Search Results (236)

This study evaluated how two commercial egg types (free-range and barn-laid) influence the physical, compositional, and rheological properties of egg white and yolk in raw and grilled states. Free-range eggs showed stronger correlations between external dimensions and internal composition, suggesting potential for nondestructive grading, whereas barn eggs exhibited heavier shells but weaker morphometric–composition relationships. Haugh units differentiated production systems, and yolk redness was the only color parameter clearly associated with free-range origin. Mechanical tests revealed that barn eggs had shells capable of absorbing more energy during rupture. Rheological measurements showed matrix-dependent behaviors: in raw samples, egg white behaved as a weakly structured viscoelastic fluid, while yolk exhibited characteristics of a concentrated lipoprotein emulsion. Stress, frequency, and temperature sweeps revealed contrasting behaviors between the two commercial egg types: barn-laid eggs displayed a stronger egg-white protein network, whereas free-range eggs showed a more reinforced yolk lipoprotein matrix under the conditions evaluated. Yolk behavior fitted the weak gel model with excellent accuracy (R² ≈ 1), while egg white did not. Steady shear and three-step tests confirmed pronounced shear thinning and thixotropic behavior in both matrices, with barn eggs showing higher viscosities but lower structural recovery. Thermal treatment reduced the strong rheological differences between raw egg white and yolk, yet production system effects persisted. All grilled samples behaved as weak gels, with barn egg whites forming stiffer networks and free-range yolks generating more elastic, cohesive, and energy-absorbing gels. A trend toward higher MUFA levels was observed in raw free-range yolks. Microscopy further clarified how production system shapes the structural and functional behavior of egg matrices. Full article

Caviar extract is widely used in luxury cosmetics and is generally defined as a homogeneous ingredient derived exclusively from sturgeon eggs. However, its molecular composition remains inadequately characterised. In this study, proteomic analyses were performed on 14 commercial caviar samples from different sturgeon species and geographical origins, examined independently in two laboratories. Across three single-origin samples (Germany, Poland, China), 1437 protein groups and 3452 unique peptides were identified, with consistent overlaps with sturgeon ovarian fluid (≥25–38 proteins). Extending this analysis across multiple species confirmed the presence of ovarian fluid-associated proteins in all examined groups, including 69 in Acipenser baerii, 61 in A. gueldenstaedtii, 55 in A. schrenckii, and 49 in H. huso. The results showed that ovarian fluid is consistently co-extracted during standard roe harvesting processes due to its strong egg surface adhesion, making this co-extraction intrinsic rather than incidental. Proteomic profiling revealed a complex mixture of egg- and ovarian fluid-derived proteins, including zona pellucida glycoproteins, immunoglobulins, complement components, proteases, coagulation factors, and antioxidant enzymes. Many of these proteins influence skin biology, suggesting that the functional effects attributed to caviar extract may partially originate from ovarian fluid constituents rather than yolk-derived nutrients alone. At the same time, the presence of immune-active and enzymatic proteins raises important questions regarding safety assessment and regulatory oversight. Species-specific proteomic clustering also indicates considerable composition heterogeneity, challenging assumptions of ingredient standardisation. Together, these results highlight a discrepancy between current definitions and the molecular reality and underscore the need for improved molecular characterisation, updated regulatory definitions, and the consideration of alternative, cell-based production strategies for cosmetic applications. Full article

The aim of this study was to investigate the substitution of egg yolk in mayonnaise-type sauces with alternative protein components and to optimize the hydrocolloid composition for improved stability and rheological properties. Mustard powder (1%), soybean flour (1%), casein (2%), and cream powder (1%) blends were employed as emulsifiers. The influence of the ratio of potato starch, carboxymethylcellulose (CMC), pectin, and xanthan gum (0–1% each) on the properties of low-fat mayonnaise formulations with 30% oil content was examined. Sedimentation and thermal stability tests revealed high resistance of all samples (98–99%) after 24 h of storage. Optical microscopy confirmed a homogeneous structure with individual dispersed particles of 100–150 μm corresponding to plant protein inclusions. The particle size distribution D [3,4] exhibited a bimodal profile with peaks at 0.1–1 μm and 2–8 μm, indicating efficient homogenization. Storage experiments demonstrated an increase in particle size by 1.4–1.6 times and a decrease in viscosity, likely due to flocculation and aggregation of polysaccharide clusters into larger agglomerates. Among the tested formulations, the sample containing 0.3% CMC, 0.3% xanthan gum, and 0.4% pectin showed the most favorable physicochemical and sensory properties, highlighting the synergistic effect of hydrocolloid blends in stabilizing reduced-fat mayonnaise-type emulsions. Full article

