WO2014181284A1

WO2014181284A1 - Reactor for increasing the quantity of polyphenols and/or the turbidity stability of extra-virgin olive oil, system and method using said reactor

Info

Publication number: WO2014181284A1
Application number: PCT/IB2014/061296
Authority: WO
Inventors: Leonardo Masotti; Maurizio SERVILI; Gionatan Torricelli; Fabio CIORIA; Giulio PELOSI; Moreno Vannini
Original assignee: Insono S.R.L.
Priority date: 2013-05-08
Filing date: 2014-05-08
Publication date: 2014-11-13
Also published as: EP2994225A1; ITFI20130104A1

Abstract

Reactor for increasing the quantity of polyphenols and/or the turbidity stability of olive oil over time, comprising a cavity adapted to receive a product constituted of olive oil or olive paste from which to obtain olive oil, and at least one source of ultrasound adapted to vibrate the body of said cavity.

Description

REACTOR FOR INCREASING THE QUANTITY OF POLYPHENOLS AND/OR THE TURBIDITY STABILITY OF EXTRA-VIRGIN OLIVE OIL,

SYSTEM AND METHOD USING SAID REACTOR

DESCRIPTION

Technical Field

The present invention relates to the field of production of virgin olive oil, and more preferably of extra-virgin olive oil. More specifically, the object of the invention is a reactor for increasing the quantity of polyphenols and/or the turbidity stability of virgin olive oil or extra-virgin olive oil over time. The reactor can act on the olive paste used during the process to obtain olive oil or directly on the olive oil produced. A further object of the invention is a system that uses said reactor and a method for increasing the quantity of polyphenols and/or the turbidity stability of virgin olive oil or extra-virgin olive oil over time.

State of the art

As is known, the typical process for producing extra-virgin olive oil involves a series of preliminary operations on the olives (such as washing, for example), followed by a subsequent milling operation (classic milling or pressing), in which the olives are subjected to mechanical actions that break the cellular structures and membranes, thereby releasing the oil and other substances. The product obtained from this phase is generally an oil paste, in other words a semi-fluid mass composed of a solid fraction (fragments of olive stones, skins and pulp) and a liquid fraction (an emulsion of water and oil).

This is followed by a phase referred to as "kneading", the aim of which is to break the emulsion down into water and oil and cause the micelles of oil to coalesce into larger drops that tend to separate spontaneously from the water.

The kneading phase is followed by the extraction phase, which consists in the separation of the oil must from the olive pomace (the solid fraction made up of fragments of olive stones, skins and pulp fragments), for example by means of centrifuging or pressing. This is followed by the separation of the remaining water part from the oil part, for example by means of centrifuging.

Olive oil is a particularly high-quality product, not only for its undeniable organoleptic qualities, which make it one of the most appreciated food season- ing products, but also for its considerable nutritional ingredients, which include polyphenols. The quantity of polyphenols in the olive oil is a few percent; while most, around 50%, are retained in the production vegetation water. Polyphenols are produced during the pressing and kneading phase. In particular, it is the lipoxygenase enzyme, a content mainly of the pulp, that gives rise to polyphenols.

Extra-virgin olive oil production is also inseparably linked to the image of naturalness required even at legislative level, since the very definition of extra- virgin olive oil is based on the production approach. Indeed, unlike the production of any other type of oil, the production process for this particular type of product must be entirely physical so as not to alter the naturalness of the product. In this case, therefore, the use of chemical treatments or refinement processes, which are common in all other extractive processes, is strictly prohibited.

As in every production sector, also in the olive oil production sector there is a need to increase the process yield, in other words to increase the quantity of olive oil produced starting from the same quantity of olives.

Olive oil is a very high quality product, both on a nutritional level and a sensory level. It is therefore fundamental that those properties that ensure this qualitative value are maintained during its production.

To date, all production systems that have attempted to increase the quantity of olive oil with respect to the typical production system described above have not been able to maintain a high qualitative standard, in other words any system offering increased production also results in a lowering of the qualitative level of the olive oil produced.

