A comparative structural and proteomic analysis of bovine milk fat globule membrane (MFGM) ingredients: Industrial vs laboratory isolation approaches

Composition and functionality of milk fat globule membrane (MFGM)-based ingredients being prepared at either laboratory or industrial scale vary with their processing history. Using confocal microscopy (with raw milk reference) and label-free proteomics, this study systematically compared four bovine MFGM-related materials: whey-derived acid whey powder (AWP), cream-derived buttermilk powder (BMP), refined commercial whey-fat concentrate (WFC), and laboratory-prepared MFGM fraction (MFGM-lab). Microscopy revealed substantial processing-induced structural alterations. Proteomics identified 1128 proteins in MFGM-lab, the highest among all samples, with MFGM-associated proteins constituting 36% of its proteome, compared to 20% in WFC. A fundamental compositional dichotomy was uncovered: WFC was enriched in key extracellular vesicle (EV)-associated proteins (e.g., tetraspanins) and immunomodulatory proteins, whereas MFGM-lab contained a comprehensive profile of both canonical MFGM and intracellular proteins. These findings enable a targeted selection of MFGM ingredients - WFC for EV-oriented bioactivities or MFGM-lab for proteomic coverage - bridging fundamental research with product innovation.