PLANT AND PROCESS FOR PRODUCING PUREE AND/OR JUICE AT HIGH VISCOSITY FROM A FOOD PRODUCT OF VEGETABLE ORIGIN

DESCRIPTION

Field of the invention

The present invention relates to the food field and, in particular, relates to a plant for producing puree and/or juice with a high viscosity from a food product of vegetable origin.

Furthermore, the invention relates to the process for producing puree and/or juice carried out by the aforementioned plant.

Background of the invention

As it is known, the industrial extraction of juice and puree mainly from vegetable products, such as fruits and vegetables, is carried out by rotating machines, such as rough extractors and refiner extractors. These, normally, comprise a rotor provided with blades and mounted within a fixed, or movable sieve, having a cylindrical, or conical shape, and provided with holes of determined size. The rotor is operatively connected to a driving group which causes the same to rotate about a rotation axis. The centrifugal force thus generated by the blades of the rotor on the treated product forces the same against the sieve causing the same to be separated into the extracted food product, i.e. the juice, or puree, which passes through the holes of the sieve and is discharged through a first outlet, and the waste part, mainly seeds, skins and petioles which, instead, does not pass through the holes of the sieve and is discharged through a second outlet. See for example at this regard US4643085.

A known process of this type is the extraction at room temperature, also said "cold" extraction, that is, normally, carried out in two steps. In a first step a grinding and/or softening of the food pulps is carried out, for example, applying a series of pulses in quick succession as for example described in EP0511174, and in a second step within an extraction is carried out the aforementioned separation of the treated product into an extracted food product, i.e. the juice and the puree, from the solid parts to be wasted. Normally, the puree extracted at room temperature is, then, heated within a heating plant for blocking the enzymatic activity and stabilizing the same, this process is known as enzymatic inactivation.

Another type of process is the hot extraction, which, instead, provides to carry out the extraction after having heated the product in a heating section up to reach a determined temperature.

A drawback both of the plants for carrying out the "cold" extraction and of the plants for carrying out the "hot" extraction is that when a creamy final product, i.e. having a high viscosity, is to be produced, it is necessary to carry out the extraction working at a high rotation speed of the rotor. In this way, in fact, the turbulence produced by the rotor within the machine during rotation is increased and, therefore, the processed product is homogenized, because a great part of the waste product, which comprises skin, seeds, and petioles, originally present in the product reduces its size and, therefore, can pass through the sieve, thus, increasing the viscosity of the final product. However, as known, in the extraction section the great part of the main product is that passes through the sieve at the first portion of the same. Therefore, even though a high angular velocities of the rotor is reached, it is, anyway, not possible, to significantly increase the viscosity of the final product, because the resident time of the treated product within the extraction section is, anyway, not sufficient. In addition to the above, working at high angular velocities means also to have high energetic consumptions.

Therefore, with both the cold and hot extraction sections of known type, it is not possible to obtain a creamy product, i.e. having a high viscosity.

In IT PR20120056 a method and related plant for producing puree of fruit are described. The method provides a separation step for separating the juice followed by a thermal treatment for heating the product and therefore a step is provided of sub-molecular disintegrating the extracted product in order to reduce the size of the solid parts to values less than 150 pm. This step is carried out by a rotor which rotates within a stator at a very high velocity. The product obtained during the disintegration step is, then fed into a refiner extractor.

However, the method and the related plant described in IT PR20120056 do not allow to obtain a highly viscous product. In fact, the very high speed at which the rotor is caused to rotate within the stator causes the product to be excessively worked, whereby a decreasing of the viscosity is produced. In addition to the above, the very high speed at which the rotor is caused to rotate within the stator causes the product to be overheated thus unavoidably compromising the organoleptic properties. Summary of the invention

It is, therefore, an object of the present invention to provide a plant for producing puree and/or juice, from a food product of vegetable origin which allows to overcome the prior art drawbacks described above.

It is, in particular, an object of the present invention to provide a plant for producing puree and/or juice, from a food product of vegetable origin which allows to obtain a final creamy product, i.e. with a high viscosity, and, at the same time, to reduce the energetic consumptions.

