High-density lipoproteins from egg yolk's effect on hyperlipidemia in a high-fat-diet obese mouse using lipidomic analysis

Complexation of starch and konjac glucomannan during screw extrusion exhibits obesity-reducing effects by modulating the intestinal microbiome and its metabolites

Dietary interventions have been shown to improve gut health by altering the gut flora, preventing obesity, and mitigating inflammatory disorders. This study investigated the benefits of a rice starch-konjac glucomannan (ERS-KGM) complex, produced via screw extrusion, for gut health and obesity prevention. Analyzed through in vitro starch digestion, scanning electron microscopy, and structural analysis, the ERS-KGM complex exhibited a notable increase in resistant starch content due to its well-ordered structure. When administered to mice on a high-fat diet for 8 weeks, the ERS-KGM complex significantly reduced body weight, white adipose tissue mass, adipocyte size, and food intake while increasing water consumption. It also improved glucose metabolism, insulin sensitivity, and lipid profiles by lowering serum triglycerides and total glycerol content. Enhanced metabolic biomarkers and enzyme activities were observed, specifically involving glycerophospholipid metabolism. It decreased the activities of aldehyde dehydrogenase, lactate dehydrogenase, and amino acid transaminase while increasing antioxidant enzymes like glutathione peroxidase and superoxide dismutase. Additionally, it elevated glycogen and positively altered gut microbiota by enriching Firmicutes, Desulfobacterota, and Bifidobacterium. This change enhanced the ability to degrade specific compounds and elevated the concentrations of short-chain fatty acids in feces. These findings suggest that the ERS-KGM complex could serve as a dietary supplement for obesity prevention.

Developing a Simple and Feasible Process for the Crude Extraction of Livetins and Phosvitin from Egg Yolk

Due to imbalanced demand favoring egg whites, the egg industry faces a surplus of egg yolk, limiting overall growth. This study designed a feasible process for the crude extraction of livetins and phosvitin (PV) and revealed the related separation mechanisms. Our method utilized a 1:9 egg yolk dilution at pH 6.15-6.29, incubated at 4-7.5 °C, to reduce the dispersibility of lipoproteins in the water-soluble fraction (WSF). Adding 0.04-0.05% (w/v) sodium alginate to WSF at pH 5.40 effectively removed suspended low-density lipoprotein (LDL) through electrostatic complexation, increasing livetins electrophoretic bands from 51.90% to 91.04%. The dispersion of the high-density lipoprotein (HDL)-PV complex was jointly affected by NaCl and pH, with phosphocalcic bridges fully disrupted when NaCl concentration exceeded 7.5% (w/v). Na+ and Ca2+ were adsorbed onto the negatively charged protein surface at pH 5-8, inducing strong hydration repulsion, thereby resulting in the individual dispersion of HDL and PV. Based on the solubility difference in low ionic strength solutions at neutral pH, HDL could be effectively removed after dialysis, increasing PV electrophoretic bands from 8.45% to 61.50%. This simple and feasible separation process may provide a reliable foundation for further purification via membrane filtration and chromatography.

Constructing myosin/high-density lipoprotein composite emulsions: Roles of pH on emulsification stability, rheological and structural properties

The emulsification activity of myosin plays a significant role in affecting quality of emulsified meat products. High-density lipoprotein (HDL) possesses strong emulsification activity and stability due to its structural characteristics, suggesting potential for its utilization in developing functional emulsified meat products. In order to explore the effect of HDL addition on emulsification stability, rheological properties and structural features of myosin (MS) emulsions, HDL-MS emulsion was prepared by mixing soybean oil with isolated HDL and MS, with pH adjustments ranging from 3.0 to 11.0. The results found that emulsification activity and stability in two emulsion groups consistently improved as pH increased. Under identical pH, HDL-MS emulsion exhibited superior emulsification behavior as compared to MS emulsion. The HDL-MS emulsion under pH of 7.0-11.0 formed a viscoelastic protein layer at the interface, adsorbing more proteins and retarding oil droplet diffusion, leading to enhanced oxidative stability, compared to the MS emulsion. Raman spectroscopy analysis showed more flexible conformational changes in the HDL-MS emulsion. Microstructural observations corroborated these findings, showing a more uniform distribution of droplet sizes in the HDL-MS emulsion with smaller particle sizes. Overall, these determinations suggested that the addition of HDL enhanced the emulsification behavior of MS emulsions, and the composite emulsions demonstrated heightened responsiveness under alkaline conditions. This establishes a theoretical basis for the practical utilization of HDL in emulsified meat products.

Effects of sn-2 Palmitic Triacylglycerols and the Ratio of OPL to OPO in Human Milk Fat Substitute on Metabolic Regulation in Sprague-Dawley Rats

In this study, the influence of total sn-2 palmitic triacylglycerols (TAGs) and ratio of 1-oleoyl-2-palmitoyl-3-linoleoylglycerol (OPL) to 1,3-dioleoyl-2-palmitoylglycerol (OPO) in human milk fat substitute (HMFS) on the metabolic changes were investigated in Sprague-Dawley rats. Metabolomics and lipidomics profiling analysis indicated that increasing the total sn-2 palmitic TAGs and OPL to OPO ratio in HMFS could significantly influence glycine, serine and threonine metabolism, glycerophospholipid metabolism, glycerolipid metabolism, sphingolipid metabolism, bile acid biosynthesis, and taurine and hypotaurine metabolism pathways in rats after 4 weeks of feeding, which were mainly related to lipid, bile acid and energy metabolism. Meanwhile, the up-regulation of taurine, L-tryptophan, and L-cysteine, and down-regulations of lysoPC (18:0) and hypoxanthine would contribute to the reduction in inflammatory response and oxidative stress, and improvement of immunity function in rats. In addition, analysis of targeted biochemical factors also revealed that HMFS-fed rats had significantly increased levels of anti-inflammatory factor (IL-4), immunoglobulin A (IgA), superoxide dismutase (SOD), and glutathione peroxidase (GSH-px), and decreased levels of pro-inflammatory factors (IL-6 and TNF-α) and malondialdehyde (MDA), compared with those of the control fat-fed rats. Collectively, these observations present new in vivo nutritional evidence for the metabolic regulatory effects of the TAG structure and composition of human milk fat substitutes on the host.

