Identification and comparison of milk fat globule membrane and whey proteins from Selle Français, Welsh pony, and Tieling Draft horse mare's milk

Horse's milk, with a high nutritional value and few allergenic proteins, could substitute cow's milk for infant consumption. Herein, a label-free, proteomic method was used to identify and compare milk fat globule membrane (MFGM) and whey proteins from three different horse breeds: Selle Français (SF), Welsh pony (WP), and Tieling Draft Horse (TDH). In MFGMs, 16 (SF), 66 (WP), and 45 (TDH) unique proteins were identified, which are involved in the endocytosis, ribosome, and staphylococcus aureus infection pathways, respectively. In whey, 31 (SF), 75 (WP), and 23 (TDH) unique proteins were identified, which are involved in the autophagy-animal, phenylalanine metabolism, and Vasopressin-regulated water reabsorption pathways, respectively. SF contained the lowest concentration of β-lactoglobulin, which can cause allergic reactions in humans. Our findings describe the nutritional differences and functional diversities of MFGM and whey proteins in different horse breeds, which could support developing formula more suitable for human infants.

Utilization of low-temperature heating method to improve skim milk production: Microstructure, stability, and constituents of milk fat globule membrane

In the process of defatting milk, preheating treatment is an important factor affecting the flavor of skim milk. Here, raw milk was preheated at different times and temperatures. Then laser confocal microscopy, multiple-light scattering instrument, and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) were used to analyze the microstructure of milk fat globule membrane (MFGM), milk stability, and MFGM protein (MFGMP) components. Results showed that phospholipid domain of MFGM changed from an ordered state (Lo) to a disordered state (Ld) with increase in treatment temperature and time, leading to an increase in MFGMP content in skim milk. During the stability test, the stability of raw milk decreased significantly with increase in preheating temperature, while the opposite was true for skim milk. Finally, the results of MFGMP differentiation analysis showed that, the content of ten taste-related MFGMPs in the control group samples was significantly lower compared to the optimal group (P < 0.05).

Quantitative label-free site-specific glycoproteomic analysis of the milk fat globule membrane protein in human colostrum and mature milk

Human milk fat globule membrane (MFGM) proteins, which are N-glycosylated, play essential roles in neonatal development and physiological health. However, the profiles and landscape changes in the site-specific N-glycosylation of human MFGM proteins during lactation remain unclear. Therefore, in this study, based on an intact glycopeptide-centred strategy, 2617 unique site-specific N-glycans of 221 MFGM glycoproteins in human colostrum and 986 unique site-specific N-glycans of 200 MFGM glycoproteins in mature milk were characterised and quantified using label-free glycoproteomics. With milk maturation, 33 site-specific N-glycans on 10 N-glycoproteins increased significantly, and 113 site-specific N-glycans on 25 N-glycoproteins decreased significantly. Moreover, human MFGM glycoproteins with core-α1,6-fucosylated structures and Lewis and sialylated branching structures play a role in the biological processes of antigen processing and presentation. This study reveals the dynamic changes in human MFGM protein N-glycosylation patterns during lactation. Meanwhile, the study deepens our understanding of site-specific N-glycosylation of human MFGM glycoproteins. The results of the study provide a background reference for the development of infant formulas.

Differences in milk fat globule membrane proteins among Murrah, Nili-Ravi and Mediterranean buffaloes revealed by a TMT proteomic approach

Milk fat globule membrane (MFGM) proteins contribute to human nutrition and health. However, differences in MFGM proteome among the buffalo breeds are unknown. In this study, MFGM proteins from Murrah, Nili-Ravi and Mediterranean buffaloes were identified using a tandem mass tag proteomic approach to characterize the components and their potential activities. A total of 1258 MFGM proteins were identified and 103 differentially expressed proteins were found in the studied buffalo breeds. Of these, toll-like receptor 2 had higher abundance in Mediterranean milk; endoplasmic reticulum resident protein 29 had higher levels in Nili-Ravi milk; uromodulin had higher abundance in Murrah milk. A number of 781 newly proteins in buffalo milk exerted antioxidant, antibacterial, and anti-inflammatory activities. Our findings reveal the component complexity and functional diversity of MFGM proteins in different buffalo breeds. Thus, our data may path the way to promote raw buffalo milk as a healthy and functional dairy product.