These and other objects are achieved by a plant, according to the invention, for producing juice and/or puree from a food product of vegetable origin said plant comprising:

- a first extraction section configured to subject said food product to a first extraction operation and comprising:

- an inlet for introducing said food product;

- a first rotor operatively connected to a first driving group configured to cause the first rotor to rotate about a first rotation axis at a first predetermined angular velocity;

- a first sieve provided with a plurality of holes and arranged to be positioned externally to said first rotor, said food product being forced by said first rotor against said first sieve in such a way to divide the same into a first extracted food product comprising said puree, or juice, which passes through said first sieve and is discharged through a first outlet, and in a first waste product which, instead, does not pass through said sieve and is discharged through a second outlet;

- a second extraction section positioned downstream of said first extraction section, said second extraction section being configured to subject an entering product to a second extraction operation, and comprising:

- an inlet for introducing said food product;

- a second rotor operatively connected to a second driving group arranged to cause said second rotor to rotate about a second rotation axis at a second predetermined angular velocity;

- a second sieve provided with a plurality of holes and arranged to be positioned about said second rotor, said entering food product being forced by said second rotor against said second sieve in such a way to divide the same into a second extracted food product comprising said puree, or juice, which passes through said second sieve and is discharged through a first outlet, and in a second waste product which, instead, does not pass through said second sieve and is discharged through a second outlet; whose main characteristic is that between said first and second extraction sections a treatment section is provided comprising an inlet for introducing said first extracted food product, and an outlet for discharging a treated product arranged to be fed into said second extraction section, that said treatment section is configured in such a way that the quantity of extracted food product entered in the treatment section is equal to the quantity of treated food product which exits the same that the treatment section comprises a fixed hollow body cylindrical, or conical shaped within which a third rotor also this cylindrical, or conical shaped is positioned, that said third rotor is operatively connected to a third driving group configured to cause said third rotor to rotate about a third rotation axis at a third predetermined angular velocity (w3), that said third predetermined angular velocity (w3) is greater than said first angular velocity (wΐ) and said second angular velocity (w2), and that the third predetermined angular velocity (w3) is less than 8000 rpm, in such a way that said second extracted food product has a high viscosity.

Other features of the invention and related embodiments are defined by the dependent claims.

According to another aspect of the invention, a method for producing juice and/or puree from a food product comprises the steps of:

- extracting, within a first extraction section, a starting food product, said extraction section being equipped with a first sieve provided with a plurality of holes and with a first rotor mounted within said first sieve and operatively connected to a first driving group, said first driving group being arranged to cause said first rotor to rotate about a first rotation axis to generate a centrifugal force which pushes said starting food product against said sieve causing the same to be divided into a first extracted food product which passes through the holes of said first sieve and is discharged through a first outlet and a first waste product, which does not pass through said holes of said sieve and is discharged through a second outlet;

- feeding a predetermined quantity of said first extracted food product into a treatment section positioned downstream of said first extraction section;

- treating said first extracted food product within said treatment section obtaining a treated product;

- discharging a predetermined quantity of said treated product from said treatment section, said predetermined quantity of said discharged treated product being equal to said predetermined quantity of said first extracted food product fed into said treatment section;

- feeding said treated product into a second extraction section, said second extraction section being equipped with a second sieve provided with a plurality of holes and with a second rotor mounted within said second sieve and operatively connected to a second driving group, said second driving group being arranged to cause said second rotor to rotate about a second rotation axis to generate a centrifugal force which pushes said treated food product against said second sieve causing the division of the same into a second extracted food product which passes through the holes of said second sieve and is discharged through a first outlet and a second waste product which does not pass through said holes of said second sieve and is discharged through a second outlet; whose main characteristic of said method is that the quantity of said product fed into said treatment section is equal to the quantity of said product discharged from said treatment section and fed into said second extraction section, that said treatment is carried out by a third rotor cylindrical, or conical shaped positioned within a fixed hollow body also this cylindrical, or conical shaped that said third rotor is operatively connected to a third driving group configured to cause said third rotor to rotate about a third rotation axis at a third predetermined angular velocity (w3), that said third predetermined angular velocity (w3) is said third predetermined angular velocity (w3) is greater than both the first angular velocity (wΐ) and the second angular velocity (w2), and that said third predetermined angular velocity (w3) is less than 8000 rpm, in such a way that said second extracted food product has a high viscosity.

