Quantitative Phosphoproteomics of Milk Fat Globule Membrane in Human Colostrum and Mature Milk: New Insights into Changes in Protein Phosphorylation during Lactation

Insights into the microscopic heterogeneity of whey proteins between yak colostrum and mature milk based on 4D lable-free quantitative phosphoproteomics

This study aimed to reveal the change patterns of the phosphorylation modification status of yak whey phosphoproteins during lactation and their physiological effects. Herein, we comprehensively characterized whey phosphoproteome in yak colostrum and mature milk using an ultra-high throughput phosphoproteomics approach incorporating trapped ion mobility technology. A total of 344 phosphorylation sites from 206 phosphoproteins were identified, with individual site modification predominating. Notably, 117 significantly different phosphorylation sites were distributed on 89 whey phosphoproteins. Gene ontology analysis indicated that these significantly different whey phosphoproteins (SDWPPs) were mainly annotated to carbohydrate metabolic process, membrane, extracellular region and calcium ion binding. Metabolic pathway enrichment analysis demonstrated that SDWPPs were critically involved in protein processing in endoplasmic reticulum, NOD-like receptor signaling pathway and N-glycan biosynthesis. Our results elucidate the phosphorylation profiles of yak whey phosphoproteins at different lactations and their adaptive regulatory role in meeting the nutritional requirements of yak calves during development.

Proteomic and phosphoproteomic reveal immune-related function of milk fat globule membrane in bovine milk of different lactation periods

Information regarding protein expression and phosphorylation modifications in the bovine milk fat globule membrane is scarce, particularly throughout various lactation periods. This study employed a complete proteome and phosphoproteome between bovine colostrum and mature milk. A total of 11 proteins were seen in both protein expression and phosphorylation levels. There were 400 proteins identified in only protein expression, and 104 phosphoproteins identified in only phosphorylation levels. A total of 232 significant protein characteristics were identified within the proteome and significant phosphorylation sites within 86 phosphoproteins of the phosphoproteome. Biological activities and pathways primarily exhibited associations with the immune system. Simultaneously, a comprehensive analysis of proteins and phosphorylation sites using a multi-omics approach. Hence, the data we have obtained has the potential to expand our understanding of how the bovine milk fat globule membrane might be utilized as a beneficial component in dairy products.

Association of breast milk-derived arachidonic acid-induced infant gut dysbiosis with the onset of atopic dermatitis

OBJECTIVE

The specific breast milk-derived metabolites that mediate host-microbiota interactions and contribute to the onset of atopic dermatitis (AD) remain unknown and require further investigation.

DESIGN

We enrolled 250 mother-infant pairs and collected 978 longitudinal faecal samples from infants from birth to 6 months of age, along with 243 maternal faecal samples for metagenomics. Concurrently, 239 corresponding breast milk samples were analysed for metabolomics. Animal and cellular experiments were conducted to validate the bioinformatics findings.

RESULTS

The clinical findings suggested that a decrease in daily breastfeeding duration was associated with a reduced incidence of AD. This observation inspired us to investigate the effects of breast milk-derived fatty acids. We found that high concentrations of arachidonic acid (AA), but not eicosapentaenoic acid (EPA) or docosahexaenoic acid, induced gut dysbiosis in infants. Further investigation revealed that four specific bacteria degraded mannan into mannose, consequently enhancing the mannan-dependent biosynthesis of O-antigen and lipopolysaccharide. Correlation analysis confirmed that in infants with AD, the abundance of Escherichia coli under high AA concentrations was positively correlated with some microbial pathways (eg, 'GDP-mannose-derived O-antigen and lipopolysaccharide biosynthesis'). These findings are consistent with those of the animal studies. Additionally, AA, but not EPA, disrupted the ratio of CD4/CD8 cells, increased skin lesion area and enhanced the proportion of peripheral Th2 cells. It also promoted IgE secretion and the biosynthesis of prostaglandins and leukotrienes in BALB/c mice fed AA following ovalbumin immunostimulation. Moreover, AA significantly increased IL-4 secretion in HaCaT cells costimulated with TNF-α and INF-γ.

CONCLUSIONS

This study demonstrates that AA is intimately linked to the onset of AD via gut dysbiosis.

