A process for extracting, at room temperature, juice or puree from a food product, the process comprising the steps of:
- providing the food product having a predetermined consistency;
- providing an input parameter related to the consistency of the food product;
- providing a machine consisting of:
- a softening section of the food product having a first stator and a first rotor provided with a plurality of blades, said first rotor having a first axis and being arranged to rotate at a first speed driven by a first rotor drive means consisting of a first shaft on which the first rotor is mounted and a first motor operating the first shaft, said softening section producing a softened product;
- an extraction section arranged downstream of the softening section, and having a second stator and a second rotor, the second rotor having a second axis and arranged to rotate at a second speed driven by a second rotor drive means consisting of a second shaft on which the second rotor is mounted and a second motor operating the second shaft, the first and the second speed being operated independently from each other;
- wherein the outlet of the softening section and the inlet of the extraction section are connected to each other by a connection duct;
- wherein the connection duct consists of a first connection portion and a second connection portion connected to each other at respective flange portions screwed by bolts, and wherein a resilient member is provided between the flange portions;
- wherein the connection duct is internally provided with an inclined surface at an end portion of the connection duct close to the extraction section for providing an axial component to the softened product entering the extraction section, thereby assisting the feeding step of the softened product, which includes a solid or viscous softened product, into the extraction section;
- wherein the machine is provided with a speed adjusting means operatively connected to the first rotor drive means and to the second rotor drive means, the speed adjusting means comprising a processor;
- wherein the process further comprises the steps of:
- entering, in the processor, the input parameter related to the consistency of the food product to be processed;
- computing, by the processor, a ratio between the first speed and the second speed, on the basis of the input parameter;
- entering, in the softening section, the food product;
- actuating the first and the second rotor drive means by the speed adjusting means according to the ratio between the first and the second speed computed by the processor,
- wherein the actuating step causes the first shaft to rotate independently from the rotation of the second shaft;
- softening the food product by the first rotor rotating at the first speed in the softening section, and conveying all the softened food product in the extraction section through an outlet;
- discharging the softened product tangentially from the softening section through the outlet;
- feeding, by the inclined connection duct, the softened product downwards from the softening section to the inlet of the extraction section, the feeding of the softened product being carried out axially to the extraction section;
- extracting juice or puree from the softened food product by the second rotor rotating at the second speed in the extraction section, and separating extracted juice or puree from waste material;
- wherein the softening section and the extraction section are positioned laterally to each other and the connection duct is inclined at a predetermined angle with respect to the vertical direction;
- and
- wherein a setting step is provided for setting the speed of rotation vr of the first rotor, expressed in rpm according to the following equation:
- vr
- ·
- ∅
- i
- =
- 500
- ÷
- 2000
- wherein ø is the diameter of the circumference described by the blades of the first rotor during rotation about the first axis, and i is the distance between the first axis and the second axis.