted the formation of more disulfide bonds, which increased the strength and stability of the gel network. Overall, this research proved OVM plays a critical role in the performance improvement of AEWG, which provides a new insight into the quality control of preserved egg and protein gel foods.

Chain reactions of temperature-induced egg white protein amorphous aggregates: Formation, structure and material composition of thermal gels.

Egg white protein is widely used in food, chemical, medical and other fields due to its excellent thermal gel properties. However, the regularity of egg white thermal gel (EWTG) by temperature influence is still unknown. In this study, we investigated the potential mechanism of temperature (75-95 °C, 15 min) gradient changes inducing thermal aggregation and gel formation of EWTG. The results showed that changes in textural characteristics and water holding capacity (WHC) of EWTGs depended on switching in protein aggregation morphology (spherical shape - chain shape - regiment shape) and gel network structure differences ("irregular bead-like" - "regular lamellar structure"). In addition, proteomics indicated that the generation of amorphous protein aggregates at 95 °C might be related to Mucin 5B as the aggregation core. The research revealed the EWTG formation from "whole egg white protein" to "single molecules", aiming to provide a reference for quality control in gel food processing.

A water-resistant egg white/chitosan/pectin blending film with spherical-linear molecular interpenetrating network strengthened by multifunctional tannin-nisin nanoparticles.

Edible films are effective alternatives to plastic packaging, however, the hydrophilicity of edible films based on protein and polysaccharide limits the application. Therefore, we fabricated a water-stable hybrid film with a linear-spherical interpenetrating molecular topology network using egg white (EW), chitosan (CS), and pectin. Meanwhile, the nisin-tannin acid self-assembly complex nanoparticles were employed as a multifunctional cross-linker, antibacterial and antioxidant agent to improve the performance of films. The FTIR, XRD, and SEM analysis revealed that the conformation and crystalline structure rearrangement of chitosan induced by the alkaline environment provided by egg white enhanced the network structure of films, effectively avoided the addition of modifying reagents. The proposed hybrid films exhibited excellent properties, with EW/TNPCS3 showing the best overall performance. The water contact angle (WCA) increased to 105.27 ± 1.62°, and its dissolution and swelling rates were significantly lower than pure egg white and pure chitosan films. Moreover, tannin-nisin (TN) nanoparticles endowed the films with excellent antimicrobial activity against the common Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria. Thus, the prepared blending films have great application potential in food preservation, especially to maintain stable performance in high humidity environment.

Preparation and Study of the Physicochemical and Functional Properties of Nano/Micromicellar Structures Containing Chokeberry Fruit Pomace Extracts Using Egg White and Egg Yolk.

There is currently a growing interest in health-promoting foods. The beneficial effects of food on human health are actively promoted by health professionals and nutritionists. This growing awareness is influencing the increasing range of functional foods and the pursuit of more innovative solutions. Recent research indicates that spherical nanoparticles have the potential to be used as functional biomaterials in the food industry, particularly for encapsulating hydrophobic natural phytochemicals. Techniques and systems based on micro- and nano-encapsulation are of great importance in the food and pharmaceutical industries. It is of paramount importance that encapsulation materials are safe for use in food. The aim of this study was to obtain micelles containing extracts from chokeberry fruit pomace using egg yolk powder (EYP) for emulsification (as a source of lecithin) and egg white powder (EWP) for stabilisation. The structural properties of the micelles in the resulting powders were characterised using Fourier transform infrared spectroscopy (FTIR). Scanning electron microscopy (SEM) analysis confirmed the presence of spherical micellar structures between 500 and 1000 nm in size. The water activity and water content of the obtained powders were determined, and the thermal (DSC) and antioxidant properties were investigated. The results indicated that the powder with the micellar structures had a higher stability compared to the powder obtained by simple mixing without the use of encapsulation techniques.

Metabolome analysis of egg yolk and white following dietary supplementation with Ampelopsis grossedentata extract.

