What's new in chicken egg research and technology for human health promotion? - A review

Influence mechanisms of linoleic acid and oleic acid on the gel properties of egg yolk protein

BACKGROUND

Gel property is among the crucial functional properties of egg yolk (EY), which determines the texture and flavor of EY products. In the present study, the effects of two unsaturated fatty acids [monounsaturated fatty acid oleic acid (OA) and diunsaturated fatty acid linoleic acid (LA)] on the gel properties of EY protein were investigated.

RESULTS

Compared with the blank group, the addition of LA and OA (10-50 g kg-1) improved the gel hardness (from 270.54 g to 385.85 g and 414.38 g, respectively) and viscosity coefficient (from 0.015 Pa.sn to 11.892 Pa.sn and 1.812 Pa.sn, respectively). The surface hydrophobicity of EY protein increased to a maximum value of 40 g kg-1 with the addition of both fatty acids (39.06 μg and 41.58 μg, respectively). However, excess unsaturated fatty acids (≥ 50 g kg-1) disrupted the completeness of the gel matrix and weakened the structural properties of the EY gel.

CONCLUSION

Both fatty acids improved the gel properties of EY protein. At the same addition level, OA was superior to LA in improving gel properties. The present study provides a theoretical underpinning for the sensible application of unsaturated fatty acids in improving EY gel properties. © 2024 Society of Chemical Industry.

Conjugation of Lysozyme and Epigallocatechin Gallate for Improving Antibacterial and Antioxidant Properties

One of the main interests in the food industry is the preservation of food from spoilage by microorganisms or lipid oxidation. A novel alternative is the development of additives of natural origin with dual activity. In the present study, a chemically modified lysozyme (Lys) with epigallocatechin gallate (EGCG) was developed to obtain a conjugate (Lys-EGCG) with antibacterial/antioxidant activity to improve its properties and increase its application potential. The modification reaction was carried out using a free radical grafting method for the Lys modification reaction, using ascorbic acid and hydrogen peroxide as radical initiators in an aqueous medium. The synthesis of Lys-EGCG conjugate was confirmed by spectroscopic (FT-IR, 1H-RMN, and XPS) and calorimetry differential scanning (DSC) analyses. The EGCG binding to the Lys biomolecule was quantified by the Folin-Ciocalteu method; the antibacterial activity was evaluated by minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MCB) against Staphylococcus aureus and Pseudomonas fluorescens; the antioxidant activity was evaluated by ABTS, DPPH, and FRAP. The spectroscopic results showed that the Lys-EGCG conjugate was successfully obtained, and the DSC analysis revealed a 20 °C increase (P < 0.05) in the denaturation temperature of Lys due to EGCG modification. The EGCG concentration in Lys-EGCG was 97.97 ± 4.7 µmol of EGCG/g of sample. The antibacterial and antioxidant activity of the Lys-EGCG conjugate was higher (P < 0.05) than pure EGCG and Lys. The chemical modification of Lys with EGCG allows for the bioconjugate with a dual function (antibacterial/antioxidant), broadening the range of Lys and EGCG applications to different areas such as food, cosmetic, and pharmaceutical industries.

The Chicken Egg: An Advanced Material for Tissue Engineering

The chicken egg, an excellent natural source of proteins, has been an overlooked native biomaterial with remarkable physicochemical, structural, and biological properties. Recently, with significant advances in biomedical engineering, particularly in the development of 3D in vitro platforms, chicken egg materials have increasingly been investigated as biomaterials due to their distinct advantages such as their low cost, availability, easy handling, gelling ability, bioactivity, and provision of a developmentally stimulating environment for cells. In addition, the chicken egg and its by-products can improve tissue engraftment and stimulate angiogenesis, making it particularly attractive for wound healing and tissue engineering applications. Evidence suggests that the egg white (EW), egg yolk (EY), and eggshell membrane (ESM) are great biomaterial candidates for tissue engineering, as their protein composition resembles mammalian extracellular matrix proteins, ideal for cellular attachment, cellular differentiation, proliferation, and survivability. Moreover, eggshell (ES) is considered an excellent calcium resource for generating hydroxyapatite (HA), making it a promising biomaterial for bone regeneration. This review will provide researchers with a concise yet comprehensive understanding of the chicken egg structure, composition, and associated bioactive molecules in each component and introduce up-to-date tissue engineering applications of chicken eggs as biomaterials.

Knowledge and handling practices for raw hen's eggs during purchase, preparation, storage, and consumption: a cross sectional study

The study aimed to assess the hen's eggs knowledge, handling practices, and consumption among Palestinian consumers using the cross-sectional survey design. Online questionnaire was sent via social media platforms including well-known Facebook and WhatsApp groups in West bank, Gaza and Jerusalem, along with an invitation explaining the research objectives and the voluntary participation. The online questionnaire consisted of three main sections: socio demographic, knowledge and practices for hen's eggs during purchase, preparation, storage, and consumption. The items were developed based on previous literature and international guidelines for hen's eggs purchase and handling, and subjected to content validity process, followed by a pilot study to determine the reliability of the questionnaire using Cronbach's alpha test. The final data were analysed based on the dichotomous Rach model for knowledge and polytomous Rasch model for practices using Winsteps version 5.1.3. The Rasch SPSS output interval data files were used in the inferential analyses tests (one-way ANOVA test and independent samples t-test). The Rasch analysis showed that on average the participants had quite low level of knowledge of hen's eggs consumption safety, (person ability Mean 0.10 logit). The item difficulty measures ranged between + 1.65 (most difficult) and - 2.24 logit (easiest). It was not easy for the participants to endorse the items pertaining their practices in handling the hen's eggs during purchase, preparation, storage and consumption, (person ability Mean - 0.11 logit). The item difficulty measures ranged between + 2.68 logits (most difficult) to - 2.45 logit (easiest). In addition, female participants significantly outperformed males in knowledge scores; and the level of hen's eggs hygiene practices and storage during purchase depended on participants' knowledge level. The research recommended interventional programs to enhance Palestinians' awareness and knowledge about hen's eggs knowledge, handling practices, and consumption. Further quantitative and qualitative research studies were also recommended.

