A process for treating tomato concentrates obtainable by concentration by evaporation, having a dry residue in percentage by weight higher than 15%, generally at least of about 18%, comprising the following steps: I) mixing of the tomato concentrate (component a)) with water (component b)); II) liquid separation by a separation solid-liquid apparatus, wherein the mass to be filtered is maintained under a slow stirring; III) addition of water and/or serum to the solid mass obtained in II).