Advances in the value of eggs and egg components for human health

Dietary Chinese herbal formula supplementation improves yolk fatty acid profile in aged laying hens

Chinese herbal formula (CHF) has the potential to improve the performance of aged laying hens through integrated regulation of various physiological functions. The present study aimed to investigate the effects of dietary CHF supplementation on the yolk fatty acid profile in aged laying hens. A total of 144 healthy 307-day-old Xinyang black-feather laying hens were randomly allocated into two groups: a control group (CON, fed a basal diet) and a CHF group (fed a basal diet supplemented with 1% CHF; contained 0.30% Leonurus japonicus Houtt., 0.20% Salvia miltiorrhiza Bge., 0.25% Ligustrum lucidum Ait., and 0.25% Taraxacum mongolicum Hand.-Mazz. for 120 days). The fatty acid concentrations in egg yolks were analyzed using a targeted metabolomics technology at days 60 and 120 of the trial. The results showed that dietary CHF supplementation increased (p < .05) the concentrations of several saturated fatty acids (SFA, including myristic acid and stearic acid), monounsaturated fatty acids (MUFA, including petroselinic acid, elaidic acid, trans-11-eicosenoic acid, and cis-11-eicosenoic acid), polyunsaturated fatty acids (PUFA, including linolelaidic acid, linoleic acid, γ-linolenic acid, α-linolenic acid, 11c,14c-eicosadienoic acid, eicosatrienoic acid, homo-γ-linolenic acid, arachidonic acid, and docosapentaenoic acid), and fatty acid indexes (total MUFA, n-3 and n-6 PUFA, PUFA/SFA, hypocholesterolemic/hypercholesterolaemic ratio, health promotion index, and desirable fatty acids) in egg yolks. Collectively, these findings suggest that dietary CHF supplementation could improve the nutritional value of fatty acids in egg yolks of aged laying hens, which would be beneficial for the production of healthier eggs to meet consumer demands.

Protein aggregation caused by pasteurization processing affects the foam performance of liquid egg white

Pasteurization is necessary during the production of liquid egg whites (LEW), but the thermal effects in pasteurization could cause an unavoidable loss of foaming properties of LEW. This study intended to investigate the mechanism of pasteurization processing affects the foam performance of LEW. The foaming capacity (FC) of LEW deteriorated significantly (ΔFCmax = 72.33 %) and foaming stability (FS) increased slightly (ΔFSmax = 3.64 %) under different temperature-time combinations of pasteurization conditions (P < 0.05). The increased turbidity and the decreased solubility together with the decreased absolute value of Zeta potential indicated the generation of thermally induced aggregates and the instability of the protein particles, Rheological characterization demonstrated improved viscoelasticity in pasteurization liquid egg whites (PLEW), explaining enhanced FS. The study revealed that loss in foaming properties of PLEW resulted from thermal-induced protein structural changes and aggregation, particularly affecting FC. This provided a theoretical reference for the production and processing of LEW products.

Dextran sulfate acting as a chaperone-like component on inhibition of amorphous aggregation and enhancing thermal stability of ovotransferrin

The tendency of ovotransferrin (OVT) to unfold and aggregate under 60 °C severely restricted sterilization temperature during egg processing. Searching for efficient strategies to improve OVT thermal stability is essential for improving egg product quality and processing suitability. Here, we investigated the effect of sulfate polysaccharide (dextran sulfate, DS) on heat-induced aggregation of OVT. We found that DS can effectively suppress amorphous aggregation of OVT at pH 7.0 after heating. Strikingly, the addition of 5 µM DS fully suppressed insoluble aggregates formation of 0.5 mg/mL OVT. Structure analysis confirmed that DS preserves nearly the entire secondary and tertiary structure of OVT during heating. The steric hindrance effect arising from strong electrostatic interactions between OVT and DS, coupled with reduced OVT hydrophobicity, is the underlying mechanism in suppressing protein-protein interactions, thus enhancing thermal stability. These findings suggest DS could act as protein stabilizers and chaperones, enhancing the thermostability of heat-sensitive proteins.

Evaluation and Discrimination of Lipid Components and Iron and Zinc Levels in Chicken and Quail Eggs Available on the Polish Market

All over the world, birds' eggs are an important and valuable component of the human diet. This study aimed to compare the content of lipid components and their nutritional value as well as iron and zinc levels in chicken and quail eggs commonly available on the market. In egg lipids, unsaturated fatty acids were dominant, especially oleic acid, the content of which was about 40% of the total fatty acids (TFAs). Linoleic acid was the major polyunsaturated fatty acid. Compared to other products of animal origin, eggs were characterized by favorable values of lipid quality indices, especially the index of atherogenicity, thrombogenicity, and the hypocholesterolemic-to-hypercholesterolemic ratio. In the present study, no differences were found in the content of tested nutrients between eggs from different production methods (organic, free-range, barn, cages). Based on linear discriminant analysis, inter-breed differences were noticed. Cluster analysis showed that eggs enriched in n3 PUFAs (according to the producers' declarations) differed from other groups of chicken eggs. However, in eggs from one producer only, the amount of EPA and DHA exceeds 80 mg per 100 g, entitling the use of the nutrition claim on the package. Quail eggs differed from chicken eggs in FA profile and cholesterol and iron levels.

Constructing an Antibiotic-Free Protein Expression System for Ovalbumin Biosynthesis in Probiotic Escherichia coli Nissle 1917

Ovalbumin (OVA) is the principal protein constituent of eggs. As an alternative to eggs, cell-cultured OVA can reduce the environmental impact of global warming and land use. Escherichia coli Nissle 1917 (EcN), a probiotic with specific endogenous cryptic plasmids that stably exist in cells without the addition of antibiotics, was chosen as the host for the efficient heterologous expression of the OVA. OVA yield reached 20 mg·L-1 in shake flasks using the OVA expression cassette containing a tac promoter (Ptac) upstream of the OVA-coding sequences on the endogenous plasmid pMUT2. Subsequently, we improved the level of the expression of the OVA by employing a dual promoter (PP5 combined with Ptac via a sigma factor binding site 24) and ribosome binding site (RBS) substitution. These enhancements increased the level of production of OVA in shake flasks to 30 and 42 mg·L-1, respectively. OVA by EcNP-P28 harboring plasmid L28 equipped with both dual promoter and the strong RBS8 reached 3.70 g·L-1 in a 3 L bioreactor. Recombinant OVA and natural OVA showed similar biochemical characteristics, including secondary structure, isoelectric point, amino acid composition, and thermal stability. This is currently the highest OVA production reported among prokaryotes. We successfully constructed an antibiotic-free heterologous protein expression system for EcN.

Inactivation of Salmonella enteritidis in liquid egg yolk and egg white using bacteriophage cocktails

Salmonella Enteritidis (SE) is a significant global cause of foodborne illness, often linked to egg contamination. This study evaluated the inhibitory effects of eight bacteriophages (phages) against three SE strains isolated from poultry environments. The most effective phages were selected to formulate different phage cocktails, to enhance the efficacy and prolong inhibition. Four phage cocktails were tested at a multiplicity of infection (MOI) of 100 in tryptic soy broth (TSB), and at MOIs of 100 and 1000 in liquid egg white (EW) and egg yolk (EY) with storage at 8 °C for up to 30 days (d). The effectiveness of the phage cocktails varied significantly among bacterial strains, yet all demonstrated significant reductions compared to the positive control in liquid culture (P < 0.05). Similarly, the tested SE strains in both EW and EY showed significant reductions with phage treatments (P < 0.005), although the effectiveness was influenced by the MOI and medium composition. Treating EY proved to be more challenging, with lower magnitudes of reduction and longer treatment durations required, compared to EW. Reductions ranged from 1 to greater than 4 log CFU/mL in EW and EY after 30 d, with consistently higher reductions achieved at MOI 1000. Phage titers decreased initially, but remained stable following SE inoculation in broth and liquid eggs at 8 °C, indicating that lysis from without mechanisms may have contributed to the inhibitory effect. Notably, phages exhibited stronger attachment to SE in EW, which can be attributed to be less viscous nature of EW compared to EY. This study demonstrated that phage applications in both EW and EY effectively reduced SE counts at 8 °C, with no regrowth during long-term storage. These findings contribute to the development of biocontrol methods that enhance food safety and reduce foodborne outbreaks associated with contaminated egg products.