Protein profiles in the transfected oviductal secreting cells of laying hen (Gallus gallus domesticus)

Due to the intensive development of novel biopharming applications, there is a need for the in vitro verification models prior to in vivo testing. Laying hen has been already applied as an animal bioreactor to produce the therapeutical enzyme in a rare disease called lysosomal acid lipase deficiency. In this study, we aimed to verify how the proteome of the transfected oviduct epithelial cells would be affected by genetic nonviral modification with the human exogene. The study was based on a previously developed method to cultivate chicken oviduct epithelial cells (COEC). The typical characteristics of the COEC epithelial cells were retained across the experiments. The mean efficiency of nucleofection ranged from 2.6 to 19.7% depending on the cells' isolation and location in the oviduct (upper, infundibulum site, or magnum). The PCR confirmed the incorporation of human interferon alpha2a (hIFNα2a) exogene into the nucleofected COEC but, the production of hIFNα2a protein did not exceed the detection level in this study. The ovalbumin protein was detected in the nontransfected and transfected COEC, which confirmed the normal secreting functions of the cells subject to modification. Proteomic analysis revealed an increase in abundance of the cell adhesion molecules and collagen molecules after introducing gene under ovalbumin promoter. According to the bioinformatic analyses there was a limited negative impact of transfection on cells, and the normal biochemical pathways were not severely disordered. In conclusion, the observations provide new knowledge about the proteomic profile of the manipulated COEC with regard to the retained normal functionality of the cells, which can be informative for avian biopharma research.

Selenium- and/or Zinc-Enriched Egg Diet Improves Oxidative Damage and Regulates Gut Microbiota in D-Gal-Induced Aging Mice

Eggs, with their high nutritional value, are great carriers for enriching nutrients. In this study, selenium- and/or zinc-enriched eggs (SZE) were obtained and their effects on ameliorating oxidative stress injury, alleviating cognitive impairment, and maintaining intestinal flora balance in a D-gal-induced aging mice model were investigated. As determined by the Y-maze test, SZE restored the learning and memory abilities and increased the Ach level and AChE activity of aging mice (p < 0.05). Meanwhile, supplementation of low-dose SZE increased antioxidant levels and decreased inflammation levels (p < 0.05). High-dose SZE increased anti-inflammatory levels but were less effective than low dose. Additionally, SZE maintained the intestinal flora balance and significantly increased the ratio of Firmicutes and Bacteroidota. Blautia, as a probiotic, was negatively correlated with pro-inflammatory factors and positively correlated with antioxidant levels (p < 0.05). These results suggest that SZE might improve organ damage and cognitive function by attenuating oxidative stress and inflammatory response and maintaining healthy gut flora.

Treatment and optimization of high-strength egg-wash wastewater effluent using electrocoagulation and electrooxidation methods

Egg-washing wastewater contains a high concentration of nutrition and organic matter since eggs are broken during the washing and cleaning processes. Moreover, the wastewater contains small amounts of detergents or sanitizing agents. These contaminants may pose environmental challenges when they are not properly managed or treated. The study scrutinizes the efficiency of electrocoagulation (EO) and electrooxidation (EO) approaches for egg-wash wastewater treatment. The response surface methodology was employed to optimize the operational parameters. The removal efficiencies of soluble chemical oxygen demand (sCOD 90%), ammonia (NH3-N 91%), nitrate (NO3--N 97%), nitrite (NO2--N 89.3%), total dissolved nitrogen (TDN 91%), and phosphate (90%) were measured under various treatment conditions. The optimum treatment conditions achieved in the combined EC + EO process were pH 6.0, current density 20 mA cm-2, and electrolysis time of 60 min, respectively. Degradation kinetics of the egg-wash pollutants showed a significant reduction in half-life (t1/2) with EO (after EC-Aluminum) at 15 min, 12 min, 17 min, and 15 min for sCOD, NO2--N. NO3--N, and TDN, respectively. Whereas the half-life of NH3-N (18 min) and phosphate (17 min) reduced significantly with the EO (after EC-iron). Al and Fe electrodes coupled with boron-doped diamond were found efficient for pollutant removal. Environmental implication. Egg-wash wastewater has a high protein content and contains nutrients that are essential for living organisms. While these compounds can be valuable for agricultural use by increasing soil phosphate concentration, they can also become an issue if the excess nutrients are not properly managed. The soil has a threshold limit for holding phosphate, and any excess amount may be transported through surface runoff or contaminate groundwater through leachate, potentially affecting aquatic ecosystems and water quality. This study explores the efficiency of electrocoagulation and electrooxidation methods in treating egg-wash wastewater. These methods aim to remove pollutants and reduce their environmental impact.

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.

Carotenoid enrichment in eggs: From biochemistry perspective

The emergence of safe and functional eggs for consumer acceptance has gained focus. The production of carotenoid-enriched eggs has received attention due to its multifunctional biological properties. Nutritional modification of laying hens' diet can be a strategy to produce such eggs. This review presents the chemistry of carotenoids in nature and eggs, the accumulation process of carotenoids into eggs, and the functions of carotenoids in eggs. Our findings showed that carotenoids can be deposited into the egg and contribute to improving its nutritive value. The biosynthesis, chemical structure, and metabolism pathways of carotenoids lead to the deposition of carotenoids into eggs in their original or metabolized forms. Also, some factors modulate the efficiency of carotenoids in fowls before accumulation into eggs. Carotenoid-enriched eggs may be promising, ensuring the availability of highly nutritive eggs. However, further studies are still needed to comprehend the full metabolism process and the extensive functions of carotenoids in eggs.

