Process of purification of sialyllactose comprises obtaining sialyllactose enriched raffinate by ion exclusion chromatography of a solution containing the sialyllactose on a strong cationic resin in monovalent majority, i.e. sodium or potassium form. An independent claim is included for a process of enriching maternized milk with sialalylactose comprising production of the sialyllactose by the process and addition of the obtained sialyllactose with maternized milk or its precursor.L'invention fournit donc un procédé de purification de sialyllactose par chromatographie d'exclusion ionique d'une solution contenant le sialyllactose sur une résine cationique forte sous forme majoritaire monovalente, Na ou K, et obtention d'un raffinât enrichi en sialyllactose.