Brief description of the drawings

The invention will be now illustrated with the following description of an exemplary embodiment thereof, exemplifying but not limitative, with reference to the attached drawings wherein:

Fig. 1 diagrammatically shows a first embodiment of the plant, according to the invention, for producing puree, or juice, from a food product of vegetable origin;

Figures 2 and 3 diagrammatically show longitudinal cross-section view, respectively, of the first and the second extraction sections of the plant of figure 1; Fig. 4 diagrammatically shows longitudinal cross- section view the treatment section of the plant of figure 1;

Figures from 5A to 5F show transversal cross-section views of some possible embodiments of the treatment section of figure 4;

Fig. 6 diagrammatically shows longitudinal cross- section view a possible alternative embodiment treatment section of figure 4;

Fig. 7A shows a perspective side elevation view of the rotor of the treatment section of figure 6;

Fig. 7B diagrammatically shows an enlargement of a portion of a blade of the rotor of figure 7A;

Figures 8A and 8B diagrammatically show a front view and a perspective view, respectively, of another embodiment provided by the invention for the rotor of the treatment section;

Figures from 9 to 18 diagrammatically show further embodiments of the plant of figure 1 provided by the present invention.

Detailed description of some exemplary embodiments of the invention

As diagrammatically shown in figure 1, a plant 1, according to the invention, for producing juice and/or puree from a starting food product of vegetable origin 100, comprises a first extraction section 10 in which the starting food product 100 is introduced through an inlet 11 to be subjected to a first extraction operation.

More in particular, come diagrammatically shown in figure 2, the first extraction section 10 comprises a first rotor 15 operatively connected to a first driving group 81, advantageously by a motor shaft 61, to be caused to rotate about a first rotation axis 115 at a first predetermined angular velocity wΐ. Externally to the first rotor 15, surrounding the same, a first sieve 16 is positioned provided with a plurality of holes 17. As it is known, the rotation of the first rotor 15 generates a centrifugal forces which forces the food product 100 against the sieve 16 causing the same to be divided into a first extracted food product 101 comprising the puree and/or the juice, which passes through the first sieve 16 and is discharged through a first outlet 13, and in a first waste product 102 which, instead, does not pass through the first sieve 16 and is discharged through a second outlet 14. The first extracted food product 101 is discharged from the first extraction section 10 and, therefore, fed through an inlet 31 into a treatment section 30 positioned downstream of the first extraction section 10. In particular, the treatment section 30 is arranged to treat the first extracted food product 101 and to discharge the obtained treated product 103 through an outlet 32. The treatment section 30 is, advantageously, configured in such a way that the quantity of product 101 that is introduced is equal to the quantity of treated product 103 discharged from the treatment section 30.

According to what is provided by the invention, the treated product 103 discharged through the outlet 32 is fed into a second extraction section 20 positioned downstream of the treatment section 30 and configured in such a way to carry out a second extraction operation. In particular, as diagrammatically shown in figure 3, the second extraction section 20 is configured analogously to the first extraction section 10. More in particular, the second extraction section 20 provides an inlet 21 for introducing the treated product 30. Within the second extraction section 20 a second rotor 25 is installed operatively connected to a second driving group 82, which provides to cause the same to rotate about a second rotation axis 125 at a second predetermined angular velocity w2. Externally to the second rotor 25, surrounding the same, a second sieve 26 is positioned provided with a plurality of holes 27. More precisely, the treated product 103 introduced through the inlet 21, is forced by the second rotor 25 against the second sieve 26 and is, therefore, divided into a second extracted food product 104 comprising the puree and/or the juice, which passes through the second sieve 26 and is discharged through a first outlet 23, and in a second waste product 105 which, instead, does not pass through the second sieve 26 and is discharged through a second outlet 24. In particular, the holes 17 of the first sieve 16 of the first extraction section 10 can have size greater than the size of the holes 27 of the second sieve 26 of the second extraction section 20. Therefore, in the first extracted food product 101 in addition to puree and juice, a great quantity of a more fibrous product, essentially consisting of skins and seeds is also present that pass through the holes 17 of the sieve 16. This part of fibrous product is discharged from the first extraction section 10 together with the extracted food product 101, is shredded into the treatment section 30 due to the high mechanical stress subjected to the same. Therefore, when the treated product 103 is subjected to the successive extraction step that is carried out into the second extraction section 20, high quantity of the fibrous part of the processed product are able to pass through the holes 27 of the sieve 26 thus, increasing, the viscosity of the second extracted food product which will be, therefore, "dense" and "creamy".