Potential Implication of in ovo Feeding of Phytogenics in Poultry Production

Hatchery's goals include maximizing revenue by achieving high hatchability with day-old birds of excellent quality. The advancement of technology has benefited the poultry sector since breeding and genetics technology have increased the rates of meat maturation in developing birds in a short period of time. Excessive use of in-feed antibiotics has been shown in studies to increase the chance of resistance to human infections. Bacterial resistance and antibiotic residues in animal products raised concerns about using antibiotics as growth promoters, eventually leading to a prohibition on using in-feed antibiotics in most industrialized nations. In ovo technology is a novel method for delivering bioactive chemicals to developing avian embryos. In ovo feeding technologies may provide additional nutrients to the embryos before hatching. The introduction of bioactive compounds has the potential to assist in decreasing and eventually eliminating the problems associated with traditional antibiotic delivery in chicken production. Phytobiotics were advocated as an alternative by researchers and dietitians. So far, several studies have been conducted on the use of phytogenic feed additives in poultry and swine feeding. They have primarily demonstrated that phytobiotics possess antibacterial, antioxidant, anti-inflammatory, and growth-stimulating properties. The antioxidant effect of phytobiotics can improve the stability of animal feed and increase the quality and storage duration of animal products. In general, the existing documentation indicates that phytobiotics improve poultry performance. To effectively and efficiently use the in ovo technique in poultry production and advance research in this area, it is important to have a thorough understanding of its potential as a means of nutrient delivery during the critical stage of incubation, its effects on hatching events and posthatch performance, and the challenges associated with its use. Overall, this review suggests that in ovo feeding of phytobiotics has the potential to improve the antioxidant status and performance of chickens.

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.

Egg yolk phospholipids as an ideal precursor of fatty note odorants for chicken meat and fried foods: A review

Egg yolk phospholipids (PLs) have been demonstrated to generate large quantities of lipid-derived odorants, especially the fatty note odorants. Recently, egg yolk PLs have been successfully used in chicken meat and fried foods to improve aroma. This review comprehensively summarizes the properties of egg yolk PLs as precursors of fatty note odorants, including their classes, extraction, identification, oxidation, decomposition and odorant formation, applications, considerations and future prospects in the food industry. Most likely, phosphatidylcholine (PC) is the most abundant class in egg yolk PLs, and PC is more efficient than phosphatidylethanolamine in generating fatty note odorants; moreover, the predominant polyunsaturated fatty acid is linoleic acid, and its corresponding predominant hydroperoxide is 9-hydroperoxy-10,12-octadecadienoic acid during autoxidation, which is the precursor of 2,4-decadienals and 2,4-nonadienals, the key fatty note odorants. Therefore, egg yolk PLs could be an ideal precursor of fatty note odorants for chicken meat and fried foods.

Isolation, identification, and mode of action of antibacterial peptides derived from egg yolk hydrolysate

Egg yolk is a coproduct of egg white processing. The protein hydrolysis of egg yolks to exhibit antimicrobial activity is a strategy for its valorization. The objective of this study is to fractionate antibacterial peptides from pepsin-hydrolyzed egg yolks using flash chromatography. In addition, the mode of actions of the fractionated peptides were elucidated and plausible antibacterial peptides were reported. The fraction 6 (F6) obtained from a C18-flash column exhibited antibacterial activity against Staphylococcus aureus ATCC 29213 and Salmonella typhimurium TISTR 292 at minimal inhibitory concentration (MIC) values of 0.5 to 1 mmol/L (Leucine equivalent). The fractionated peptides induced DNA leakage as monitored by 260 nm. Propidium iodide and SYTO9 staining observed under a confocal microscope suggested the disintegration of cell membranes. Synchrotron-based Fourier-transform infrared spectroscopy analysis revealed that the egg yolk peptides at 1 × MIC induced an alteration of phospholipids at cell membranes and modified conformation of intracellular proteins and nucleic acids. Scanning electron microscopy revealed obvious cell ruptures when S. aureus was treated at 1 × MIC for 4 h, whereas damage of cell membranes and leakage of intracellular components were also observed for the transmission electron microscopy. Egg yolk peptides showed no hemolytic activity in human erythrocytes at concentrations up to 4 mmol/L. Peptide identification by LC-MS/MS revealed 3 cationic and 10 anionic peptides with 100% sequence similarity to apolipoprotein-B of Gallus gallus with hydrophobicity ranging from 27 to 75%. The identified peptide KGGDLGLFEPTL exhibited the highest antibacterial activity toward S. aureus at MIC of 2 mmol/L. Peptides derived from egg yolk hydrolysate present significant potential as antistaphylococcal agents for food and/or pharmaceutical application.

Discrimination of Free-Range and Caged Eggs by Chemometrics Analysis of the Elemental Profiles of Eggshell

As one of the foods commonly eaten all over the world, eggs have attracted more and more attention for their quality and price. A method based on elemental profiles and chemometrics to discriminate between free-range and caged eggs was established. Free-range (n1 = 127) and caged (n2 = 122) eggs were collected from different producing areas in China. The content of 16 elements (Zn, Pb, Cd, Co, Ni, Fe, Mn, Cr, Mg, Cu, Se, Ca, Al, Sr, Na, and K) in the eggshell was determined using a inductively coupled plasma atomic emission spectrometer (ICP-AES). Outlier diagnosis is performed by robust Stahel-Donoho estimation (SDE) and the Kennard and Stone (K-S) algorithm for training and test set partitioning. Partial least squares discriminant analysis (PLS-DA) and least squares support vector machine (LS-SVM) were used for classification of the two types of eggs. As a result, Cd, Mn, Mg, Se, and K make an important contribution to the classification of free-range and caged eggs. By combining column-wise and row-wise rescaling of the elemental data, the sensitivity, specificity, and accuracy were 91.9%, 91.1%, and 92.7% for PLS-DA, while the results of LS-SVM were 95.3%, 95.6%, and 95.1%, respectively. The result indicates that chemometrics analysis of the elemental profiles of eggshells could provide a useful and effective method to discriminate between free-range and caged eggs.