Advanced functional materials as reliable tools for capturing food-derived peptides to optimize the peptidomics pre-treatment enrichment workflow

Peptidomics strategies with high throughput, sensitivity, and reproducibility are key tools for comprehensively analyzing peptide composition and potential functional activities in foods. Nevertheless, complex signal interference, limited ionization efficiency, and low abundance have impeded food-derived peptides' progress in food detection and analysis. As a result, novel functional materials have been born at the right moment that could eliminate interference and perform efficient enrichment. Of note, few studies have focused on developing peptide enrichment materials for food sample analysis. This work summarizes the development of endogenous peptide, phosphopeptide, and glycopeptide enrichment utilizing materials that have been employed extensively recently: organic framework materials, carbon-based nanomaterials, bio-based materials, magnetic materials, and molecularly imprinted polymers. It focuses on the limitations, potential solutions, and future prospects for application in food peptidomics of various advanced functional materials. The size-exclusion effect of adjustable aperture and the modification of magnetic material enhanced the sensitivity and selectivity of endogenous peptide enrichment and aided in streamlining the enrichment process and cutting down on enrichment time. Not only that, the immobilization of metal ions such as Ti4+ and Nb5+ enhanced the capture of phosphopeptides, and the introduction of hydrophilic groups such as arginine, L-cysteine, and glutathione into bio-based materials effectively optimized the hydrophilic enrichment of glycopeptides. Although a portion of the carefully constructed functional materials currently only exhibit promising applications in the field of peptide enrichment for analytical chemistry, there is reason to believe that they will further advance the field of food peptidomics through improved pre-treatment steps.

Revealing the diversity of endogenous peptides and parent proteins in human colostrum and mature milk through peptidomics analysis

Endogenous peptides and their parent proteins are important nutritional components with diverse biological functions. The objective of this study was to analyze and compare endogenous peptides and parent proteins found in human colostrum (HC) and human mature milk (HM) using a 4D label-free technique. In total, 5162 and 940 endogenous peptides derived from 258 parent proteins were identified in human milk by database (DB) search and de novo, respectively. Among these peptides, 2446 differentially expressed endogenous peptides with various bioactivities were identified. The Gene Ontology analysis unveiled the cellular components, biological processes, and molecular functions associated with these parent proteins. Metabolic pathway analysis suggested that neutrophil extracellular trap formation had the greatest significance with 24 parent proteins. These findings will offer a fresh perspective on the development of infant formula powder, highlighting the potential for incorporating these changes to enhance its nutritional composition and benefits.

Phosphoproteomics Revealed Differentially Expressed Sites and Function of the Bovine Milk Fat Globule Membrane in Colostrum and Mature Milk

One type of large and intricate post-translational modification of milk proteins that has significant biological implications is phosphorylation. The characterization of phosphoproteins found in the bovine milk fat globule membrane (MFGM) is still mostly unknown. Here, label-free phosphoproteomics was used to identify 94 phosphorylation sites from 54 MFGM phosphoproteins in bovine colostrum (BC) and 136 phosphorylation sites from 91 MFGM phosphoproteins in bovine mature milk (BM). αs1-Casein and β-casein were the most phosphorylated proteins in bovine colostrum. In bovine mature milk, perilipin-2 was the protein with the greatest number of phosphorylation sites. The results show that bovine colostrum MFGM phosphoproteins were mainly involved in immune function, whereas bovine mature MFGM phosphoproteins were mainly involved in metabolic function. Plasminogen and osteopontin were the most strongly interacting proteins in colostrum, whereas perilipin-2 was the most strongly interacting protein in bovine mature milk. This work demonstrates the unique alterations in the phosphorylation manner of the bovine MFGM protein during lactation and further expands our knowledge of the site characteristics of bovine MFGM phosphoproteins. This result confirms the value of MFGM as a reference ingredient for infant formula during different stages.

Comparative metabolomic analysis and antigenicity comparison of cow milk and enzymatically treated cow milk

BACKGROUND

Amino acids (AAs) are important protein building blocks that play a critical role in the function of the immune system. However, comprehensive comparative metabolomics and antigenicity analyses of cow milk (CM) and enzymatically treated CM are relatively scarce. This study analyzed the AAs in the CM and Flavourzyme-treated milk groups (FT), and their antigenicity was also explored.

