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• Application of structured illumination microscopy to examine milk ultrastructure. • Pasteurization significantly impacts PC and SM in the outer membrane. • Heat treatment reduces glycerolipids with AA/DHA and glycerophospholipids. • Addition of phospholipids and freeze-drying enhance polar lipid content. • SIM effectively displays nanoscale changes in fat globules during processing. The introduction of exogenous lipids in the production of infant formula induces significant alterations in milk lipid composition, content, and membrane structure, thus affecting the lipid digestion, absorption, and utilization. This study meticulously tracks these changes throughout the manufacturing process. Pasteurization has a significant effect on phosphatidylcholine and sphingomyelin in the outer membrane, decreasing their relative contents to total polar lipids from 12.52% and 17.34% to 7.72% and 12.59%, respectively. Subsequent processes, including bactericidal-concentration and spray-drying, demonstrate the thermal stability of sphingomyelin and ceramides, while glycerolipids with arachidonic acid/docosahexaenoic acid and glycerophospholipids, particularly phosphatidylethanolamine, diminish significantly. Polar lipids addition and freeze-drying technology significantly enhance the polar lipid content and improve microscopic morphology of infant formula. These findings reveal the diverse effects of technological processes on glycerolipid and polar lipid compositions, concentration, and ultrastructure in infant formulas, thus offering crucial insights for optimizing lipid content and structure within infant formula. [ABSTRACT FROM AUTHOR]

For the enrichment of milk with vitamin A and β-carotene, vitaton is used, which contains up to 10% of trans-β-carotene, which can be converted into vitamin A, and demonstrate antioxidant, immunostimulating and anticarcinogenic effects in the body. Previous studies have demonstrated that in sanitary terms, the biomass of the fungus Bl. trispora is safe for animals and can be used in animal husbandry to prevent diseases of the mammary gland, and digestive organs, increase reproductive function and obtain healthy viable offspring. The research was conducted on cows of the Ukrainian black-and-white dairy breed in the conditions of LLC “Kuibysheve”, Poltava region. The purpose of the research was to determine the content of fatty acids in milk fat of lactating cows, as with the introduction of vitatons, lipids, higher saturated and unsaturated fatty acids, vitamins E and B, which to some extent can affect the processes of synthesis of milk components in the mammary gland. Determination of lipid content and their fractions in milk fat was performed on a gas chromatograph-mass spectrometer Agilent Technologies. Established that the introduction of vitaton in the diet for cows increases the fat content in milk by an average of 0.26% and enhances the synthesis of phospholipids in the mammary gland by 1.8 times. The ratio of unsaturated to saturated free fatty acids in the milk fat of cows of the experimental group did not vary from the control, which indicates a positive effect of β-carotene on the intensity of milk fat biosynthesis in the secretory epithelium of the mammary gland of cows. Vitaton stimulated the establishment and inclusion of two unsaturated fatty acids, namely nonadecanoic and α-linolenic acids in the composition of milk fat against the background of the disappearance of the arachidonic acid peak on the chromatogram. It is established that the samples of milk fat from cows of the control group contained arachidonic acid, which was absent in the milk of cows of the experimental group, which is probably due to the inclusion of these higher fatty acids and their isomers, which are part of vitaton, in the composition of milk fat, and the effect of β-carotene on the synthesis of milk lipids. The results of the research are essential for the production of biologically complete milk and its products, which will have antioxidant properties and will be enriched with vitamin A and β-carotene [ABSTRACT FROM AUTHOR]

Reverse osmosis with polyamide spiral wound membranes is used to concentrate milk to reduce its volume before transport to processing facilities. The main aim of this work was to identify the cause of unusually low flux through a membrane that had been used in an industrial facility. The fluxes of new and used industrial membranes were measured using a flat-sheet cross-flow laboratory system. It was found that the fouling characteristics of laboratory fouled membranes were entirely different from the industrial membrane. The laboratory membranes could be restored to a high flux with a regime of water flushing, caustic and acid. FTIR showed no significant build-up on the membrane. In contrast the industrial membrane could not be cleaned in this manner. FTIR and FT-Raman showed species associated with milk lipids. Cleaning by solvent extraction using a two-phase mixture of water, isopropanol and cyclohexane increased the flux from 1% to almost 50% of the value of a new membrane. Analysis of the solvent-extracted material indicated the presence of phospholipids with a relatively high concentration of sphingomyelin. It was concluded that the laboratory experiments did not mimic industrial processes and an effective industrial cleaning system was not found. [ABSTRACT FROM AUTHOR]

