Driven by the acknowledged health and functional properties of milk fat globules (MFGs), there is a growing interest to develop gentle methodologies for separation of fat from milk. In this study, separation of fat from raw milk and fractionation in streams containing MFGs of different size was achieved using a series of two silicon carbide ceramic membranes. A first step consisting of a 1.4 µm membrane aimed to concentrate the bulk of the fat, i.e. the larger MFGs (D[4,3] ∼ 4 µm) followed by a 0.5 µm fractionation aimed to concentrate the residual milk fat in the permeate, i.e. fraction with the smaller MFGs (D[4,3] ∼ 1.8-2.4 µm. The fat separation performance showed a yield of 92 % for the 1.4 µm membrane and 97 % for the 0.5 µm membrane. Both fat enriched retentates showed, by the confocal laser scanning microscopy, intact MFGs with limited damage in the MFG membrane. The fatty acid profile analysis and SAXS showed minor differences in fat acid composition and the crystallization behavior was related to differences in the fat content. The 0.5 µm permeate containing the smallest MFGs however showed larger aggregates and a trinomial particle size distribution, due to probably pore pressure induced coalescences. The series of silicon carbide membranes showed potential to concentrate some of MFGM proteins such as Periodic Schiff base 3/4 and cluster of differentiation 36 especially in the 0.5 µm retentates. A shift in casein to whey protein ratio from 80:20 (milk) to 50:50 was obtained in the final 0.5 µm permeate, which opens new opportunities for product development.

Exosomes are cell-derived extracellular vesicles (EVs) with diameters between 30 and 120 nm. In recent years, several studies have evaluated the therapeutic potential of exosomes derived from different fluids due to their low immunogenicity and high biocompatibility. However, producing exosomes on a large scale is still challenging. One of the fluids from which they could be isolated in large quantities is milk. Moreover, regeneration is a well-known property of milk. The present work seeks to optimize a method for isolating exosomes from bovine and human milk, comparing different storage conditions and different extraction protocols. We found differences in the yield extraction associated with pre-storage milk conditions and observed some differences according to the processing agent. When we removed milk fat globules and added rennet before freezing, we obtained a cleaner final fraction. In summary, we attempted to optimize a rennet-based new milk-exosome isolation method and concluded that pre-treatment, followed by freezing of samples, yielded the best exosome population.

Milk fat globules or milk fat globule membranes (MFGs/MFGM) have been added to the infant formula to fortify the phospholipids and narrow the nutritional gap from breast milk. The main aim of this study was to profile the interfacial and thermal properties of MFGs/MFGM prepared from ultrasonicated bovine milk. Bovine milk was sonicated at ultrasonic intensities of 20 kHz and 40 kHz independently or synchronously with the duration time of 0 min (control), 5 min, 10 min, and 15 min (work/rest cycles = 5 s: 3 s). Ultrasonic treatments at 20 kHz/ 5 min and 20 + 40 kHz/ 5 min improved the volume density (%) of smaller particles (1-10 µm) while significantly decreasing the surface hydrophobicity (H0) (p < 0.05). 40 kHz/5 min samples showed significantly higher ζ- potential than the other samples (p < 0.05), which might be because more negative charges were detected. In comparison with control samples, ultrasonic treatments decreased the interfacial tension (π) between the air and MFGs/MFGM liquid phase. 20 kHz ultra-sonicated treatments decreased the diffusion rate (k diff) of MFGs/MFGM interfacial compositions significantly as the duration prolonged from 5 min to 15 min (p < 0.05) but did not affect the adsorption or penetration rate (k a) (p > 0.05). X-ray diffraction (XRD) results showed that α-crystal peaks only existed in control and ultrasonicated 5 min samples but disappeared in all 15 min samples. According to the different scanning calorimetry (DSC), one or two new exothermic events (in the range of 17.29 - 18.81 ℃ and 22.14 - 25.21 ℃) appeared after ultrasonic treatments, which, however, were not found in control samples. Ultrasonic treatments resulted in the low-melting fractions (LMF) (TM1) peaks undetectable in MFGs/MFGM samples in which only peaks of medium-melting fractions (MMF) (TM2) and high-melting fractions (HMF) (TM3) were detected. Compared with the control, both enthalpies of crystallisation (ΔHC) and melting (ΔHM) decreased in ultrasonicated samples. In conclusion, ultrasonic treatment affects the interfacial and thermal properties of MFGs/MFGM.

Hypothyroidism has been found to have an effect on the nutritional composition of human milk during pregnancy. This study aims to explore the combined influence of rheological properties, macronutrient content, particle size, and the zeta potential of milk fat globules, as well as the composition of milk fat globule membrane (MFGM) proteins on the quality of human milk in gestational hypothyroidism. The study revealed that human milk from the group with hypothyroidism during pregnancy (AHM) was less viscoelastic and stable when compared with normal pregnancy group human milk (NHM). Furthermore, the particle size and macronutrient content of NHM were found to be larger than that of AHM. In contrast, the zeta potential of AHM was greater than that of NHM. The sodium dodecyl sulfate-PAGE results disclosed that the composition of MFGM proteins in these 2 groups were generally the same, but the content of AHM was lower than that of NHM. In conclusion, this study confirms that hypothyroidism during pregnancy can have a significant effect on the quality of human milk.