RESULTS

Overall, 50 AAs were detected in the CM and FT groups, with 23 significantly different AAs. The interaction network of these significantly different AAs was analyzed, and 34 significantly different metabolic pathways were found to be involved. It was also found that the antigenicity of the FT group was significantly reduced in comparison with that of the CM group.

CONCLUSION

These results enhance our understanding of AAs and antigenicity regarding CM and FT, and provide new ideas and directions for the development of high-quality hypoallergenic dairy products. © 2023 Society of Chemical Industry.

Proteomics and Peptidomics As a Tool to Compare the Proteins and Endogenous Peptides in Human, Cow, and Donkey Milk

Cow's milk is the most widely used ingredient in infant formulas. However, its specific protein composition can cause allergic reactions. Finding alternatives to replace cow's milk and fill the nutritional gap with human milk is essential for the health of infants. Proteomic and peptidomic techniques have supported the elucidation of milk's nutritional ingredients. Recently, omics approaches have attracted increasing interest in the investigation of milk because of their high throughput, precision, sensitivity, and reproducibility. This review offers a significant overview of recent developments in proteomics and peptidomics used to study the differences in human, cow, and donkey milk. All three types of milks were identified to have critical biological functions in human health, particularly in infants. Donkey milk proteins were closer in composition to human milk, were less likely to cause allergic reactions, and may be developed as novel raw materials for formula milk powders.

Analytical Ultracentrifugation-Calibrated Anion-Exchange Chromatography for Sensitive and Intact Determination of Osteopontin in Infant Formula and Dairy Products

Osteopontin is a crucial protein ingredient that has been applied in fortified dairy products and infant formula. It has great significance to infant gut health and brain development. However, current techniques including enzyme-linked immunosorbent assay and liquid chromatography coupled with mass spectrometry are still facing the bottleneck of low sensitivity and indirect quantification. Moreover, the unavailable certified commercial OPN standard hinders its accurate quantification. Herein, a novel method of anion-exchange chromatography was established to determine OPN concentration in several dairy matrices. The polarity-reversed capillary isoelectric focusing was utilized to measure the exact isoelectric point (pI) to support method development for OPN separation. Analytical ultracentrifugation was used to calibrate the purity of intact OPN to develop an in-house reference standard. The method showed the merits of limits of detection to 0.04 mg/100 g, relative standard deviation of reproducibility <5% for 13 out of 14 tested matrices, and an average recovery rate of 101.3%. This method has shown the potential to be adopted as an international standard method for the quantification of intact OPN in infant formula and dairy products.

Milk Osteopontin and Human Health

Osteopontin (OPN) is a multifunctional protein found in all vertebrates. OPN is expressed in many different cell types, and is consequently found in most tissues and physiological secretions. OPN is involved in a multitude of biological processes, such as activation and regulation of the immune system; biomineralization; tissue-transformative processes, including growth and development of the gut and brain; interaction with bacteria; and many more. OPN is found in the highest concentrations in milk, where it is believed to initiate and regulate developmental, immunological and physiological processes in infants who consume milk. Processes for the isolation of bovine OPN for use in infant formula have been developed, and in recent years, many studies have investigated the effects of the intake of milk OPN. The purpose of this article is to review and compare existing knowledge about the structure and function of milk OPN, with a particular focus on the effects of milk OPN on human health and disease.

Quantitative phosphoproteome analysis reveals differential whey phosphoproteins of bovine milk during lactation

Whey proteins in bovine milk, as the most widely used nutritional components for infant formulae, have been paid more attention. However, the phosphorylation of proteins in bovine whey during lactation has not been thoroughly researched. In this study, a total of 185 phosphorylation sites on 72 phosphoproteins were identified in bovine whey during lactation. 45 differentially expressed whey phosphoproteins (DEWPPs) in colostrum and mature milk were focused on by bioinformatics approaches. Gene Ontology annotation indicated that blood coagulation, extractive space, and protein binding played a key role in bovine milk. The critical pathway of DEWPPs was related to the immune system according to KEGG analysis. Our study investigated the biological functions of whey proteins from a phosphorylation perspective for the first time. The results elucidate and increase our knowledge of differentially phosphorylation sites and phosphoproteins in bovine whey during lactation. Additionally, the data might offer fresh insight into the development of whey protein nutrition.

