Functional Properties and Extraction Techniques of Chicken Egg White Proteins

Chlorella sp. as a promising protein source: insight to novel extraction techniques, nutritional and techno-functional attributes of derived proteins

Amidst the mounting environmental crises and ever-increasing global population, the quest for sustainable food production and resource utilization solutions has taken center stage. Microalgae, with Chlorella species at the forefront, present a promising avenue. They serve as a bountiful protein source and can be conveniently grown in waste streams, thereby tackling food security, environmental sustainability, and economic feasibility. This article embarks on a comprehensive journey through recent research on Chlorella by shedding light on its unique characteristics, its market value, cultivation techniques, and harvesting methods. It also delves into traditional and innovative extraction methods, underscoring the hurdles and breakthroughs in achieving high protein yields from the Chlorella biomass. Moreover, exploration of the protein's nutritional properties, bioactive peptides, and techno-functional attributes, enhance its potential for food applications. Further, this review also examines current market trends in consumer acceptance of this alternative protein and discusses strategies for reducing greenhouse gas emissions in their production. By providing invaluable insights into the current status and future prospects of Chlorella protein, it aspires to make a significant contribution to the ongoing dialogue on sustainable food production and resource management.

Dynamic changes of volatile compounds during the processing of egg white powder based on GC-IMS investigation

Processing is a crucial stage in the production of egg white powder (EWP), yet its effect on flavor remains unclear. This study aimed to investigate the impact of processing on flavor in EWP by analyzing volatile compounds (VCs) using Gas Chromatography-Ion Mobility Spectrometry (GC-IMS). This study identified 29 VCs, with the highest diversity observed during fermentation, desugaring, and spray drying. Key flavor contributors, such as 1-penten-3-one and 2-ethyl-5-methylpyrazine, were identified, indicating specific processing conditions that enhance desirable flavors. The results suggest that specific processing techniques can significantly influence the flavor profile of EWP. This work can help optimize processing methods, enhance flavor profiles, and increase consumer acceptance of EWP products. Additionally, it demonstrates that GC-IMS can effectively monitor dynamic changes in flavor, offering valuable insights for future research and development.

Research note: Study on liquid-liquid phase separation of thick and thin egg white

"Gel-like" thick egg white (TKEW) and "solution-like" thin egg white (TNEW) are not mutually soluble in fresh egg white, showing a natural liquid-liquid phase separation phenomenon. The effects of storage temperature, storage time, ultrasonic force, mechanical stirring and chemical ions on the stability of liquid-liquid phase of TKEW and TNEW were systematically analyzed in this paper. It was found that the collapse of TKEW gel structure was the key to cause two phase separation. Room temperature storage was easier to cause the structure of TKEW collapsed and the viscosity decreased, which led to the phase separation interface between TKEW and TNEW began to lose stability. Besides, ultrasonic treatment, stirring and phosphate-buffered saline (20 mmol/L) in acidic environment also reduced the proportion of TKEW, and result in the disappearance of the two-phase interface. While, the salt at physiological concentration was found to contribute to the stability of TKEW. The rule of liquid-liquid phase separation of TKEW and TNEW provided an important basis for egg white storage and diversified utilization.

"Allergolds": Gold Nanocluster-Based Bioconjugates of Food Allergens with Reduced Immunoglobulin E Binding

Allergen-specific immunotherapy represents the only method of achieving a lasting reduction in the severity of allergic symptoms. However, the need to expose patients to the allergens to which they are sensitized carries risks. One solution is to use denatured allergens whereby the structure of allergenic proteins is disrupted, preventing their recognition by immunoglobulin E (IgE) antibodies and thus reducing the risk of adverse reactions. Denaturation is often carried out by using chemical cross-linking to generate allergoids. Gold nanoclusters (AuNCs) are emerging as versatile tools in biotechnology due in part to their ability to conjugate a wide range of biological molecules. Previous works have described the formation of AuNC using egg allergens such as Gal d 4 (lysozyme), Gal d 2 (ovalbumin), and whole egg whites. In all cases, AuNC bioconjugation disrupted the protein structure, allowing for their use in biosensing applications. In this work, we hypothesize that these AuNC-allergen bioconjugates could be used to generate "Allergolds", chemically altered versions of allergenic proteins analogous to traditional allergoid formulations. Using spectroscopic techniques, we confirm that the formation of AuNC bioconjugates of the chicken egg Gal d 4 and Gal d 2 disrupts protein structure when generated from both purified protein and whole egg whites. This structural perturbation was found to be resilient to a range of chemical conditions and successfully disrupted recognition by human IgE. These results establish Allergolds as a potential tool for generating systematically denatured allergens from both purified proteins and biological extracts.

