ARTICLE | doi:10.20944/preprints202103.0161.v1
Subject: Life Sciences, Biochemistry Keywords: chicken eggs; quail eggs; fatty acids; iron; zinc; cholesterol
Online: 4 March 2021 (14:02:38 CET)
All over the world birds’ eggs are an important and valuable component of the human diet. The 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 acids were dominated, especially oleic acid, the content of which was about 40% of total fatty acids (TFA). Linoleic acid was the major polyunsaturated fatty acid. Compared to other products of animal origin, eggs were characterized by favourable values of lipid quality indices, especially index of atherogenicity, thrombogenicity and hypocholesterolemic to hypercholesterolemic ratio. In the present study, no differences in the content of tested nutrients between eggs from different production methods (organic, free-range, barn, cages), as well as inter-breed differences were noticed. Cluster analysis showed that eggs enriched in n3 PUFA (according to producers’ declaration) differ from other groups of chicken eggs. However, only in eggs from one producer, the amount of EPA and DHA exceed 80 mg per 100 g, entitling to use the nutrition claim on the package. Quail eggs differed from chicken eggs in FA profile; they also had much higher iron and cholesterol levels.
ARTICLE | doi:10.20944/preprints202210.0145.v1
Subject: Life Sciences, Cell & Developmental Biology Keywords: oxidative stress; Xenopus laevis; eggs; overactivation; cell death
Online: 11 October 2022 (07:08:01 CEST)
Excessive activation of frog eggs (overactivation) is a pathological process that renders eggs unfertilizable. Its physiological inducers are unknown. Previously, oxidative stress was shown to cause time- and dose-dependent overactivation of Xenopus laevis frog eggs . Here, we demonstrate that the oxidative stress-induced egg overactivation is a calcium-dependent phe-nomenon which can be attenuated in the presence of the selective calcium chelator BAPTA. Degradation of cyclin B2, which is known to be initiated by calcium transient in fertilized or parthenogenetically activated eggs, can also be observed in the overactivated eggs. Decline in mitochondrial membrane potential, ATP depletion and termination of protein synthesis manifest in the eggs within one hour of triggering overactivation. These intracellular events occur in the absence of caspase activation. Furthermore, plasma membrane integrity is compromised in the overactivated eggs, as evidenced by ATP leakage and egg swelling. In sum, our data demonstrate that oxidative stress-induced overactivation of frog eggs causes fast and dramatic disruption of cellular homeostasis, resulting in robust and expedited cell death by a calcium-dependent non-apoptotic mechanism.
Subject: Life Sciences, Other Keywords: Asian tiger mosquito; eggs diapause; insecticides efficacy; mosquito control
Online: 10 August 2021 (08:13:40 CEST)
Aedes albopictus is an invasive mosquito species responsible for local transmission of chikungunya and dengue viruses in Europe. In the absence of available treatments, insecticides-based control is one of the most important viable strategies to prevent emerging problems. Diflubenzuron (DFB) and Bacillus thuringiensis var. israelensis (Bti) are among the most commonly used larvicides for Ae. albopictus control which pose major concerns for potential resistance development. Studies on the resistance emergence of Ae. albopictus to both DFB and Bti and its persistence in the wild are essential for the efficient and sustainable planning of the control programs. In this concept, larvae from a recently laboratory established population were subjected to increasing selective pressure for nine successive generations against both DFB and Bti. At the end of this process, the resistance levels and the overwintering success of the selected populations relative to control (colonies that received no selection) were determined. Results revealed a substantial and a moderate increase on the resistance levels following selection with DFB and Bti respectively. Interestingly, the selection process to both larvicides had no apparent impacts on the overwintering capability relative to control suggesting the successful persistence of the resistant individuals in the wild from year to year.
ARTICLE | doi:10.20944/preprints202007.0738.v1
Subject: Social Sciences, Other Keywords: animal representation; animal-based foods; marketing; eggs; hen welfare
Online: 31 July 2020 (08:19:40 CEST)
How a species is represented by marketers of animal-based products both reflects and shapes how consumers think about that animal. By examining the explicit statements, and implicit messages encoded in the imagery on supermarket egg boxes, this paper explores how hens are represented by whole egg retailers. Content analysis reveals two prominent messages purveyed through eggbox graphics, namely those pertaining to hen welfare and human health. The later disenfranchises hens from their products by focusing on the nutritional value of eggs, whereas the former reflects a public concern for the welfare of egg-laying hens. Although claims of improvements in welfare practices are undoubtedly exploited as marketing tools, they serve to raise awareness and drive competitors to adopt similar practices. Welfare claims are a direct response to public concerns about the plight of hens, and may positively influence industry welfare standards. However, idyllic depictions displayed on eggboxes also lull consumers into the belief that those eggs are an ethically sound food choice, regardless of the actual standard of living experienced by the hens.
ARTICLE | doi:10.20944/preprints201801.0055.v1
Subject: Life Sciences, Biotechnology Keywords: orange peel essential oil; green extraction; liquid whole eggs; biopreservation; shelf-life
Online: 8 January 2018 (09:22:37 CET)
A possible way to valorize citrus peels, which are byproducts of the juice extraction industry, is to use them as natural biopreservatives. In this paper we present early results from a compared Solvent Free Microwave Extraction (SFME) with Hydro-Distillation (HD) and Cold Pressing (CP) of essential oils (EOs) using fresh orange peel (Citrus sinensis L. var. Valencia late), a by-product in the production of orange juice in Algeria. The EOs were analyzed by gas chromatography coupled to mass spectrometry (GC-MS). All extracted C. sinensis EOs were chemotype limonene (94.64 to 95.48%). SFME is performed without added any solvent or water. SFME increases EO yield and eliminate wastewater treatment, resulting in a great progress in terms of time and cost efficiency. In its second part, the present study was conducted to evaluate “in vitro”, the antioxidant activities of Solvent Free Microwave (SFM) extracted orange EO by using the DPPH• (2,2-di-phenyl-1-picrilhydrazyl) free radical scavenging assay. The ability of orange EO to scavenge the free radical DPPH• was high, exceeding 80%. The result of the DPPH assay gives an IC50 range value of 89.25 μg/mL (0.09 mg/mL) for the studied sample. Accordingly to the scientific literature, C. sinensis EO tested in the present study presented strong antioxidant activity, when looking to its values of AAI = 1.12 μg/mL. The feasibility of biopreservation used EOs as an alternative to synthetic techniques for liquid whole egg (LWE) stored under commercial retail conditions was investigated. The orange EO extracted by SFM was screened for its antibacterial and antioxidant activities in LWE at concentrations of 0.1, 0.3 and 0.5%. The TBA-RS results showed that the EO treatments significantly (p < 0.05) reduced the lipid oxidation in LWE. The long term oxidative, microbial and organoleptical stability of the LWE during display was positively influenced by orange EO treatments. Therefore, the results obtained here confirm that EO treatment as a promising technology to extend the commercial shelf-life of liquid egg products during retail/display.