Eggs are recognized for their rich nutrient profile, providing essential proteins and lipids with notable functional properties. This study examines the effects of incorporating Water Extract of Ampelopsis grossedentata (WEA) into poultry feed on egg quality, focusing on lipid content, choline, L-carnitine levels, and flavonoid compound deposition. Our results show significant increases in essential amino acids, flavonoids, and other bioactive compounds in eggs from WEA-treated hens, suggesting enhanced cardiovascular, antioxidant, and anti-inflammatory benefits. Additionally, we observed elevated levels of choline and betaine in egg yolks, alongside increased L-carnitine content, which may contribute to improved lipid metabolism and reduced cardiovascular disease risk. KEGG pathway analysis revealed upregulation of metabolites involved in critical metabolic pathways, enhancing the nutritional profile of eggs. Flavonoid compounds, traditionally associated with plant-based foods, were also significantly increased, with notable levels of 7, 4'-dihydroxyflavone, daidzein, and glycitein identified in WEA-treated eggs, indicating potential health benefits. These findings suggest that WEA supplementation can produce functional eggs with improved nutritional quality, offering a novel approach to enhancing egg production and meeting the growing demand for functional foods. Further research is needed to fully understand the bioavailability and health impacts of these enriched compounds.

The revelation of characteristic volatile compounds in egg powder and analysis of their adsorption rules based on HS-GC-IMS technology.

The study constructed fingerprints and analyzed adsorption rules of volatile compounds (VOCs) in egg powder (EP) under different production processes, including egg white powder (EWP), egg yolk powder (EYP) and whole egg powder (WEP) by HS-GC-IMS. The 29 VOCs identified were primarily ketones and aldehydes. Characteristic VOCs responsible for flavor differences were clarified by difference comparison, clustering and PCA analysis. Additionally, variations in lipid and protein were the primary causes of the VOCs differences in EP through microscopy imaging, infrared and fluorescence spectroscopy. EWP's stretched structure favored fishy-smelling VOCs adsorption but limited total aldehyde binding due to strong hydrophobic interaction. EYP's higher ß-sheet ratio and fewer hydrogen bond sites weakened its alcohol VOCs binding capacity. The abundance of ketone VOCs in EP was linked to their low steric hindrance. Therefore, this study elucidated the flavor differences reasons among EWP, EYP and WEP, laying foundation for EP applications in food industry.

Chemerin abundance in egg white and its expression with receptors in extra-embryonic annexes of Pekin ducks: implications for embryo development.

Embryonic mortality is a significant problem in the commercial duck industry worldwide. Therefore, identification of new biomarkers for duck embryo development is necessary. In the chicken (order Galliformes), we previously showed that chemerin is a hormone locally produced by the reproductive tract in hens, particularly in the magnum area, leading to its accumulation in the egg white and within the embryo annexes during embryonic development. We therefore hypothesized that the chemerin concentration in egg white could be a biomarker of egg performance and reproductive parameters in Pekin ducks (order Anseriformes). Thus, we collected eggs from Pekin ducks over a 5-d period at three stages of the laying period (before the laying peak, after the laying peak, and at the end of the laying period) to measure the chemerin concentrations in egg white by enzyme-linked immunosorbent assay. The chemerin concentration in egg white decreased during the laying period and was not associated with reproductive parameters. We found negative correlations between the chemerin level in egg white and the albumen weight. Reverse-transcriptase quantitative polymerase chain reaction showed that chemerin and its three receptors CMKLR1, GPR1, and CCRL2 were expressed in the reproductive tract and within allantoic and amniotic annexes during embryo development. Chemerin concentrations strongly increased in amniotic fluid on embryonic day 16 (ED16) when the egg white was transferred into the amniotic sac. Finally, chemerin inhibition in egg white by in ovo injections of anti-chemerin antibodies (0.01, 0.1, and 1 µg) increased the embryo mortality rate. These data demonstrate the important role of the chemerin system during egg formation and embryo development in Pekin ducks, suggesting their potential use as biomarkers for determining the quality of poultry eggs and embryo development.

