The effect of thermosonication sterilization treatment on milk fat globule membrane proteins in camel milk using label-free proteomics

In the modern dairy industry, pasteurization is used to reduce bacterial loads and increase the shelf life of milk products. Milk fat globule membrane (MFGM) proteins are crucial nutritional components in milk and are involved in many biological functions. However, little is known about the effect of low-temperature sterilization on MFGM proteins in camel milk. The purpose of this study was to investigate the effects of pasteurized and thermosonication (TS) treatments on MFGM proteins using label-free quantitative proteomics. Compared to fresh milk, 347 and 258 significant differentially expressed MFGM proteins (DEPs) were identified in pasteurized and TS milk, respectively. The DEPs in both treatments had similar functional annotations, with cell process, cell and binding being the predominant Gene Ontology (GO) annotations, while the number of proteins involved in these categories was significantly different. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis indicated that the DEPs were significantly enriched in ribosome and complement and coagulation cascades in both groups. Notably, the number of proteins in complement and coagulation cascades was significantly greater than in pasteurized milk, suggesting that TS milk may be more beneficial for the expression of immune-related proteins. Furthermore, TS treatment increased the abundance of lactotransferrin isoform X2 (LTF) and lactadherin (MFGE8), which are involved in immunoregulation. In conclusion, the composition and functional properties of MFGM proteins were influenced by low-temperature treatments, with the effect of TS treatment on immune-related MFGM proteins significantly greater than that in pasteurized treatment. • A total of 3,569 MFGM proteins were identified in fresh, low-temperature long-term pasteurization, and thermosonication milk. • 347 and 258 significant differentially expressed MFGM proteins were identified in pasteurization and thermosonication milk, compared to fresh milk. • The differentially expressed MFGM proteins had similar GO annotations and KEGG pathways while the number of proteins involved in these was significantly different. • The immune-related MFGM proteins in thermosonication milk were significantly greater than those in low-temperature long-term pasteurization treatment.