Electrical Fields in the Processing of Protein-Based Foods

Electric field-based technologies offer interesting perspectives which include controlled heat dissipation (via the ohmic heating effect) and the influence of electrical variables (e.g., electroporation). These factors collectively provide an opportunity to modify the functional and technological properties of numerous food proteins, including ones from emergent plant- and microbial-based sources. Currently, numerous scientific studies are underway, contributing to the emerging body of knowledge about the effects on protein properties. In this review, "Electric Field Processing" acknowledges the broader range of technologies that fall under the umbrella of using the direct passage of electrical current in food material, giving particular focus to the ones that are industrially implemented. The structural and biological effects of electric field processing (thermal and non-thermal) on protein fractions from various sources will be addressed. For a more comprehensive contextualization of the significance of these effects, both conventional and alternative protein sources, along with their respective ingredients, will be introduced initially.

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.

Eggs - a scoping review for Nordic Nutrition Recommendations 2023

Cardiovascular diseases (CVD), type 2 diabetes (T2D), and cancer are a significant public health burden in the Nordic and Baltic countries. High intake of eggs, mainly due to its high cholesterol content, has been suggested to have adverse health effects. The purpose of this scoping review is to describe the evidence related to the impact of egg intake on health. A literature search identified 38 systematic reviews and meta-analyses on egg consumption in relation to health outcomes published between 2011 and 30 April 2022. Overall, current evidence from systematic reviews of randomized clinical trials indicates that higher egg intake may increase serum total cholesterol concentration and the ratio of low-density lipoprotein to high-density lipoprotein cholesterol, but with substantial heterogeneity in the response. However, recent evidence from observational studies does not provide strong support for a detrimental role of moderate egg consumption (up to one egg/day) on the risk of CVD, especially in the European studies. The overall evidence from observational studies indicates that egg consumption is not associated with increased risk of mortality or T2D in European study populations. There is also little support for a role of egg consumption in cancer development, although a weak association with higher risk of certain cancers has been found in some studies, mainly case-control studies. Again, no associations with cancer risk have been observed in European studies. Systematic reviews and meta-analyses of egg consumption in relation to other health-related outcomes are scarce. There are also limited data available on the associations between the consumption of more than one egg/day and risk of diseases. Based on the available evidence, one egg/day is unlikely to adversely affect overall disease risk.

Commercial Egg Replacers in Pound Cake Systems: A Comprehensive Analysis of Market Trends and Application

Replacing eggs without influencing pound cakes' texture, appearance, and taste is challenging. Ovalbumin, the major protein in egg white, contributes to the structures of cakes by providing SH Groups that form a firm gel during baking. However, there is a shift in the consumers' behaviour regarding health, well-being, animal welfare standards, and environmental concerns. To meet upcoming trends and consumer needs, 102 egg replacement products were launched globally to the best of the authors' knowledge, with 20 of them advertised as suitable for baking applications. Ten locally available commercial egg replacers with a range of protein contents were chosen and applied in a pound cake model system to evaluate their functionality by evaluating cake and cake batter quality. Three different categories of egg replacements were chosen: replacers containing no protein (R1-R3), a low amount of protein (1-10 g/100 g; R4-R5), and a high amount of protein (>10 g/100 g; R6-R10). Those were compared to three control cakes containing powdered whole egg, fresh egg, and liquid whole egg. All the analysed egg replacers significantly differed from the control cakes, including low-protein egg replacement R4. Despite R4 achieving the highest specific volume (1.63 ± 0.07 mL/g) and comparable texture values, none of the examined egg replacers compared favourably with the egg control cakes regarding appearance, physical and textural properties, and nutritional value.

Albumen and Yolk Plasma Peptidomics for the Identification and Quantitation of Bioactive Molecules and the Quality Control of Hen Egg Products

Hen eggs and the corresponding food products are essential components of human diet. In addition to supplying basic nutrients, they contain functional peptides that are released in vivo within the intact raw material following physiological proteolytic events affecting specific proteins or derive from technological processing of albumen and yolk fractions as a result of the dedicated use of proteases from plant and microbial sources. Besides their potential importance for functional applications, peptides released under physiological conditions in intact egg can be used as markers of product storage and deterioration. Therefore, characterization and quantitation of peptides in egg and egg-derived products can be used to implement evaluation of potential bioactivities as well as to assess food product qualitative characteristics. Here, we provide dedicated information on extraction, identification, and quantitative analysis of peptides from albumen and yolk plasma; nano-liquid chromatography-mass spectrometry combined with bioinformatic analysis of resulting raw data by different software tools allowed to assign molecules based on database searching and to evaluate their relative quantity in different samples.

Effect of ultrasound and thermal pretreatments on antioxidant activity of egg white hydrolysate

The use of ultrasonic (US) treatment of egg white prior to enzymatic hydrolysis to produce hydrolysate with antioxidant activity was investigated. The state of egg white (raw vs. cooked form) along with two levels of Alcalase (1% and 10% (w/w) protein) was applied. Hydrolysis and antioxidant activity of hydrolysate increased by US pretreatment at intensity of 41.53 W/cm2 . The hydrolysate prepared from US treatment on raw egg white hydrolyzed by 1% Alcalase (US-R1%) showed the lowest degree of hydrolysis (DH); however, its 2,2'-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging and ferric reducing antioxidant power activities were the highest. In contrast, the highest cytoprotective effect and intracellular reactive oxygen species scavenging activity were more notable in the hydrolysate prepared from US treatment of boiled egg white hydrolyzed by 10% Alcalase (US-B10%), which also exhibited the highest DH and metal chelation ability. The hydrolysate possessing cellular antioxidant activity (CAA) showed the highest proportion of small molecular weight peptides (<200 Da). Fourier-transform infrared spectroscopy revealed an increase of N- and C-terminal ends at 1500 and 1400 cm-1 , respectively, in concomitant with a decrease of amide I. Principal component analysis showed clear differentiation of spectra from different levels of enzyme according to their DH, C-terminal ends, and antioxidant activity. Our findings suggested that cooked egg white followed by US pretreatment was beneficial to produce hydrolysate containing high CAA.