Comparative proteomics of whey proteins: New insights into quantitative differences between bovine, goat and camel species

Whey proteins are the leading proteins class in milk and play an essential role in the immune defense of neonatal mammals. The aim of this study was to analyze whey proteins in bovine, goat and camel milk by label free proteomics techniques. Finally, 840 proteins were identified, which considerably increasing the number of whey proteins identified in these species. The results of the PCA revealed significant differences in whey proteome patterns between bovine, goat and camel milk. Proteins such as PAEP, CST3, SERPING1, CTSB and GLG1 play an important role as markers in the classification of bovine, goat and camel milk. Statistical analysis showed that the relative abundances of many whey proteins such as ALB, LALBA, LTF and LPO were significantly different among different species. GO and KEGG functional analysis have shown that while the distribution of biological functions involved in whey proteins was relatively similar across species, they differed in terms of protein quantity. These data shed light on the quantitative differences and potential physiological functions of whey proteins across species, and may point the way to the production of specific functional whey proteins.

Quantitative Phosphoproteome of Infant Formula: New Insights into the Difference of Phosphorylation in Milk Proteins between Bovine and Goat Species

Phosphorylation is a broad post-translational protein modification, and the level of phosphorylation of milk proteins is associated with lactation, coagulation properties, and digestibility. However, phosphoproteins in bovine milk-based and goat milk-based infant formula have not been systematically explored. Here, we have analyzed six bovine and six goat milk-based infant formula using a quantitative phosphoproteomics approach, from which we identified 200 phosphoproteins with 276 phosphorylation sites and 156 phosphorylation sites from 75 phosphoproteins, respectively. Of these, 99 phosphorylation sites from 26 shared phosphoproteins were differentially expressed between bovine and goat milk-based infant formula. Especially, CSN1S1 was the most phosphoprotein with 25 quantified phosphorylation sites. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses showed that the identified phosphoproteins not only provide nutrition to the infant but also have anti-inflammatory, antipathogenic, and other biological functions. Our results shed light on the composition, phosphorylation sites, and biological functions of phosphoproteins in bovine milk and goat milk-based infant formula, which provide new insights into the key role of protein modifications during infant development. It also helps us to better understand the differences in digestibility of infant formula from different animal milk sources and thus guides the choice of milk source for infant formula.

Identifying and Analyzing Topic Clusters in a Nutri-, Food-, and Diet-Proteomic Corpus Using Machine Reading

Nutrition affects the early stages of disease development, but the mechanisms remain poorly understood. High-throughput proteomic methods are being used to generate data and information on the effects of nutrients, foods, and diets on health and disease processes. In this report, a novel machine reading pipeline was used to identify all articles and abstracts on proteomics, diet, food, and nutrition in humans. The resulting proteomic corpus was further analyzed to produce seven clusters of "thematic" content defined as documents that have similar word content. Examples of publications from several of these clusters were then described in a similar way to a typical descriptive review.

Terminal deoxynucleotidyl transferase associated with split G-quadruplex/hemin deoxyribozyme amplification detection for various contaminants in milk based on pregnancy test strip platform

Contaminant residue analysis in milk can provide essential assistance for safety quality and contamination level management of milk production, which is critical for safeguarding public health. In this study, the pregnancy test strip is employed to achieve multiple analytes detection based on the specific recognition of aptamer and terminal deoxynucleotidyl transferase associated with split G-quadruplex/hemin deoxyribozyme system. Through the subsequent enzyme catalyzed reaction, the detection signal can be further amplified to improve the sensitivity. The method does not need to assemble test strip, prepare and purify antibodies/haptens, nor design complex probe sequences. By coupling human chorionic gonadotrophin with DNA probes and combining magnetic separation technology, the targets can be determined via the test strip. Under the optimized conditions, the visual detection limits for mercury ion, bisphenol A, and penicillin are 1, 0.1 and 0.05 nM, respectively. The detection results show that the method displays good accuracy and practicability in spiked milk sample. The method presents a simple scheme, low cost as well as good design versatility, which demonstrates great application prospect for the sensitive, low-cost, and convenient detection of food matrices.

