Effect of egg consumption on inflammatory markers: a systematic review and meta-analysis of randomized controlled clinical trials

There is little evidence about whether eggs affect inflammation. The aim of this meta-analysis was to explore the effects of egg consumption on inflammation. A systematic search of online databases (Institute for Scientific Information (ISI), Scopus, Ovid, PubMed, Cochrane) was used to gather clinical trials that assessed the effect of egg consumption on circulating inflammatory biomarkers. Using a random-effects model, pooled weighted mean differences (WMD) and corresponding standard deviations (SD) were calculated. Of the 21 eligible studies found, nine trials were eligible for analysis. Eight trials assessed high-sensitivity C-reactive protein (hs-CRP), four trials assessed interleukin-6 (IL-6), and five trials assessed tumor necrosis factor-alpha (TNF-α). Egg consumption did not affect hs-CRP (WMD 0.24 mg/L; 95% CI: -0.43, 0.90; I² = 53.8; P = 0.48), IL-6 (WMD 0.20 pg/mL; 95% CI: -0.71, 1.11; I² = 69.3; P = 0.50), and TNF-α (WMD: -0.38 pg/mL; 95% CI: -0.87, 0.10; I² = 0.00; P = 0.12) relative to controls. Overall, this meta-analysis revealed that egg consumption had no significant effect on serum biomarkers of inflammation in adults. © 2019 Society of Chemical Industry     

Characterisation of emulsion properties and of interface composition in O/W emulsions prepared with hen egg yolk, plasma and granules

Comprehension of hen egg yolk emulsifying properties remains incomplete because competition between its various emulsifiers (proteins and lipoproteins containing phospholipids) has not been clearly elucidated and colloidal interactions between yolk-stabilised oil droplets have not been documented. Recent studies emphasised the interest of the fractionation of yolk into plasma and granules to improve this comprehension. In the present study, we characterised, concurrently, emulsion properties (oil droplet size and stability against creaming) and interface attributes (interfacial concentrations of proteins and phospholipids, SDS-PAGE profiles of adsorbed proteins and zeta potential) in oil-in-water (O/W) emulsions prepared with yolk, plasma and granules. We observed these features at four physicochemical conditions (pH 3.0 or 7.0 and at 0.15 or 0.55 M NaCl). Emulsion properties in emulsions made with yolk or plasma varied similarly as a function of pH and NaCl concentration whereas granules emulsions exhibited distinct properties. Therefore the main contributors to yolk emulsifying properties are to be sought for among plasma constituents (proteinaceous or phospholipids). Since, in plasma emulsions, variations of emulsion stability against creaming correlated exclusively to variations of protein interfacial concentration, a driving contribution of the proteinaceous part of plasma, namely apo-LDL, was hypothesised. In the pH and ionic strength ranges studied, zeta potentials of the interfaces were low, excluding extended electrostatic repulsion between oil droplets. We deduced that steric repulsion is the main interaction opposing to droplet aggregation in food emulsions made with yolk.     

Influence of storing time and temperature on the viscosity of an egg yolk

The influence of storing time and temperature on rheological behavior of egg yolk was investigated. The eggs of two brown egg-laying breeds (Bar Plymouth Rock and Rhode Island Red) were stored for 1, 2, 3, 4, and 8 weeks at constant temperatures: 4 °C, 8 °C, 12 °C, and 16 °C. The apparent viscosity was measured by a rotational viscometer as a function of shear rate. It was found that yolk samples exhibited shear-thinning (pseudoplastic) behavior. The shear-thinning behavior was fitted well into Herschel–Bulkley model (with a satisfying correlation of R² > 0.95). For the selected shearing rate, viscosity was measured in relation to shearing time. The time-dependant viscosity decreased rapidly with time and, at lower share rates, reached an equilibrium state. The time-dependant viscosity was also found to decrease with storage time. The value of pH changed (increased) during storing. No clear dependence between pH value and viscosity was confirmed.     

Physicochemical Characterization of Whole Egg Powder Microencapsulated by Spray Drying

Physical characterization and oxidative stability of egg powder microencapsulated by spray drying were studied in this work. The wall material (gelatin, lactose, pullulan, and their mixtures) and liquid egg mixtures were prepared by homogenization at 22,000 rpm for 60 s. The spray drying was carried out at pilot-scale spray dryer (Niro Mobile Minor, Søborg, Denmark). The spray-dried egg powders were analyzed for moisture content, water activity, peroxide value, total cholesterol oxidation products (TCOPs), particle properties, and bulk properties. Using gelatin as wall material resulted in a significant increase in the moisture content and water activity of egg powder during storage and it improved flowability. Egg powders containing pullulan as wall material showed a fibrous structure and had the lowest bulk density. Adding lactose as wall material increased the oxidative stability, which was indicated with lowest peroxide value and TCOPs level of egg powder.     

Time Matters: Transition and Transformation in Architecture

Though the contemporary world in the West has only just started to value architecture that is temporary and highly flexible rather than permanent and timeless, the East has a long building tradition respecting the transitory and ephemeral. Mark Taylor , Professor of Architecture at the University of Newcastle, Australia, looks at ways in which recent architecture in China, Japan and New Zealand has been embracing the limits and passing of time.     