The Association of Dietary Cholesterol from Egg Consumption on Cardiovascular Diseases Risk Varies from Person to Person

The public and scientists remain skeptical about egg consumption, given that cardiovascular diseases (CVDs) are the leading causes of death in worldwide. This review mainly explained the recurrence of contradictory conclusions about relationships between egg consumption and CVD risk and discussed effects of egg cholesterol intake on cholesterol homeostasis. Factors including individual health status and cholesterol sensitivity, dietary pattern, region, and race should be distinguished when understanding generalized conclusions. Identified compensatory mechanisms in response to dietary cholesterol and the resulting balance in cholesterol biosynthesis, absorption, and efflux supported the view that moderate egg consumption had no substantial overall impacts on cholesterol homeostasis in healthy people. Excessive cholesterol intake is not recommended in individuals with distempered metabolism. More than cholesterol metabolism, impacts of egg consumption as a part of overall diet on CVD risk should be considered from aspects of nutrient intake, lipid metabolism, and energy supply in the future.

Socially transferred materials: why and how to study them

When biological material is transferred from one individual's body to another, as in ejaculate, eggs, and milk, secondary donor-produced molecules are often transferred along with the main cargo, and influence the physiology and fitness of the receiver. Both social and solitary animals exhibit such social transfers at certain life stages. The secondary, bioactive, and transfer-supporting components in socially transferred materials have evolved convergently to the point where they are used in applications across taxa and type of transfer. The composition of these materials is typically highly dynamic and context dependent, and their components drive the physiological and behavioral evolution of many taxa. Our establishment of the concept of socially transferred materials unifies this multidisciplinary topic and will benefit both theory and applications.

Development of Smart Bilayer Alginate/Agar Film Containing Anthocyanin and Catechin-Lysozyme

Smart packaging can provide real-time information about changes in food quality and impart a protective effect to the food product by using active agents. This study aimed to develop a smart bilayer film (alginate/agar) with a cellulose nanosphere (CNs) from corncob. The bilayer films were prepared using 1.5% (w/w) sodium alginate with 0.25% (w/v) butterfly pea extract incorporated (indicator layer) and 2% (w/w) agar containing 0.5% (w/v) catechin−lysozyme (ratio 1:1) (active layer). The CNs were incorporated into the alginate layer at different concentrations (0, 5, 10, 20, and 30% w/w-based film) in order to improve the film’s properties. The thickness of smart bilayer film dramatically increased with the increase of CNs concentration. The inclusion of CNs reduced the transparency and elongation at break of the smart bilayer film while increasing its tensile strength (p < 0.05). The integration of CNs did not significantly affect the solubility and water vapor permeability of the smart bilayer film (p > 0.05). The smart bilayer film displayed a blue film with a glossy (without CNs) or matte surface (with CNs). The developed bilayer film shows excellent pH sensitivity, changing color at a wide range of pHs, and has a good response to ammonia and acetic acid gases. The film possesses exceptional antimicrobial and antioxidant activities. The integration of CNs did not influence the antibacterial activity of the film, despite the presence of a higher level of DPPH in film containing CNs. The smart bilayer film was effectively used to monitor shrimp freshness. These findings imply that smart bilayer films with and without CNs facilitate food safety and increase food shelf life by monitoring food quality.

Lysozyme and Its Application as Antibacterial Agent in Food Industry

Lysozymes are hydrolytic enzymes characterized by their ability to cleave the β-(1,4)-glycosidic bonds in peptidoglycan, a major structural component of the bacterial cell wall. This hydrolysis action compromises the integrity of the cell wall, causing the lysis of bacteria. For more than 80 years, its role of antibacterial defense in animals has been renowned, and it is also used as a preservative in foods and pharmaceuticals. In order to improve the antimicrobial efficacy of lysozyme, extensive research has been intended for its modifications. This manuscript reviews the natural antibiotic compound lysozyme with reference to its catalytic and non-catalytic mode of antibacterial action, lysozyme types, susceptibility and resistance of bacteria, modification of lysozyme molecules, and its applications in the food industry.

Effects of different metal ions on the physicochemical properties and microstructure of egg white gel

BACKGROUND

To ameliorate egg white gel's salinity and undesirable texture characteristics during curing, different metal ions (K⁺ , Mg²⁺ , Ca²⁺ , Zn²⁺ ) were used to replace sodium chloride (NaCl) to simulate salted eggs partially. The effects of these ions on the physicochemical properties, microstructure, and gel characteristics of egg white protein were studied.

RESULTS

Low field nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) analysis showed that adding K⁺ , Mg²⁺ , Ca²⁺ , and Zn²⁺ could decrease immobile water content and increase free water content in egg white gel. Circular dichroism/fluorescence spectrophotometry (CD/FL) analysis showed that substitutive addition of K⁺ , Mg²⁺ , Ca^2+, and Zn²⁺ changed the conformational structure of the protein, which was not conducive to the formation of the three-dimensional mesh gel structure. Differential scanning calorimetry (DSC) results show that the addition of four metal ions could reduce the thermal denaturation temperature of egg white gel. Scanning electron microscopy (SEM) showed that the gel structure of egg white in the zinc chloride (ZnCl₂ ) group was rougher and more chaotic, the crosslinking degree was worse, so it was not suitable for low sodium salted egg preparations. The gel strength of the calcium chloride (CaCl₂ ) group was significantly higher than other groups (P < 0.05), while the gel strength of the potassium chloride (KCl) group was similar to the NaCl group (P > 0.05).