Increasing the pasteurization temperature of liquid egg white by phosphorylation modification: Exploring the mechanism and application.

Pasteurization is an effective sterilization technique for the treatment of liquid egg white (LEW), but the pasteurization temperature is generally limited because increased temperature can lead to aggregation of the proteins and affect their processing properties. In this study, phosphorylation modification was used to increase the thermal stability and pasteurization temperature of LEW, aiming to enhance the pasteurization sterilizing effect. The FT-IR results showed that the phosphate groups were successfully grafted into protein molecules, improving the order degree of protein molecules. In this case, the pasteurization temperature of LEW increased from 58 °C to 61 °C, without accompanying thermal aggregation. The molecular structural results suggested that the enhanced thermal stability was attributed to the decreased average particle size and the increased electrostatic repulsion between protein molecules, which largely reduced the turbidity of LEW during pasteurization treatment. Meanwhile, this process was dominated by noncovalent interactions (hydrophobic interactions and hydrogen bonding). Furthermore, the phosphorylation modification can synchronously improve emulsifying and foaming properties of LEW. Therefore, this work suggested that phosphorylation has great potential to improve thermal stability and pasteurization temperature of LEW, which can be utilized to extend its sterilizing effect and shelf life.

Impact of NaCl perturbation on physicochemical and structural properties of preheat-treated egg white protein modulating foaming property.

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.

Study on the gelling properties of egg white/surfactant system by different heating intensities.

The aim of this study was to elucidate the different effects and difference mechanism of gelling properties among egg white (EW) treated with different heating intensities and the composite addition of rhamnolipid and soybean lecithin. Particle size analyzer, potentiometric analyzer, surface hydrophobicity method, and Fourier transform infrared spectroscopy techniques were used to determine the physicochemical properties and molecular structure, respectively. Low-field nuclear magnetic resonance, magnetic resonance imaging, texture profile analysis, and scanning electron microscopy techniques were used to analyze the gelling properties and gel structure, respectively. And we illuminate the different mechanisms in the gelling properties of the EW with various treatments and key internal factors that play important roles in improving gelling properties by establishing the link between the gelling properties and relevant characteristics by mixed effects model and visual network analysis. The results indicate raising the content of rhamnolipid decreased the migration of immobilized water in the EW gel and the free water content. At the heating intensities of 55 °C/3.5, 65 °C/2.5, and 67 °C/1.5 min, with an increase in rhamnolipid, the gel's cohesiveness, gumminess, and chewiness gradually increased. The mixed effects model indicated that heating intensities and composite ratios have a 2-way interaction on zeta potential, the relaxation time of bound water (T21), the content of bound water (P21), the content of immobilized water (P22), and fractal dimension (df) attributes (P < 0.05). The visual network analysis showed that the protein solubility, the relaxation time of immobilized water (T22), surface hydrophobicity, zeta potential, average particle size (d43) and the relaxation time of free water (T23) are critical contributors to the different gelling properties of EW subjected to various treatments and the improvement of gelling properties. This study will provide theoretical guidance for the development of egg white products and the expansion of egg white's application scope in the egg product processing industry.

Multifunctional and edible egg white/amylose-tannin bilayer film for perishable fruit preservation.

