Phosphopeptides from casein-based material

A method for producing phosphopeptides from a casein-based raw material containing phosphocaseinates of bivalent cations comprising subjecting the raw material to an enzymatic hydrolysis at a pH in the range of 7 to 9 and a temperature in the range of 37.degree. to 45.degree. C. by means of at least one proteolytic enzyme capable of substantially reproducing the proteic digestion which occurs in vivo in the human body to produce a hydrolysate containing phosphopeptides and non-phosphorylated peptides, recovering the resulting hydrolyzate, subjecting said hydrolyzate to at least one ultrafiltration step on membranes capable of retaining the phosphopeptides while letting the non-phosphorylated peptides pass therethrough to produce an ultrafiltration retentate containing phosphopeptides and the proteolytic enzyme, recovering the retentate, disaggregating the phosphopeptides contained in said retentate by acidifying said retentate, or by subjecting said retentate to the action of complexing agents, subjecting the resultant retentate containing disaggregated phosphopeptides and proteolytic enzyme to at least a second ultrafiltration step on membranes which do not retain the phosphopeptides but which retain the enzyme and recovering the phosphopeptides that pass through the membranes in said second ultrafiltration step.