Milk fat globules (MFGs) have tri-layer biological membrane structures, and their compositions are gaining more interest for their physiological benefits. In this study, the changes in MFGs and milk fat globule membrane (MFGM) proteins after cream separation from different pH bovine raw milk were investigated. Raw milk samples were adjusted to pH 5.30 and 6.30 using citric acid at 25 °C. The effect of pH and centrifugation on the structure of MFGs was evaluated by means of particle size, zeta potential and confocal laser scanning microscopy (CLSM). Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) was used to analyze the proteins in the obtained fractions. It was found that both pH and centrifugation could affect the particle size of all samples. As the volume distribution (Dv; Dv (10), Dv(50)and Dv (90)) decreased, the corresponding specific surface area (SSA) increased, and span and uniformity values showed the same trend. The decrease in the zeta potential of MFG correlated with the Dv(50), which was further confirmed by CLSM observation. More butyrophilin (BTN) and periodic acid Schiff 6/7 (PAS 6/7) were lost in cream samples at pH 5.30. The findings could provide valuable knowledge for the application of MFGs ingredient in the food industry since their structures and compositions could affect their potential functional and physiological properties.

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.

The different TAG, interfacial properties and digestion rate between goat and cow milk fat globules were investigated. The mechanism of their different lipid digestion was also elucidated. Raw goat milk fat globules had smaller size, less large molecular weight and unsaturated TAG, larger liquid-ordered region and fewer glycoproteins, which contributed to the higher digestion rate than cow milk. After homogenization, the goat lipids also had higher digestion rate that was attributed to the special structure of easy-to-digest TAG and less glycosylated molecules not globule size. More integrated phospholipid layers and glycosylated molecules of HTST milk fat globules resulted in a lower lipid digestion rate than other processed milks. No difference in digestion rate between pasteurized goat and cow milk fat globules might be explained by the more denatured proteins and glycosylated molecules, respectively. Therefore, the TAG and interfacial properties contributed to different digestion between goat and cow milk fat globules.

Factors affecting milk and milk fraction composition, such as cream, are poorly understood, with most research and human health application associated with cow cream. In this study, proteomic and lipidomic analyses were performed on cow, goat, sheep and Bubalus bubalis (from now on referred to as buffalo), bulk milk cream samples. Confocal laser scanning microscopy was used to determine the composition, including protein, lipid and their glycoconjugates, and the structure of the milk fat globules. BLAST2GO was used to annotate functional indicators of cream protein. Functional annotation of protein highlighted a broad level of similarity between species. However, investigation of specific biological process terms revealed distinct differences in antigen processing and presentation, activation, and production of molecular mediators of the immune response. Lipid analyses revealed that saturated fatty acids were lowest in sheep cream and similar in the cream of the other species. Palmitic acid was highest in cow and lowest in sheep cream. Cow and sheep milk fat globules were associated with thick patches of protein on the surface, while buffalo and goat milk fat globules were associated with larger areas of aggregated protein and significant surface adsorbed protein, respectively. This study highlights the differences between cow, goat, sheep, and buffalo milk cream, which can be used to support their potential application in functional foods such as infant milk formula.

Recently, camel milk (CM) has been considered as a health-promoting icon due to its medicinal and nutritional benefits. CM fat globule membrane has numerous health-promoting properties, such as anti-adhesion and anti-bacterial properties, which are suitable for people who are allergic to cow\'s milk. CM contains milk fat globules with a small size, which accounts for their rapid digestion. Moreover, it also comprises lower amounts of cholesterol and saturated fatty acids concurrent with higher levels of essential fatty acids than cow milk, with an improved lipid profile manifested by reducing cholesterol levels in the blood. In addition, it is rich in phospholipids, especially plasmalogens and sphingomyelin, suggesting that CM fat may meet the daily nutritional requirements of adults and infants. Thus, CM and its dairy products have become more attractive for consumers. In view of this, we performed a comprehensive review of CM fat\'s composition and nutritional properties. The overall goal is to increase knowledge related to CM fat characteristics and modify its unfavorable perception. Future studies are expected to be directed toward a better understanding of CM fat, which appears to be promising in the design and formulation of new products with significant health-promoting benefits.

Milk fat is an essential nutrient for infant development. The effects and mechanisms of human, caprine, and bovine milk fat globules (MFGs) on the gut microbiota were investigated in this study. Human MFGs enhance the efficacy of probiotics by inhibiting pathogen function. Akkermansia and Bifidobacterium were identified as the dominant microbiota by human MFGs. Mucin and complement inhibitory proteins in human MFGs were found to inhibit different pathogens. Caprine MFGs directly promoted the colonization of probiotics and the emergence of the biomarker Allobaculum. Mucin 1 in caprine MFGs was primarily responsible for inducing probiotic adhesion. Bovine MFGs increased the abundance of Oscillospira, which reduces the risk of obesity. Due to the enrichment of cell-cell junction proteins and the lack of mucin, the regulation of gut microecology by bovine MFGs was not readily apparent. In short, this study paves the way for the development of functional infant formula.