Changes in Human Milk Fat Globule Composition Throughout Lactation: A Review

There has been a growing interest in understanding how the relative levels of human milk fat globule (MFG) components change over the course of lactation, how they differ between populations, and implications of these changes for the health of the infant. In this article, we describe studies published over the last 30 years which have investigated components of the MFG in term milk, focusing on changes over the course of lactation and highlighting infant and maternal factors that may influence these changes. We then consider how the potential health benefits of some of the milk fat globule membrane (MFGM) components and derived ingredients relate to compositional and functional aspects and how these change throughout lactation. The results show that the concentrations of phospholipids, gangliosides, cholesterol, fatty acids and proteins vary throughout lactation, and such changes are likely to reflect the changing requirements of the growing infant. There is a lack of consistent trends for changes in phospholipids and gangliosides across lactation which may reflect different methodological approaches. Other factors such as maternal diet and geographical location have been shown to influence human MFGM composition. The majority of research on the health benefits of MFGM have been conducted using MFGM ingredients derived from bovine milk, and using animal models which have clearly demonstrated the role of the MFGM in supporting cognitive and immune health of infants at different stages of growth and development.

Functional Significance of Different Milk Constituents in Modulating the Gut Microbiome and Infant Health

Human milk, the gold standard for optimal nourishment, controls the microbial composition of infants by either enhancing or limiting bacterial growth. The milk fat globule membrane has gained interest in gut-related functions and cognitive development. The membrane proteins can directly interact with probiotic bacteria, influencing their survival and adhesion through gastrointestinal transit, whereas membrane phospholipids increase the residence time of probiotic bacteria in the gut. The commensal bacteria in milk act as the initial inoculum in building up the gut colonization of an infant, whereas oligosaccharides promote proliferation of beneficial microorganisms. Interestingly, milk extracellular vesicles are also involved in influencing the microbiota composition but are not well-explored. This review highlights the contribution of different milk components in modulating the infant gut microbiota, particularly the fat globule membrane, and the complex interplay between host- and brain-gut microbiota signaling affecting infant and adult health positively.

Qualitative Proteome-Wide Analysis Reveals the Diverse Functions of Lysine Crotonylation in Dendrobium huoshanense

The lysine crotonylation of histone proteins is a newly identified posttranslational modification with diversified cellular functions. However, there are few reports on lysine crotonylation of non-histone proteins in medicinal plant cells. By using high-resolution liquid chromatography-mass spectrometry (LC-MS) coupled with highly sensitive-specific immune-affinity antibody analysis, a whole crotonylation proteome analysis of Dendrobium huoshanense was performed. In total, 1,591 proteins with 4,726 lysine crotonylation sites were identified; among them, 11 conserved motifs were identified. Bioinformatic analyses linked crotonylated proteins to the drought stress response and multiple metabolic pathways, including secondary metabolite biosynthesis, transport and catabolism, energy production and conversion, carbohydrate transport and metabolism, translation, and ribosomal structure and biogenesis. This study contributes toward understanding the regulatory mechanism of polysaccharide biosynthesis at the crotonylation level even under abiotic stress.

Quantitative analysis of differentially expressed milk fat globule membrane proteins between donkey and bovine colostrum based on high-performance liquid chromatography with tandem mass spectrometry proteomics

This study was designed to provide novel insights into milk fat globule membrane (MFGM) proteins in donkey colostrum (DC) and bovine colostrum (BC) using quantitative proteomics. In total, 179 (DC) and 195 (BC) MFGM proteins were characterized, including 71 shared, 108 DC-specific, and 124 BC-specific proteins. Fifty-one shared proteins were selected as differentially expressed MFGM proteins, including 21 upregulated and 30 downregulated proteins in DC. Gene ontology analysis showed that these proteins were mainly enriched in cellular components, including the extracellular exosome, extracellular space, and plasma membrane. Additionally, they were further involved in metabolic pathways, including cholesterol metabolism, the peroxisome proliferator-activated receptor signaling pathway, and purine metabolism. Furthermore, several key protein factors with high connectivity were identified via protein-protein interaction analysis. These results provide more comprehensive knowledge of differences in the biological properties of MFGM proteins in DC and BC as well as pave the way for future studies of the nutritional and functional requirements of these important ingredients toward the development of dairy products based on multiple milk sources.

