A method for producing a composition containing beta-casein, the method comprises the steps of: a) pre-heating the milk by adjusting the pre-heating temperature (Tpre) in the range of 20-60 degrees Celsius with a maintenance time in the interval of 1 minute - 1 hour, thus providing a hot milk, b) subjecting the hot milk to microfiltration (MF), thus providing a first MF permeate and a first MF retentate, c) optionally, subjecting the first MF retentate a MF-diafiltration, d) adjust the temperature of a first composition derived from the first MF retentate at a cold temperature (Cold) in the range of 0-15 degrees Celsius and, maintain the temperature of the first composition within said range for a duration (cold) of at least 0.5 hours, thus obtaining a first cold composition, e) subjecting the first cold composition to MF, thus obtaining a second retentate and a second permeate, whose second permeate e is enriched with respect to beta-casein, and f) optionally, subjecting the second MF retentate to MF-diafiltration, g) optionally, subjecting the second composition derived from the second permeate to one or more other processing steps, for example to another purification and / or concentration steps, thereby providing the beta-casein-containing composition.Un método para producir una composición que contiene beta-caseína, el método comprende las etapas de: a) pre-calentar la leche ajustando la temperatura de pre-calentamiento (Tpre) en el intervalo de 20-60 grados Celsius con un tiempo de mantenimiento en el intervalo de 1 minuto - 1 hora, proporcionando así una leche caliente, b) someter a la leche caliente a microfiltración (MF), proporcionando así un primer permeato MF y un primer retentado MF, c) opcionalmente, someter al primer retentado MF a MF-diafiltración, d) ajustar la temperatura de una primera composición derivada del primer retentado MF a una temperatura fría (Tfría) en el intervalo de 0-15 grados Celsius y, mantener la temperatura de la primera composic