This result cannot be, instead, achieved by the prior art extractors, or finishers, where the resident time of the product within the machine is not sufficient to significantly increase the viscosity of the extracted product.

As diagrammatically shown in the figures 4 to 7, the treatment section 30 comprises a hollow body 33 provided with an internal wall 34 and within which a third rotor 35 is installed that have a plurality of blades 36 arranged substantially radially. More precisely, the third rotor 35 is operatively connected to a third driving group 83 by a third motor shaft 63 (figure 4). The third driving group 83 is arranged to cause the third rotor 35 to rotate about a third rotation axis 135 at a third predetermined angular velocity w3. This, according to what is provided by the invention, is greater than both the first angular velocity (wΐ) and the second angular velocity (w2). In particular, the third predetermined angular velocity (w3) can be less than 8000 rpm, in such a way that the second extracted food product has a high viscosity.

In particular, the third predetermined angular velocity w3 can be comprised between 1500 and 7000 rpm, advantageously, between 1500 and 6000 rpm. In particular, the third predetermined angular velocity w3 can be less than 5000 rpm, more in particular comprised between 1500 and 4500 rpm.

Advantageously, the third predetermined angular velocity w3 can be less than 3500 rpm, for example comprised between 900 and 3000 rpm, preferably comprised between 1200 and 2700 rpm.

In particular, it has been observed that for angular velocities in the treatment section 30 greater than determined values the product is laminated so much too cause a decreasing, and not an increasing of its viscosity, which is, instead, the scope of the present invention. Furthermore, angular velocities w3 greater than the aforementioned threshold value causing the product to be overheated thus modifying its organoleptic properties. In addition to the above, the solution according to the invention allows to avoid that the treated product, when moves from the treatment section 30 to the second extraction section 20 can be subjected to an abrupt slowdown. In fact, the angular velocity w2 of the rotor of the second extraction section 20 is, advantageously, less than 4000 rpm, advantageously comprised between 800 and 4000 rpm, in particular comprised between 1000 and 2500 rpm.

An abrupt slowdown of the product, in fact, could make difficult the movement of the same from the treatment section 30 to the second extraction section 20, and could cause the product to be accumulated downstream of the treatment section 30 and, therefore, a clogging of the ducts and the sections involved with the need to stop the machine in order to remove the product, with consequent loss of productivity, time and product.

According to an embodiment, the first angular velocity wΐ can be less than the second angular velocity w2. For example, the first angular velocity wΐ can be comprised between 400 and 1000 rpm, advantageously comprised between 500 and 900 rpm.

In particular, the internal wall 34 of the hollow body 33 can have a cylindrical, or conical, surface, substantially "smooth" (figure 5A). Alternatively, the internal wall 34 of the hollow body 33 can be "waved" and provided with a plurality of recessed portions 39a from a base surface (figure 5B). In a further embodiment of the invention, the internal wall 34 of the hollow body 33 can comprise a plurality of recessed portions 39a and a plurality of protruding portions 39b with respect to a base surface alternating to each other (figure 5C).

In further embodiments of the inventions, the internal wall 34 of the hollow body 33 can comprise a series of straight portions forming the recessed portions 39a from the base surface (figure 5D), or recessed portions 39a and protruding portions 39b alternating to each other, in which the straight portions are connected in such a way to form sharp edges (figures 5E and 5F). In particular, as shown in figure 5C, the recessed portions 39a of the internal wall 34 of the fixed hollow body 33 are positioned at a maximum distance dmax from rotor 35, in particular from the ends of its blades 36, instead, the protruding portions 39b are positioned at a minimum distance dmin from rotor 35. More in particular, the ratio between the maximum distance dmax and the minimum distance dmin can be comprised between 1 and 20, i.e. l£dmax/dmin£20, advantageously comprised between 1 and 10, i.e. l£dmax/dmin£l0. For example, the minimum distance dmin can be comprised between 0,1 mm and 10 mm, advantageously between 0,2 mm and 10 mm, preferably between 0,5 mm and 5 mm.

