Advances in techniques for reducing cholesterol in egg yolk: A review

Difference in the complexation of cholesterol with β-cyclodextrin derivatives: A combined theoretical and experimental study

This study aimed to compare differences in interactions between cholesterol and β- cyclodextrin and its derivatives for selecting a suitable β-cyclodextrin derivative to efficiently remove cholesterol from high-melting-point foods. First, the formation of cholesterol/β-cyclodextrin derivative complexes was investigated using Fourier transform infrared spectroscopy and thermogravimetric analysis. Secondly, the conformations of β-cyclodextrin derivatives were determined from experimental and calculated 1H NMR spectra, and the weak interactions between cholesterol and β-cyclodextrin derivatives were studied by computational approach. Cholesterol/hydroxypropyl-β-cyclodextrin complex had the lowest complexation energy. Besides, two moderate hydrogen bonds were formed between cholesterol and hydroxypropyl-β-cyclodextrin and between cholesterol and sulfobutyl ether-β-cyclodextrin, while one weak hydrogen bond was formed between cholesterol and methyl-β-cyclodextrin. Finally, the efficiency of cholesterol removal by hydroxypropyl-β-cyclodextrin was 5.47% higher than that by β-cyclodextrin at their optimal temperature. This work provided a theoretical basis for selecting a competent adsorbent to effectively remove cholesterol from high-melting-point foods.

Carotenoid enrichment in eggs: From biochemistry perspective

The emergence of safe and functional eggs for consumer acceptance has gained focus. The production of carotenoid-enriched eggs has received attention due to its multifunctional biological properties. Nutritional modification of laying hens' diet can be a strategy to produce such eggs. This review presents the chemistry of carotenoids in nature and eggs, the accumulation process of carotenoids into eggs, and the functions of carotenoids in eggs. Our findings showed that carotenoids can be deposited into the egg and contribute to improving its nutritive value. The biosynthesis, chemical structure, and metabolism pathways of carotenoids lead to the deposition of carotenoids into eggs in their original or metabolized forms. Also, some factors modulate the efficiency of carotenoids in fowls before accumulation into eggs. Carotenoid-enriched eggs may be promising, ensuring the availability of highly nutritive eggs. However, further studies are still needed to comprehend the full metabolism process and the extensive functions of carotenoids in eggs.

Frequency of Egg Intake Associated with Mortality in Chinese Adults: An 8-Year Nationwide Cohort Study

Whether egg consumption plays a beneficial/detrimental role in affecting human health and longevity has been debated for decades. Large-scale cohort evidence from low- and middle-income populations are scarce. In this study, we aimed to assess the association of egg consumption with mortality in Chinese adults. A nationwide cohort of 30,835 participants ages 16-110 years were enrolled from 25 provincial regions in China's mainland. Dietary intake (e.g., egg, meat, vegetable) was assessed by a food-frequency questionnaire. Cox proportional hazards models were used to examine associations between egg consumption and mortality, adjusting for demographic characteristics, dietary factors and health status. Dose-response relationships were investigated using the smoothing function of restricted cubic splines. Several subgroup analyses were performed. A total of 1651 all-cause deaths occurred during a median follow-up of 8.1 years. Egg consumption was associated with lower risks of mortality, with the lowest risk occurring in the group of moderate egg intake (3-6 times/week). Compared with non-consumers, the hazard ratios (95% confidence intervals) for mortality were 0.84 (0.72-0.97) for 3-6 times/week and 0.82 (0.69-0.98) for ≥7 times/week, whereas no significant associations were observed among the lower egg intake group (1-2/week). An approximately inverted J-shaped association was observed in three models, while restricting our analysis in the multivariable model (model 3) did not identify a significant violation for the linear relationship (p for nonlinear = 0.122). There were no statistically significant effect modifications in the subgroup analyses. Egg consumption may be associated with lower risks of mortality in Chinese adults. Our findings found moderate-to-high egg consumption might be beneficial for improving long-term health and longevity.