Liver proteomics analysis reveals the differentiation of lipid mechanism and antioxidant enzyme activity during chicken embryonic development

Chicken embryo development is a dynamic process. However, no detailed information is available about the protein abundance changes associated with the lipid mechanism and antioxidant enzyme activity during the egg embryo development. Thus, in the present study, an TMT-based proteomic approach was used to quantify protein abundance changes at different stages of chicken embryonic development. A total of 289 significantly differentially abundant hepatic proteins were quantified, of which 180 were upregulated and 109 were downregulated in the comparison of Day 20 with Day 12 in chicken embryos. Pathway analysis showed that metabolic pathways were the most highly enriched pathways, followed by arachidonic acid metabolism and steroid biosynthesis. Integration of proteomic-based studies profiling of three incubation stages revealed that the two compare groups (Day 12 vs Day 20 and Day 16 vs Day 20) shared some key differentially abundant proteins (DAPs), including LBFABP, FABP5, CYP4V2, PDCD4, LAL, APOA1, APOA4, SAA, FABP2, ACBSG2, FABP2, CYP51A1, and FBXO9. The STRING database and GO analysis results showed that there was close connectivity between APOA4, LBFABP, SERPINC1, APOA1, FGB, FGA, ANGPTL3 and these proteins were involved in the oxidation-reduction process, lipid transport, iron ion, heme, and lipid binding. Importantly, APOA4, FABP2, and CYP51A1 might be key factors to control fat deposition and antioxidant enzyme activity during chicken embryonic development. These findings will facilitate a better understanding of antioxidant and lipid mechanisms in chicken embryo and these DAPs can be further investigated as candidate markers to predict lipid deposition and the activity of antioxidant enzymes.

Effects of quercetin and daidzein on egg quality, lipid metabolism, and cecal short-chain fatty acids in layers

In this study, the effects of quercetin and daidzein on egg quality, lipid metabolism, and cecal short-chain fatty acids (SCFAs) were compared in layers. Hyline brown layers at 385 days of age with a similar laying rate (81.36% ± 0.62%) and body weight (2.10 kg ± 0.04 kg) were randomly divided into three treatments, six replicates per treatment, and 20 layers per replicate. Layers in control, quercetin, and daidzein treatment were fed by a basal diet supplemented with 0 mg/kg, 500 mg/kg quercetin, and 30 mg/kg of daidzein for 10 weeks. Results showed that eggshell strength and albumen height in week 4, egg yolk diameter in week 10, and eggshell thickness and egg yolk height in weeks 4 and 10 were significantly increased in the quercetin treatment (P ≤ 0.05); contents of phospholipid (PL) and lecithin (LEC) in egg yolk and high-density lipoprotein (HDL) content in serum were significantly increased; however, contents of malondialdehyde (MDA), total cholesterol (TC), and triglyceride (TG) in egg yolk, contents of TC, TG, low-density lipoprotein (LDL), and very-low-density lipoprotein (VLDL) in serum, and contents of TC and TG in the liver were significantly decreased in the quercetin treatment (P ≤ 0.05); contents of isobutyric acid and valeric acid were significantly increased in the cecum of the quercetin treatment (P ≤ 0.05), compared with control. Moreover, egg yolk height in week 10 and eggshell thickness in weeks 4 and 10 were significantly increased in the daidzein treatment (P ≤ 0.05); contents of MDA, TC, and TG in egg yolk, TC, TG, and VLDL in serum, and TC and TG in liver were significantly decreased in the daidzein treatment (P ≤ 0.05); and HDL content was significantly increased in serum of the daidzein treatment (P ≤ 0.05) compared with control. However, daidzein did not affect SCFA content in the cecum. In conclusion, egg quality was improved by quercetin and daidzein by increasing the antioxidant ability of egg yolk and by regulating lipid metabolism in layers. Quercetin worked better than daidzein in improving egg quality under this experimental condition.

Physicochemical Index Analyses of the Egg White in Blue-Shelled Eggs and Commercial Brown-Shelled Eggs during Storage

To compare the physical and chemical changes in egg whites during storage, assisting in the evaluation of differences in egg freshness between various chicken breeds, we chose 240 blue-shelled eggs (Blue group) and 240 commercial brown-shelled eggs (Brown group) that 28-week-old hens had laid. In this study, all eggs were stored at 25 °C. The egg weight, egg components' weight and proportion, Haugh Unit value and the contents of S-ovalbumin, ovomucin and lysozyme in the thick albumen (KA) and thin albumen (NA) were measured at eight time points every 3 days until the 21st day of storage. The eggshell, yolk and KA proportions in the Brown group were significantly lower, whereas the NA proportion was significantly higher than that in the Blue group (p < 0.001). The Haugh Unit value and S-ovalbumin in the Brown group were significantly higher, whereas KA ovomucin and NA lysozyme were significantly lower than those in the Blue group (p < 0.001). There existed significant negative correlations between the KA and NA, irrespective of weight or proportion. The Haugh Unit value was significantly positively correlated with lysozyme and ovomucin, but significantly negatively correlated with S-ovalbumin. During storage, the KA weight (proportion), Haugh Unit value, lysozyme and ovomucin decreased, whereas the NA weight (proportion) and S-ovalbumin increased. At each time point, the NA lysozyme in the Brown group was lower than that in the Blue group (p < 0.05). After storage for 6 days, the KA ovomucin in the Brown group began to be lower than that in the Blue group (p < 0.05). The study showed that the weight (proportion) differences in egg components between blue-shelled eggs and commercial brown-shelled eggs are mainly due to the NA. The Haugh Unit value and albumin protein indexes of blue-shelled eggs were better than those of brown-shelled eggs, and showed mild changes during storage, indicating the better storage performance of blue-shelled eggs.

The enhanced properties and bioactivity of poly-ε-caprolactone/poly lactic-co-glycolic acid doped with carbonate hydroxyapatite-egg white

Synthetic polymers, such as PCL and PLGA, are among the main material choices in tissue engineering because of their stable structures and strong mechanical properties. In this study, we designed polycaprolactone (PCL)/polylactic-co-glycolate acid (PLGA) nanofibers doped with carbonate hydroxyapatite (CHA) and egg white (EW) with enhanced properties. The addition of CHA and EW significantly influenced the properties and morphology of PCL/PLGA nanofibers; whereby the CHA substitution (PCL/PLGA/CHA) greatly increased the mechanical properties related to the Young's modulus and EW doping (PCL/PLGA/CHA/EW) increased the elongation at break. Bioactivity tests of PCL/PLGA/CHA/EW after immersion in the SBF for 3 to 9 days showed increased fiber diameters and a good swelling capacity that could improve cell adhesion, while biocompatibility tests with NIH-3T3 fibroblast cells showed good cell proliferation (85%) after 48 h and antibacterial properties against S. aureus.

Elemental Profile in Chicken Egg Components and Associated Human Health Risk Assessment

Egg is a food product of high nutritional quality, extensively consumed worldwide. The objectives of this study were the determination of the elemental profile in eggs (egg white, yolk, and eggshell), the estimation of the non-carcinogenic health risk associated with the presence of heavy metals in investigated egg samples, and the development of statistical models to identify the best predictors for the differentiation of egg components. The assessments were carried out in a total set of 210 samples, comprising home-produced and commercial eggs, using inductively coupled plasma mass spectrometry. The results suggested measurable differences amongst hen eggs coming from different husbandry systems. The statistical models employed in this study identified several elemental markers that can be used for discriminating between market and local producer samples. The non-carcinogenic risk related to the consumption of the analyzed egg samples was generally in the safe range for the consumers, below the maximum permitted levels set by Romanian and European legislation. Food contamination is a public health problem worldwide, and the risk associated with exposure to trace metals from food products has aroused widespread concern in human health, so assessing the heavy metal content in food products is mandatory to evaluate the health risk.