Perfluorinated contaminants in fur seal pups and penguin eggs from South Shetland, Antarctica

Perfluorinated compounds (PFCs) have emerged as a new class of global environmental pollutants. In this study, the presence of perfluorochemicals (PFCs) in penguin eggs and Antarctic fur seals was reported for the first time. Tissue samples from Antarctic fur seal pups and penguin eggs were collected during the 2003/04 breeding season. Ten PFC contaminants were determined in seal and penguin samples. The PFC concentrations in seal liver were in the decreasing order, PFOS > PFNA > PFHpA > PFUnDA while in Adélie penguin eggs were PFHpA > PFUnDA > PFDA > PFDoDA, and in Gentoo penguin eggs were PFUnDA > PFOS > PFDoDA > PFHpA. The PFC concentrations differed significantly between seals and penguins (p < 0.005) and a species-specific difference was found between the two species of penguins (p < 0.005). In our study we found a mean concentration of PFOS in seal muscle and liver samples of 1.3 ng/g and 9.4 ng/g wet wt, respectively, and a mean concentration in Gentoo and Adélie penguin eggs of 0.3 ng/g and 0.38 ng/g wet wt, respectively. PFCs detected in penguin eggs and seal pups suggested oviparous and viviparous transfer of PFOS to eggs and off-springs.     

Egg yolk conjugated linoleic acid alters phospholipid molecular species in chick tissues

The effects of egg conjugated linoleic acid (CLA) on chick yolk sac and liver phospholipid composition and molecular species were determined. Fertile eggs with no (control), low (CLA1) or high (CLA2) levels of CLA were incubated. Upon hatching, total lipid in the remnant yolk sac constituted 11.5, 18.9 and 15.3% in control, CLA1 and CLA2, respectively (p <0.05). Maternal CLA led to a decrease in phosphatidylcholine (PtdCho) and phosphatidylethanolamine (PtdEtn) and an increase in lysophosphatidylcholine (LPtdCho) in the yolk sac and liver tissues of CLA1 and CLA2 when compared to control (p <0.05). The effect of maternal dietary CLA was very prominent in yolk sac PtdCho (34:1) where 13 and 38% reductions were observed in CLA1 and CLA2, respectively, when compared to control. Among different liver PtdCho species, the highest difference was found in 36:2, where a 41% increase was observed in CLA2 when compared with control chicks. The liver LPtdCho of CLA1 and CLA2 chicks had a 92% increase in 16:0 and 18:0 when compared to control. Over 80% increase was observed for 18:2 and 20:4 in the liver LPtdCho of CLA2 chicks compared to control. These results suggest that the yolk CLA content alters the proportions of phospholipids in the progeny during avian embryogenesis.     

Electrospinning of food-grade nanofibers from cellulose acetate and egg albumen blends

Edible nanofibrous thin films were fabricated for the first time from blend solutions of cellulose acetate (CA) in 85% acetic acid and egg albumen (EA) in 50% formic acid by electrospinning. The mass percentage ratios of CA–EA in the mixed solvents varied from 100:0 to 91:9, 77:23, 66:34 and 0:100. Effects of the blend ratios on the solution properties and morphology of the resulting electrospun products were studied. The results showed that EA lacked sufficient entanglement and also possessed very high surface tension, thereby being unable to form nanofibers. The addition of CA and surfactant (Tween40®) decreased both the electrical conductivity and the surface tension of the blends (p < 0.05), which facilitated the formation of CA–EA blend nanofibers. Scanning electron microscopic images showed that the continuity of the blend fibers was improved with an increase in the EA ratio. Fourier-transformed infrared spectroscopy and thermo-gravimetric analysis results indicated that the obtained fibers were composed of both CA and EA constituents. This study demonstrated a potential to fabricate edible nanofibers from natural food biopolymers using the electrospinning technique. Due to the properties of EA, these nanofibers could provide new functionalities with respect to in vivo-controlled release of nutraceuticals and drugs.     

Rheological properties of angel food cake made with pH unfolded and refolded egg albumen

Angel food cake was made using egg albumen subjected to the pH-induced unfolded and refolded treatment. The effect of treatment on the rheological properties of angel food cake was investigated. Egg albumen solutions were prepared and pH was adjusted to 1.5, 4.5, 8.5 or 12.5 and then held 60 min to unfold the proteins. After holding, the solutions were readjusted to pH 4.5 or 8.5, and held for 45 min to partially refold the proteins. Egg white foam with sucrose was whipped and flour and the rest of sucrose were folded into the foam. The foam batter was heated in a TA Instrument AR 2000 controlled stress rheometer equipped in a parallel geometry. Samples were heated from 21 °C to 150 °C at a rate of 8.5 °C per min and then cooled down to 21 °C to bake the angel food cake. At 21 °C, oscillatory stress sweep was performed. There was no relationship between the G′ value of angel cake batter and its G′ value at 150 °C. Changes in rheological properties of batters and angel food cakes using different combinations of ingredients were studied. The pH unfolding and refolding procedure led to more rigid final products compared to the controls with egg albumen samples not subjected to pH treatment. Adding sucrose to the flour increased the starch gelation temperature up to 82 °C. Higher protein concentrations resulted in better foams in the cake batter, but the batter made with an intermediate protein concentration produced the most rigid angel food cake. Adding egg albumin did not change gelation temperature of the starch. It appears that incorporation of flour with the egg white foam, leads to about a ten times decrease in the strength of the foam, and a decrease in the gelatinization process of starch after adding sugar, are crucial in forming of an angel food cake texture.