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Foods (Basel, Switzerland) Feb 2023In this study, differences in the protein content and functional and physicochemical properties of four varieties of egg white (EW) were studied by adding 4-10% sucrose...
In this study, differences in the protein content and functional and physicochemical properties of four varieties of egg white (EW) were studied by adding 4-10% sucrose or NaCl and then heating them at 70 °C for 3 min. According to a high-performance liquid chromatography (HPLC) analysis, the percentages of ovalbumin, lysozyme and ovotransferrin rose with an increase in the NaCl or sucrose concentration; however, the percentages of ovomucin and ovomucoid decreased. Furthermore, the foaming properties, gel properties, particle size, α-helixes, β-sheets, sulfhydryl groups and disulfide bond content also increased, whereas the content of β-turns and random coils decreased. In addition, the total soluble protein content and functional and physicochemical properties of black bone (BB) chicken and Gu-shi (GS) EWs were higher than those of Hy-Line brown (HY-LINE) and Harbin White (HW) Ews ( < 0.05). Subsequently, transmission electron microscopy (TEM) confirmed the changes in the EW protein structure in the four varieties of Ews. As the aggregations increased, the functional and physicochemical properties decreased. The protein content and functional and physicochemical properties of Ews after heating were correlated with the concentration of NaCl and sucrose and the EW varieties.
PubMed: 36832956
DOI: 10.3390/foods12040881 -
Nutrients Feb 2023Food allergy is one of the major existing health problems, but no effective treatment is available. In the current work, a murine model that closely mimics pathogenesis...
A Murine Model of Food Allergy by Epicutaneous Adjuvant-Free Allergen Sensitization Followed by Oral Allergen Challenge Combined with Aspirin for Enhanced Detection of Hypersensitivity Manifestations and Immunotherapy Monitoring.
Food allergy is one of the major existing health problems, but no effective treatment is available. In the current work, a murine model that closely mimics pathogenesis of human food allergy and its quantifiable diagnostic parameter design, even for mild hypersensitivity reactions, were established. BALB/c mice were epicutaneously sensitized with 1 mg chicken egg ovomucoid (OVM) or cow's milk casein, free of adjuvants, five times a week for two consecutive weeks. Eleven days later, allergen-specific IgG1 and IgE in serum were measured by ELISA. On day 25, 20 mg OVM or 12 mg α-casein was administered orally, and allergic reactions such as the fall in rectal temperature, symptom scores during 90-120 min, serum mast cell protease-1 and cytokine levels were monitored. The detection of mild allergic reactions due to adjuvant-free allergen sensitization and oral allergen challenge routes was amplified by the combination of oral allergen and aspirin administration simultaneously or aspirin administration within 15-30 min before an allergen challenge. Quantification of the maximum symptom score and the frequency of symptoms during the monitoring period improved evaluation accuracy of food allergy signals. Based on these results, efficacy of casein oral immunotherapy for cow's milk allergies, which are generally difficult to detect, was monitored adequately.
Topics: Humans; Female; Cattle; Mice; Animals; Allergens; Caseins; Aspirin; Disease Models, Animal; Food Hypersensitivity; Milk Hypersensitivity; Adjuvants, Immunologic; Ovomucin; Immunotherapy
PubMed: 36771462
DOI: 10.3390/nu15030757 -
Ultrasonics Sonochemistry Sep 2022The effects of ultrasonic treatment on the structure, functional properties and bioactivity of Ovomucin (OVM) were investigated in this study. Ultrasonic treatment could...
The effects of ultrasonic treatment on the structure, functional properties and bioactivity of Ovomucin (OVM) were investigated in this study. Ultrasonic treatment could significantly enhance OVM solubility without destroying protein molecules. The secondary structure changes, including β-sheet reduction and random coil increase, indicate more disorder in OVM structure. After ultrasonic treatment, the OVM molecule was unfolded partially, resulting in the exposure of hydrophobic regions. The changes in OVM molecules led to an increase in intrinsic fluorescence and surface hydrophobicity. By detecting the particle size of protein solution, it was confirmed that ultrasonic treatment disassembled the OVM aggregations causing a smaller particle size. Field emission scanning electron microscopy (FE-SEM) images showed that ultrasonic cavitation significantly reduced the tendency of OVM to form stacked lamellar structure. Those changes in structure resulted in the improvement of foaming, emulsification and antioxidant capacity of OVM. Meanwhile, the detection results of ELISA showed that ultrasonic treatment did not change the biological activity of OVM. These results suggested that the relatively gentle ultrasound treatment could be utilized as a potential approach to modify OVM for property improvement.
