Extraction of protein having at least one hydrophobic pocket and a negative charge at the natural pH of the milk, present in milk comprises skimming and defatting the milk, passing the defatted and skimmed fraction containing the protein on a chromatography medium on which a ligand having both hydrophobic and ionic character is grafted under pH conditions that retains the protein on the medium, eluting the protein, purifying the eluted fraction by removing the milk proteins from the eluted fraction and recovering the protein. An independent claim is included for the use of a positive zeta potential filter glass for simultaneously skimming and defatting the milk.