Research Note: Aggregation-depolymerization of chicken egg yolk granule under different food processing conditions

Chicken egg yolk granule is a natural micro-nano aggregate in egg yolk, and its assembly structure varies under different processing conditions. In this study, the effects of NaCl concentration, pH, temperature, and ultrasonic treatment on the properties and microstructure of yolk granule were determined. The results showed that ionic strength (above 0.15 mol/L), alkaline environment (pH 9.5 and 12.0), and ultrasonic treatment induced the depolymerization of egg yolk granule; while freezing-thawing, heat treatment (65°C, 80°C, and 100°C), and mild acidic pH (pH 4.5) induced the aggregation of yolk granule. Scanning electron microscopy observation showed the assembly structure of yolk granule varied with different treatment conditions and confirmed the aggregation-depolymerization of yolk granule under different conditions. Correlation analysis showed that turbidity and average particle size are the 2 most critical indicators that can reflect the aggregation structure of yolk granule in solution. The results are important for understanding the changing mechanism of yolk granule during processing, and provide important information for the applications of yolk granule.

Novel extraction technologies and potential applications of egg yolk proteins

The high nutritional value and diverse functional properties of egg yolk proteins have led to its widespread use in the fields of food, medicine, and cosmetics. Various extraction methods have been reported to obtain the proteins from egg yolk, however, their utilization is limited due to the relatively low extraction efficiency and/or toxic solvents involved. Several simpler and greener technologies, especially physical fields (ultrasound), have been successfully developed to improve the extraction efficiency. The egg yolk proteins may exert multiple biological activities, enabling them to be a promising tool in improve human health and wellbeing, such as anti-obesity, anti-atherosclerosis, anti-osteoporosis, diagnosis and therapy for SARS-CoV-2 infections. This article summarizes the novel extraction technologies and latest applications of the egg yolk proteins in the recent 5 years, which should stimulate their utilization as health-promoting functional ingredients in foods and other commercial products.

The Association of Dietary Cholesterol from Egg Consumption on Cardiovascular Diseases Risk Varies from Person to Person

The public and scientists remain skeptical about egg consumption, given that cardiovascular diseases (CVDs) are the leading causes of death in worldwide. This review mainly explained the recurrence of contradictory conclusions about relationships between egg consumption and CVD risk and discussed effects of egg cholesterol intake on cholesterol homeostasis. Factors including individual health status and cholesterol sensitivity, dietary pattern, region, and race should be distinguished when understanding generalized conclusions. Identified compensatory mechanisms in response to dietary cholesterol and the resulting balance in cholesterol biosynthesis, absorption, and efflux supported the view that moderate egg consumption had no substantial overall impacts on cholesterol homeostasis in healthy people. Excessive cholesterol intake is not recommended in individuals with distempered metabolism. More than cholesterol metabolism, impacts of egg consumption as a part of overall diet on CVD risk should be considered from aspects of nutrient intake, lipid metabolism, and energy supply in the future.

Network pharmacology combined with metabolomics and lipidomics to reveal the hypolipidemic mechanism of Alismatis rhizoma in hyperlipidemic mice

Alismatis rhizoma (AR), the dried rhizome of Alisma orientale (Sam) Juzep, is effective in treating hyperlipidemia, but the mechanisms involved require further exploration. This study evaluated the hypolipidemic properties of AR using an integrated strategy combining network pharmacology with metabolomics and lipidomics. Firstly, a hyperlipidemia mouse model induced by a high-fat diet was established to evaluate the therapeutic effects of AR. Secondly, plasma metabolomics and lipidomics were used to identify differential metabolites and lipids, and metabolic pathway analysis was performed using MetaboAnalyst. Thirdly, network pharmacology, based on the metabolic profile of AR in vivo, was used to discover potential therapeutic targets. Finally, key targets were obtained through a compound-target-metabolite network, which was verified by molecular docking and quantitative real-time PCR (qPCR). Biochemistry analysis and histological examinations showed that AR exerted hypolipidemic effects on hyperlipidemic mice. Seventy potential biomarkers for the AR treatment of hyperlipidemia were identified by metabolomics and lipidomics, which were mainly involved in lipid metabolism, energy metabolism and amino acid metabolism. Eighteen potentially active compounds were identified in the plasma of mice after oral administration of AR, which were associated with 83 potential therapeutic targets. The PPAR signaling pathway was considered a crucial signaling pathway of AR against hyperlipidemia by KEGG analysis. The joint analysis showed that 6 upstream key targets were regulated by AR, including ALB, TNF, IL1B, MMP9, PPARA and PPARG. Molecular docking showed that active compounds of AR had high binding affinity with these key targets. qPCR further demonstrated that AR could reverse the mRNA expression of these key targets in hyperlipidemic mice. This study integrates network pharmacology with metabolomics and lipidomics to reveal the regulatory effects of AR on endogenous metabolites and validates key therapeutic targets, and represents the most systematic and in-depth study on the hypolipidemic activity of AR.