• Metabolomics and lipidomics were employed to analysis raw milk quality of cows. • Subclinical ketosis affected the profiles of metabolites and lipid species. • Subclinical ketosis cows had lower percentage of PUFA and CLA than healthy cows. • Fifteen volatiles were identified to be correlated with the health status of cows. • The nutritional quality of milk of subclinical ketosis cows were reduced. The metabolic status of dairy cows directly influences the nutritional quality and flavor of raw milk. A comprehensive comparison of non-volatile metabolites and volatile compounds in raw milk from healthy and subclinical ketosis (SCK) cows was performed using LC–MS, GC-FID, and HS-SPME/GC–MS. SCK can significantly alter the profiles of water-soluble non-volatile metabolites, lipids, and volatile compounds of raw milk. Compared with healthy cows, milk from SCK cows had higher contents of tyrosine, leucine, isoleucine, galactose-1-phosphate, carnitine, citrate, phosphatidylethanolamine species, acetone, 2-butanone, hexanal, dimethyl disulfide and lower content of creatinine, taurine, choline, α-ketoglutaric acid, fumarate, triglyceride species, ethyl butanoate, ethyl acetate, and heptanal. The percentage of polyunsaturated fatty acids in milk was lowered in SCK cows. Our results suggest that SCK can change milk metabolite profiles, disrupt the lipid composition of milk fat globule membrane, decrease the nutritional value, and increase the volatile compounds associated with off-flavors in milk. [ABSTRACT FROM AUTHOR]

[Display omitted] The milk fat globule membrane (MFGM) provides infants and adults with several health benefits. These are not derived solely from its unique composition, but also from arrangement of lipids in the MFGM that, in the case of newborns, could reach the intestine partially intact. Fluorochromes associated with lipid derivatives were used to prove a fusion process between the MFGM and the cellular membrane of differentiated Caco-2 cells. To explore the mechanism of this interaction, incubations of MFGM with Caco-2 cells were carried out in the presence of fusogenic agents or compounds that block other MFGM interaction pathways with cells. Confocal fluorescence microscopy provided visual evidence of the fusion process. Lastly, determination on the lipid profile of cells after their interaction with MFGM indicated a metabolic rearrangement of lipids leading to accumulation of triacylglycerols. [ABSTRACT FROM AUTHOR]

The naturally occurring milk sphingomyelin is of particular interest owing to its complex composition and involvement in the formation of the milk fat globule membrane (MFGM). Knowledge of membrane organization and nanomechanical stability has proved to be crucial in understanding their properties and functions. In this work, two model membrane systems composed of 1, 2 dioleoyl- sn -glycero-3-phosphocholine (DOPC), egg sphingomyelin (egg-SM) and cholesterol, and DOPC, milk sphingomyelin (milk-SM) and cholesterol were exposed to both RT and 10 °C. The morphological and nanomechanical changes were investigated using atomic force microscopy (AFM) imaging and force mapping below RT using a designed liquid cell with temperature-control. In both systems, the size and shape of SM/Chol-enriched liquid ordered domains (L o ) and DOPC-enriched liquid disordered phase (L d ) were monitored at controlled temperatures. AFM based force-mapping showed that rupture forces were consistently higher for L o domains than L d phases and were decreased for L d with decreasing temperature while an increase in breakthrough force was observed in L o domains. More interestingly, dynamic changes and defect formations in the hydrated lipid bilayers were mostly detected at low temperature, suggesting a rearrangement of lipid molecules to relieve additional tension introduced upon cooling. Noteworthy, in these model membrane systems, tension-driven defects generally heal on reheating the sample. The results of this work bring new insights to low temperature induced membrane structural reorganization and mechanical stability changes which will bring us one step closer to understand more complex systems such as the MFGM. [ABSTRACT FROM AUTHOR]

