b-Caseinephospholipid monolayers as model systems to understand lipideprotein interactions in the milk fat globule membrane

Phospholipideprotein monolayer films were studied as model systems to mimic the structure of the native bovine milk fat globule membrane (MFGM) and to understand lipideprotein interactions at the surface of the globule. Phospholipids extracted from bovine raw milk, raw cream, processed milk and buttermilk powder were spread onto the airewater interface of a Langmuir trough, b-casein was then added to the sub-phase, and LangmuireBlodgett films were studied by epifluorescence microscopy and atomic force microscopy. In all films, b-casein was responsible for clustering of the sphingomyelinand cholesterol-rich microdomains into larger platforms. This suggests that the same phenomenon may happen at the surface of the milk fat globule, where specific MFGM proteins may cause aggregation of