Batch process for the manufacture of oxidized starch by contacting an aqueous medium comprising already oxidized starch with native starch and with at least one oxidizing agent selected from a peroxide compound or from an alkali metal hypochlorite, and by reacting them at a temperature below the gelatinization temperature of the native starch and of the oxidized starch, the reaction being conducted in the presence of a homogeneous manganese-based complex coordination catalyst when the oxidizing agent is a peroxide compound. The resulting oxidized starch can be used as an additive for the paper industry or for the food industry.