CONCLUSION

CaCl₂ and KCl could be used as partial NaCl substitutes to study the addition level and ratio further and improve salted egg white quality. © 2021 Society of Chemical Industry.

What Intentions and Interesting Information Can Attract Consumers to Scan QR Code While Buying Eggs?

A Quick Response Code (QR Code) aims to provide accurate and traceable information to consumers wanting to verify the quality of agri-food products. This study aimed to investigate the experiences and intentions of scanning QR Code in traditional markets and supermarkets. Furthermore, the types of egg information in the QR Code were explored to identify consumer interests when purchasing eggs. The empirical data were collected from 1112 valid responses throughout Taiwan from July to September, 2020. The Logit, Probit models, and the Bivariate Probit model were used to examine the data. Results showed that shoppers' propensity to scan QR Code revealed a significant difference between traditional markets and supermarkets, i.e., supermarket shoppers having higher a propensity to scan a QR Code. Of the 10 types of potential egg information in the QR Code, over half of respondents said that the production certificate label and inspection information were the top reasons that they would be interested in scanning a QR Code. This was particularly the case for homemakers aged between 51 and 60 years old and those who had scanned QR Code before and would like to pursue more egg information. Since the egg producers have resisted joining the traceability system, the implication of this study provides very practical strategies for government, policy makers, and producers in Taiwan.

Effect of glycation degree on the structure and digestion properties of ovalbumin: A study of amino acids and peptides release after in vitro gastrointestinal simulated digestion

Glycation can improve the functional properties of protein. However, in vitro and animal studies have shown that glycation induced lysine blockage and impaired protein digestibility. This study aimed to explore the effects of different glycation degree on the structure and digestive characteristics of ovalbumin. The results showed that glycation decreased the turbidity and hydrophobicity of the protein and changed the protein structure. Moreover, the results of in vitro simulated digestion revealed that glycation reduced the contents of essential amino acids and total amino acids after digestion. Glycation changed the amino acids and peptides release from the protein by resisting the digestion of digestive enzymes, especially trypsin. In conclusion, this work links glycation, protein digestibility, and the release of amino acids and peptides. This emphasizes the importance of the balance between improving properties and ensuring the digestibility of proteins during food processing.

Potential Implications of Natural Antioxidants of Plant Origin on Oxidative Stability of Chicken Albumen during Storage: A Review

Enhanced albumen quality is reflected in increased thick albumen height, albumen weight, and Haugh unit value, while the antimicrobial, antioxidant, foaming, gelling, viscosity, and elasticity attributes are retained. Improved albumen quality is of benefit to consumers and to the food and health industries. Egg quality often declines during storage because eggs are highly perishable products and are most often not consumed immediately after oviposition. This review provides insights into albumen quality in terms of changes in albumen structure during storage, the influence of storage time and temperature, and the mitigation effects of natural dietary antioxidants of plant origin. During storage, albumen undergoes various physiochemical changes: loss of moisture and gaseous products through the shell pores and breakdown of carbonic acid, which induces albumen pH increases. High albumen pH acts as a catalyst for structural changes in albumen, including degradation of the β-ovomucin subunit and O-glycosidic bonds, collapse of the ovomucin-lysozyme complex, and decline in albumen protein–protein interactions. These culminate in declined albumen quality, characterized by the loss of albumen proteins, such as ovomucin, destabilized foaming and gelling capacity, decreased antimicrobial activity, albumen liquefaction, and reduced viscosity and elasticity. These changes and rates of albumen decline are more conspicuous at ambient temperature compared to low temperatures. Thus, albumen of poor quality due to the loss of functional and biological properties cannot be harnessed as a functional food, as an ingredient in food processing industries, and for its active compounds for drug creation in the health industry. The use of refrigerators, coatings, and thermal and non-thermal treatments to preserve albumen quality during storage are limited by huge financial costs, the skilled operations required, environmental pollution, and residue and toxicity effects. Nutritional interventions, including supplementation with natural antioxidants of plant origin in the diets of laying hens, have a promising potential as natural shelf-life extenders. Since they are safe, without residue effects, the bioactive compounds could be transferred to the egg. Natural antioxidants of plant origin have been found to increase albumen radical scavenging activity, increase the total antioxidant capacity of albumen, reduce the protein carbonyl and malondialdehyde (MDA) content of albumen, and prevent oxidative damage to the magnum, thereby eliminating the transfer of toxins to the egg. These products are targeted towards attenuating oxidative species and inhibiting or slowing down the rates of lipid and protein peroxidation, thereby enhancing egg quality and extending the shelf life of albumen.

An Overview of Antimicrobial Activity of Lysozyme and Its Functionality in Cheese

Due to the concern of consumers about the presence of synthetic preservatives, researchers and food manufacturers have recently conducted extensive research on the limited use of these preservatives and the introduction and use of natural preservatives, such as herbal extracts and essential oils, bacteriocins, and antimicrobial enzymes. Lysozyme is a natural enzyme with antimicrobial activity that has attracted considerable attention to be potentially utilized in various industries. Since lysozyme is an intrinsic component of the human immune system and has low toxicity; it could be considered as a natural antimicrobial agent for use in food and pharmaceutical industries. Lysozyme exerts antimicrobial activity against microorganisms, especially Gram-positive bacteria, by hydrolyzing 1,4-beta-linkages between N-acetylmuramic acid and N-acetylglucosamine in the cell wall. In addition, increased antimicrobial activity of lysozyme against Gram-negative bacteria could be achieved by the modification of lysozyme through physical or chemical interactions. Lysozyme is presented as a natural preservative in mammalian milk and can be utilized as a bio-preservative in dairy products, such as cheese. Both bacteria and fungi can contaminate and spoil the cheese; especially the one that is made traditionally by raw milk. Furthermore, uncontrolled and improper processes and post-pasteurization contamination can participate in the cheese contamination. Therefore, besides common preservative strategies applied in cheese production, lysozyme could be utilized alone or in combination with other preservative strategies to improve the safety of cheese. Hence, this study aimed to review the antimicrobial properties of lysozyme as natural antimicrobial enzyme and its functionality in cheese.

