Method for processing of a ground meat mass, comprising: - depositing a ground meat mass in a hopper, - discharging said mass from said hopper to a positive displacement pump having an inlet and an outlet for the mass, the pump having one or more pump chambers that each are successively in communication with the pump inlet for the introduction of mass into the one or more pump chambers and with the pump outlet for the discharge of mass from the one or more pump chambers, - expelling the mass from the outlet of the pump into a tube structure that is connected to the outlet of the positive displacement pump, said tube structure having at least one mouth from which said mass is discharged, said mass being shielded by said tube structure from the surrounding atmosphere, - using a controllable vacuum assembly to subject the mass to a controlled evacuation of air at one or more locations in the trajectory of the mass starting from and including the hopper to and including a pump chamber at a position thereof where it is in communication with the pump inlet, characterized in that the method further comprises - subjecting the mass at one or more locations in the tube structure between the pump outlet and the mouth to a controlled introduction of a gas into the mass by a controllable aeration assembly, said aeration assembly comprising a source of pressurized gas and an aeration member (53; 80; 90) that is disposed in the tube structure between the pump outlet and the mouth, said aeration member being connected to the source of pressurized gas and having one or more orifices from which said gas is emitted, and said aeration assembly comprising a gas pressure control device adapted to regulate said introduction of said gas into the mass at a controlled pressure that is at least equal to the actual pressure of the mass at the location of introduction of the gas into the mass. - depositing a ground meat mass in a hopper, - discharging said mass from said hopper to a positive displacement pump having an inlet and an outlet for the mass, the pump having one or more pump chambers that each are successively in communication with the pump inlet for the introduction of mass into the one or more pump chambers and with the pump outlet for the discharge of mass from the one or more pump chambers, - expelling the mass from the outlet of the pump into a tube structure that is connected to the outlet of the positive displacement pump, said tube structure having at least one mouth from which said mass is discharged, said mass being shielded by said tube structure from the surrounding atmosphere, - using a controllable vacuum assembly to subject the mass to a controlled evacuation of air at one or more locations in the trajectory of the mass starting from and including the hopper to and including a pump chamber at a position thereof where it is in communication with the pump inlet, characterized in that the method further comprises - subjecting the mass at one or more locations in the tube structure between the pump outlet and the mouth to a controlled introduction of a gas into the mass by a controllable aeration assembly, said aeration assembly comprising a source of pressurized gas and an aeration member (53; 80; 90) that is disposed in the tube structure between the pump outlet and the mouth, said aeration member being connected to the source of pressurized gas and having one or more orifices from which said gas is emitted, and said aeration assembly comprising a gas pressure control device adapted to regulate said introduction of said gas into the mass at a controlled pressure that is at least equal to the actual pressure of the mass at the location of introduction of the gas into the mass.