At the same time, no systems are known that are able to increase the qualitative value of the olive oil produced, both on a nutritional level and a sensory level.

Object and summary of the invention

The object of the present invention is to provide a method that makes it possible to increase the qualitative level of the oil produced, and a device and a system for achieving this increase. Part of the above-mentioned object, and an important aim of the present invention, is to provide a method, and an apparatus for the implementation thereof, for the treatment of intermediate products or the end product of olive oil production lines, particularly cold products, through the use of ultrasound to simultaneously maximize the production yield and/or the presence of antioxidants in the end product and/or the parameters linked to quality, whether they are chemical/physical or perceptive/organoleptic, and/or commercial parameters that increase the value of the product, and that can also guarantee little or no deterioration in the intrinsic characteristics of the product and its freshness.

Another important object of the present invention is to provide a method, and an apparatus for the implementation thereof, for increasing the turbidity and the quantity of polyphenols in the olive oil.

A further important object of the present invention is to provide a treatment, and an apparatus for the implementation thereof, for the olive paste obtained as a result of grinding the olives, through diffuse exposure of the olive paste to ultrasonic radiation prior to the extraction and separation phases (carried out by means of filtration, centrifuging or any other procedure) in order to simultaneously maximize the production yield, the presence of antioxidants in the end product, the parameters linked to quality, whether they are chemical/physical or perceptive/organoleptic, and commercial parameters that increase the value of the product, while preserving its initial freshness and intrinsic characteristics.

Yet another important aim of the present invention is to identify process solutions that can result in an increase in quality before an increase in yield, particularly in the production of particularly prized extra-virgin olive oils; in the case of medium-low quality olive oil, on the other hand, the aim of the present invention is to provide solutions that can maximize yield without notable deterioration in qualitative terms, in the short, medium and long term.

Another important aim of the present invention, given the high degree of appreciation for olive oil, is to provide a method, and an apparatus for the implementation thereof, for maximizing the qualitative parameters of the olive oil and also maximizing the conservation of these parameters over time. Yet another important aim of the present invention is to provide an olive oil production system for increasing the turbidity and/or the quantity of polyphenols in virgin or extra-virgin olive oil, a treatment reactor for increasing the turbidity and the quantity of polyphenols in virgin or extra-virgin olive oil.

According to a first aspect, the invention relates to a reactor for increasing the quantity of polyphenols and/or the turbidity stability of extra-virgin olive oil, comprising a cavity adapted to receive a product constituted of extra-virgin olive oil or olive paste from which to obtain extra-virgin olive oil, and at least one source of ultrasound adapted to vibrate the body of said cavity

Advantageously, in preferred embodiments of the invention, this cavity is a conduit in which the product can transit; this at least one source of ultrasound is located on the external surface of said conduit. This means that the source is not immersed in the product in transit through the conduit. This enables a more uniform distribution of the ultrasound through the product in transit, without resulting in excessive local treatment of the product (as is the case with ultrasound probes in direct contact with the product), which would cause a drop in quality due to the excessive energy density transmitted in the space next to the probe.

The term 'conduit' refers to a tubular body with a mainly axial extension, so that the product transits in an axial direction, and with an axial length greater than the transversal size of the body; the axis may extend in different directions and therefore the tubular body and the conduit may be straight, bent, with several bends of alternating concavity, or in the shape of an S, U, C etc., and in general any type of shape. According to this definition, a cavity of the reactor in the shape of a tray or tank or a widened container with an ultrasound source associated with its walls, is not considered a conduit.

Among other things, the use of a conduit with external sources makes it possible to develop product treatment processes that are continuous, and not discontinuous.

The action of the reactor increases the production of polyphenols and also favors their solubility in the oil phase rather than in the water phase.

Preferably, this conduit has a plurality of successive sections arranged so as to form portions of the conduit with concave and/or convex forms, preferably lying on the same plane. The concavity or convexity depends on the direction from which one looks at the conduit and more generally defines a plurality of conduit sections that taken together do not form a straight or almost straight line, such as a winding shape, for example.