Topics: Antioxidants; Enzyme-Linked Immunosorbent Assay; Hydrophobic and Hydrophilic Interactions; Ovomucin; Ultrasonics
PubMed: 36088894
DOI: 10.1016/j.ultsonch.2022.106153 -
Foods (Basel, Switzerland) Aug 2022Chicken egg whites contain hundreds of proteins, and are widely used in the food, biological and pharmaceutical industries. It is highly significant to study the... (Review)
Review
Chicken egg whites contain hundreds of proteins, and are widely used in the food, biological and pharmaceutical industries. It is highly significant to study the separation and purification of egg white proteins. This review first describes the structures and functional properties of several major active proteins in egg whites, including ovalbumin, ovotransferrin, ovomucoid, lysozyme, ovomucin, ovomacroglobulin and avidin. Then, the common techniques (including precipitation, chromatography and membrane separation) and some novel approaches (including electrophoresis, membrane chromatography, aqueous two-phase system and molecular imprinting technology) for the separation and purification of egg white proteins broadly reported in the current research are introduced. In addition, several co-purification methods for simultaneous separation of multiple proteins from egg whites have been developed to improve raw material utilization and reduce costs. In this paper, the reported techniques in the last decade for the separation and purification of chicken egg white proteins are reviewed, discussed and prospected, aiming to provide a reference for further research on egg proteins in the future.
PubMed: 36010434
DOI: 10.3390/foods11162434 -
Frontiers in Nutrition 2022Albumen 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,... (Review)
Review
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 -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, 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.
PubMed: 35757269
DOI: 10.3389/fnut.2022.875270 -
Antioxidants (Basel, Switzerland) Mar 2022Enhanced albumen quality is reflected in increased thick albumen height, albumen weight, and Haugh unit value, while the antimicrobial, antioxidant, foaming, gelling,... (Review)
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 -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.
PubMed: 35453315
DOI: 10.3390/antiox11040630 -
Allergology International : Official... Oct 2022Early food introduction induces tolerance, but epicutaneous exposure, especially via eczema lesions, promotes IgE sensitization. Aiming for safe and effective primary...
BACKGROUND
Early food introduction induces tolerance, but epicutaneous exposure, especially via eczema lesions, promotes IgE sensitization. Aiming for safe and effective primary prevention of egg allergy, we examined several protease-digested egg-white (EW) products for three properties: 1) induction of oral tolerance that prevents IgE sensitization, 2) weak IgE binding that can prevent allergic reactions even in IgE-sensitized mice, and 3) minimal epicutaneous IgE sensitization even when in contact with inflamed skin.
METHODS
Heated EW was digested with several proteases under optimal conditions. First, three-week-old BALB/c female mice were intragastrically administered EW or each protease-digested EW product, followed by intraperitoneal ovalbumin (OVA) or ovomucoid (OVM) injection with alum. Serum OVA- and OVM-specific IgE titers were measured. Second, six-week-old mice were sensitized with OVA/OVM, and the rectal temperature was measured after intraperitoneal administration of EW or each protease-digested EW. Third, EW or each protease-digested EW product was applied to the tape-stripped skin for 3 days/week for 3 weeks. Serum OVA- and OVM-specific IgE titers were measured.
RESULTS
Orally administered pepsin-digested EW product (PDEW) and Thermoase PC10F-digested EW product (TDEW) significantly suppressed OVA-/OVM-specific IgE production. Neither product elicited a body temperature decline (anaphylaxis) in OVA-/OVM-sensitized mice. Serum OVA-/OVM-specific IgE levels were significantly lower in mice epicutaneously exposed to PDEW or TDEW than in EW-exposed mice.
CONCLUSIONS
Two protease-digested EWs showed potential as optimal EW products for early introduction for primary prevention of egg allergy.
Topics: Allergens; Animals; Egg Hypersensitivity; Eggs; Female; Immunoglobulin E; Mice; Mice, Inbred BALB C; Ovalbumin; Ovomucin; Pepsin A; Peptide Hydrolases
PubMed: 35443911
DOI: 10.1016/j.alit.2022.03.006 -
International Archives of Allergy and... 2022Molecular studies of hen's egg allergens help define allergic phenotypes, with IgE to sequential (linear) epitopes on the ovomucoid (OVM) protein associated with a...
INTRODUCTION
Molecular studies of hen's egg allergens help define allergic phenotypes, with IgE to sequential (linear) epitopes on the ovomucoid (OVM) protein associated with a persistent disease. Epitope profiles of other egg allergens are largely unknown. The objective of this study was to construct an epitope library spanning across 7 allergens and further evaluate sequential epitope-specific (ses-)IgE and ses-IgG4 among baked-egg reactive or tolerant children.
METHODS
A Bead-Based Epitope Assay was used to identify informative IgE epitopes from 15-mer overlapping peptides covering the entire OVM and ovalbumin (OVA) proteins in 38 egg allergic children. An amalgamation of 12 B-cell epitope prediction tools was developed using experimentally identified epitopes. This ensemble was used to predict epitopes from ovotransferrin, lysozyme, serum albumin, vitellogenin-II fragment, and vitellogenin-1 precursor. Ses-IgE and ses-IgG4 repertoires of 135 egg allergic children (82 reactive to baked-egg, the remaining 52 tolerant), 46 atopic controls, and 11 healthy subjects were compared.
