Lactose-containing product in powder form and production process thereof

Process for the production of a lactose-containing product in powder form having a dry matter content of at least 90% by weight on its total weight and comprising lactose in a quantity of at least 85% by weight on its total weight, wherein said product has a dispersed bulk density which is greater or equal to 0.65 g/cm3, said process comprising the steps of:

• a) providing a lactose-containing liquid having a dry matter content between 18% and 65% by weight on its total weight;
• b) concentrating said lactose-containing liquid at a temperature between 55° C. and 200° C., for a time comprised between 1 minute and 10 minutes and at a pressure which is lower or equal to 20000 Pa, until an over-concentrated fluid product having a dry matter content between 50% and 80% by weight on its total weight is obtained;
• c) mixing the over-concentrated fluid product obtained by the previous step with a lactose-containing powder having a dry matter content of at least 95% by weight on its total weight, until a powdered mixture having a dry matter content of at least 85% by weight on its total weight is obtained;
• d) drying said powdered mixture until said product in powder form having a dry matter content of at least 90% by weight on its total weight and containing lactose in a quantity of at least 85% by weight on its total weight is obtained, thereby obtaining fully formed crystals of α-lactose monohydrate, and said product in powder form being characterized by a melting enthalpy between −105 J/g and −125 J/g;
• wherein said concentration step b) comprises the following steps:
• providing a turbo-concentrator comprising a cylindrical tubular body having an inlet opening and a discharge opening, a heating jacket to bring the cylindrical tubular body to a predetermined temperature value, and a rotor, arranged in the cylindrical tubular body and comprising a shaft provided with elements radially projecting therefrom;
• supplying a continuous flow of said lactose-containing liquid in the turbo-concentrator, so as to form, through the action of the rotor, a turbulent film continuous flow;
• centrifuging the lactose-containing liquid against the inner wall of the turbo-concentrator, the rotor being driven into rotation at a speed which is higher or equal to 100 rpm, with formation of a highly turbulent, dynamic, thin tubular fluid film, the turbulent film of the lactose-containing liquid advancing in substantial contact with the inner wall of the turbo-concentrator towards the discharge opening, so as to obtain said over-concentrated fluid product;
• and,
• discharging from the discharge opening a continuous flow of over-concentrated fluid product.