A process for the isolation and/or purification of a desired component, particularly 3&prime；sialyl lactose, from whey, particularly cheese whey, comprising the steps of: optionally subjecting the whey to ultrafiltration to provide a protein concentrate and a whey permeate； contacting the whey or whey permeate with at least one series of ion exchange resins, said series comprising a first weak acid cation resin, a first weak base anion resin, a second strong acid cation resin, a second weak base anion resin to demineralize the whey permeate； contacting this demineralized permeate with two final ion exchange resins comprising a strong acid cation resin and a final weak base anion resin, wherein the desired component, such as 3&prime； sialyl lactose, is taken up on the final anion resin； and eluting the desired component from the final anion resin.
