A method for easily and efficiently separating a sialyllactose material from a milk material by exploiting the pH-dependent interactions between whey proteins and sialyllactose is disclosed. The method comprises concentrating a milk material at a pH of 5.2 or lower to obtain a concentrate, adjusting the pH of the concentrate to 5.5 or higher, and obtaining a low-molecular-weight fraction from the pH-adjusted concentrate. Since the method also allows separation of sialyllactose from lactose and minerals, sialyllactose may be obtained at high purity. The resulting sialyllactose material is highly useful for food, pharmaceutical, and other applications.