Preferably, said at least one source is located on the external surface of the conduit, preferably on the side opposite the concavity; preferably this source is located in the intersection zone between two adjacent sections of conduit.

In preferred embodiments, at least two adjacent sections of conduit are at least in part straight and at right angles to one another.

Advantageously, the reactor may comprise one or more basic modules connected to one another in series or in parallel.

Preferably, each basic module comprises a plurality of said straight sections; preferably it comprises a straight inlet section and a straight outlet section substantially aligned with one another, and a concave portion between said inlet and outlet sections with a substantially U shape.

According to other embodiments, said conduit is substantially straight, preferably with a circular, quadrangular or oval cross-section, in which there is a plurality of said sources of ultrasound located on the external surface of said conduit.

According to embodiments of the invention, the sources of ultrasound are arranged in rows on opposite sides with respect to the axis of the conduit.

According to preferred embodiments of the invention, inside the cavity of the reactor there is at least one mixing blade assembly.

In preferred embodiments, the mixing blade assembly is fixed with respect to the walls of the cavity.

According to other embodiments, the blade assembly can rotate in said cavity. Preferably, there may be a plurality of said rotating mixing blade assemblies.

According to some preferred embodiments, said at least one blade assembly is associated with at least one source of ultrasound adapted to vibrate said at least one blade assembly and to transmit ultrasonic radiation to the product contained in the cavity.

Preferably, this at least one source is connected to one end of the rotating blade assembly; preferably this source is external to said cavity.

According to preferred embodiments, the reactor comprises a cavity adapted to receive a product constituted of olive oil or olive paste from which to obtain olive oil, and at least one source of ultrasound adapted to vibrate the body of said cavity.

According to preferred embodiments, the reactor emits an acoustic power/energy of between 1^*10^~12 kWh/l and 5 kWh/l and more preferably between 1*10^~9 kWh/l and 5^*10^"2 kWh/l, and even more preferably between 1*1 fJ⁶ kWh/l and 5^*10^"3 kWh/l for the treatment of the end product (oil), and between 1*10^"12 kWh/l and 15 kWh/l and more preferably between 1*10^'9 kWh/l and 1.5 kWh/l, and even more preferably between 1^*10^"6 kWh/l and 5*10^"1 kWh/l for the treatment of the intermediate product (olive paste), at any point of the oil production chain.

According to preferred embodiments, the reactor emits an ultrasonic radiation with a power density at the interface with the treated means of between 1* 0exp-9 W/cm^A2 and 500W/cm^A2 and more preferably between 1*10exp-6 W/cm^A2 and 50W/cm^A2, and even more preferably between 1* 0exp-3 W/cm^A2 and 5 W/cm^A2.

Advantageously, said at least one source emits an ultrasonic radiation in the frequency range between Hz and 50 MHz and more preferably between 10 KHz and 10 MHz, and even more preferably between 15kHz and 4MHz.

According to other aspects, the reactor in the configurations described above makes it possible to increase the quantity of oil produced in a production (or extraction) system for olive oil, preferably extra-virgin olive oil.

According to another aspect, the invention relates to an olive oil production system for olive oil, preferably extra-virgin olive oil, comprising at least one reactor according to one or more of the configurations described above.

Preferably, the system comprises, in succession, an olive insertion zone, a first treatment zone including a milling device, such as preferably an oil press, a second treatment zone, a third treatment zone including a separation device, such as preferably a decanter or horizontal centrifuge, and a fourth treatment zone including a separator or vertical centrifuge.

Preferably, the second treatment zone may include a kneading machine and at least one said reactor, or either one or more reactors, without a kneading machine.

According to some embodiments, said at least one reactor is interposed between said first treatment zone and said second treatment zone.

According to some embodiments, said at least one reactor is interposed between said second treatment zone and said third treatment zone.