Recent innovations for improving the techno-functional properties of plant-based egg analogs and egg-mimicking products to promote their industrialization and commercialization

Recent advancements in plant-based egg analogs (PBEAs) and plant-based egg-mimicking products (PEMP) are driven by growing consumer demand and the need for alternatives to animal-derived products. This movement is being encouraged by several factors, including a drive toward specifically sustainability, increased allergenicity, and consumer preferences for flexitarian diets. We comprehensively overviewed the current research on the formulation and characterization of PBEAs and PEMP that are vital for diverse food applications. We also highlighted the techno-functional features of these ingredients and their impact in PBEA and PEMP-based formulas and evaluated up-to-date outcomes that display the availability of economically viable substitutes. However, to efficiently mimic the sensorial and textural features of eggs, further innovation and intensive work are still needed. For instance, challenges persist in achieving desired quality attributes, controlling costs, and scaling-up the production, which limit broader market adoption of PBEAs and PEMP. Addressing these obstacles through persistent research and development can improve the functionality and acceptance of PBEAs in the food industry, aligning with evolving consumer preferences for plant-based protein alternative options.

Analysis of bioactive compounds of hen egg components at the first half of incubation

A comparative analysis of mass-volume characteristics of structural and morphological components of hen eggs before incubation and on the fifth (HH25-HH27) and 10th (HH36) days of incubation was carried out. During incubation, egg weight decreased by 9.25% (10 days), mainly due to a decrease in albumen weight (35.8%). The ratio of lipid-soluble fraction (LSF) and water-soluble fraction (WSF) in the mixed components and yolk did not change significantly. The total amount of solids in the mixed substances practically does not change during incubation. Antiradical activity of substances increased significantly by more than three times on the fifth day and additionally by 38.6% at the 10th day in relation to the fifth day. Total antioxidant activity increased by 18.9% on the fifth day and by 24.3% on the 10th day, compared to eggs before incubation. Transformation of the main components of WSF and LSF of albumin, yolk, and chicken embryo (CE) was studied using high-performance liquid chromatography and gas chromatography with mass spectrometry. On the 10th day, an increase in the number of high-molecular proteins is recorded, which indicates the activation of enzymatic processes of transformation of the main albumen proteins into proteins of organs and tissues of CE. This may cause an increase in the biological activity of substances. It was found that in conditions of in vitro digestion, antiradical activity increases by two times, anti-inflammatory activity increases by 2.4 times, and an angiotensin-converting enzyme inhibitory effect occurs in the mixed components of a 10-day incubation egg.

Modification Effects of Microorganisms and Enzymes on Egg Components: A Review

In eggs, there are several components: eggshell (ES), eggshell membrane (ESM), egg white (EW), and egg yolk (EY). Many modification methods exist, such as thermal treatment, high pressure, freeze-thaw cycles, ultrasonic treatment, ozonation, phosphorylation, and acylation, all aimed at improving the functional properties of EW and EY. Additionally, microorganism and enzyme modifications have proven effective in enhancing the functional properties of EW and EY. ES and ESM are unique components of eggs. The eggshell is rich in calcium carbonate, while the eggshell membrane is rich in protein. The effective utilization of ES and ESM can help promote economic income in the poultry industry and benefit the environment. Research on the modification of ES and ESM has shown that microorganisms and enzymes have the potential to improve their functional properties. After modification, egg components can be utilized in the production of egg-based and other food products for improved performance. Furthermore, enzyme modification of egg components can produce bioactive peptides, which have the potential to treat specific diseases and may even be used in the biomedical field. This review primarily focuses on the effects of microorganisms and enzymes on the modification of egg components and summarizes the roles of microbial and enzymatic modifications in this context.