The effects of L-carnitine-loaded solid lipid nanoparticles on performance, antioxidant parameters, and expression of genes associated with cholesterol metabolism in laying hens

The purpose of this study was to investigate the production performance, antioxidant parameters, egg yolk cholesterol content, and expression of genes related to cholesterol metabolism in laying hens fed L-carnitine (LC) and L-carnitine-loaded solid lipid nanoparticles (LC-SLNs). A total of 350 Hy-Line (w-36) laying hens at 50 wk of age (1520.0 ± 0.7 g) were randomly assigned to 35 units (5 replicates and 50 hens in each treatment) with seven dietary treatments as a completely randomized design. The dietary treatments were corn-soybean meal-based diets, including 1) Control (basal diet); 2) Basal diet +50 mg/kg LC (50LC); 3) Basal diet +100 mg/kg LC (100LC); 4) Basal diet +150 mg/kg LC (150LC); 5) Basal diet +50 mg/kg LC-SLNs (50LC-SLNs); 6) Basal diet +100 mg/kg LC-SLNs (100LC-SLNs) and 7) Basal diet +150 mg/kg LC-SLNs (150LC-SLNs). Results showed that the 50LC-SLNs had the least feed conversion ratio (FCR) in all groups (P < 0.05). The dietary supplementation of 100LC-SLNs decreased (P < 0.01) the egg yolk cholesterol concentration from 14.71 to 11.76 mg/g yolk (25%). The 50LC-SLNs group produced the most total antioxidant capacity with a difference of 58.44% compared to the control group (P < 0.01). The greatest amount of total superoxide dismutase was found for 50LC-SLNs (P < 0.05), while the glutathione peroxidase was not affected by the experimental treatments (P > 0.05). Serum malondialdehyde levels were reduced by 50.52% in laying hens fed 50LC-SLNs compared to the control group (P < 0.05). The transcript level of 3-hydroxy-3-methylglutaryl coenzyme A reductase was significantly decreased (P < 0.01) in the LC and LC-SLNs groups. The expression of cholesterol 7α-hydroxylase was significantly increased (P < 0.01) in the plain LC (∼83%) and LC-SLNs (∼91%) groups. The inclusion of LC-SLNs in the diet increased (P < 0.05) the villus height and decreased villus width in all three parts of the small intestine. Dietary inclusion of LC was found to reduce egg yolk and serum cholesterol content by improving the production performance and antioxidant status. The LC-SLNs groups were more affected than the plain LC groups, which may be attributed to the increased bioavailability of LC.

Associations of Dietary Cholesterol, Serum Cholesterol, and Egg Consumption With Overall and Cause-Specific Mortality: Systematic Review and Updated Meta-Analysis

BACKGROUND

Despite substantial research highlighting the importance of exogenous dietary cholesterol intake and endogenous serum cholesterol level in human health, a thorough evaluation of the associations is lacking. Our study objective was to examine overall and cause-specific mortality in relation to dietary and serum cholesterol, as well as egg consumption, and conduct an updated meta-regression analysis of cohort studies.

METHODS

We conducted a prospective analysis of 27 078 men in the ATBC Study (Alpha-Tocopherol, Beta-Carotene Cancer Prevention). Multivariable-controlled cause-specific Cox proportional hazards regression models were used to calculate hazard ratios and 31-year absolute mortality risk differences. A systematic review and meta-analysis of cohort studies was also performed (PROSPERO [URL: https://www.crd.york.ac.uk/prospero/; Unique identifier: CRD42021272756]).

RESULTS

Based on 482 316 person-years of follow-up, we identified 22 035 deaths, including 9110 deaths from cardiovascular disease (CVD). Greater dietary cholesterol and egg consumption were associated with increased risk of overall and CVD-related mortality. Hazard ratios for each additional 300 mg cholesterol intake per day were 1.10 and 1.13 for overall and CVD-related mortality, respectively; for each additional 50-g egg consumed daily, hazard ratios were 1.06 and 1.09, respectively, for overall and CVD-related mortality (all P values<0.0001). After multivariable adjustment, higher serum total cholesterol concentrations were associated with increased risk of CVD-related mortality (hazard ratios per 1 SD increment, 1.14; P<0.0001). The observed associations were generally similar across cohort subgroups. The updated meta-analysis of cohort studies on the basis of 49 risk estimates, 3 601 401 participants, and 255 479 events showed consumption of 1 additional 50-g egg daily was associated with significantly increased CVD risk (pooled relative risk, 1.04 [95% CI, 1.00-1.08]; I²=80.1%). In the subgroup analysis of geographic regions (P_interaction=0.02), an increase of 50-g egg consumed daily was associated with a higher risk of CVD in US cohorts (pooled relative risk, 1.08 [95% CI, 1.02-1.14]) and appeared related to a higher CVD risk in European cohorts with borderline significance (pooled relative risk, 1.05), but was not associated with CVD risk in Asian cohorts.