According to some embodiments, in the place of said kneading machine there is said at least one reactor.

According to another aspect, the invention relates to an olive oil treatment system for increasing the turbidity stability of said oil, comprising a reactor as described in one or more of the above-mentioned configurations. Preferably, said cavity is defined by a container for the oil, and said at least one source of ultrasound is located on the base of said container, preferably on the exterior of said base.

According to other embodiments, on the other hand, said cavity is preferably defined by a conduit in which the oil transits, and said at least one source of ultrasound is located externally on the walls of the conduit.

According to another aspect, the invention relates to a method for increasing the turbidity stability, or the quantity of polyphenols in extra-virgin olive oil, or both, involving the vibration by means of ultrasound of a reactor containing a product constituted of extra-virgin olive oil or a semi-finished product destined to become extra-virgin olive oil, or olive paste from which to obtain extra-virgin olive oil.

Preferably, the ultrasound originates from at least one source on at least one portion of the reactor housing said product.

Preferably, the method involves the transit of the product along at least said reactor in the form of a conduit, and the ultrasonic radiation of said product by means of ultrasound originating from at least one source on at least one portion of said at least one conduit against which said product slides. Preferably, said at least one source is external to the conduit, preferably located on the external surface of the conduit.

Preferably, the ultrasonic radiation of the product is achieved with an acoustic power of between 1^*10^"12 kWh/l and 5 kWh/l and more preferably between 1*10^"9 kWh/l and 5^*10^"2 kWh/l, and even more preferably between 1*10^~6 kWh/l and 5^*10^"3 kWh/l for the treatment of the end product (oil), and between 1^*10^"12 kWh/l and 15 kWh/l and more preferably between 1*10^"9 kWh/l and 1.5 kWh/l, and even more preferably between 1^*10^"6 kWh/l and 5^* 0^"1 kWh/l for the treatment of the intermediate product (olive paste), at any point of the oil production chain.

Preferably, the ultrasonic radiation of the product is achieved with sources of ultrasound capable of generating a power density at the interface with the treated means of between 1*10^"9 W/cm^A2 and 500W/cm^A2 and more preferably between 1*10^"6 W/cm^A2 and 50W/cm^A2, and even more preferably between 1^*10^'3 W/cm^A2 and 5 W/cm^A2.

Preferably, the ultrasonic radiation of the product is in the frequency range between 1 Hz and 50 MHz and more preferably between 10 KHz and 10 MHz, and even more preferably between 15 KHz and 4MHz.

Preferably, the product flows in a conduit with a shape formed by successive sections arranged so as to define portions of conduit with concave and/or convex forms.

According to some embodiments, the method may include a mixing of the product during ultrasound radiation. Preferably, the mixing is achieved by means of a static or rotating blade assembly.

According to preferred embodiments, said blade assembly is vibrated by means of sources of ultrasound, in order to radiate with ultrasound the product being mixed.

A further object of the invention is the use of ultrasound to increase the turbidity stability of and/or the quantity of polyphenols in the olive oil, in a flow of olive oil or of olive paste from which to obtain olive oil, along at least one conduit, wherein said ultrasound originates from at least one source on at least one portion of said at least one conduit against which said product slides. Brief description of the drawings

Further characteristics and advantages of the invention will become more apparent from the following description of a preferred but non-exclusive embodiment thereof, illustrated by way of non-limiting example in the accompanying drawings, wherein:

figure 1 shows a traditional system layout for the production/extraction of extra-virgin olive oil;

figure 2 shows a system layout for the production/extraction of extra-virgin olive oil according to the invention;

figure 3 shows a first system layout according to the invention for increasing the turbidity stability of crude olive oil;

figure 4 shows a second system layout according to the invention for increasing the turbidity stability of crude olive oil;

figures 5 to 8 show different system layouts for the production/extraction of olive oil according to the invention;

figures 9 to 14 show axonometric views, possibly in cross-section, of reactors, or parts or reactors, according to the invention.

