Patent ID: 8394441

Claim:
A low temperature extrusion process for energy optimized, viscosity adapted micro-structuring of a frozen aerated food product, the process comprising the steps of: locally adjusting a rotational screw speed of an extruder screw that rotates within an extruder screw channel formed by an inner barrel wall, the extruder screw channel having an inner diameter and a length, pins fixed to the inner barrel wall extending into the inner diameter of the extruder screw channel; locally adjusting a mass flow rate of a partially frozen, aerated food product, the mass flow rate adjusted by a positive replacement pump installed at an extruder inlet; locally adjusting width variation of cuts in a screw flight, the cuts extending axially into the screw flight, the pins intermeshing with the cuts in the screw flight; and locally adjusting a cooling temperature at an inner wall of an extruder housing, the cooling temperature adjusted by an evaporation pressure of refrigerant, the process providing a mechanical treatment of the partially frozen, aerated food product over a length of an extruder screw channel zone with respect to its local viscosity, performed such that, in each of a subsequent zone there is a dispersing of air bubbles/air cells and at a same time a temperature decrease and related increase of the frozen water fraction is achieved, the process further providing a viscosity-adapted increase in shear treatment in a first 25% to 70% of a length of the extruder screw measured from an extruder inlet such that after about half or two-thirds of the extruder screw length a freezing degree of greater than 55% frozen water fraction related to the freezable water is reached.