Comparison of bovine milk fat globule membrane protein retention by different ultrafiltration membranes using a label-free proteomic approach

Abstract

Abstract Ultrafiltration (UF) is an effective method for separating and enriching milk proteins. This study aims to analyze the protein profile of milk fat globule membrane (MFGM) materials enriched by UF membranes from butter serum with different molecular mass cutoffs through a label-free proteomic approach. In total, 616 MFGM proteins were identified in all groups, of which 395, 399, 399 and 484 proteins were identified with a 30\xa0kDa, 50\xa0kDa and 100\xa0kDa UF membrane and without UF, respectively. It was more efficient to enrich fatty acid binding protein and mucin 15 using a 30\xa0kDa membrane, whereas mucin 1 was more abundant when using a 50\xa0kDa membrane. Compared with the 30\xa0kDa and 50\xa0kDa membranes, the 100\xa0kDa membrane led to the optimal efficiency with low permeation of the most major MFGM proteins and high permeation of non-MFGM proteins. Butyrophilin, adipophilin, xanthine oxidase/dehydrogenase, and periodic acid Shiff6/7 were concentrated approximately twofold in the 100\xa0kDa retentate. Meanwhile, the relative abundances of β-lactoglobulin and α-lactalbumin were reduced by approximately 17.3% and 16.2%, respectively. This work will facilitate the development of MFGM protein isolation using membrane separation processes and provide a theoretical reference for the production of MFGM proteins.