Alterations in the fat globule membrane proteome of cow, yak, buffalo, and camel milk in response to homogenization and heat treatment

Heat processing notably affects the heat-sensitive components of milk; however, comparative information on the milk fat globule membrane (MFGM) proteome among different species following homogenization and heat treatment remains limited. This study aimed to characterize alterations in MFGM proteins from Holstein cow, buffalo, camel, and yak milk subjected to homogenization and heat treatment using a label-free liquid chromatography-MS/MS proteomic approach. A total of 855, 636, 605, and 538 MFGM proteins were identified in Holstein cow, buffalo, camel, and yak milk, respectively, with 239 proteins co-expressed across all species. In general, homogenization and heat treatment influence the abundance of several proteins, including xanthine dehydrogenase or oxidase, perilipin-2, butyrophilin subfamily 1 member A1, lactoperoxidase, and lactoferrin, with the extent of these changes varying according to species and treatment intensity. Sulfhydryl oxidase 1(QSOX1) abundance increased in Holstein cow, camel, and yak milk after processing, whereas no significant change was observed in buffalo milk. Additionally, the levels of β-casein, κ-casein, α_S1-casein, and α_S2-casein increased following homogenization and heat treatment in Holstein cow, buffalo, and yak milk, and only κ-casein showed an increase in camel milk. Buffalo and yak milk MFGM were more susceptible to homogenization, whereas yak milk MFGM exhibited higher sensitivity to heat treatment. These findings enhance our understanding of species-specific responses of MFGM proteins to industrial processing and provide valuable insights for optimizing thermal processing strategies for milk from diverse dairy animals.