Fuente: WIPO "milk" The invention relates to a process for producing a ��-casein glycomacropeptide. The pH of a solution of milk starting materials containing the ��-casein glycomacropeptide is adjusted to below 4. The solution is treated by ultrafiltration with a membrane having a fraction molecular weight of 10,000-50,000. The obtained filtrate is concentrated with a membrane having a fraction molecular weight of 50,000 or less. In a preferred process the pH value of the filtrate obtained by the ultrafiltration treatment is readjusted to 4 or higher before the filtrate is concentrated. The molecular weight of the ��-casein glycomacropeptides sharply changes at pH 4.