CONCLUSIONS

In this prospective cohort study and updated meta-analysis, greater dietary cholesterol and egg consumption were associated with increased risk of overall and CVD-related mortality. Our findings support restricted consumption of dietary cholesterol as a means to improve long-term health and longevity.

Vegan Egg: A Future-Proof Food Ingredient?

Vegan eggs are designed with the aim to provide a healthier and more sustainable alternative to regular eggs. The major drivers of this industry are the increasing prevalence of egg allergies, awareness towards environmental sustainability, and the shift to vegan diets. This study intends to discuss, for the first time, the vegan egg market, including their formulation, nutritional aspects, and some applications (i.e., mayonnaise and bakery products). Recreating the complete functionality of eggs using plant-based ingredients is very challenging due to the complexity of eggs. Current, but scarce, research in this field is focused on making mixtures of plant-based ingredients to fit specific food formulations. Nutritionally, providing vegan eggs with similar or higher nutritional value to that of eggs can be of relevance to attract health-conscious consumers. Claims such as clean labels, natural, vegan, animal-free, gluten-free, and/or cholesterol-free can further boost the position of vegan eggs in the market in the coming year. At present, this market is still in its infancy stages, and clear regulations of labeling, safety, and risk assessment are deemed mandatory to organize the sector, and protect consumers.

Effects of Dietary Selenium Sources on Physiological Status of Laying Hens and Production of Selenium-Enriched Eggs

Developing new sources of organic selenium (Se) has potential benefits for animal production and human nutrition via animal-based foods enriched with Se. The objective of this study was to evaluate the effects of Se-enriched insect protein (SEIP) in comparison with other sources, such as sodium selenite (SS) and selenium-enriched yeast (SEY), on performance, egg quality, selenium concentration in eggs, serum biochemical indices, immune capacity, and intestinal morphology of laying hens. Four hundred and fifty 24-week-old Hy-Line Brown laying hens with 94.0 ± 1.5% laying rate were randomly allocated to five groups with six replicates of 15 hens each. The control diet was prepared without adding exogenous selenium (calculated basal Se content of 0.08 mg/kg). The normal group was fed basal diets supplemented with 0.3 mg/kg of Se provided by sodium selenite. Three treatment groups (SS, SEY, and SEIP, respectively) were fed basal diets supplemented with 2 mg/kg of Se provided by sodium selenite, Se-enriched yeast, and SEIP, respectively. The feeding trial lasted for 12 weeks. Results revealed that dietary supplementation of 2 mg/kg of Se increased egg weight, decreased feed conversion ratio, and enhanced the antioxidant capacity of eggs in laying hens relative to the control group, whereas no significant differences were observed among SS, SEY, and SEIP treatment groups for the same. The organic source of Se provided by SEY or SEIP showed higher bio efficiency, as indicated by higher selenium content in eggs of SEY and SEIP compared with SS, although higher content was observed in SEY compared with SEIP. Also, the organic Se source significantly improved antioxidant capacity and immune functions of laying hens than the inorganic Se source. Diets supplemented with SEIP and SS significantly improved jejunal morphology of the laying hens compared with SEY, whereas SEIP was more effective than SEY to improve the oviduct health of laying hens. The results of this work evidently points the additive effect and nontoxicity of SEIP. Thus, SEIP could be used as another organic source of Se in the diet of laying hens and production of selenium-enriched eggs for humans.

Supercritical Fluid-Based Decellularization Technologies for Regenerative Medicine Applications

Supercritical fluid-based extraction technologies are currently being increasingly utilized in high purity extract products for food industries. In recent years, supercritical fluid-based extraction technology is transformed in biomaterials process fields to be further utilized for tissue engineering and other biomedical applications. In particular, supercritical fluid-based decellularization protocols have great advantage over the conventional decellularization as it may allow preservation of extracellular matrix components and structures. In this review, the latest technological development utilizing the supercritical fluid-based decellularization for regenerative medicine is introduced.

