High-throughput lipidomic profiling of high-density lipoprotein from egg yolk (EYHDL): comparison based on UPLC-MS/MS and GC–MS

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.

Real-time authentication of minced shrimp by rapid evaporative ionization mass spectrometry

Minced shrimp is popular seafood due to its delicious flavor and nutritional value. However, the biological species of raw material of minced shrimp are not distinguished by naked eyes after processing. Thus, an in situ and real-time minced shrimp authentication method was established using iKnife rapid evaporative ionization mass spectrometry (REIMS) based lipidomics. The samples were analyzed under ambient ionization without any tedious preparation step. Seven economic shrimp samples were tested, whose phenotypes were used to develop a real-time recognition model. A total of 19 fatty acids and 45 phospholipid molecular species were efficiently identified and statistically analyzed by multivariate statistical analysis. The results showed that the seven shrimp species were well distinguished, and the most contributing ions at m/z 255.2, 279.2, 301.2, 327.2, 699.5, 742.5, etc., were revealed by variable importance in projection. The proposed iKnife REIMS showed excellent performance in minced shrimp authentication.

Akkermansia muciniphila Enhances Egg Quality and the Lipid Profile of Egg Yolk by Improving Lipid Metabolism

Akkermansia muciniphila (A. muciniphila) has shown potential as a probiotic for the prevention and treatment of non-alcoholic fatty liver disease in both humans and mice. However, relatively little is known about the effects of A. muciniphila on lipid metabolism, productivity, and product quality in laying hens. In this study, we explored whether A. muciniphila supplementation could improve lipid metabolism and egg quality in laying hens and sought to identify the underlying mechanism. In the first experiment, 80 Hy-Line Brown laying hens were divided into four groups, one of which was fed a normal diet (control group), while the other three groups were administered a high-energy, low-protein diet to induce fatty liver hemorrhagic syndrome (FLHS). Among the three FLHS groups, one was treated with phosphate-buffered saline, one with live A. muciniphila, and one with pasteurized A. muciniphila. In the second experiment, 140 Hy-Line Brown laying hens were divided into two groups and respectively fed a basal diet supplemented or not with A. muciniphila lyophilized powder. The results showed that, in laying hens with FLHS, treatment with either live or pasteurized A. muciniphila efficiently decreased body weight, abdominal fat deposition, and lipid content in both serum and the liver; downregulated the mRNA expression of lipid synthesis-related genes and upregulated that of lipid transport-related genes in the liver; promoted the growth of short-chain fatty acids (SCFAs)-producing microorganisms and increased the cecal SCFAs content; and improved the yolk lipid profile. Additionally, the supplementation of lyophilized powder of A. muciniphila to aged laying hens reduced abdominal fat deposition and total cholesterol (TC) levels in both serum and the liver, suppressed the mRNA expression of cholesterol synthesis-related genes in the liver, reduced TC content in the yolk, increased eggshell thickness, and reshaped the composition of the gut microbiota. Collectively, our findings demonstrated that A. muciniphila can modulate lipid metabolism, thereby, promoting laying hen health as well as egg quality and nutritive value. Live, pasteurized, and lyophilized A. muciniphila preparations all have the potential for use as additives for improving laying hen production.

Exploring the Lipidome: Current Lipid Extraction Techniques for Mass Spectrometry Analysis

In recent years, high-throughput lipid profiling has contributed to understand the biological, physiological and pathological roles of lipids in living organisms. Across all kingdoms of life, important cell and systemic processes are mediated by lipids including compartmentalization, signaling and energy homeostasis. Despite important advances in liquid chromatography and mass spectrometry, sample extraction procedures remain a bottleneck in lipidomic studies, since the wide structural diversity of lipids imposes a constrain in the type and amount of lipids extracted. Differences in extraction yield across lipid classes can induce a bias on down-stream analysis and outcomes. This review aims to summarize current lipid extraction techniques used for untargeted and targeted studies based on mass spectrometry. Considerations, applications, and limitations of these techniques are discussed when used to extract lipids in complex biological matrices, such as tissues, biofluids, foods, and microorganisms.

Biological Activities of Egg Yolk Lipids: A Review

As one of six dietary nutrients, lipid derived from different food matrices has been extensively studied and has an appropriate application in food, medicine, and cosmetic industry. Egg is a richly nutritive food, of which proteins and lipids possess excellent functional characteristics and biological activities. In recent years, egg yolk lipid has been successively separated and investigated, such as egg yolk oil, phospholipids, and fatty acids, which have anti-inflammatory activity, antioxidant activity, cardiovascular protection, and memory improvement, involving the regulation of cell function and physiological homeostatic balance. In this paper, the biological activities and underlying benefit of egg yolk lipids and fat-soluble components have been highlighted and summarized. Meanwhile, the quantitative data of egg yolk lipids needed to achieve any of the described biological effects and recommended concentrations relevant for dietary intake are reviewed. Finally, current challenges and crucial issues of high-efficiency utilization of egg yolk lipids are also discussed.