Buffalo milk fat globules and their biological membrane: [i]in situ[/i] structural investigations
Résumé
Milk fat globules and their surrounding biological membrane (the MFGM) are not well understood despite the
importance of thesemilk components in human nutrition and the role of fat globules in determining the properties
of dairy products. The objectives of this study were to investigate these unique colloidal assemblies and the
microstructure of the MFGM in buffalo milk, which is the second largest global source of dairy products. In-situ
structural investigations were performed at roomtemperature using confocalmicroscopy withmultiple fluorescent
probes (Nile Red, Rh-DOPE, the lectinWGA-488). Microscopic observations showed cytoplasmic crescents
around fat globules and the heterogeneous distribution of glycosylatedmolecules and polar lipidswith the occurrence of lipid domains. The lipid domains in the buffaloMFGMappear to formby the segregation of lipids with a
high phase transition temperature (e.g. sphingomyelin and saturated phosphatidylcholine molecular species)
and cholesterol resulting in a gel phase or a Lo phase forming circular domains. The structure of the buffalo
MFGM results from a non-random mixing of components, consistent with observations for other species. Structural
heterogeneities of theMFGMcould affect the processability of buffalo fat globules and the bioavailability of
milk lipids.