This study aimed to determine the effects of incorporating probiotic fermented natural lactic acid bacteria (PFJ) into the drinking water of laying quails subjected to temperature stress on egg production, egg quality, cecum microbiology, blood parameters, and incubation performance. A total of 260 Japanese quails (Coturnixcoturnix japonica) aged 8 weeks were used, of which 200 were females, and 60 were males. The quails were divided into four groups, each containing 50 individuals, and further split into five subgroups of 10 quails. For every 10 female quails, three male quails were housed together in cages. The experiment was conducted under normal environmental conditions in control, PFJ, heat-stressed control, and heat-stressed PFJ groups. Temperature stress (34–36 °C) was applied for 8 h daily. The results indicated that by the end of weeks 1–4, the feed conversion ratios of all groups were significantly different, with the best feed conversion ratio of 2.36 found in the PFJ group under temperature stress. Throughout the periods of weeks 1–4 and 5–8, there were statistically significant differences (p < 0.01) in the daily average feed consumption and egg weights among all treated groups. Temperature stress and the addition of PFJ significantly affected shell thickness, Haugh units, albumen weight, yolk weight, and yolk color; no significant impacts were observed on egg shape index, yolk percentage (%), albumen percentage (%), and specific gravity (g/cm³). The highest counts of lactic acid bacteria (LAB) were found in the PFJ-treated groups under both normal and temperature-stressed conditions. Under temperature stress, the levels of Enterobacter, coliform, and E. coli decreased with the addition of PFJ. Regarding blood parameters, significant differences (p < 0.05) were observed in total protein values among groups, while differences in chloride, triglycerides, total cholesterol, LDL cholesterol, HDL cholesterol, and triglyceride concentrations were not statistically significant (p > 0.05). Furthermore, the addition of temperature stress and PFJ significantly affected fertility rates, incubation efficiency, and hatchability. In conclusion, these findings suggest that PFJ could be considered a potential probiotic alternative for improving nutrition in laying quails under conditions of temperature stress. Full article

Microbial proteases are fundamental towards the eco-sustainability of proteolysis at the industrial scale. A proteolytic broth was obtained from a bioreactor fermentation of a proteolytic Bacillus strain isolated from an industrial alkaline bath. Broth proteolytic activity was applied to leather tanning and to the removal of protein stains. The hide tanned with the microbial proteolytic fermentation broth showed better physical properties than the one tanned with commercial pancreatic proteases of the same activity (780 LVU). Proteinaceous stains on cotton fabric were removed more efficiently using the Bacillus proteolytic broth than water or a commercial detergent. Blood and egg yolk disappeared in less than 30 min. The removal of soya and English sauce stains was even faster. Broth proteolytic activity was characterised by caseinolytic (5200 LVU), collagenolytic (10.0 U mg⁻¹), elastolytic (3.7 U mg⁻¹), and keratinolytic (0.7 U mg⁻¹) activities, which were compared with those of a commonly used commercial protease. Alkaline protease activity in the broth was demonstrated by a 20% increase in caseinolytic activity from pH 5 to 8. Besides the demonstrated applications in the leather and detergent industries, the produced alkaline microbial proteases can also be used in the treatment of proteinaceous wastes and effluents, offering potential environmental benefits reinforcing and impacting the bioeconomy. Full article

Background: Presence of milk, fruits, eggs, fish, nuts and wheat antigens in the amniotic fluid is described in the literature. Studies show a contradictory relationship between maternal exposure to allergens and early sensitization of the fetus to allergens. Hemochorionic type of the human placenta allows for easier transfer of nutrients and antibodies from the mother’s blood to the fetal circulation through the direct contact of maternal blood with the fetal chorion. During the third trimester of pregnancy, immunoglobulin G (IgG) is actively transferred through the placenta into the fetal via neonatal FcRN receptor (FcRN). In addition, monomeric immunoglobulin E (IgE) cannot cross the placenta Aim: The objective of our study is to track intrauterine sensitization to essential food proteins at birth in umbilical cord blood in mothers with established peripheral blood eosinophilia and in their infants using allergen-specific IgE and IgG. Methods: An observational study was carried out in a cohort of 22 mothers with eosinophilia and their babies. Differences in expression between groups were assessed. Blood samples were collected to determine serum IgE and IgG specific to a set of inhalant and food allergens. Results: We did not find a significant correlation between specific IgE to cow’s milk (p = 0.857), egg white (p = 0.926) and egg yolk (p = 0.096) in umbilical cord blood and maternal blood samples taken immediately before birth. Spearman’s correlation of the specific IgE and IgG in umbilical cord blood showed no dependence between the two variables. In contrast, statistical analysis showed that maternal eosinophilia in peripheral blood could be a risk factor for the development of allergy in the offspring (χ², p = 0.0347). However, given the small number of patients, this claim needs to be confirmed with further studies. Conclusions: Due to the functional immaturity of the developing immune system of the fetus, the generation and maintenance of an independent immune response to allergens are incomplete. Maternal IgG (specific) passes to the baby and high maternal IG to a specific allergen reduces babies IgE production. In addition, low maternal specific IgG may promote IgE production in the baby under the influence of microenvironmental factors (cytokine background). The main limitation of our study is the small number of patients. Further research is needed in this direction to clarify the mechanisms and risk factors for early sensitization in newborns. Full article