Food allergen analysis: Considerations for establishing a reference measurement system to implement EU legislation

Inconsistent quantification results obtained from various analytical methods for food allergen testing hamper an accurate quantitative risk assessment and its regulatory implementation. In order to overcome such problems, a concept aiming at ensuring the comparability of quantitative food allergen measurement results is presented here. It is based on an approach called reference measurement system for food allergens, which uses a commonly agreed reference, namely the 'mass fraction of total protein of the allergenic ingredient in food'. The necessary system components are outlined, consisting of a primary reference measurement method, a certified reference material and a reference laboratory. This metrology-based concept can be applied to quantify various food allergens determined with different analytical procedures. The example of 'milk in cookies' is used to demonstrate the approach.

Yolk Fatty Acid Profile and Amino Acid Composition in Eggs from Hens Supplemented with ß-Hydroxy-ß-Methylbutyrate

In recent years, a supplementation of livestock animals, including poultry, with β-Hydroxy-β-methylbutyrate (HMB) has gained attention for its effects on protein and fat metabolism. This study investigates the effects of HMB in the laying hen diet on egg quality, focusing on amino acid and fatty acid composition. Laying hens were supplemented with 0.02% HMB, with performance parameters and egg components analyzed. HMB supplementation led to increased albumen weight, influencing egg weight while also reducing feed intake per egg without affecting laying rate, yolk indices, fat, or cholesterol content. Notably, the study revealed significant changes in egg amino acid and fatty acid profiles due to HMB supplementation. Various amino acids, including glycine, serine, and isoleucine, were altered in the yolk, impacting nutritional value and potential health benefits. Regarding fatty acids, the study observed changes in both saturated as well as n-6 and n-3 fatty acids, affecting the overall lipid profile of egg yolks. However, the shifts in fatty acid composition could have implications for cardiovascular health due to altered ratios of n-6/n-3 fatty acids. Further research is required to comprehensively understand the implications of these findings for consumer-oriented egg quality and health benefits.

Safety of Oral Food Challenge for Individuals with Low Egg White and Ovomucoid-Specific IgE Antibodies

INTRODUCTION

During an oral food challenge (OFC), there is a risk of adverse reactions, including anaphylaxis. Therefore, the physician should carefully conduct the OFC. This study aimed to evaluate the OFC results in individuals with low levels of egg white (EW)- and ovomucoid (OVM)-specific immunoglobulin E (sIgE) and the safety of a hen's egg (HE) OFC in these individuals.

METHODS

A total of 2,058 individuals with low EW- or OVM-sIgE underwent HE-OFC at two institutions in Kumamoto prefecture, located in the western area of Japan, between January 1, 2017, and December 31, 2021, within 1 year of recorded sIgE measurements. The ImmunoCAP systems were used to measure sIgEs. The HE-OFC test was performed according to the 2017 Food Allergy Guidelines in an open and unblinded method.

RESULTS

Five hundred and one individuals (24.3%) had low EW-sIgE levels (class 2 or lower), and 926 (45.0%) had low OVM-sIgE levels (class 2 or lower). Individuals with low EW-sIgE had lower total IgE and OVM-sIgE than did those with high EW-sIgE (greater than class 2). Those with low OVM-sIgE had lower total IgE and EW-sIgE than did those with high OVM-sIgE (greater than class 2). Among the individuals with low EW-sIgE, 86.4% (433/501 cases) passed the OFC without symptoms. Among the individuals with low OVF-sIgE, 82.6% (765/926 cases) passed the OFC without symptoms.

CONCLUSION

More than 80% of individuals with suspected IgE-dependent HE allergy and low levels of EW- or OVM-specific IgE were able to consume at least a small amount of HE. As the OFC results are independent of the loading dose in cases with low EW- or OVM-sIgE, a medium-dose HE-OFC may be performed safely in individuals with no history of anaphylaxis.

Quasi-Targeted Metabolomics Approach Reveal the Metabolite Differences of Three Poultry Eggs

As a food resource and nutrient, eggs play an important role in reducing malnutrition and improving the health status around the world. We studied the metabolite profile of three kinds of eggs using a widely-targeted metabolomics-based technique to better understand the difference in metabolites among chicken, duck, and quail eggs. We identified 617 metabolites, of which 303, 324, 302, 64, 81, and 80 differential metabolites were found by two group comparisons: quail egg yolk (QY) vs. quail egg albumen (QW), chicken egg yolk (HY) vs. chicken egg albumen (HW), duck egg yolk (DY) vs. duck egg albumen (DW), quail egg (Q) vs. duck egg (D)/chicken egg (H), and duck egg (D) vs. chicken egg (H), respectively. The Venn diagram showed that 147 metabolites were shared among the chicken, duck, and quail eggs. Additionally, the nucleotide and its derivates had the largest variations among the different types of eggs. This indicates that the flavor difference of the chicken eggs, duck eggs, and quail eggs may be related to their nucleotides and their derivates. The differential metabolites between egg yolk and albumen were primarily correlated with amino acid metabolism, protein metabolism, and immune performance. The discovery of these differential metabolites paves the way for further research on the nutritional potentials of various egg types.

Egg Usual Intake is Associated with Choline Adequacy in US Infants and Young Children

Although most US children do not meet recommendations for choline intake, there are also no data available assessing usual egg intake in younger children and choline adequacy. Therefore, data from the National Health and Nutrition Examination Survey, 2001-2018 were analyzed to identify usual egg intake in infants (birth to 1 y; N = 4770) and young children (2-5 y; N = 6930) and to determine mean percentage of infants and children above the Adequate Intake (AI) for daily choline intake. The percent of infants above the AI when consuming the lowest usual egg intake level (<0.25 oz eq) was 33.4 ± 1.3. When comparing 0.25-0.5, 0.5-0.75, 0.75-1.0, and ≥1.0 oz eq to <0.25 oz eq of usual egg intake, the percent of infants above the AI for choline was 67.4 ± 1.6, 84.9 ± 2.1, 93.2 ± 1.5, and 98.1 ± 1.3, respectively (all P < 0.0001). The percent of children above the AI when consuming the lowest usual egg intake level (<0.25 oz eq) was 22.31. Comparing 0.25- 0.5, 0.5-0.75, 0.75-1.0, and ≥1.0 oz eq to <0.25 oz eq of usual egg intake demonstrated significant increases in the percent of toddlers above the AI for choline, such that 51.41%, 72.57%, and 84.94% and 92.57%, respectively, were above the recommended daily intake for choline (all P < 0.0001). Similar findings were seen when assessing infants and children of different socioeconomic status. Overall, the percent of infants and children above the AI was higher with each increasing level of usual egg intake. Given the association of higher choline intakes with egg consumption, increasing usual egg intake in infants and young children may help elevate the percentage meeting the established AI for choline intake and thus, improve choline adequacy in childhood.

Ultrasound-assisted free radical modification on the structural and functional properties of ovalbumin-epigallocatechin gallate (EGCG) conjugates

The influence of ultrasound-assisted free radical modification on the structure and functional properties of ovalbumin-epigallocatechin gallate (OVA-EGCG) conjugates was investigated by experimental measurements and computer simulations. Compared with the traditional free radical condition, the ultrasonic-assisted processing significantly increased the conjugating efficiency of OVA and EGCG and shortened the conjugating from 24 h to 1 h without affecting the equivalent amount of EGCG conjugating. The sodium dodecyl sulfate-polyacrylamide gel electrophoresis and multi-spectroscopy analysis (Fourier transform infrared spectroscopy, intrinsic fluorescence spectroscopy, and UV spectroscopy) indicated that the covalent conjugates could be formed between OVA and EGCG. And modification in the conformation of OVA was induced by EGCG. Furthermore, molecular docking results demonstrated the possession of high-affinity EGCG binding location on OVA, supporting and clarifying the experimental results. In addition, the functional properties of OVA including emulsification (emulsifying activity and emulsion stability) and antioxidant properties (DPPH scavenging capacity and ABTS scavenging capacity) were significantly improved after conjugation with EGCG, especially in ultrasound-assisted conditions. Overall, OVA-EGCG conjugates produced by ultrasound-assisted free radical treatment could be applied as a potential emulsifier and antioxidant, thereby expanding the application of OVA as a dual-functional ingredient.

