Distribution and isolation of milk fat globule membrane proteins during dairy processing as revealed by proteomic analysis

The milk fat globule membrane (MFGM) has received great attention due to health-beneficial properties, highlighting the potential to use MFGM isolates in manufacturing nutraceutical and functional foods. A proteomic approach employing liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used to evaluate a procedure to isolate MFGM from milk and to determine the distribution of MFGM proteins during dairy processing. In total, 225 MFGM-associated proteins were identified. Among the newly found MFGM-associated proteins, 25 were detected with greater than five peptide matches. The distribution of MFGM proteins into buttermilk and butter during churning of cream was different, especially for minor MFGM proteins. Microfiltration of reconstituted industrial buttermilk after dissociating the casein micelles resulted in a change of protein prevalence in the retentate, leading to a greater number of minor MFGM proteins detected using LC-MS/MS.