Immunomodulatory activity of egg yolk protein hydrolysates prepared by novel two-step hydrolysis: A study of mechanism and stability after in vitro digestion model

The aim of this study was to determine the immunomodulatory activity of 2-step egg yolk protein hydrolysates. A two-step hydrolysate of egg yolk protein was prepared using 2 enzymes sequentially, pancreatin and neutrase (EYPH-PN). Our results illustrated that EYPH-PN increased the expression of inducible nitric oxide synthase (iNOS) mRNA in macrophages, resulting in increased nitric oxide (NO) production. EYPH-PN could also enhance the production of tumor necrosis factor (TNF)-α and interleukin (IL)-6 at both the mRNA and protein levels in macrophages. In addition, treatment with EYPH-PN increased the phagocytic activity of macrophages. According to the evaluation with specific inhibitors, both p38 and JNK cell signaling pathways were involved in the activation of macrophages induced by EYPH-PN. As the TLR-2 receptor of macrophages was blocked, the NO production induced by EYPH-PN was decreased. These results suggest that EYPH-PN activates RAW 264.7 macrophages via the TLR-2/p38/JNK pathway to increase the production of NO, TNF-α, and IL-6, and increases phagocytic activity. Furthermore, the immunomodulatory activity of EYPH-PN was maintained even after applying the in vitro digestion model. Taken together, EYPH-PN could be used as a functional food ingredient with excellent immunomodulatory activity in the food industry. Therefore, this study suggests a new alternative method to effectively utilize egg yolk protein, a by-product of the poultry industry.

Egg Yolk Protein Water Extracts Modulate the Immune Response in BALB/c Mice with Immune Dysfunction Caused by Forced Swimming

The objective of this study was to determine the immunomodulatory effects of egg yolk protein–water extract (EYW) on splenocyte proliferation, cytokine secretion, immunoglobulin production, and NK cell cytotoxic activity in BALB/c mice. The forced swimming test (FST) was used to provide a model for suppressing immune regulation. The proliferation of B cells in the EYW supplementation group was significantly increased from the level to which it was reduced by the FST (from 40.9% to 81.8%, p < 0.05). EYW supplementation affected cytokine secretion of splenocytes. Levels of interleukin (IL)-2 and IL-10—as Th1 and Th2 cytokines, respectively—were decreased after the FST. However, EYW supplementation showed that secretion levels of these cytokines were significantly increased to pre-FST levels (p < 0.05). The production of immunoglobulins (IgA and IgG) was increased abnormally after the FST, whereas EYW supplementation significantly decreased it to pre-FST levels (p < 0.05). EYW supplementation also improved NK cell cytotoxic activity against YAC-1 tumor cells compared to the PC group (p < 0.05). These data suggest that EYW has potential as an immunomodulatory agent in the food and/or pharmaceutical industries.

Effects of storage temperature on the quality of eggs coated by cassava starch blended with carboxymethyl cellulose and paraffin wax

A blend of cassava starch (CS), carboxymethyl cellulose (CMC), and paraffin was prepared as a coating material to maintain the quality of eggs during 4 wk of storage at different temperatures. The efficacy of the CS/CMC/paraffin (6/1/0.5% w/v) coating was investigated in terms of the Haugh unit (HU), weight loss, pH, and microbial load at the end of storage. The best egg storage temperature was 4°C, which maintained an HU of grade AA in coated and uncoated eggs for 4 wk. Lower weight loss (2.14%) was observed in coated eggs at 4°C storage than at 30°C storage (3.26%). The pH in the albumen of coated and uncoated eggs at 4°C increased from 6.84 to 6.88 and 7.01 to 7.03, respectively, after 4 wk of storage. No microbes were detected in the coated and uncoated eggs at 4°C. The maximum microbial count was 728 ± 35 cfu/mL in uncoated eggs at 30°C storage. Egg coating prevented microbial contamination of eggs stored at 30°C for 4 wk. The freshness of the eggs did not affect the nutrient content. The egg-coating material effectively maintained egg quality, prevented microbial contamination of eggs, and increased the shelf life of eggs at storage temperatures of 25 and 30°C.

Effect of Egg-Coating Material Properties by Blending Cassava Starch with Methyl Celluloses and Waxes on Egg Quality

An egg-coating material was developed to extend the shelf-life and freshness of eggs by blending cassava starch (CS) with gelling agents and waxes. The effects of the properties of this egg coating on egg quality were investigated. Hydroxypropyl methylcellulose (HPMC), carboxymethyl cellulose (CMC), beeswax, and paraffin wax were used. CS blended with low-molecular-weight paraffin (Paraffin(L)) and CMC coating material displayed a tensile strength of 4 MPa, 34% elongation at break, 0.0039 g day⁻¹ m⁻² water vapor permeability, and a water contact angle of 89° at 3 min. Eggs coated with CS/CMC/Paraffin(L) solutions had a Haugh unit value of 72 (AA grade) and exhibited a weight loss of 2.4% in 4 weeks. CMC improved the compatibility of CS and Paraffin(L). This improvement and the hydrophobicity of Paraffin(L) provided suitable mechanical and water-resistance properties to the coating material that helped to maintain the quality of the coated AA-grade eggs with low weight loss for 4 weeks.

