Changes in bovine milk fat globule membrane protein components of cream caused by different extent of churning using a label-free proteomic approach

Churning is a common method to separate milk fat globule membrane (MFGM) from milk fat globules. In this work, we qualitatively and relative quantitatively analyzed the MFGM components obtained by churning cream for different time using a label-free proteomic approach. The result showed that 794 MFGM proteins were identified in all groups, of which 51, 14, 60 and 44 unique proteins were contained after churning cream for 2 min, 4 min, 6 min and 8 min, respectively. The sample churned for 6 min possessed the largest portion of total and unique proteins compared with other three groups. The relative abundances of proteins butyrophilin and xanthine dehydrogenase/oxidase, proteins cluster of differentiation 36 and fatty acid binding protein had the same change tendency during the continuous agitation process. Some milk serum proteins also were detected in the buttermilk. The analysis of protein profiles of MFGM at different churning time had an important guidance for enriching a certain MFGM protein.