The conventional method for detecting protein content in egg albumen is the Kjeldahl method, but this method cannot be applied in practical production due to cost limitations. Therefore, we developed albumen density (AD), which had certain potential application value in low-cost and efficient evaluation of albumen protein content. We calculated the heritability of AD in White Leghorn (WL) chickens and its correlation with average albumen protein quantity (AAP), total albumen protein quantity (TAP), albumen weight (AW), albumen volume (AV), egg weight (EW), albumen height (AH), haugh unit (HU), and yolk color (YC). It is worth noting that albumen protein content was measured in a small subset of samples. The average value of AD in eggs was 0.97 and its heritability was less than 0.1. The average value of AAP in eggs was 10.1%, and the average value of TAP in eggs was 2.95 g. There were significant positive correlations between AAP, TAP, AW, AV, AD, and EW, and there were strong positive genetic and phenotypic correlations between EW, AW, AV, and AD. The results of this study indicated that AD might have potential value as a supplementary tool for albumen protein trait selection in breeding. Full article

Due to global increases in poultry meat and egg production, consumers request sustainable agricultural practices, requiring alternative solutions for future feeding. Global egg production increased by over 41% between 2000 and 2020, from 51 to 87 million tonnes, at an average increasing rate of 3%. Similarly, the production of poultry meat reached 145 million tonnes in 2023 and continues to increase, which amplifies the pressure on sustainable alternative feed solutions. Commercial poultry diets are typically based on a cereal (corn or wheat) as an energy source and a quality protein source, especially soybean meal (SBM), to provide essential amino acids. Soybean production is associated with deforesting and land use in several countries, sensitiveness to supply chains and price volatility. As a response to these challenges over the last decade, research and commercial innovation have intensively focused on alternative and novel feed resources that can be integrated into both broiler and layer diets. Some future candidate ingredients are insect meal, algae, agro-industrial by-products such as distiller’s dried grains with solubles (DDGS), brewery spent grains (BSG) and fermented feedstuffs (oilseed cakes/meals). Literature data showed that moderate inclusion of these alternative ingredients can be partly integrated in poultry diets, without compromising egg or meat quality. In some cases, studies showed improvements of productive performances and specific quality traits (yolk color, fatty acids and antioxidant compounds), offering potential to valorize waste streams, improve local circularity and provide functional ingredients for animals and humans. However, challenges still remain, especially in terms of nutrient variability, digestibility limitations, higher processing costs and still-evolving regulations which constrain mainstream adoption of some of these potential future alternatives. Full article

The egg industry continues to search for alternative feed ingredients that support production efficiency, enhance egg quality, and add nutritional value. Microalgae are rich in protein, pigments, and long-chain polyunsaturated fatty acids, making them promising candidates for poultry diets. This study evaluated the effects of dietary inclusion (1 and 2%) of four microalgae species, Arthrospira platensis (Spirulina), Hydrodictyon sp., Uronema sp., and Vaucheria sp., on laying hen performance, egg quality, yolk fatty acid composition, and bone strength. Seventy-six Lohmann LSL-Lite hens (92 weeks of age) were randomly assigned to nine treatments (control diet or one of eight microalgae diets). Feed intake, egg production, egg mass, feed conversion ratio, eggshell traits, yolk color, yolk fatty acids, and tibial breaking strength were measured. Inclusion of microalgae did not negatively affect hen performance, egg quality, nor bone strength. Spirulina significantly improved egg production and egg mass (p < 0.05). Increasing levels of Spirulina, Hydrodictyon sp., and Uronema sp. enhanced yolk color (all p < 0.05), while Vaucheria sp. showed no effect (p > 0.05). Yolk fatty acid profiles were only modestly altered, with increased docosahexaenoic acid observed in hens fed Hydrodictyon and Uronema (p < 0.05). In conclusion, low-level dietary inclusion of these microalgae species appears safe for laying hens and may provide added value through improved yolk pigmentation and modest omega-3 enrichment. Full article