Transcription activator-like effector nuclease-mediated deletion safely eliminates the major egg allergen ovomucoid in chickens

Among the major egg allergens, ovomucoid (OVM) is very stable against heat and digestive enzymes, making it difficult to remove physiochemically and inactivate allergens. However, recent genome editing technology has made it possible to generate OVM-knockout chicken eggs. To use this OVM-knockout chicken egg as food, it is important to evaluate its safety as food. Therefore, in this study, we examined the presence or absence of mutant protein expression, vector sequence insertion, and off-target effects in chickens knocked out with OVM by platinum TALENs. The eggs laid by homozygous OVM-knockout hens showed no evident abnormalities, and immunoblotting showed that the albumen contained neither the mature OVM nor the OVM truncated variant. Whole genome sequencing (WGS) revealed that the potential TALEN-induced off-target effects in OVM-knockout chickens were localized in the intergenic and intron regions. The WGS information confirmed that plasmid vectors used for genome editing were only transiently present and did not integrate into the genome of edited chickens. These results indicate the importance of safety evaluation and reveal that the eggs laid by this OVM knockout chicken solve the allergy problem in food and vaccines.

Proteins and their functionalization for finding therapeutic avenues in cancer: Current status and future prospective

Despite the remarkable advancement in the health care sector, cancer remains the second most fatal disease globally. The existing conventional cancer treatments primarily include chemotherapy, which has been associated with little to severe side effects, and radiotherapy, which is usually expensive. To overcome these problems, target-specific nanocarriers have been explored for delivering chemo drugs. However, recent reports on using a few proteins having anticancer activity and further use of them as drug carriers have generated tremendous attention for furthering the research towards cancer therapy. Biomolecules, especially proteins, have emerged as suitable alternatives in cancer treatment due to multiple favourable properties including biocompatibility, biodegradability, and structural flexibility for easy surface functionalization. Several in vitro and in vivo studies have reported that various proteins derived from animal, plant, and bacterial species, demonstrated strong cytotoxic and antiproliferative properties against malignant cells in native and their different structural conformations. Moreover, surface tunable properties of these proteins help to bind a range of anticancer drugs and target ligands, thus making them efficient delivery agents in cancer therapy. Here, we discuss various proteins obtained from common exogenous sources and how they transform into effective anticancer agents. We also comprehensively discuss the tumor-killing mechanisms of different dietary proteins such as bovine α-lactalbumin, hen egg-white lysozyme, and their conjugates. We also articulate how protein nanostructures can be used as carriers for delivering cancer drugs and theranostics, and strategies to be adopted for improving their in vivo delivery and targeting. We further discuss the FDA-approved protein-based anticancer formulations along with those in different phases of clinical trials.

Combined Effect of Feed and Housing System Affects Free Amino Acid Content of Egg Yolk and Albumen in Brown Layer Chickens

In recent years, the market share for cage-free eggs has gradually increased. Because commercially available cage-free eggs are often produced not only by several housing systems but also with different feed crude protein (CP) levels, there are combined effects of feed and housing systems between cage-free and cage eggs. Therefore, using field data, this study aimed to determine the combined effects of feed and housing systems on egg traits and yolk and albumen amino acids in table eggs. Brown layers (n = 40) at the middle laying stage under two feed and housing systems (cage, CP 15.5% diet; barn, CP 17.0% diet) were used. One-way analysis of variance and Pearson's correlation analysis were used to evaluate 10 egg traits, 19 yolk amino acid traits, and 20 albumen amino acid traits. We observed significant effects of feed and housing on two egg traits (yolk weight and eggshell color redness), 16 yolk amino acids (Asp, Glu, Asn, Ser, Gln, His, Arg, Thr, Ala, Tyr, Met, Cys, Ile, Leu, Phe, and Lys), and 14 albumen amino acids (Asp, Asn, Ser, Gln, Gly, His, Arg, Thr, Ala, Val, Met, Cys, Ile, and Leu). This study revealed that eggs from the barn system (CP 17.0%) contained higher levels of free amino acids in 15 yolk and nine albumen amino acid traits. Phenotypic correlations among the 49 egg traits indicated similar correlation patterns in both systems, which implies that the balance of free amino acid content in yolk and albumen is similar in each system. Although some potential confounding factors may be present for comparing egg content between cage (CP 15.5%) and barn (CP 17.0%) systems, this study suggests that commercially available cage-free eggs may be different from cage eggs not only in external egg traits but also yolk and albumen amino acid traits.

Egg consumption reduces the risk of depressive symptoms in the elderly: findings from a 6-year cohort study

BACKGROUND

Accumulating evidence showed that dietary habits might modify the risk of depression. This study aimed to evaluate the longitudinal association of egg consumption with depressive symptoms in the Chinese elderly.

METHODS

We analyzed the data from Zhejiang Ageing and Health Cohort Study including 8289 participants. The Patient Health Questionnaire-9 scale (PHQ-9) was used to assess depressive symptoms at baseline and three waves of follow-up (2015, 2016, and 2019-2020). A PHQ-9 cut-off score ≥ 5 was used to define depressive symptoms. The participants with depressive symptoms at baseline were excluded. Egg consumption was evaluated through the diet habits section of the baseline questionnaire. Self-reported egg consumption was measured as the number of eggs per week and categorized into three categories. Log-binomial regression models with Generalized Estimating Equations were utilized to evaluate the association of egg consumption with depressive symptoms and estimate relative risks (RRs).

RESULTS

The mean age of included participants was 68.6 years. After 6 years of follow-up, 1385 (16.7%) participants were indicated with depressive symptoms by PHQ-9 at least once. Compared with non-consumers or less-than-weekly consumers, participants consuming < 3 eggs/week and ≥ 3 eggs/week had 30% (RR = 0.70, 95%CI 0.62-0.80) and 38% (RR = 0.62, 95%CI 0.54-0.71) lower risks of depressive symptoms, respectively. A linear association was confirmed (P for trend < 0.01), and each egg increment per week was associated with a 4% lower risk of depressive symptoms (RR = 0.96, 95%CI 0.93-0.99). Sensitivity analyses yielded consistent results to the main analyses.

CONCLUSIONS

Egg consumption is prospectively related to a lower risk of depressive symptoms in the Chinese elderly. More prospective studies are needed to verify the association.

Deciphering the interactions of phytochemicals with ovalbumin, the major food allergen from egg white: spectroscopic and computational studies

Ovalbumin (OVA), the major component of egg white, has been used as a model carrier protein to study the interaction of four bioactive phytochemicals 6-hydroxyflavone, chrysin, naringin, and naringenin. A static quenching mechanism was primarily associated with the complexation of the flavonoids with OVA. Hydrophobic forces play a major part in the stability of the complexes. The structural changes within the protein in response to flavonoid binding revealed a decrease in OVA's α-helical content. The hypothesized binding site for flavonoids in OVA overlaps with one or more immunoglobulin E-binding epitopes that may have some effect in the immunoglobulin E response pathway. The flavonoids remain in the same binding site throughout the simulation time and impart protein stability by forming different noncovalent interactions. This study presents comprehensive information about the interaction of the flavonoids with OVA and the associated structural variations after the binding, which might help researchers better comprehend similar medication pharmacodynamics and provide critical information for future therapeutic development.