According to an embodiment provided by the invention and diagrammatically shown in figure 4, the fixed hollow body 33 and the rotor 35 of the treatment section 30 can be positioned at a first distance dl, at a first end 30a, in particular closer to inlet 31, and at a second distance d2, with d2<dl, at a second end 30b, in particular further from inlet 31. In this way a "funnel" is formed that assists the introduction of the product between the rotor 35 and the internal wall 34 of the fixed hollow body 33 and its movement along the treatment section 30. The difference between the first and the second distance dl and d2 can be obtained, in case that the wall 34 and the rotor 35 are both substantially cylindrical shaped, as shown in figure 4, by providing for the rotor 35 a portion tapered at its end closer to inlet 31 which, then, increases its cross-section and, therefore, maintains its distance from the internal wall 34, constant to value d2 up to the end 30b. In case that the wall 34 is substantially cylindrical shaped and the rotor 35 substantially conical shaped, this latter is, advantageously, provided having the portion with the smaller cross-section positioned closer to the inlet 31 that increase going towards outlet 32. In case that both the internal wall 34 and the rotor 35 are substantially conical shaped the aforementioned reduction of the distance from dl to d2 can be obtained by a different conicities between the two surfaces. These two last cases are not shown in figure for reason of simplicity but can be easily derived by the skilled person in the art from the embodiment of figure 4.

Advantageously, the aforementioned cylindrical, or conical, surface of the hollow body 33, or its planar development, can be at least equal to 50% of the surface of the second sieve 26 of the second extraction section 20, or its planar development, advantageously equal at least to 60% of the surface of the second sieve 26, or its planar development, preferably at least to 70% of the surface of the second sieve 26, or its planar development.

In this way, the product treated in the treatment section 30 is subjected to a strong treatment for the time necessary to longitudinally cross the aforementioned surface of the hollow body 33, that is much higher than the prior art solutions. Therefore, with respect to the prior art solutions, the fibrous fraction of the treated product is shredded and, once introduced into the second extraction section 20, passes through the sieve together with the second main product.

In particular, at least one between the first sieve 16 of the first extraction section 10, and the second sieve 26 of the second extraction section 20 is conical, or cylindrical shaped. More in particular, in case that the sieve is substantially conical, or cylindrical shaped, also the corresponding first and/or second rotor 15, or 25, is, advantageously, substantially conical, or cylindrical shaped.

According to an embodiment of the invention, diagrammatically shown in the figures 1, 4, 6 and from 9 to 14, the aforementioned third rotation axis 135 can be a horizontal, or substantially horizontal, rotation axis in particular forming an angle smaller than, or equal to 30° with respect to the horizontal direction. This technical solution allows, in particular, to control more accurately the aforementioned treatment section 30 with respect to the technical solutions with inclined, or vertical, axis, where the gravity force introduces forces and stresses that are difficult to control.

According to an embodiment of the invention, the second predetermined angular velocity w2 can be comprised between 900 and 2800 rpm, in particular, between 1000 and 2500 rpm, advantageously between 1600 and 2500 rpm.

According to an alternative embodiment of the invention diagrammatically shown in the figures from 6 to 7B, at least a part of the aforementioned blades 36 of the rotor 35, at the edge 37 which faces, in use, towards the aforementioned internal wall 34 of the hollow body 33, can be provided with a plurality of recessed portions, or depressions, 38. All the recessed portions 38 can have the same width and depth, or, as provided by an alternative embodiment of the invention, can have a width and/or a depth which decreases going from the inlet 31 to the exit 32 of the treatment section 30.

In particular, the recessed portions, or depressions, 38 change the axial velocity of the product into the treatment section 30 and create turbulences which contributes to further increase the viscosity of the treated product.

As diagrammatically shown in the figures 8A and 8B, respectively in a front view and in a perspective view, according to an embodiment provided by the invention, the blades 36 of the aforementioned rotor 35 can be portions radially protruding from a main body 36'. In particular, the blades 36 can be obtained subjecting a starting full cylindrical, or conical, body to a working step, for example, a milling step arranged to make a series of longitudinal recessed portions 36". Also in this case, the edges 37 of the blades 36 can be provided with the aforementioned depressions 38.

Alternatively, the blades 36 can be independent bodies which are fixed, for example by welding, to a main body.

In figure 9 an alternative embodiment of plant 1, according to the invention, is diagrammatically shown, wherein between the first extraction section 10 and the treatment section 30 a heating section 40 is provided configured to heat the first extracted food product 101 from a first temperature Tl to a second temperature T2 with T2>T1. For example, the heating section 40 can be configured to heat the product from a temperature Tl comprised between 0°C and 25°C to a temperature T2 comprised between 65 °C and 110 °C, advantageously a temperature T2 comprised between 65 °C and 85 °C, or a temperature T2 comprised between 85 °C and 110 °C.