Ovotransferrin, an alternative and potential protein for diverse food and nutritional applications

Ovotransferrin(OVT)is a protein found in many types of egg white and has a wide range of functional properties. It has 50% homology with human/bovine lactoferrin, and is expected to be one of the most important alternative proteins for use in food and nutritional applications. This paper mainly reviews the structural characteristics and chemical properties of OVT, as well as its extraction and purification methods. It also systematically describes the various biological activities of OVT and its applications in food and medical industries. The challenges and limitations in the research of OVT were suggested. This review recommends some possible methods such as nanoparticle carriers and microencapsulation to improve the bioavailability and stability of OVT. In addition, this review highlights several strategies to overcome the limitations of OVT in terms of preparation and purification. This review systematically summarizes the recent advances in OVT and will provide guidance for the its development for food and nutritional applications.

The Utilization of Chicken Egg White Waste-Modified Nanofiber Membrane for Anionic Dye Removal in Batch and Flow Systems: Comprehensive Investigations into Equilibrium, Kinetics, and Breakthrough Curve

This study investigated the use of chicken egg white (CEW) waste immobilized on weak acidic nanofiber membranes for removing the anionic acid orange 7 (AO7) dye in batch and continuous flow modes. Different experiments were conducted to evaluate the effectiveness of CEW-modified nanofiber membranes for AO7 removal, focusing on CEW immobilization conditions, adsorption kinetics, and thermodynamics. The CEW-modified nanofiber membrane (namely NM-COOH-CEW) exhibited a maximum AO7 adsorption capacity of 589.11 mg/g within approximately 30 min. The Freundlich isotherm model best represented the equilibrium adsorption data, while the adsorption kinetics followed a pseudo-second-order rate model. Breakthrough curve analysis using the Thomas model and the bed depth service time (BDST) model showed that the BDST model accurately described the curve, with an error percentage under 5%. To investigate AO7 elution efficiency, different concentrations of organic solvents or salts were tested as eluents. The NM-COOH-CEW nanofiber membrane exhibited promising performance as an effective adsorbent for removing AO7 dye from contaminated water.

Improvement of foaming properties of ovalbumin: Insights into the synergistic effect of preheating and high-intensity ultrasound on physicochemical properties and structure analysis

Ovalbumin (OVA), characterized by its high concentration in eggs, possesses remarkable foaming properties. Nevertheless, OVA is highly sensitive to thermal changes and acid-base conditions, substantially hampering its application potential for foaming purposes within the food industry. This experiment aimed to examine the effects of preheating and high-intensity ultrasound (HIU) treatment at different powers on OVA foaming properties and explore the underlying mechanisms. The results revealed that OVA exhibited the highest foaming capacity (31.5 %) and foaming stability (96.7 %) under the treatment condition of 200w + 60°C. Additionally, significant improvements were observed in the content of free sulfhydryl groups (37.27 μmg/g), solution viscosity (142.33 mPa·s), and surface hydrophobicity (37.27 μg BPB) under this condition. The absolute value of the zeta potential (-10.28 mV) was significantly increased in the 200w + 60°C treatment group. Moreover, the polymer dispersity index of OVA (0.6045) was significantly reduced, resulting in improved dispersion than the control group. The structural analysis revealed significant changes in the α-helix and β-sheet content of OVA after treatment at 200w + 60 °C. The X-ray diffraction pattern exhibited sharper peaks, indicating a crystal structure, and the fluorescence peak displayed a slight blue shift along with increased hydrophobicity. Moreover, the preheating and HIU treatment induced a continuous uneven and irregular pore structure in OVA, which ultimately enhanced its foaming properties. In conclusion, the preheating and HIU treatment offers a novel approach to enhance the foaming properties of OVA.