Plant-and Animal-Based Protein Sources for Nutritional Boost of Deep-Fried Dough

Flaxseed (Linum usitatissimum L.) is an oilseed that is used in both industry and food production. Flaxseed contains biologically active compounds including linolenic acid, linoleic acid, and lignans. Flaxseed powder (2.5–10% w/w) and chicken eggs (10–30% v/w) were substituted in cake wheat flour for fried dough (magwinya) production. The physicochemical properties of the fried dough were determined and compared with the control. There was a significant (p &lt; 0.05) increase in moisture, protein, ash, and hardness and a decrease in fat content of fried dough enriched with egg (FDE) and flaxseed powder (FDFX). Enrichment with 30% (v/w) egg and/or 7.5–10% flaxseed powder resulted in higher protein, oil reduction, and ash contents compared with the rest of the products. With the current interest in plant-based protein, flaxseed is a good choice of flour-based snacks for consumers without compromise in nutrition.

Review on the extraction of calcium supplements from eggshells to combat waste generation and chronic calcium deficiency

When faced with a plethora of issues, the possibility of one problem becoming the solution of another is a rare, yet beneficial scenario. This report explores the prospect of viewing the accumulation of organic waste matter in India as a potential calcium reservoir to relieve the issue of calcium deficiency in the population. Waste generation has seen gradual growth, and it has created a problem of waste disposal. A large segment of the generated waste primarily consists of food waste which contains significant amounts of nutrients. Food waste such as eggshells, waste from shellfish, bones, and fish scales contain good amounts of bioavailable calcium, and large quantities of this discarded bioavailable calcium remain unused. Global studies show India to have significantly lower levels of calcium intake than the global average, thus increasing the risk of calcium deficiency-related diseases. Furthermore, research shows that for over the past half of the century, the intake of dietary calcium has declined drastically throughout India. This has led to chronic calcium deficiency-related diseases throughout most of the Indian population. Hence, development of calcium supplements from calcium-rich waste material has the potential to not only reduce the strain on waste management, but also to provide the calcium-deficient population with a cheaper alternative to traditional supplements. Owing to the abundance and ease of separation, eggshells have been chosen as the focus of the review. This review highlights and compares their extraction methods of providing cheap calcium supplements while reducing the amount of eggshell waste.

Review of sialic acid's biochemistry, sources, extraction and functions with special reference to edible bird's nest

Sialic acids are a group of nine-carbon α-keto acids. Sialic acid exists in more than 50 forms, with the natural types discovered as N-acetylneuraminic acid (Neu5Ac), deaminoneuraminic acid (2-keto-3-deoxy-nonulononic acid or Kdn), and N-glycolylneuraminic acid (Neu5Gc). Sialic acid level varies depending on the source, where edible bird's nest (EBN), predominantly Neu5Ac, is among the major sources of sialic acid. Due to its high nutritive value and complexity, sialic acid has been studied extensively through acid, aqueous, and enzymatic extraction. Although detection by chromatographic methods or mass spectrometry is common, the isolation and recovery work remained limited. Sialic acid is well-recognised for its bioactivities, including brain and cognition development, immune-enhancing, anti-hypertensive, anticancer, and skin whitening properties. Therefore, sialic acid can be used as a functional ingredient in the various industries. This paper reviews the current trend in the biochemistry, sources, extraction, and functions of sialic acids with special reference to EBN.

Protein nanofibrils for next generation sustainable water purification

Water scarcity is rapidly spreading across the planet, threatening the population across the five continents and calling for global sustainable solutions. Water reclamation is the most ecological approach for supplying clean drinking water. However, current water purification technologies are seldom sustainable, due to high-energy consumption and negative environmental footprint. Here, we review the cutting-edge technologies based on protein nanofibrils as water purification agents and we highlight the benefits of this green, efficient and affordable solution to alleviate the global water crisis. We discuss the different protein nanofibrils agents available and analyze them in terms of performance, range of applicability and sustainability. We underline the unique opportunity of designing protein nanofibrils for efficient water purification starting from food waste, as well as cattle, agricultural or dairy industry byproducts, allowing simultaneous environmental, economic and social benefits and we present a case analysis, including a detailed life cycle assessment, to establish their sustainable footprint against other common natural-based adsorbents, anticipating a bright future for this water purification approach.

Immunotherapeutic Efficacy of IgY Antibodies Targeting the Full-Length Spike Protein in an Animal Model of Middle East Respiratory Syndrome Coronavirus Infection

Identified in 2012, the Middle East respiratory syndrome coronavirus (MERS-CoV) causes severe and often fatal acute respiratory illness in humans. No approved prophylactic or therapeutic interventions are currently available. In this study, we developed chicken egg yolk antibodies (IgY Abs) specific to the MERS-CoV spike (S) protein and evaluated their neutralizing efficiency against MERS-CoV infection. S-specific IgY Abs were produced by injecting chickens with the purified recombinant S protein of MERS-CoV at a high titer (4.4 mg/mL per egg yolk) at week 7 post immunization. Western blotting and immune-dot blot assays demonstrated specific binding to the MERS-CoV S protein. In vitro neutralization of the generated IgY Abs against MERS-CoV was evaluated and showed a 50% neutralizing concentration of 51.42 μg/mL. In vivo testing using a human-transgenic mouse model showed a reduction of viral antigen positive cells in treated mice, compared to the adjuvant-only controls. Moreover, the lung cells of the treated mice showed significantly reduced inflammation, compared to the controls. Our results show efficient neutralization of MERS-CoV infection both in vitro and in vivo using S-specific IgY Abs. Clinical trials are needed to evaluate the efficiency of the IgY Abs in camels and humans.