Even though it is possible to discharge the first extracted product 101 from the first extraction section 10 to the treatment section 30 by gravity, it is also provided the possibility, diagrammatically shown in figure 10, that the first extracted food product 101 can be sucked at the outlet 12 of the first extraction section 10 and fed into the treatment section 30 by a pumping device 50.

As diagrammatically shown in figure 11, furthermore, in a further embodiment of the invention, the possibility is also provided that both the heating section 40, as described above with reference to figure 9, and the pumping device 50, as described above with reference to figure 10, can be positioned between the first extraction section 10 and the treatment section 30.

According to an embodiment of the invention, the treatment section 30 is positioned at a first height hi from a base surface, and the second extraction section at a second height h2, with hl>h2. In this case, the treated product 103 exiting the treatment section 30 can be arranged to be introduced into the second extraction section 20 by gravity. According to an alternative embodiment, but not shown for reasons of simplicity, between the treatment section 30 and the second extraction section 20, a pumping device can be positioned that is arranged to suck the treated product 103 from the outlet 32 and to feed the same into the second extraction section 20 at the inlet 21.

As diagrammatically shown in figure 12, according to a further embodiment of the invention, a control unit 300 can be provided arranged to receive data concerning the second angular velocity w2 at which the second rotor 25 rotates and to actuate the third motor 83 of the treatment section 30 in order to cause the third rotor 35 to rotate at a correspondent angular velocity w3, when the angular velocity w2 is determined that allows to have a determined yield h at the extraction section 20. More precisely, as described above, the ratio between the angular velocity w3 and the angular velocity w2 is equal to a value comprised between 1.5 and 3.5, advantageously equal to a value comprised between 2 and 3. Therefore, once a determined yield is obtained for the second extraction section 20, in particular during a preliminary calibration, or testing, step, the control unit 300 actuates the motor 83 of the treatment section 30 in order to cause the rotor 35 at the aforementioned angular velocity w3 and to have an extracted product 104 with determined properties, in particular a high viscosity.

According to the embodiment diagrammatically shown in figure 13, between the first extraction section 10 and the treatment section 30 a diverter device 70 is provided. This, for example a three way electro-valve, is configured to divert the flow of extracted product 101 exiting the first extraction section 10 and to divide the same into a first flow 101a, which is fed into the treatment section 30 where is subjected to the treatment as described above, and a second flow 101b, which, instead, bypasses the treatment section 30 and is directly fed downstream of the same. More in particular, the second flow 101b can be directly fed into the second extraction section 20, case that is not shown in the figure for reasons of simplicity, or, as shown in the example of figure 13, mixed with the treated product 103 exiting the treatment section 30, for example by a "T" connector member, or by a second diverter device similar to the diverter device 70, not shown in the figure for reasons of simplicity, obtaining a mixed product, which is, therefore, fed into the second extraction section 20. In this way, it is possible to obtain a flow of product comprising a more viscous fraction essentially consisting of product 103 discharged from the treatment section 30, and obtained by treating the aforementioned first flow 101a, immersed in a more fluid fraction, essentially consisting of the aforementioned second flow 101b.

According to another embodiment of the invention, a device in-line is provided for measuring viscosity 75, for example a viscometer, positioned upstream, or downstream, of the second extraction section 20, for instantaneously determining the viscosity, respectively, of the product fed to the second extraction section 20, or the second extracted product 104. In particular, as shown in the example of figure 14, the device for measuring viscosity 75 can be arranged to send the detected signal of viscosity to a control unit 300, for example the same control unit 300, which actuates the driving groups 82 and 83, as described above. The control unit 300, according to the measured value of viscosity can actuate a greater, or less, opening of the diverter device 70 in order to increase, or decrease, the fraction of product 101, i.e. the first flow 101a, fed into the treatment section 30, and, therefore, to increase, or decrease, the viscosity of the product 103' fed into the second extraction section 20.

According to the further embodiment diagrammatically shown in figure 15, the second flow 101b of extracted product 101, which is diverted by the diverter device 70 to bypass the treatment section 30, is directly fed into the second extraction section 20, advantageously along an axial direction. Advantageously, also in this case, the aforementioned device 75 for measuring the viscosity with the same functions described above with reference to figure 14.