Effectiveness of adequate chicken egg white consumption on dyspnea degree and exacerbation incidence in stable COPD patients practicing strength and endurance exercises

Lack of physical exercise and inadequate nutritional intake in chronic obstructive pulmonary disease (COPD) patients could lead to low muscle mass and function, which causes reduced respiratory function, increased incidence of exacerbations, exercise intolerance, increased visits to health facilities, and low health status. Therefore, physical exercise and good nutritional intake are the main foundations of a comprehensive pulmonary rehabilitation program for COPD patients. The aim of the study was to determine the effect of chicken egg white supplementation on dyspnea degree and the incidence of exacerbations in stable COPD patients who perform physical exercise independently at home. A quasi-experimental study was conducted in 38 stable COPD patients based on the Global Initiative for Chronic Lung Disease (GOLD) 2021 classification criteria. The patients were divided into two groups: the control group who did smartphone application-assisted physical exercises and the intervention group who did the same physical exercises plus chicken egg white supplementation for 12 weeks. Performed physical exercises included both strength and endurance training. The degree of dyspnea was assessed with modified Medical Research Council (mMRC) dyspnea scale and the incidence of exacerbations was assessed by direct interviews at the beginning and at the end of the intervention. A Fisher's exact test was used to assess the association between the intervention with dyspnea degree and exacerbation incidence. In the intervention group, chicken egg white supplementation for 12 weeks lowered the dyspnea degree by 3.16 times than the control (relative risk 3.16 with p=0.001). Furthermore, the incidence of exacerbations was also reduced by 1.8 times compared to the control group (relative risk 1.8, p=0.001). This study highlights a significant improvement in dyspnea degree and exacerbation incidence in COPD patients with the combination of protein supplementation and physical exercise. Therefore, adding chicken egg white intake could be beneficial for stable COPD patients practicing physical exercises.

Well-designed protein amyloid nanofibrils composites as versatile and sustainable materials for aquatic environment remediation: A review

Amyloid nanofibrils (ANFs) are supramolecular polymers originally classified as pathological markers in various human degenerative diseases. However, in recent years, ANFs have garnered greater interest and are regarded as nature-based sustainable biomaterials in environmental science, material engineering, and nanotechnology. On a laboratory scale, ANFs can be produced from food proteins via protein unfolding, misfolding, and hydrolysis. Furthermore, ANFs have specific structural characteristics such as a high aspect ratio, good rigidity, chemical stability, and a controllable sequence. These properties make them a promising functional material in water decontamination research. As a result, the fabrication and application of ANFs and their composites in water purification have recently gained considerable attention. Despite the large amount of literature in this field, there is a lack of systematic review to assess the gap in using ANFs and their composites to remove contaminants from water. This review discusses significant advancements in design techniques as well as the physicochemical properties of ANFs-based composites. We also emphasize the current progress in using ANFs-based composites to remove inorganic, organic, and biological contaminants. The interaction mechanisms between ANFs-based composites and contaminants are also highlighted. Finally, we illustrate the challenges and opportunities associated with the future preparation and application of ANFs-based composites. We anticipate that this review will shed new light on the future design and use of ANFs-based composites.

Egg White and Yolk Protein Atlas: New Protein Insights of a Global Landmark Food

(1) Background: The chicken egg is an animal product of great agronomic interest. The egg white and yolk constitute high-quality protein sources for humans with high digestibility and well-balanced amino acid profiles. Despite the egg white and yolk protein's undisputed value, research to unravel their full proteome content and its properties is still ongoing. We aimed to exhaustively analyze the proteome of egg white and yolk by applying intrinsic proteomics and bioinformatics approaches in order to unravel the full protein potential of this landmark food. (2) Methods: A total of 45 freshly laid, unfertilized, chicken eggs were subjected to nanoLC-MS/MS Orbitrap analysis following a peptide pre-fractionation step. A comprehensive bioinformatics processing step was undertaken towards elucidating potential activities and roles of identified molecules. In parallel, the literature was mined concerning all reported egg white and yolk protein identifications. (3) Results: Our analysis revealed 371 and 428 new proteins, reported for the first time to be present in the egg white and yolk, respectively. From the bioactivity standpoint, egg white and yolk proteins showed high enrichment for antioxidant and anti-inflammatory processes, while exerting high relevance for the apoptosis and focal adhesion pathways. (4) Conclusions: Egg white and yolk proteins exert diverse and multifaceted properties. A total of 799 proteins were reported for the first time as being part of the egg and yolk. Our novel protein data enriched those already published in the literature and the first ever chicken egg white and yolk Protein Atlas, comprising 1392 protein entries, was generated. This dataset will provide a cornerstone reference for future studies involving egg proteins.