RESULTS
183 peptides from OVM and OVA were screened and used to create an aggregate algorithm, improving predictions of 12 individual tools. A final library of 65 sequential epitopes from 7 proteins was constructed. Egg allergic children had higher ses-IgE and lower ses-IgG4 to predominantly OVM epitopes than both atopic and healthy controls. Baked-egg reactive children had similar ses-IgG4 but greater ses-IgE than tolerant group. A combination of OVA-sIgE with ses-IgEs to OVM-023 and OVA-028 was the best predictor of reactive phenotype.
CONCLUSION
We have created a comprehensive epitope library and showed that ses-IgE is a potential biomarker of baked-egg reactivity.
Topics: Allergens; Animals; Chickens; Egg Hypersensitivity; Epitopes; Female; Humans; Immunoglobulin E; Immunoglobulin G; Ovalbumin; Ovomucin; Peptides; Vitellogenins
PubMed: 34818647
DOI: 10.1159/000519618 -
Poultry Science Oct 2021Virus injection into EGK-X embryos is a well-defined approach in avian transgenesis. This system uses a chicken ovalbumin gene promoter to induce transgene expression in...
Virus injection into EGK-X embryos is a well-defined approach in avian transgenesis. This system uses a chicken ovalbumin gene promoter to induce transgene expression in the chicken oviduct. Although a reconstructed chicken ovalbumin promoter that links an ovalbumin promoter and estrogen-responsive enhancer element (ERE) is useful, a large viral vector containing the ovalbumin promoter and a target gene restricts viral packaging capacity and produces low-titer virus particles. We newly developed recombinant chicken promoters by linking regulatory regions of ovalbumin and other oviduct-specific genes. Putative enhancer fragments of the genes, such as ovotransferrin (TF), ovomucin alpha subunit (OVOA), and ovalbumin-related protein X (OVALX), were placed at the 5`-flanking region of the 2.8-kb ovalbumin promoter. Basal promoter fragments of the genes, namely, pTF, lysozyme (pLYZ), and ovomucoid (pOVM), were placed at the 3`-flanking region of the 1.6-kb ovalbumin ERE. The recombinant promoters cloned into each reporter vector were evaluated using a dual luciferase assay in human and chicken somatic cells, and LMH/2A cells treated with 0-1,000 nM estrogen, and cultured primary chicken oviduct cells. The recombinant promoters with linking ovalbumin and TF, OVOA, pOVM, and pLYZ regulatory regions had 2.1- to 19.5-fold (P < 0.05) higher luciferase activity than the reconstructed ovalbumin promoter in chicken oviduct cells. Therefore, recombinant promoters may be used to efficiently drive transgene expression in transgenic chickens.
Topics: Animals; Chickens; Fallopian Tubes; Female; Humans; Ovalbumin; Oviducts; Promoter Regions, Genetic; Transgenes
PubMed: 34375836
DOI: 10.1016/j.psj.2021.101365 -
Nutrients Jun 2021We investigated the effects of different types of heat treatments on hen's egg white (HEw) and quail egg white (QEw) proteins and their cross-reactivity in young...
We investigated the effects of different types of heat treatments on hen's egg white (HEw) and quail egg white (QEw) proteins and their cross-reactivity in young children. Crude extracts of raw and water-boiled HEw and QEw and commercially developed stone-baked HEw were prepared. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) was then performed. Patients diagnosed with HEw allergy were enrolled, and pooled sera were tested with each extract in an enzyme-linked immunosorbent assay (ELISA)-inhibition test. A skin prick test (SPT) and oral food challenge (OFC) were also performed. The median age of 12 patients was 2.5 years. SDS-PAGE results revealed strongly stained bands for the ovomucoid of boiled HEw and QEw, while stone-baked HEw displayed remarkable changes for all protein fractions. In the ELISA-inhibition test, pre-incubation of the sera led to a profound decrease, moderate decrease, and minimal decrease in the amount of IgE binding to boiled and raw HEw, boiled and raw QEw, and stone-baked HEw proteins, respectively. SPTs and OFC demonstrated cross-reactivity values of 41.7% (5/12) and 16.7% (2/12) for boiled QEw and stone-baked HEw, respectively. We observed moderate cross-reactivity between QEw and HEw. Boiling had a limited effect on altering egg allergenicity. Commercially developed, stone-baked HEw can be an alternative food for children with HE allergy.
Topics: Allergens; Animals; Chickens; Child, Preschool; Cooking; Cross Reactions; Denaturing Gradient Gel Electrophoresis; Egg Hypersensitivity; Egg Proteins; Eggs; Enzyme-Linked Immunosorbent Assay; Female; Hot Temperature; Humans; Male; Ovomucin; Prospective Studies; Quail; Skin Tests
PubMed: 34202741
DOI: 10.3390/nu13072172