Lipids are a complex group of chemical compounds that are a significant component of the human diet and are one of the main constituents of milk. In mammals, lipids are produced in the milk-secreting cells in the form of milk fat globules. The chemical properties of these compounds necessitate developing separate processes for effective management of non-polar substances in the polar environment of the cell, not only during their biosynthesis and accumulation in the cell interior and secretion of intracytoplasmic lipid droplets outside the cell, but also during digestion in the offspring. Phospholipids play an important role in these processes. Their characteristic properties make them indispensable for the secretion of milk fat as well as other milk components. This review investigates how these processes depend on the coordinated flux and availability of phospholipids and how the relationship between the surface area (phospholipids) and volume (neutral lipids) of the cytoplasmic lipid droplets must be in biosynthetic balance. The structure formed as a result (i.e. a milk fat globule) is therefore a result of specified structural limitations inside the cell, whose overcoming enables the coordinated secretion of milk components. This structure and its composition also reflects the nutritional demands of the developing infant organism as a result of evolutionary adaptation. [ABSTRACT FROM AUTHOR]

• Identification of 1302 molecular species in bovine milk. • Seasonal and feeding-related differences between hay and regular milk. • Short- and medium-odd chain TGs were upregulated in hay milk during summer. • Short- and medium-even chain TGs increased in regular milk during spring and winter. • Lipidomes in hay and regular milk were different along the industrial processing. Bovine milk plays an important role in human nutrition and is one of the main products of dairy industry. Its composition changes in response to various factors including forage, which are rapidly reflected by the milk lipidome. Most cows receive a silage-based diet despite a recent trend towards more traditional husbandry relying on hay-feeding. Here, changes in the lipidome upon different animal diets were addressed by studying milk of cows from two different feeding regimes and associated seasonal variations over one year. Extracted lipids were analyzed by reversed-phase liquid chromatography coupled on-line to high resolution mass spectrometry. Overall, 1302 lipid molecular species were identified including 1038 triacylglycerides (∼80%), whereas the remaining 20% were represented by a variety of species from twelve lipid classes. A semi-absolute quantitation of 264 lipid species showed diet- and season-induced variations in the milk lipidome with many odd chain triacylglycerides upregulated in hay milk. [ABSTRACT FROM AUTHOR]

Objective: The effect of milk lipids compared to sardine oil on antioxidant enzymes activities was evaluated in rats fed an atherogenic diet. Methods: Male Wistar rats were divided into three groups (n = 8 for each). Two experimental groups received a 20% casein diet combined with 5% milk lipids or sardine oil and 1% cholesterol for 4 weeks. The control group was fed a standard diet without cholesterol. Results: In red blood cells, superoxide dismutase (SOD) activity was 1.4- and 1.3-fold higher in the milk lipids group compared to the sardine oil and control groups, respectively. In tissues, SOD activity was respectively 2.5- and 1.8-fold lower in heart and aorta, but 1.2- fold higher in liver of rats fed milk lipids compared to those fed sardine oil. In milk lipids group, liver glutathione reductase (GR) and catalase (CAT) activities were respectively 2.5- and 1.2- fold lower compared to sardine oil group. In contrast, liver and heart glutathione peroxidase (GSH-Px) activities were respectively 1.2- and 2.3-fold higher. In aorta, milk lipids decreased SOD, GR, GSH-Px, and CAT activities and the values were respectively 1.8-, 1.7-, 1.2- and 1.5-fold lower than those found in the sardine oil group. Brain GSH-Px and CAT activities were respectively increased by 1.2- and 1.9-fold in the milk lipids group compared with the sardine oil. Milk lipids improved lecithin:cholesterol acyltransferase (LCAT) activity (2.5-fold) when compared with sardine oil. However, serum paraoxonase (PON)1 activity was 2-fold lower in milk lipids group vs control whereas, compared with the sardine oil group, PON1 activity had a tendency to decrease, but not significantly. Conclusion: This study shows that milk lipids and sardine oil intake modulate differently enzymatic antioxidant defense in hypercholesterolemic rats. Milk lipids improve reverse cholesterol transport from peripheral tissues to the liver by enhancing LCAT activity, leading to anti-atherogenic effects. [ABSTRACT FROM AUTHOR]