Effect of Natural and Chemical Colorant Supplementation on Performance, Egg-Quality Characteristics, Yolk Fatty-Acid Profile, and Blood Constituents in Laying Hens

Natural and chemical colorants are attracting a lot of attention as sustainable feed additives due to their effect on food color and because presentation matters to consumers. Color also is a major sensory factor that helps consumers determine food quality and its possible health benefits. For example, highly colored egg yolks can only come from healthy laying hens fed a well-balanced, nutrient-rich diet. Consumers associate an intense yolk color with healthy, nutrient-rich food. There is a growing market request for eggs with rich yolk coloring. The purpose of the current study was to evaluate the impact of natural (paprika) and chemical (carmoisine) colorant supplementation on the performance, egg-quality characteristics, yolk fatty-acid profile, and blood constituents in laying hens. A total of 240 Bovans laying hens were randomly distributed in a completely randomized design in four treatments according to four experimental diets: a control diet (without supplementation of any colorants), a control diet supplemented with 4 kg/ton paprika, a control diet supplemented with 150 g carmoisine/ton, and a control diet supplemented with a combination of 4 kg/ton paprika plus 150 g carmoisine/ton, fed from 42 to 54 weeks of age. Each treatment consisted of 10 replications with six hens. Dietary inclusion of paprika colorant improved (p < 0.05) the feed-conversion ratio and egg-production rate, while final body weight, weight change, feed intake, and egg weight and mass were not affected. The degrees of egg yolk and white were increased (p < 0.05) by the dietary supplements. Yolk color and shell thickness were enhanced (p < 0.05) by adding paprika and/or carmoisine colorants. Supplementation of the paprika colorant alone or in combination with carmoisine increased (p < 0.05) linolenic acid, oleic acid, and vitamin E concentrations in egg yolks. In contrast, egg yolk palmitic acid and liver malondialdehyde contents were decreased (p < 0.05). Paprika and carmoisine colorants and their combination improved (p < 0.05) blood lipid profile in treated hens. We concluded that the dietary supplementation of natural (paprika) colorants has an influential role in improving egg yolk color, production performance, and egg yolk fatty-acid profile in laying hens.

Functional Food for Elderly High in Antioxidant and Chicken Eggshell Calcium to Reduce the Risk of Osteoporosis-A Narrative Review

The elderly population is increasing globally and is predicted to reach 1.5 billion in 2050. The quality of life of the elderly must be concerned, for example, with developing functional food for the elderly. In this article, the development of functional food to reduce the risk of osteoporosis in the elderly is reviewed. Oxidative stress is one of the factors which accelerates osteoporosis. Various antioxidants, including vitamin C, vitamin E, polyphenols, or lycopene, have been proven by former studies to have antioxidant activity, therefore, could reduce the risk of osteoporosis. Additionally, the application of eggshell powder in various food products has been reported to improve calcium intake, and its usage is environmentally sustainable as this could contribute to reducing food waste. The application of both antioxidants and calcium could be a good combination, but the amount of some antioxidants must be concerned so it would not interfere with the bioavailability of calcium. Therefore, this review aims to explore the functional food for the elderly to reduce the risk of osteoporosis, particularly with antioxidants and calcium from chicken eggshells. The eating preference and dietary pattern of the elderly are also considered to determine the suitable form of functional food for the elderly. The results presented in the study may be the basis for the development of new calcium-enriched food products for the elderly.

Evaluating the effect of cooking and gastrointestinal digestion in modulating the bio-accessibility of different bioactive compounds of eggs

Eggs' nutritional value has been enhanced by enriching hen's diet with bioactive compounds, but factors influencing bio-accessibility are unspecified. This study investigated the effect of hen breed, diet enrichment, and cooking methods in modulating the egg compounds' bio-accessibility after gastrointestinal (GI) digestion. White Leghorn (WLH) and Rhode Island Red (RIR) hens were fed a corn-soybean-based diet enriched with flaxseed and carotenoids; eggs were collected, cooked, and subjected to simulated GI digestion. The results showed that egg proteins were equally digestible with no change in the degree of hydrolysis (DH). The linolenic fatty acid in enriched-cooked samples remained bio-accessible after GI digestion. The lutein bio-accessibility in enriched eggs decreased after GI digestion except in RIR fried sample. Eggs from WLH and RIR achieved similar peptide content after GI digestion. These results elucidate the bio-accessibility of different bioactive compounds in cooked eggs and the use of eggs as potential functional foods.

Lecithins from Vegetable, Land, and Marine Animal Sources and Their Potential Applications for Cosmetic, Food, and Pharmaceutical Sectors

The aim of this work was to review the reported information about the phospholipid composition of lecithins derived from several natural sources (lipids of plant, animal, and marine origin) and describe their main applications for the cosmetic, food, and pharmaceutical sectors. This study was carried out using specialized search engines and according to the following inclusion criteria: (i) documents published between 2005 and 2020, (ii) sources of lecithins, (iii) phospholipidic composition of lecithins, and (iv) uses and applications of lecithins. Nevertheless, this work is presented as a narrative review. Results of the review indicated that the most studied source of lecithin is soybean, followed by sunflower and egg yolk. Contrarily, only a few numbers of reports focused on lecithins derived from marine animals despite the relevance of this source in association with an even higher composition of phospholipids than in case of those derived from plant sources. Finally, the main applications of lecithins were found to be related to their nutritional aspects and ability as emulsion stabilizers and lipid component of liposomes.

Development of a liquid chromatography-tandem mass spectrometry method for simultaneous quantification of hen's egg white allergens Gal d 1-4 in fresh and processed eggs

Hen's egg white allergens, namely Gal d 1-4, cause food allergies worldwide and their intake must be strictly controlled by allergic individuals. However, an efficient method for quantifying these allergens is currently unavailable. We aimed to develop an LC-MS/MS method for simultaneous Gal d 1-4 quantification. Purified Gal d 1-4 proteins were trypsin-digested and the resulting peptides used in LC-MS/MS analysis. The limits of quantification were 9.77-39.1 ng/mL. The Gal d 1-4 recovery in fresh and processed eggs was 68.3-121.3%, and intra- and interassay coefficients of variation were 1.5-15.7% and 2.4-38.1%, respectively, indicating high sensitivity, accuracy, and reproducibility. In addition, the high specificity of this method was confirmed by testing 27 other foods. This newly developed method could provide reliable information to the industrial food and clinical fields, facilitating improved quality of life for individuals with egg allergies.