Egg quality is a critical economic trait in poultry production, influencing consumer preference and production efficiency. The genetic and epigenetic regulation of egg quality involves complex biological pathways across various traits such as shell quality, albumen composition, and yolk biochemistry. This review synthesizes recent advances in the genetic, molecular, and epigenetic mechanisms that determine poultry egg quality. Specifically, it focuses on external traits such as eggshell strength, color, and thickness, and internal traits including albumen height, yolk composition, and the Haugh unit. Through genome-wide association studies (GWAS), quantitative trait loci (QTL) mapping, whole-genome sequencing (WGS), and multi-omics approaches, key candidate genes such as OC-116, CALB1, CA2 (shell formation), OVAL, SPINK5, SERPINB14 (albumen quality), and FGF9, PIAS1, NOX5 (lipid metabolism) have been identified. These genes play a pivotal role in shell biomineralization, albumen protein regulation, and yolk lipid transport. This review also explores the heritability of these traits, emphasizing the challenges posed by polygenic architecture and the influence of environmental factors. Furthermore, it addresses the dynamic spatiotemporal regulation of egg quality traits, including epigenetic layers such as DNA methylation, histone modifications, RNA methylation, and post-translational protein modifications. This paper highlights the application of these findings to breeding programs via genomic selection, marker-assisted breeding, and epigenetic engineering approaches. Future directions for precision breeding and the development of functional eggs with enhanced quality are also discussed. Full article

Egg products are a convenient and safe form of eggs, possessing valuable nutritional and functional properties. The egg processing industry is responsible for the enormous amounts of biomass in the form of animal by-products (ABPs). According to EU legislation, the ABPs are under strict control from the formation to the disposal of biomass, as they carry a risk to the ecosystem and public health. For this reason, restrictions have been introduced on their use after disposal, ranging from bioactive applications in medical, cosmetic, and pharmaceutical products, as well as feed. The shells are subject to special conditions for processing and use. The by-products of egg breaking are divided into solid (eggshells and eggshell membranes) and liquid (technical albumen) by-products. The biological value is determined by the composition, which varies significantly across the by-products. In the context of the circular economy, all egg by-products contain valuable substances that can be used in food and non-food industries. First, eggshells are the leading by-product, composing 95% of the inorganic substance calcium carbonate, which, after processing, can be used in agriculture, food and feed industries, and medicine. Second, there is a liquid by-product containing proteins from the egg white and a small part of fats from the yolk. Literature data on this by-product are scarce, but there is information about its use as a feed additive, while the extracted and purified proteins can be useful in pharmacy. Egg membranes constitute only 1% of the egg mass, but humanity has long known about the benefits of collagen, keratin, and glycosaminoglycans, including hyaluronic acid, which compose this material. The processed membranes can be used as a food additive, in cosmetics, medicine, or pharmacy, just like other egg by-products mentioned above. This literature review focuses on the possible methods and techniques for processing by-products and their potential application. The literature sources in this review have been selected according to their scientific and practical applicability. The utilization of these by-products not only reduces the impact on the environment but also facilitates the creation of value-added materials. Full article

Egg quality loss during storage is a major concern in the poultry industry, particularly for eggs from older hens, which are more susceptible to shell thinning, albumen liquefaction, and yolk weakening. This study evaluated the effect of whey protein, Aloe vera, and carnauba-wax coatings on the internal quality of eggs from 86-week-old laying hens stored at room temperature for 21 days. The experimental design consisted of four treatments (uncoated control and three coatings) and four storage times (0, 7, 14, and 21 days). Internal quality was assessed by Haugh unit (HU), yolk index (YI), albumen pH, and yolk color parameters (L*, a*, b*). The results showed that storage time significantly affected all internal quality traits (p < 0.05). Whey protein coating consistently maintained higher HU and YI values and lower albumen pH compared with the control, indicating better preservation of albumen viscosity and CO₂ retention. Aloe vera and carnauba-wax coatings had only transient effects, with values similar to the control after 14 days. Yolk color stability also declined over time, with minor protection observed only for the whey protein treatment. In conclusion, whey protein coating provided the best overall preservation of egg internal quality during storage, demonstrating superior gas barrier properties and structural stability. These findings suggest that protein-based coatings may be an effective strategy to extend the shelf life of eggs from aged laying hens. Full article