A High-Throughput Comparative Proteomics of Milk Fat Globule Membrane Reveals Breed and Lactation Stages Specific Variation in Protein Abundance and Functional Differences Between Milk of Saanen Dairy Goat and Holstein Bovine

Large variations in the bioactivities and composition of milk fat globule membrane (MFGM) proteins were observed between Saanen dairy goat and Holstein bovine at various lactation periods. In the present study, 331, 250, 182, and 248 MFGM proteins were characterized in colostrum and mature milk for the two species by Q-Orbitrap HRMS-based proteomics techniques. KEGG pathway analyses displayed that differentially expressed proteins in colostrum involved in galactose metabolism and an adipogenesis pathway, and the differentially expressed proteins in mature milk associated with lipid metabolism and a PPAR signaling pathway. These results indicated that the types and functions of MFGM proteins in goat and bovine milk were different, and goat milk had a better function of fatty acid metabolism and glucose homeostasis, which can enhance our understanding of MFGM proteins in these two species across different lactation periods, and they provide significant information for the study of lipid metabolism and glycometabolism of goat milk.

Human milk proteome: what's new?

PURPOSE OF REVIEW

The proteome is one of the most complicated and multifunctional components in human milk. Recently, numerous novel characteristics of the human milk proteome have been discovered, which are described and critically examined in this review.

RECENT FINDINGS

Recent human milk proteomics studies have focused on how external factors like geography and environment, or maternal and infant's factors affect the milk proteins, endogenous peptides, their posttransitional modifications (PTMs) and infant utilization. Most of these studies have shown that major protein and endogenous peptide profiles are similar for healthy women and infants. The human milk proteome has been expanded by providing novel insights into PTMs like glycosylation and phosphorylation, and how the proteins and peptides are digested and utilized by the infant. All human milk proteomics studies are subject to conditions in which the samples were collected, handled and stored.

SUMMARY

Significant technological advancements in mass spectrometry have considerably enabled a deeper and more comprehensive identification and characterization of the expanded human milk proteome. However, data concerning human milk from mothers with infections or illnesses and mothers nursing more vulnerable infants are still limited and the roles of the components of the human milk proteome have not yet been sufficiently elucidated.

Milk Fat Globule Membrane Proteome and Micronutrients in the Milk Lipid Fraction: Insights into Milk Bioactive Compounds

Milk lipids are composed of milk fat globules (MFGs) surrounded by the milk fat globule membrane (MFGM). MFGM protects MFGs from coalescence and enzymatic degradation. The milk lipid fraction is a “natural solvent” for macronutrients such as phospholipids, proteins and cholesterol, and micronutrients such as minerals and vitamins. The research focused largely on the polar lipids of MFGM, given their wide bioactive properties. In this review we discussed (i) the composition of MFGM proteome and its variations among species and phases of lactation and (ii) the micronutrient content of human and cow’s milk lipid fraction. The major MFGM proteins are shared among species, but the molecular function and protein expression of MFGM proteins vary among species and phases of lactation. The main minerals in the milk lipid fraction are iron, zinc, copper and calcium, whereas the major vitamins are vitamin A, β-carotene, riboflavin and α-tocopherol. The update and the combination of this knowledge could lead to the exploitation of the MFGM proteome and the milk lipid fraction at nutritional, biological or technological levels. An example is the design of innovative and value-added products, such as MFGM-supplemented infant formulas.

Ionic liquid modification of metal-organic framework endows high selectivity for phosphoproteins adsorption

Zr-based metal-organic framework, UiO-66-NH₂, provides favorable adsorption capacity to phosphoproteins, however, it exhibits obvious nonspecific adsorption to other proteins. In the present work, we report a facile strategy to reduce the nonspecific adsorption of nonphosphoproteins by modifying UiO-66-NH₂ with imidazolium ionic liquids (ILs). With respect to bare UiO-66-NH₂, the modified counterpart, UiO@IL, exhibits much improved selectivity to phosphoproteins while maintains comparable adsorption performance. The surface of UiO@IL presents a strong hydrophilicity due to the modification of ILs. Hydrophobic and electrostatic interaction between the absorbent and nonphosphoprotein is significantly reduced. In addition, the interaction between imidazole group of ILs moiety and phosphate group in phosphoprotein ensures the favorable adsorption capacity of UiO@IL for phosphoproteins. Anionic moieties of ILs, i.e., Cl^-, Br^-, BF₄^-, CF₃SO₃^-, play negligible effect in the adsorption process. As a representative, phosphoprotein β-casein (β-ca) is selectively enriched at a mass ratio of BSA:β-ca = 100:1. UiO@IL was further applied for the selective enrichment of phosphoprotein in milk.

