Proteomic Characterization of Nonenzymatic Modifications Induced in Bovine Milk Following Thermal Treatments

Bovine milk and dairy products are heated according to various technological processes to preserve microbiological safety and extend their shelf-life. These treatments induce structural modifications in milk proteins, among which those associated with the Maillard reaction present a relevant significance. In the last decade, various bottom-up proteomic approaches have been used to characterize the modifications induced in model systems and in purified proteins from heated bovine milk samples, including the assignment of the modified amino acids. Similarly, various gel-based and shotgun proteomic approaches have been utilized for the identification and structural characterization of glycation/glycoxidation/oxidation protein targets in various commercial milks. This information is important for milk nutritional, biological, and immunogenic properties, since thermally-modified milk proteins are a large component of the human diet, either directly or as ingredients in other foods. This article provides an updated overview of the proteomic procedures developed for the proteomic characterization of heated milk, emphasizing the limits associated with the concomitant sheer diversity, chemical complexity, and variable abundance of the derivatives to be assayed.