Spotty liver disease (SLD), primarily caused by Campylobacter hepaticus and (less frequently) by Campylobacter bilis, significantly impacts commercial layer hens by causing liver lesions, reducing egg production, and increasing mortality, meaning it can result in serious economic losses for farmers. This study explored the relationship between infection, liver dysfunction, and reproduction, aiming to identify host genetic markers for tracking SLD progression. Hens were orally inoculated with the C. hepaticus strain NSW44L and monitored over a seven-day period. Pathogen colonisation was quantified using qPCR across the liver, bile, caeca, spleen, and ovarian follicles, while liver lesions were scored and hepatic transcriptomes analysed using RNA-seq. C. hepaticus was detected in the liver, caeca, and spleen from one day post-inoculation (dpi) (1.44–1.68 log₁₀ CFU/mL), appeared in bile by the third dpi (3.64 log₁₀ CFU/mL), and reached the follicles by the fourth dpi (3.25 log₁₀ CFU/mL). The highest bacterial loads were found in bile on days six and seven (up to 7.18 CFU/mL). Liver lesions were first observed on the fourth dpi, reaching their peak at the sixth and seventh dpi. Gene expression analysis in liver tissue revealed a notable downregulation of yolk-precursor and metabolic genes, such as prolactin receptor (PRLR), 7-dehydrocholesterol reductase (DHCR7), and malic enzyme 1 (ME1). In contrast, from days three to seven post-infection, there was significant upregulation of avidin (AVD), a biotin-binding protein, and versican (VCAN), which is linked to tissue remodelling and inflammation. These findings correlate with the disease’s progression from initial liver infection to widespread bacterial presence, suggesting value as host biomarkers for effective SLD monitoring and the development of targeted therapies. Full article

The present study aimed to valorise the harbour crab (Liocarcinus depurator), a common bycatch species, by evaluating its protein as an egg yolk substitute in a mayonnaise-type sauce. The harbour crab was firstly characterised for its physicochemical and elemental composition (including amino acid profile, macrominerals, trace, and heavy metals). Protein was extracted by precipitation at the isoelectric point (with or without a previous delipidation step), and the foaming and emulsifying properties of the resulting protein extracts were evaluated. The method that did not involve prior delipidation resulted in a higher protein extraction yield. Furthermore, this method resulted in a protein extract with superior emulsifying activity. This protein extract was used as an egg-yolk replacer in the preparation of a mayonnaise-type sauce. Sensory evaluation revealed that the sauce formulated with crab protein was comparable to the egg-based control in terms of overall flavour and acceptability, but only with the addition of curry to mask the seafood taste. The results of this study demonstrate that crab meat protein, when extracted without previous lipid removal and combined with curry, can be used as a viable egg yolk substitute in mayonnaise-type sauces. Full article

Chicken egg is included among the main components of the human diet as an important source of nutrients, such as proteins, lipids, vitamins, minerals and carotenoids. The latter are terpenoid pigments present in egg yolks, providing their color and playing a vital role because of their significant bioactivities. The carotenoid content of egg yolk varies considerably since it is strongly influenced by the respective laying hens’ farming and feeding procedures, and there is therefore a need to establish an efficient method for their assessment. The absence of such a method prompted us to develop a novel procedure consisting of the extraction, saponification and quantitative assessment of contained carotenoids. For this purpose, the optimal conditions for the extraction of carotenoids from egg yolks were defined, along with the optimal saponification conditions of carotenoids, with respect to reaction duration and pH influence on the extract’s contents of lutein and zeaxanthin. The carotenoid content of extracts was determined using a novel, developed herein LC-MS/MS method that allows the accurate, fast and simultaneous quantitation of the 11 most abundant carotenoids in egg yolks. The method accuracy and reliability were validated for six different parameters determined for each analyte. The novel procedure was applied for the assessment of the carotenoid content of ten egg yolks of diverse origin, indicating the bioactive carotenoids lutein and retinol as the most abundant, while lesser amounts of the remaining natural and synthetic carotenoids were found and there was no trace of fucoxanthin or astaxanthin molecules. The results herein revealed a variation in the carotenoid content of chicken eggs that depended on the diet and farming method of egg-laying hens. Full article