Exogenous testosterone administration decreases rates of ovarian follicle growth in domestic chickens

Avian egg yolks provide critical nutrients and energy reserves for a growing embryo. Once a follicle is selected into the ovulatory hierarchy, rings of yolk precursors are deposited daily until the yolk is large enough to ovulate. The composition of hen egg yolk and the mechanisms responsible for deposition in the ovarian follicle are well-studied. However, the factors that affect the rate of yolk deposition, and the number of days it takes for follicles to grow to the optimal size for ovulation, are less well-known. Social interactions appear to impact the rate of yolk deposition in many avian species and testosterone is a key hormone involved in regulating those interactions. Therefore, we hypothesized that testosterone would influence the rate of follicle growth. We tested the influences of exogenous testosterone treatment by rubbing either testosterone propionate cream (1.25 %) or a control cream to hen combs daily for 7 days to increase plasma testosterone concentrations. We then collected eggs and measured egg and yolk weight, yolk diameters, and stained and counted the number of concentric rings in each yolk. Testosterone-treated hens laid fewer eggs and grew their yolks more slowly than control hens. Testosterone also caused an increase in yolk weight but not yolk diameter. These results indicate that testosterone may play a role in the rate of yolk deposition in birds.

Dietary Theabrownin Supplementation Improves Production Performance and Egg Quality by Promoting Intestinal Health and Antioxidant Capacity in Laying Hens

Theabrownin, an activated and ample pigment in Pu-erh tea, is known to exert antiobesity and antihyperlipidemic effects in humans, mice, and rats. In this study, we aimed to explore the effects of theabrownin (TB) dietary supplementation on production performance, egg quality, intestinal health, and antioxidant capacities in laying hens. In total, 160 Lohmann laying hens (25 weeks old) were randomly split into four groups (each group 40 hens), namely the CONT (control, basal diet + 0 mg/kg TB), TB1 (basal diet + 100 mg/kg TB), TB2 (basal diet + 200 mg/kg TB), and TB4 (basal diet + 400 mg/kg TB) groups, respectively. These were supplemented with TB for 12 weeks. The results showed that the TB1 group exhibited a significantly higher laying rate during 9 to 12 weeks and higher egg weight and feed conversion efficiency (lower FCR) during 5 to 8 weeks and in the overall period (1 to 12 weeks) than the CONT group (p < 0.05). Compared with the CONT group, the eggs from the TB4 group had higher albumen height and Haugh unit than those from the other treatment groups after the 8th and 12th week; notably, the same was also observed in the TB1 and TB2 groups but only after the 12th week (p < 0.05). The albumen quality (albumen height and Haugh unit) after 3 weeks of storage was significantly higher in the TB1, TB2 and TB4 groups than in the CONT group (p < 0.05). Furthermore, TB supplementation lowered the serum levels of total cholesterol and total triglyceride (p < 0.05). Expression analysis revealed that TB2 and TB4 groups had reduced expression of tumor necrosis factor-α (p < 0.05), while TB1, TB2, and TB4 had significantly decreased expression of interleukin-1β and IL-6 (p < 0.05). Conversely, zonula occludens-1, claudin-1, and mucin-2 were upregulated in the TB2 and TB4 groups (p < 0.05). Meanwhile, dietary TB supplementation ameliorated the antioxidant status of the ovary and the magnum, showing a significant reduction in malondialdehyde and 8-hydroxydeoxyguanosine levels in the magnum, the upregulation of glutathione in the ovary, and superoxide dismutase and catalase in the magnum (p < 0.05). Overall, dietary supplementation with TB (>100 mg/kg) improved production performance and egg storage quality by improving the intestinal health and antioxidant capacities of the reproductive system in laying hens.

COMPARİSON OF EGG WHİTE AND Ε-POLYCAPROLACTONE FOR THREE-DİMENSİONAL CELL CULTURE

It is increasingly becoming important to develop three-dimensional (3-D) cell culture systems due to their numerous advantages over traditional monolayer culture. The aim of this study is to investigate the interaction of adipose derived stem cells (ADSCs) with scaffolds composed of ε-polycaprolactone (ε-PCL) and egg white. In our study; ε-PCL and egg white scaffolds were fabricated from their monomers under the catalysis of tin octoate and by polymerization by heat respectively. Characterization of PCL was carried out with Gel permeability chromatography (GPC), Fourier Transform Infrared Spectrophotometry (FTIR), Proton Nuclear Magnetic Resonance (H-NMR), Differential Scan Calorimetry (DSC) and Scanning Electron Microscopy (SEM). CM-DiI labeled ADSCs were cultured for 12 days on egg white and ε-PCL scaffolds. Cell viability was performed using MTT and nitric oxide level was evaluated for toxicity. Results showed that the number of ADSCs on egg white scaffold increased periodically throughout 12 days compared with the other groups. Although the number of ADSCs on ε-PCL scaffold increased until the 6th day of the culture, the cell number began to decrease after day 6.. These results were associated with the decomposition of PCL scaffolds that occurs through catabolic reactions. This causes the release of lactic acid which makes toxic effect on the cells. Thus, these results showed that egg white scaffold increases and protects cell adhesion and cell viability more than ε-Polycaprolactone scaffold, thus it can be used as a scaffold in tissue engineering studies that involve stem cells.

Effects of Dietary Essential Oils Supplementation on Egg Quality, Biochemical Parameters, and Gut Microbiota of Late-Laying Hens

The objective of this study was to explore the effects of adding essential oils (EO) to diets on egg quality, biochemical parameters and intestinal flora of late laying hens. The number of 252 Dawu Golden Phoenix laying hens (55 weeks old) were randomly sorted into two groups: the control group (CG) fed a basal diet and the EO group fed a basal diet with 300 mg/kg of essential oils. The average egg weight, feed-to-egg ratio, and egg production rate were determined every week. The trial started at week 55 and lasted for 8 weeks. During the experiment’s last week, 36 eggs out of each group were chosen at random to test. In our study, dietary supplementation with EO considerably decreased the egg breaking rate (p = 0.01) and increased the shell-breaking strength (p = 0.04). The treatment group’s alanine aminotransferase (ALT) levels were considerably lower than those of the control group (p = 0.03). The EO group had substantially higher total antioxidant capacity (T-AOC) and total superoxide dismutase (T-SOD) (p = 0.04 and p =0.03, respectively). However, there were no differences in alpha diversity indicators between the two groups. It is worth noting that Firmicutes were increased considerably (p < 0.05), while Spirochaetota and Proteobacteria were significantly reduced in the EO group. At genus levels, the EO supplementation increased the relative abundance of Intestinimonas (p < 0.05) and Megamonas (p < 0.01). In conclusion, a dietary supplementation of 300 mg/kg EO can improve the production performance of laying hens and the egg quality. It can also regulate the abundance of cecal flora and serum biochemical indicators.

