Method and system for directly heating a protein-enriched milk product by introducing steam into said milk product

A method for directly heating a protein-enriched milk product by introducing steam into the protein-enriched milk product, wherein:

• (a) during direct heating, the steam heats the protein-enriched milk product to produce a high-temperature pasteurized protein-enriched milk product by means of direct high-temperature pasteurization to a high pasteurization temperature,
• (b) before the direct heating, the protein-enriched milk product is preheated indirectly to a preheating temperature and, following on from the preheating when viewed in a direction of flow of the protein-enriched milk product, a first instance of keeping the protein-enriched milk product at the preheating temperature is carried out for a defined and controlled first dwell time,
• (c) following on from the direct heating to the high pasteurization temperature when viewed in the direction of flow of the protein-enriched milk product, a second instance of keeping the protein-enriched milk product at the preheating temperature is carried out for a defined and controlled second dwell time,
• (d) flash cooling the protein-enriched milk product by means of decompression of the steam from a first pressure to a lower pressure, and removal of water from the high-temperature pasteurized protein-enriched milk product in an amount corresponding to that of the steam supplied to the high-temperature pasteurized protein-enriched milk product that has been kept at the preheating temperature,
• the protein-enriched milk product that is preheated indirectly and kept at the high pasteurization temperature is indirectly cooled before the direct heating by means of a recuperative cooling step so that a temperature difference between the preheating temperature and a cool-down temperature is in a range from 5 K to 10 K,
• the direct heating from the cool-down temperature to the high pasteurization temperature is controlled by means of adjusting direct heating setting parameters, and
• in accordance with the feature (d), the protein-enriched milk product is cooled by flash cooling from the high pasteurization temperature to an exit temperature.