Application of Selenium Conjugated to Animal Protein in Laying Hens' Diet for the Production of Selenium-Enriched Eggs

The current experiment was conducted to investigate the application effects of selenium conjugated to insect protein (SCIP) in the production of selenium-enriched eggs. A total of 450 laying hens were randomly assigned to five dietary groups, each group consisting of six replicates. Hens in the control group received a diet without selenium supplementation, whereas hens in the other four groups received diets supplemented with either 1, 2, 5, or 10 mg/kg of selenium from SCIP. The productive performance, egg quality, antioxidant and immune capacity, biochemical indices, intestinal morphology, and oviduct health of laying hens were evaluated. The results showed that the supplementation of organic selenium provided by SCIP in the diets of laying hens enhanced performance and egg quality without any toxicity effect, even at the 10 mg/kg inclusion level. A level of 2 mg/kg of selenium provided by SCIP in diets tentatively improved the serum antioxidant and immune capacity, intestinal development, and oviduct health of laying hens in a conspicuous manner. Hence, the biosafety and positive effects of SCIP as a feed additive supplement in laying hens' diet have been demonstrated with the enhanced production of safe and selenium-enriched eggs.

Influence of Different Tetracycline Antimicrobial Therapy of Mycoplasma (Mycoplasma synoviae) in Laying Hens Compared to Tea Tree Essential Oil on Table Egg Quality and Antibiotic Residues

The food of animal origin that is the most consumed is the table egg, but laying hens treated with antibiotics can produce eggs contaminated with antibiotic residues. Residues of antibiotics may present a risk for consumer health. Keeping in mind that laying hens almost always suffer from Mycoplasma (Mycoplasma synoviae), for which they are treated with antibiotics, high-quality egg production is even harder. Our research aimed to investigate the influence of three different antibiotics compared to the tea tree (Melaleuca alternifolia) essential oil administered to naturally infected laying hens with M. synoviae, on antibiotic residues in eggs as well as the egg nutritive and sensory qualities. A total of 20,000 laying hens, housed in one facility and divided into four lines each consisting of 5000 hens naturally infected with M. synoviae, was used. For the antimicrobial therapy, tetracycline (TC), oxytetracycline (OTC) and chlortetracycline (CTC) were used, respectively. As a control, tea tree essential oil (TT) was used. Based on the gained results all tetracyclines treatment residue values were significantly (p < 0.05) higher compared to the control treatment (TT), but without any significant differences (p > 0.05) between themselves. The results showed no differences in the nutritive and the sensory qualities of eggs between the control and the experimental treatments (p > 0.05). Keeping in mind the obtained results from this study, it can be concluded that tea tree essential oil could be successfully used as a natural antibiotic in the treatment of M. synoviae, without any adverse effects on table egg quality.

Comparative Reduction of Egg Yolk Cholesterol Using Anionic Chelating Agents

Egg yolk is used as an emulsifying agent. Nevertheless, its high concentration of cholesterol is linked to chronic degenerative diseases that cause cardiovascular disease. In this study, three methods for reducing the level of cholesterol in egg yolks were studied. The first method consisted of physical separation of the granules contained in the yolk (Na_G). The second method applied was the use of anionic chelating biopolymers, such as arabic gum solution (AG) and mesquite gum solution (MG), and the third method was extraction with a solvent (S_A). For this purpose, the cholesterol present in egg yolks, the microstructure, particle size, zeta potential, and its emulsifying capacity were determined. The amount of cholesterol removed was 97.24% using 1% mesquite gum (MG_1%), and 93.26% using 1% Arabic gum (AG_1%). The zeta potential was determined, and the isoelectric point (ζ = 0) of egg yolk was identified as pH 4.6. While, at this pH, the zeta potential of mesquite gum was −14.8 mV, the zeta potential for the arabic gum was −16 mV. The emulsifying capacity of MG_1% was 62.95%, while the emulsifying capacity of AG_1% was 63.57%. The complex obtained can be used in the development of functional foods reduced in cholesterol.