Integrated Microbiome and Metabolomic Analysis Reveal the Repair Mechanisms of Ovalbumin on the Intestine Barrier of Colitis Mice

The development and progression of colitis would detrimentally destroy the intestine barrier. However, there remains a paucity of evidence on whether ovalbumin (OVA) can be used as a nutritional food protein to repair the intestinal barrier. In this study, the repairing mechanism of OVA on intestinal barrier was thoroughly investigated by gut microbiota and untargeted metabolomics techniques. The findings demonstrated that OVA reduced intestinal permeability and restored mucin (0.75 ± 0.06) and tight junction (TJ) protein (0.67 ± 0.14) expression in colitis mice caused by 3% dextran sulfate sodium (DSS). In addition, the inflammation response and oxidative stress were also attenuated. The intake of OVA upregulated the abundance of Lactobacillaceae (7.60 ± 3.34%) and Akkermansiaceae (10.39 ± 5.97%). Furthermore, OVA upregulated the abundance of inosine (6.06 ± 0.36%), putrescine (4.14 ± 0.20%), and glycocholic acid (5.59 ± 0.23%) in colitis mice through ATP binding cassette (ABC) transporters and bile secretion pathways. In summary, our findings revealed that OVA could maintain intestinal health, which may provide crucial insights for preventing and treating intestinal diseases.

The Impact of Processing and Extraction Methods on the Allergenicity of Targeted Protein Quantification as Well as Bioactive Peptides Derived from Egg

This review article discusses advanced extraction methods to enhance the functionality of egg-derived peptides while reducing their allergenicity. While eggs are considered a nutrient-dense food, some proteins can cause allergic reactions in susceptible individuals. Therefore, various methods have been developed to reduce the allergenicity of egg-derived proteins, such as enzymatic hydrolysis, heat treatment, and glycosylation. In addition to reducing allergenicity, advanced extraction methods can enhance the functionality of egg-derived peptides. Techniques such as membrane separation, chromatography, and electrodialysis can isolate and purify specific egg-derived peptides with desired functional properties, improving their bioactivity. Further, enzymatic hydrolysis can also break down polypeptide sequences and produce bioactive peptides with various health benefits. While liquid chromatography is the most commonly used method to obtain individual proteins for developing novel food products, several challenges are associated with optimizing extraction conditions to maximize functionality and allergenicity reduction. The article also highlights the challenges and future perspectives, including optimizing extraction conditions to maximize functionality and allergenicity reduction. The review concludes by highlighting the potential for future research in this area to improve the safety and efficacy of egg-derived peptides more broadly.

1Progress, applications, challenges and prospects of protein purification technology

Protein is one of the most important biological macromolecules in life, which plays a vital role in cell growth, development, movement, heredity, reproduction and other life activities. High quality isolation and purification is an essential step in the study of the structure and function of target proteins. Therefore, the development of protein purification technologies has great theoretical and practical significance in exploring the laws of life activities and guiding production practice. Up to now, there is no forthcoming method to extract any proteins from a complex system, and the field of protein purification still faces significant opportunities and challenges. Conventional protein purification generally includes three steps: pretreatment, rough fractionation, and fine fractionation. Each of the steps will significantly affect the purity, yield and the activity of target proteins. The present review focuses on the principle and process of protein purification, recent advances, and the applications of these technologies in the life and health industry as well as their far-reaching impact, so as to promote the research of protein structure and function, drug development and precision medicine, and bring new insights to researchers in related fields.