Protocol for isolation, fractionation, and system biology-based profiling of gastrointestinal digested dairy colostrum and milk proteome

Colostrum and milk from dairy sources consist of whey, casein, and fat, which have notable pharmacological properties due to their proteins and peptides. Here, we present a protocol for isolating, simulating in vitro gastrointestinal digestion, and fractionating colostrum and milk hydrolysates from any dairy source. We also describe steps for nano-liquid chromatography-electrospray ionization-tandem mass spectrometry (nano-LC-ESI-MS/MS) identification of proteins and peptides and in silico system biology-based profiling of the proteins and peptides present in the hydrolysates.