According to the invention, the first extraction section 10 can provide a first sieve 16 with holes of size greater than 1 mm, for example comprised between 4 mm and 8 mm. In this case, the first extraction section 10 will essentially work as a "stone remover", whilst the extraction of the main product, i.e. the puree and juice, will be a secondary effect. Alternatively, the holes 17 of the first sieve 16 can have a size greater than 10 mm, advantageously greater than 20 mm, preferably comprised between 10 mm and 30 mm. In this case, inside of the first extraction section 10, in particular in the case of fruits such as tomatoes, also the herbaceous and/or ligneous parts of the plant that is fed into the plant together with the fruits are cut and shredded, in order to avoid that the second extraction section 20, where, instead, the holes are advantageously smaller, in particular smaller than half size of the holes of the first sieve 16, can be obstructed due to the presence of the aforementioned herbaceous and/or ligneous parts.

According to a further embodiment of the invention, the holes 17 of the first sieve 16 can have a size comprised between 1 mm and 2 mm. In this case, therefore, in the first extraction section 10 a significant extraction operation of the main product, i.e. puree, or juice will be carried out.

Advantageously, the holes of the second sieve 26 can have a size comprised between 0,4 mm and 0,7 mm.

In particular the diameter of the primo, of the secondo and of the third rotor can be comprised between 200 and 1000 mm. More in particular, the diameter of the primo and of the second rotor 15 and 25 can be comprised between 200 and 850 mm, preferably comprise between 200 and 650 mm. Advantageously, the diameter of the third rotor can be comprised between 200 mm and 800 mm, preferably comprised between 200 and 600 mm.

According to another embodiment of the invention, diagrammatically shown in figure 16, upstream of the first extraction section 10, a preliminary treatment section 60 can be provided configured to preliminary treat the food product of vegetable origin. According to an embodiment provided by the invention, the aforementioned preliminary treatment section 60 can be a division section configured to divide the starting food product of vegetable origin into pieces of predetermined size. In particular, the aforementioned preliminary treatment section 60 can be arranged to divide the starting food product of vegetable origin into pieces of size comprised between 2 mm and 50 mm, advantageously pieces of size comprised between 5 mm and 30 mm. According to an alternative embodiment, the preliminary treatment section 60 can be configured to apply a sequence of compression stresses in rapid succession in order to reduce the consistency of the product. In particular the preliminary treatment section 60 can comprise a cylindrical, or conical, rotor actuated by a driving group to rotate within a stator, also this cylindrical, or conical shaped, in particular of the type described in EP0511174. Even though in figure 16 the preliminary treatment section 60 is shown positioned upstream of the embodiment of figure 11, the possibility is, anyway, also provided that the same can be positioned upstream of any embodiment according to the invention and in particular shown in the figures 1 and from 9 to 15.

According to an embodiment of the invention, the first extraction section 10 and the treatment section 30 can be positioned on the same line, advantageously be part of the same machine, preferably housed within the same machine body. In this case the product 101 extracted in the first extraction section 10 can be axially fed into the treatment section 30. In particular, the first extraction section 10 and the treatment section 30 can be actuated by the same driving group 82 arranged to cause the respective rotors 15 and 35 to rotate about the same rotation axis (case shown in figure 17).

According to another embodiment the treatment section 30 and the second extraction section 20 can be positioned on the same line and be part of the same machine. In particular, the treatment section 30 and the extraction section 20 can be actuated by the same driving group 82 arranged to cause the respective rotors 35 and 25 to rotate about the same rotation axis (case shown in figure 18).

In particular, the embodiment of the first extraction section 10 and of the treatment section 30 that is shown in figure 17 as well as the embodiment of the treatment section 30 and of the second extraction section 20 shown in figure 18 can be used in any embodiment of plant 1 according to the invention 1 that are shown in the figures 1 and from 9 to 12.

The foregoing description of a specific embodiment will so fully reveal the invention according to the conceptual point of view, so that others, by applying current knowledge, will be able to modify and/or adapt for various applications such an embodiment without further research and without parting from the invention, and it is therefore to be understood that such adaptations and modifications will have to be considered as equivalent to the specific embodiment. The means and the materials to realise the different functions described herein could have a different nature without, for this reason, departing from the field of the invention. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation.