Process for preserving low-lactose or lactose-free milk product

A process for the preparation of a well-preserving low-lactose, lactose-free or carbohydrate-free milk product, comprising the steps of:

• separating sugars and proteins in a milk raw material or milk and whey raw material mixture into a sugar fraction and a protein fraction, respectively,
• thermally treating at least the protein fraction at 60 to 70° C. for 2 to 10 hours to inactivate the natural plasmin enzyme systems and other harmful enzymes therein either during or after the separation into the sugar and protein fractions,
• heat treating the thermally treated protein fraction and the sugar fraction, and
• composing the well-preserving low-lactose, lactose-free or carbohydrate-free milk product with a desired composition and sweetness from the resultant heat-treated protein fraction.