The substantial waste of perishable foods during transportation significantly contributes to greenhouse gas emissions, intensifying the climate crisis. To mitigate the rapid spoilage of fruits, an eco-friendly bilayer film was developed using natural egg white (EW), amylose (Am), and tannic acid (TA). The EW/Am-TA bilayer film features a primary layer of amphiphilic EW, ensuring a uniform coating on hydrophobic fruit surfaces, and a secondary layer composed of Am and TA, imparting notable tensile strength (5.3 ± 0.5 MPa) and elongation at break (28.5 ± 4.1 %). This bilayer film effectively shields fruits from UV-B and UV-C radiation (~0 % transmittance at 280 and 330 nm) and exhibits antioxidant and antibacterial properties due to the presence of TA. Fruits such as bananas, avocados, and cherry tomatoes, when dip-coated with the optimized EW/Am-TA bilayer, maintained their freshness, color, weight, and texture for up to seven days, demonstrating the effectiveness of this bilayer coating in food preservation. The natural materials in the coated film are edible and can be safely removed with tap water at room temperature in <10 s, posing no food safety risks. Thus, the proposed bilayer coating presents a significant solution to the global problem of food waste.

Egg white-derived peptides reduced blood glucose in high-fat-diet and low-dose streptozotocin-induced type 2 diabetic mice via regulating the hepatic gluconeogenic signaling and metabolic profile.

Food proteins are considered an ideal source for the identification of bioactive peptides with the potential to intervene in nutrition-related chronic diseases such as cardiovascular disease, obesity, and diabetes. Egg white-derived peptides (EWPs) have been shown to improve glucose tolerance in insulin-resistant rats. However, underlying mechanisms are to be elucidated. Therefore, we hypothesized that EWP exerts a hypoglycemic effect by regulating hepatic glucose homeostasis. Our results showed that 7 weeks of EWP treatment reduced the fasting blood glucose in T2DM mice and the inhibition of the liver gluconeogenic pathway was involved in the mechanisms of actions. Using the untargeted metabolomics technique, we found that EWP treatment also altered the hepatic metabolic profile in T2DM mice, in which, the role of fatty acid esters of hydroxy fatty acids in mediating the hypoglycemic effect of EWPs might be pivotal.

Study on the effect of enzymolysis combined fermentation on reducing the off-flavor of egg white powder.

BACKGROUND: The application of egg white powder (EWP) was subject to its off-flavor. In the present study, flavourzyme and lactic acid bacteria were used to treat egg white powder (EWP) and the mechanism effects of enzymolysis-fermentation were explored. RESULTS: Compared with the control group, enzymolysis combined with fermentation treatment group (EW-EF) reduced the four-representative off-flavor compounds (geranyl acetone, 1-octen-3-ol, octanal and nonanal) by more than 62.66%. Fermentation produced esters with good flavor, and enzymolysis produced fresh amino acids. Characterization of protein structure indicated that fermentation decreased both fluorescence intensity and surface negative charges, accelerating the aggregation of proteins; enzymolysis promoted aggregation and degradation, improving the stability of the egg white proteins. Meanwhile, enzymolysis broke down the hydrophobic cavities bound to off-flavor compounds, releasing protein-bound off-flavor compounds and removing them through fermentation. CONCLUSION: EW-EF had the best effect of off-flavor removal on EWP. The results of the present study could provide a green and effective method for improving the flavor of EWP. © 2024 Society of Chemical Industry.

Using salted egg white in steamed bread: Impact on functional and structural characteristics.

Steamed bread has long been an important part of Chinese cuisine. This study investigated the effects of salted egg white (SEW) (5, 10, 15, and 20% w/w) on the quality of steamed breads. Findings revealed that SEW notably enhanced the bread's volume and texture, with a 20% inclusion significantly boosting water retention and rheological properties, albeit reducing bread's lightness. In addition, the H-bond absorption band intensity in the Fourier transform infrared spectroscopy (FTIR) analysis showed increased peak intensities with higher SEW levels, indicative of protein structure alterations. X-ray diffraction confirmed the presence of an amylose-lipid complex. Scanning electron microscope (SEM) and Confocal laser scanning microscope (CLSM) imaging depicted a smooth, consistent protein network with SEW addition. Consumer sensory evaluation responded favourably to the SEW15 steamed bread, suggesting its potential for food industry application. Overall, the study considers SEW an effective ingredient for improving steamed bread quality.