Highlights: [•] GC×GC–MS/FID was used for the analysis of the unsaponifiable fraction of milk lipids. [•] The structure of many constituents was confirmed by using GC–high resolution ToF MS. [•] Sensitivity and group-type patterns were the GC×GC characteristics most exploited. [ABSTRACT FROM AUTHOR]

Abstract: Milk has co-evolved with mammals and mankind to nourish their offspring and is a biological fluid of unique complexity and richness. It contains all necessary nutrients for the growth and development of the newborn. Structure and function of biomolecules in milk such as the macronutrients (glyco-) proteins, lipids, and oligosaccharides are central topics in nutritional research. Omics disciplines such as proteomics, glycomics, glycoproteomics, and lipidomics enable comprehensive analysis of these biomolecule components in food science and industry. Mass spectrometry has largely expanded our knowledge on these milk bioactives as it enables identification, quantification and characterization of milk proteins, carbohydrates, and lipids. In this article, we describe the biological importance of milk macronutrients and review the application of proteomics, glycomics, glycoproteomics, and lipidomics to the analysis of milk. Proteomics is a central platform among the Omics tools that have more recently been adapted and applied to nutrition and health research in order to deliver biomarkers for health and comfort as well as to discover beneficial food bioactives. [Copyright &y& Elsevier]

• First adoption of Paterno-Buchi reaction in studying milk lipid fine structure. • Unsaturated fatty acids show a non-specific regio-distribution in phospholipids. • Regioisomers are widespread in milk phospholipid species. • Double-bond isomers of C18:1 and C18:2 are widely detected in milk phospholipids. Hundreds of phospholipid (PL) species with defined fatty acid (FA) composition have been identified previously in bovine milk using liquid chromatography tandem mass spectrometry (LC-MS/MS). Paterno-Buchi photochemical reaction coupled with LC-MS/MS was applied in this study to further unravel the regio-distribution and double bond (DB) locations of FAs. Using SPE-purified PLs and 2-acetylpyridine as the photochemical derivatization reagent, we were able to reveal the non-specific regio-distribution of unsaturated FAs and the widespread occurrence of regioisomers in milk PLs. Although Δ9 and Δ9,12 were found to be the predominant DB location(s) for C18:1 and C18:2 respectively, other DB positional isomers such as C18:1Δ11, C18:1Δ12 and C18:1Δ13 and C18:2Δ9,11 were widely detected in PL structures, implying that the minor isomers of C18:1 and C18:2 equally participate in the synthesis of PLs. Our study provides novel information on the fine structure of milk PLs and further underlines the complexity of milk lipid composition. [ABSTRACT FROM AUTHOR]

Several studies have been published regarding the effect of different factors on the digestion of milk lipids, considering their natural structural arrangement as milk fat globules and the efficiency of the digestive enzymes in the lipolysis of such complex structures. During digestion, the lipolytic products are dispersed in vesicles and micelles, which are the source for absorption of digested lipids. Therefore, it is necessary to consider the isolation of the micellar phase from the digesta to appropriately determine the amounts and classes of lipids which are bioaccessible. This study presents an integrative approach that included an isolation procedure to separate the micellar fraction from undigested and non-micellar parts, and the distribution of digested milk lipids in micelles determined directly through chromatographic techniques. Four groups of five full term mothers donated colostrum or mature milk. Two sets of samples were analyzed directly (raw), and two sets were pasteurized and then analyzed. Our data revealed that the profile of digested milk lipids is different depending on the lactation period and processing stage, while the carbon atom number distribution of the digested triacylglycerols in the micellar fraction provides a substantial information regarding the acylglycerols species that are less available for absorption. [ABSTRACT FROM AUTHOR]