Hen Egg Lysozyme Alleviates Static Mechanical Pain Via NRF1-Parkin-TACAN Signaling Axis in Sensory Neurons

Mechanical allodynia impinges on the life quality of patients. Hen Egg Lysozyme (HEL) is a substance extracted from eggs that is commonly used to inhibit bacterial activity. The role of HEL in regulating and treating pain is unclear. Here, we find that HEL selectively attenuates static mechanical allodynia of mice induced by complete Freund's adjuvant (CFA), spinal nerve ligation (SNL) and chemotherapeutic agent. RNA-seq screening reveals that CFA significantly reduces the expression of Parkin in dorsal root ganglion (DRG) neurons of mice, while pre-administration of HEL increases the expression of Parkin and remits the static mechanical allodynia induced by Parkin-siRNA. Moreover, HEL increases the interaction between nuclear respiratory factor 1 (NRF1) and histone acetyltransferase P300 and then enhances the NRF1 mediated histone acetylation in prkn promoter region in DRGs of mice. Further, Parkin interacts with mechanotransducing ion channel TACAN (Tmem120a) and knockdown of Parkin significantly increases the membrane trafficking of TACAN in sensory neurons of mice. While pre-administration of HEL inhibits the increased membrane trafficking of TACAN in sensory neurons of mice induced by Parkin-siRNA. In addition, pre-given of HEL also significantly attenuates the static mechanical allodynia induced by overexpression of TACAN in mice, and the effect of HEL can be blocked by Parkin-siRNA. This indicates that HEL increases the expression of Parkin through epigenetic mechanisms and then decreases TACAN membrane trafficking in sensory neurons to relieve static mechanical hypersensitivity. Therefore, we reveal a novel function of HEL, which is a potential substance for the treatment of static mechanical pain.

Egg white protein-based delivery system for bioactive substances: a review

Some bioactive substances in food have problems such as poor solubility, unstable chemical properties and low bioavailability, which limits their application in functional food. Recently, many egg white protein-based delivery carriers have been developed to improve the chemical stability, biological activity and bioavailability of bioactive substances. This article reviewed the structure and properties of several major egg white proteins commonly used to construct bioactive substance delivery systems. Several common carrier types based on egg white proteins, including hydrogels, emulsions, micro/nanoparticles, aerogels and electrospinning were then introduced. The biological functions of common bioactive substances, the limitations, and the role of egg white protein-based delivery systems were also discussed. At present, whole egg white protein, ovalbumin and lysozyme are most widely used in delivery systems, while ovotransferrin, ovomucoid and ovomucin are less developed and applied. Egg white protein-based nanoparticles are currently the most commonly used delivery carriers. Egg white protein-based hydrogels, emulsions, and microparticles are also widely used. Future research on the application of various egg white proteins in developed new delivery systems will provide more choices for the delivery of various bioactive substances.

The Health Benefits of Egg Protein

Once the general public accepts that dietary cholesterol is not a concern for cardiovascular disease risk, foods that have been labeled as high-cholesterol sources, including eggs, may be appreciated for their various other dietary components. One of the nutrients in eggs that deserves further discussion is egg protein. Egg protein has been recognized to be highly digestible and an excellent source of essential amino acids, with the highest attainable protein digestibility-corrected amino acid score. Egg protein has been shown to decrease malnutrition in underdeveloped countries, possibly increase height in children, and protect against kwashiorkor. Egg protein has been demonstrated to be important to skeletal muscle health and protective against sarcopenia. Egg protein also can decrease appetite, resulting in a reduction in the caloric intake from the next meal and weight reduction. Other protective effects of egg protein addressed in this review include protection against infection as well as hypotensive and anti-cancer effects.

Recent Advances in Electrochemical Sensing Strategies for Food Allergen Detection

Food allergy has been indicated as the most frequent adverse reaction to food ingredients over the past few years. Since the only way to avoid the occurrence of allergic phenomena is to eliminate allergenic foods, it is essential to have complete and accurate information on the components of foodstuff. In this framework, it is mandatory and crucial to provide fast, cost-effective, affordable, and reliable analysis methods for the screening of specific allergen content in food products. This review reports the research advancements concerning food allergen detection, involving electrochemical biosensors. It focuses on the sensing strategies evidencing different types of recognition elements such as antibodies, nucleic acids, and cells, among others, the nanomaterial role, the several electrochemical techniques involved and last, but not least, the ad hoc electrodic surface modification approaches. Moreover, a selection of the most recent electrochemical sensors for allergen detection are reported and critically analyzed in terms of the sensors’ analytical performances. Finally, advantages, limitations, and potentialities for practical applications of electrochemical biosensors for allergens are discussed.

A 3D Printed Bone Tissue Engineering Scaffold Composed of Alginate Dialdehyde-Gelatine Reinforced by Lysozyme Loaded Cerium Doped Mesoporous Silica-Calcia Nanoparticles

A novel biomaterial comprising alginate dialdehyde-gelatine (ADA-GEL) hydrogel augmented by lysozyme loaded mesoporous cerium doped silica-calcia nanoparticles (Lys-Ce-MSNs) was 3D printed to create bioactive scaffolds. Lys-Ce-MSNs raised the mechanical stiffness of the hydrogel composite scaffold and induced surface apatite mineralization, when the scaffold was immersed in simulated body fluid (SBF). Moreover, the scaffolds could co-deliver bone healing (Ca and Si) and antioxidant ions (Ce), and Lys to achieve antibacterial (and potentially anticancer) properties. The nanocomposite hydrogel scaffolds could hold and deliver Lys steadily. Based on the in vitro results, the hydrogel nanocomposite containing Lys assured improved pre-osteoblast cell (MC3T3-E1) proliferation, adhesion, and differentiation, thanks to the biocompatibility of ADA-GEL, bioactivity of Ce-MSNs, and the stabilizing effect of Lys on the scaffold structure. On the other hand, the proliferation level of MG63 osteosarcoma cells decreased, likely due to the anticancer effect of Lys. Last but not least, cooperatively, alongside gentamicin (GEN), Lys brought about a proper antibacterial efficiency to the hydrogel nanocomposite scaffold against gram-positive and gram-negative bacteria. Taken together, ADA-GEL/Lys-Ce-MSN nanocomposite holds great promise for 3D printing of multifunctional hydrogel BTE scaffolds, able to induce bone regeneration, address infection, and potentially inhibit tumor formation and growth. This article is protected by copyright. All rights reserved.

Natural Products of Plants and Animal Origin Improve Albumen Quality of Chicken Eggs

Albumen quality is recognized as one of the major yardsticks in measuring egg quality. The elasticity of thick albumen, a strong bond in the ovomucin-lysozyme complex, and excellent biological properties are indicators of high-quality albumen. The albumen quality prior to egg storage contribute to enhance egg’s shelf life and economic value. Evidence suggests that albumen quality can deteriorate due to changes in albumen structure, such as the degradation of β-ovomucin subunit and O-glyosidic bonds, the collapse of the ovomucin-lysozyme complex, and a decrease in albumen protein-protein interaction. Using organic minerals, natural plants and animal products with antioxidant and antimicrobial properties, high biological value, no residue effect and toxicity risk could improve albumen quality. These natural products (e.g., tea polyphenols, marigold extract, magnolol, essential oils, Upro (small peptide), yeast cell wall, Bacillus species, a purified amino acid from animal blood, and pumpkin seed meal) are bio-fortified into eggs, thus enhancing the biological and technological function of the albumen. Multiple strategies to meeting laying hens’ metabolic requirements and improvement in albumen quality are described in this review, including the use of amino acids, vitamins, minerals, essential oils, prebiotics, probiotics, organic trace elements, and phytogenic as feed additives. From this analysis, natural products can improve animal health and consequently albumen quality. Future research should focus on effects of these natural products in extending shelf life of the albumen during storage and at different storage conditions. Research in that direction may provide insight into albumen quality and its biological value in fresh and stored eggs.