Whey Protein Lipid Concentrate High in Milk Fat Globule Membrane Components Inhibit Porcine and Human Rotavirus in vitro

Background: The milk fat globule membrane (MFMG) is a complex milk component that has been shown to inhibit rotavirus (RV) binding to cell membranes in vitro. Herein, a whey protein lipid concentrate high in MFGM components (WPLC) and whey protein concentrate (WPC; control) were screened for anti-infective activity against porcine OSU and human Wa strains of RV in both the African Green Monkey kidney (MA104) and the human colorectal adenocarcinoma (Caco-2) cell lines. Materials and Methods: Confluent cells were exposed to OSU or Wa RV in the presence of WPLC or WPC (control) at 0, 0.1, 0.5, 1.0, 2.5, or 5 mg/ml. Infectivity was detected by immunohistochemistry and expressed as % inhibition relative to 0 mg/ml. WPLC efficacy over WPC was expressed as fold-change. One-way ANOVA analyzed data for the independent and interactive effects of concentration, test material, and RV strain. Results: Both WPLC and WPC exhibited concentration-dependent inhibition of human Wa and porcine OSU RV infectivity in MA104 and Caco-2 cells (p < 0.0001). WPLC was 1.5-4.8-fold more effective in reducing infectivity than WPC. WPLC efficacy was independent of RV strains, but varied between cell lines. WPLC and WPC at concentrations ≥0.5 mg/mL were most effective in reducing human Wa RV infectivity in MA104 cells (p < 0.0001). Conclusions: WPLC decreased infectivity of two strains for RV which differ in their dependency on sialic acid for binding to cells. Inhibition was observed in the most commonly used cell type for RV infectivity assays (MA104) and an intestinal cell line (Caco-2). An effect on virus infectivity might be a potential mechanisms of action contributing to beneficial effects of supplementation of infant formula with MGFM reducing the risk of infections and consequently diarrhea incidence in infants.

Determination of Trace Phosphoprotein in Food Based on Fluorescent Probe-Triggered Target-Induced Quench by Electrochemiluminescence

Evaluation of the nutrition and determination of phosphoproteins is of great importance in different foods as aberrant phosphorylation changes many biological processes and can relate to health conditions. In this study, an ultrafast (5 min) and sensitive electrochemiluminescence (ECL) sensor was innovatively fabricated for the determination of phosphoproteins in foods on the basis of fluorescent probe NH₂-TiO₂/upconversion nanomaterials (UCNPs). Impressively, the ECL intensity of NH₂-TiO₂/UCNPs-rGO/GCE was remarkably enhanced by 29 times. Furthermore, the photoactive NH₂-TiO₂ layer provided not only specific selectivity but also a large surface area as well as an unprecedented photocatalytic activity for the NH₂-TiO₂/UCNPs-rGO/GCE ECL sensor (TIECLS), which could serve as an identification element for trace phosphoproteins. Under optimal conditions, the TIECLS achieved a relatively low detection limit of 9.2 × 10^-5 mg/mL (S/N = 3). Practical application of this TIECLS was carried out in different food samples with satisfying results, which were validated by laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS).

Comparative Proteomics of Milk Fat Globule Membrane (MFGM) Proteome across Species and Lactation Stages and the Potentials of MFGM Fractions in Infant Formula Preparation

Milk is a lipid-in-water emulsion with a primary role in the nutrition of newborns. Milk fat globules (MFGs) are a mixture of proteins and lipids with nutraceutical properties related to the milk fat globule membrane (MFGM), which protects them, thus preventing their coalescence. Human and bovine MFGM proteomes have been extensively characterized in terms of their formation, maturation, and composition. Here, we review the most recent comparative proteomic analyses of MFGM proteome, above all from humans and bovines, but also from other species. The major MFGM proteins are found in all the MFGM proteomes of the different species, although there are variations in protein expression levels and molecular functions across species and lactation stages. Given the similarities between the human and bovine MFGM and the bioactive properties of MFGM components, several attempts have been made to supplement infant formulas (IFs), mainly with polar lipid fractions of bovine MFGM and to a lesser extent with protein fractions. The aim is thus to narrow the gap between human breast milk and cow-based IFs. Despite the few attempts made to date, supplementation with MFGM proteins seems promising as MFGM lipid supplementation. A deeper understanding of MFGM proteomes should lead to better results.