Unravelling proteome changes of chicken egg whites under carbon dioxide modified atmosphere packaging

Quality characteristics, lysozyme activity, and albumen viscosity of fresh hatching duck eggs after a week's storage at various temperatures

The study aimed to analyze the qualitative features of Cherry Valley duck' hatching eggs during storage at different temperatures. Eggs were divided into 3 equal groups with 30 eggs each: fresh egg and stored at 7 °C and 17 °C within one week. Qualitative analyses of duck eggs were carried out, considering the morphological composition, physicochemical characteristics, lysozyme activity, and albumen viscosity. The highest weight of yolk and its percentage was found in the 17 °C group. The weight and percentage of albumen were significantly the highest in the group of fresh eggs. Higher egg weight loss was observed in the group stored at higher temperatures. Higher thick albumen height and Haugh units were found in fresh eggs and eggs stored at 7 °C. Different temperatures of egg storage did not affect lysozyme activity in thick and thin albumen. Stored eggs were characterized by lower albumen viscosity only at a shear rate of 10 rpm. The higher viscosity of thick albumen compared to thin ones was demonstrated at 10 and 20 rpm shear rates. The presented research results indicate a large diversity of selected qualitative indicators of hatching duck eggs, which may affect their storage and suitability for incubation.

Effects of γ-aminobutyric acid on freshness and processing properties of eggs during storage

Effects of γ-aminobutyric acid (GABA) on egg storage properties were investigated by comparing freshness and processing properties between eggs treated with different GABA concentrations and untreated controls. GABA treatment delayed storage-associated increases of albumen pH value and surface hydrophobicity and decreases of protein index, yolk index, Haugh unit (HU) value, albumen height, solubility, gel hardness, and apparent viscosity. Highest HU, yolk index, and emulsion stability values and peak storage performance were observed after injection of eggs with 0.05 mL of GABA (0.3 g/mL). Even after 25 days of storage, GABA-treated eggs exhibited freshness resembling that of fresh eggs, indicating that GABA treatment extended shelf life by 10 days relative to controls. Peak solubility, emulsifying activity, emulsifying stability, foaming capacity, and foaming stability values of 89.74%, 0.72, 14.18, 43.35, and 45.57, respectively, for GABA-treated eggs exceeded corresponding control group values, thus demonstrating that GABA treatment of eggs slowed storage-related deterioration of freshness and processing quality.

Packaging with hydrogen gas modified atmosphere can extend chicken egg storage

BACKGROUND

Although hydrogen gas (H₂ ) has been widely used in industry and gradually used in medicine, it is less applied to agriculture, especially in modified atmosphere packing (MAP).

RESULTS

During chicken egg storage, H₂ MAP not only slowed down or delayed the reduction in antioxidant capacities, but also alleviated the deterioration of egg quality. The extent of micro-cracks in the eggshell was also negatively influenced by H₂ , which might result in eggs being less vulnerable to microbes. The earlier results demonstrated that the H₂ MAP-extended shelf life of chicken eggs might be caused by the responses of eggshell and re-establishment of redox homeostasis. According to the data collected from different provinces of China, cost-economics analysis further suggested that the increase in the extra cost caused by H₂ was trivial compared with the original price of eggs.

CONCLUSION

Together, H₂ MAP can prolong the shelf life of chicken eggs with the prospect of wider application. © 2021 Society of Chemical Industry.

The Lipocalin Apolipoprotein D Functional Portrait: A Systematic Review

Apolipoprotein D is a chordate gene early originated in the Lipocalin protein family. Among other features, regulation of its expression in a wide variety of disease conditions in humans, as apparently unrelated as neurodegeneration or breast cancer, have called for attention on this gene. Also, its presence in different tissues, from blood to brain, and different subcellular locations, from HDL lipoparticles to the interior of lysosomes or the surface of extracellular vesicles, poses an interesting challenge in deciphering its physiological function: Is ApoD a moonlighting protein, serving different roles in different cellular compartments, tissues, or organisms? Or does it have a unique biochemical mechanism of action that accounts for such apparently diverse roles in different physiological situations? To answer these questions, we have performed a systematic review of all primary publications where ApoD properties have been investigated in chordates. We conclude that ApoD ligand binding in the Lipocalin pocket, combined with an antioxidant activity performed at the rim of the pocket are properties sufficient to explain ApoD association with different lipid-based structures, where its physiological function is better described as lipid-management than by long-range lipid-transport. Controlling the redox state of these lipid structures in particular subcellular locations or extracellular structures, ApoD is able to modulate an enormous array of apparently diverse processes in the organism, both in health and disease. The new picture emerging from these data should help to put the physiological role of ApoD in new contexts and to inspire well-focused future research.

Characterization of structure and protein of vitelline membranes of precocial (ring-necked pheasant, gray partridge) and superaltricial (cockatiel parrot, domestic pigeon) birds

Of all the known oviparous taxa, female birds lay the most diverse types of eggs that differ in terms of shape, shell pigmentation, and shell structure. The pigmentation of the shell, the weight of the egg, and the composition of the yolk correlate with environmental conditions and the needs of the developing embryos. In this study, we analyzed the structure and protein composition of the vitelline membrane (VM) of ring-necked pheasant, gray partridge, cockatiel parrot, and domestic pigeon eggs. We found that the VM structure is characteristic of each species and varies depending on whether the species is precocial (ring-necked pheasant and gray partridge) or superaltrical (cockatiel parrot and domestic pigeon). We hypothesize that a multilayer structure of VM is necessary to counteract the aging process of the egg. The multilayer structure of VM is only found in species with a large number of eggs in one clutch and is characterized by a long incubation period. An interesting discovery of this study is the three-layered VM of pheasant and partridge eggs. This shows that the formation of individual layers of VM in specific sections of the hen's reproductive system is not confirmed in other species. The number of protein fractions varied between 19 and 23, with a molecular weight ranging from 15 to 250 kDa, depending on the species. The number of proteins identified in the VM of the study birds' eggs is as follows: chicken-14, ring-necked pheasant-7, gray partridge-10, cockatiel parrot-6, and domestic pigeon-23. The highest number of species-specific proteins (21) was detected in the VM of domestic pigeon. This study is the first to present the structure and protein composition in the VM of ring-necked pheasant, gray partridge, cockatiel parrot, and domestic pigeon eggs. In addition, we analyzed the relationship between the hatching specification of birds and the structure of the VM.