Discriminant Analysis of the Nutritional Components between Organic Eggs and Conventional Eggs: A 1H NMR-Based Metabolomics Study

The difference of nutrient composition between organic eggs and conventional eggs has always been a concern of people. In this study, ¹H nuclear magnetic resonance (NMR) technique combined with multivariate statistical analyses was conducted to identify the metabolite different in egg yolk and egg white in order to reveal the nutritional components information between organic and conventional eggs. The results showed that the nutrient content and composition characteristics were different between organic and conventional eggs, among which the content of glucose, putrescine, amino acids and their derivatives were found higher in the organic eggs yolk, while phospholipids were demonstrated higher in conventional eggs yolk. Organic acid, alcohol, amine, choline and amino acids were higher in conventional eggs white, but glucose and lactate in organic egg were higher. Our study demonstrated that there are more nutritive components and higher nutritional value in organic eggs than conventional eggs, especially for the growth and development of infants and young children, and conventional eggs have more advantages in promoting lipid metabolism, preventing fatty liver, and reducing serum cholesterol. Eggs have important nutritional value to human body, and these two kinds of eggs can be selected according to the actual nutrient needs.

Interaction Mechanism between OVA and Flavonoids with Different Hydroxyl Groups on B-Ring and Effect on Antioxidant Activity

Ovalbumin (OVA) is a common carrier with high efficiency to deliver flavonoids. The aim of this study was to investigate the interaction mechanism of OVA and four flavonoids (quercetin (Que), myricetin (Myri), isorhamnetin (Ish), and kaempferol (Kaem)) with similar structures by fluorescence spectra, SDS−PAGE, FT−IR, and molecular docking analysis, and the effect on the antioxidant abilities of flavonoids was also evaluated. Results indicated that the antioxidant activity of flavonoids was positively correlated to the number of phenolic hydroxyl groups of on the B-ring, and weakened when the C-3′ position was replaced by a methoxy group. The addition of OVA enhanced the antioxidant activity of Que/Kaem, while it masked the antioxidant activity of Myri. The formation of Que/Myri/Ish/Kaem−OVA complexes was a spontaneous exothermic process driven mainly by hydrogen bond and van der Waals force, which could result in the change in OVA conformation and induce the transformation of α-helix to β-sheet. Among these, Kaem exhibited the strongest binding ability with OVA, and showed the greatest impact on the secondary and conformational structure of OVA, followed by Que. The hydroxylation of C-3′ and methoxylation of C-5′ weaken the interaction of Kaem with OVA. Molecular docking analysis suggested that Que, Myri, Ish, and Kaem formed six, three, five, and four hydrogen bonds with OVA, and the number of hydrogen bonds was not positively correlated with their binding constants. Our findings can provide a theoretical basis for the application of OVA on improving the antioxidant activity of flavonoids, and may help to explain the delivery efficiency of OVA on different bioactive constituents.

Modification methods and applications of egg protein gel properties: A review

Egg protein (EP) has a variety of functional properties, such as gelling, foaming, and emulsifying. The gel characteristics provide a foundation for applications in the food industry and research on EP. The proteins denature and aggregate to form a dense three-dimensional gel network structure, with a process influenced by protein concentration, pH, ion type, and strength. In addition, the gelation properties of EP can be altered to varying degrees by applying different treatment conditions to EP. Currently, modification methods for proteins include physical modification (heat-induced denaturation, freeze-thaw modification, high-pressure modification, and ultrasonic modification), chemical modification (glycosylation modification, phosphorylation modification, acylation modification, ethanol modification, polyphenol modification), and biological modification (enzyme modification). Pidan, salted eggs, egg tofu, and other egg products have unique sensory properties, due to the gel properties of EP. In accessions, EP has also been used as a new ingredient in food packaging and biopharmaceuticals due to its gel properties. This review will further promote EP gel research and provide guidance for its full application in many fields.

Phosphoproteomic analysis of duck egg yolk provides novel insights into its characteristics and biofunctions

BACKGROUND

Although the importance of phosphorylation in the function of proteins is known, investigation of the protein phosphorylation of duck egg yolk (DEY) is still very limited. This study aimed to conduct a detailed phosphoproteomic study of DEY using immobilized metal affinity chromatography and ultra-high liquid chromatography tandem mass spectrometry.

RESULTS

A total of 253 phosphorylation sites assigned to 66 phosphoproteins were identified in DEY, of which VTG-1, VTG-2, and fibrinogen alpha chain were found to be the highly phosphorylated proteins in DEY. The biological functions of the identified phosphoproteins were illuminated through gene ontology analysis, which showed that they were mainly involved in binding, catalytic, immune response, and metabolic activity. S-X-E and S-X-S were found to be the most conserved serine motifs of phosphorylation in DEY. The comparison of DEY phosphoproteins with those of chicken egg yolk (CEY) revealed that differences mostly involved molecular functions and biological processes. The comparison also revealed a higher phosphorylation level in DEY proteins.

CONCLUSION

The higher phosphorylation level in DEY proteins than that in CEY proteins are supposed to help enhance duck growth performance and biological activities (e.g. antibacterial and antioxidant ability) for better adapting the humid environment the duck lived. © 2021 Society of Chemical Industry.

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.

Astaxanthin improved the storage stability of docosahexaenoic acid-enriched eggs by inhibiting oxidation of non-esterified poly-unsaturated fatty acids

This study assessed the potential and mechanism of action of astaxanthin, to improve the stability of docosahexaenoic acid (22:6(n-3); DHA) enriched egg products, during storage at 4 °C. The reduction in DHA content after 42 days of storage in astaxanthin-DHA eggs (from hens fed supplemental astaxanthin and DHA) was <3%, whereas the reduction in regular-DHA eggs (hens fed DHA only) was over 17%. Astaxanthin also decreased production of oxidation products including 4-hydroxy-2-hexenal, 4-hydroxy-2-nonenal and malondialdehyde in eggs during storage, thus markedly improving the oxidative stability of DHA-enriched eggs. The yolk lipidomic profile showed higher intensities for most DHA-containing lipids, especially DHA-phosphatidylcholine, DHA-phosphatidylethanolamine and DHA-non-esterified fatty acid, compared with regular-DHA eggs. Astaxanthin acts primarily by suppressing oxidation of DHA-non-esterified fatty acid, which minimizes the degradation of DHA and appears to be the primary protection mode of yolk DHA during storage.

Sustaining Protein Nutrition Through Plant-Based Foods

Proteins are essential components of the human diet. Dietary proteins could be derived from animals and plants. Animal protein, although higher in demand, is generally considered less environmentally sustainable. Therefore, a gradual transition from animal- to plant-based protein food may be desirable to maintain environmental stability, ethical reasons, food affordability, greater food safety, fulfilling higher consumer demand, and combating of protein-energy malnutrition. Due to these reasons, plant-based proteins are steadily gaining popularity, and this upward trend is expected to continue for the next few decades. Plant proteins are a good source of many essential amino acids, vital macronutrients, and are sufficient to achieve complete protein nutrition. The main goal of this review is to provide an overview of plant-based protein that helps sustain a better life for humans and the nutritional quality of plant proteins. Therefore, the present review comprehensively explores the nutritional quality of the plant proteins, their cost-effective extraction and processing technologies, impacts on nutrition, different food wastes as an alternative source of plant protein, and their environmental impact. Furthermore, it focuses on the emerging technologies for improving plant proteins' bioavailability, digestibility, and organoleptic properties, and highlights the aforementioned technological challenges for future research work.