A rotor for a kneading machine for alimentary doughs is provided. The rotor has a flat base formed of a plurality of arms and a plurality of mixing paddles restrained to the arms. The mixing paddles are pivotally mounted on the arms about respective axes (E, F) that are parallel to the flat base. The arms are movable between a first operating position, wherein they extend from the arms along a direction (V) that is generally perpendicular to the flat base, and a second operating position, wherein they extend from the arms in opposite directions substantially parallel to the flat base. When the rotor is mounted in a kneading machine, its paddles are proximate to a bottom of the container of the machine in the second operating position, thus acting to separate the dough.