A process of precooking grains is described, which comprises the steps of: a) Charging the grains into a reactor (4) in a controlled manner； b) Applying a first negative pressure to the reactor (4)； c) Heating the grains contained in the reactor (4)； d) Applying a second negative pressure to the reactor (4)； and e) Cooling the grains. An equipment for precooking grains is also described, which comprises at least one reactor (4), which is associable with means (9) for applying negative pressure.
