Abstract: A process for the selective and quantitative elimination of lactoglobulins from a starting material containing whey proteins, wherein the starting material is brought into contact with a strongly basic type anion exchanger, the pH of the starting material being between 4 and 6 when the ash content of the starting material is between 0 and at most 1% by weight, and between 6 and 8 when the ash content is between more than 1% and 3% by weight, so as to retain the lactoglobulins selectively and quantitatively on the anion exchanger, the anion exchanger on which the lactoglobulins are retained is separated from the remainder of the starting material and the remainder, free from lactoglobulins, is collected.

Abstract: The invention relates to biotechnology. It concerns a partial hydrolysate whey proteins which contains no residual whole proteins characterized in that it contains peptides spread over the following distribution, as a function of their molar mass:______________________________________ Proportion by weight Molar mass (as g peptides per (g per mole) 100 g total peptides) ______________________________________ MM>5000 0-5 5000>MM>3500 15-25 3500>MM>1500 20-30 1500>MM>500 35-45 MM<500 5-10 ______________________________________as well as the free amino acids; the free amino acid content of the hydrolysate being less than 10% (calculated as grammes of nitrogen per 100 grammes of total nitrogen), as well as an enzymatic product for its preparation:Application to the production of dietetic milk foods.