Detailed description of an embodiment of the invention

The invention is based on the discovery that by using ultrasound for the insonification of intermediate products of olive oil production (olive paste) or freshly-pressed crude olive oil, it is possible, in certain contexts, to increase several quality factors of the end product, stabilize the turbidity of the extra- virgin olive oil, and increase the yield of an extraction system. Along with this discovery, it was also discovered that an excessive exposure to ultrasonic radiation can lead to considerable alteration of the basic constituents, which reduces the quality of the oil by accelerating certain degenerative processes. These discoveries suggested better approaches for insonification that differ considerably from those commonly used in other sectors of the food industry dealing with products of a lower value than olive oil.

For the purposes of this document, the term "yield" refers to the quantity of oil extracted in relation to the quantity of olives used to produce it.

The term "insonify" or "insonification" refers to subjecting a product to ul- trasound radiation.

The term "quality" refers to the quantity of phenolic compounds or polyphenols contained in the oil produced.

The term "turbidity of the olive oil" refers to the suspension of micro- particles in freshly-pressed crude oil, pressing being an unstable process as the oil tends to naturally decant these substances in suspension and therefore to lose its turbidity.

The term "turbidity stability" refers to the stabilization of the natural settling process typical of a freshly-pressed crude oil (separation of the water phase and hydro-soluble substances).

Stabilizing the turbidity means stopping and/or slowing the process of settling that results in the oil becoming clear. After extraction, the freshly-pressed olive oil is turbid due to the presence, in suspension, of minuscule particles of olive (pulp and stone) and humidity. The presence of these particles should not therefore be considered a defect, but rather it is proof of the genuineness of the oil. Furthermore, the presence of these micro-particles of olive tends to result in a slight improvement in the nutritional health benefits typical of extra-virgin olive oil. The presence of these particles, however, also produces the unwanted effect of reducing, often by a considerable amount, the oil's storage time. These particles tend to slowly settle on the bottom of the container in which the oil is stored (cisterns, etc.). The processes of fermentation of these particles lead to the creation of what is technically referred to as "sludge" (decanting deposits), which is actually putrefied, fermented olive pulp. As a result, the oil, which is a notable extractor of odors, in addition to having an unsightly deposit on the bottom due to this natural settling, tends over time to take on a putrid smell (a sludge defect). Freshly-pressed crude oil must therefore be consumed quickly to prevent these defects from occurring. Companies responsible for the storage and distribution of olive oil (oil mills) resolve the problem described above by filtering the crude oil purchased (or produced internally in cases where the oil mill is equipped with an oil press). Filtration, therefore, is a necessity required for the storage of extra-virgin olive oil, and is in no way linked to the oil's quality and nutritional benefits - if anything, a non-filtered oil is more genuine and healthier than a filtered oil.

Therefore, if possible, oil mills would prefer not to have to conduct this filtering operation, both because it results in having a yield of less than 100% (no matter how efficient it may be, filtration still results in a loss of oil), and because it constitutes a waste of time and productivity for the company.

Figure 1 shows a traditional system layout 1st for the production of extra- virgin olive oil. The invention propose to insert an ultrasound treatment at certain points on the extra-virgin olive oil production line, with the aim of increasing the quality of the oil produced and the turbidity stability as described above, and secondly, the system yield, while retaining the chemical-physical and organoleptic characteristics of the oil produced, so that it can continue to be called extra-virgin olive oil.

With reference to the figures, the system for the production of olive oil comprises, in succession, an olive insertion zone T, a first treatment zone including a press F (or another grinding device), a second treatment zone including a kneading machine G, a third treatment zone including for example a decanter D (or horizontal centrifuge), and a fourth treatment zone including a separator S (or vertical centrifuge).

Figure 2 shows a first schematic example of the system according to the invention, indicated by the reference 1 , in which a treatment is carried out in the second treatment zone that improves the start of the art and involves the use of ultrasound on the olive paste in transit between the press F and decanter D.

The treatment involves one or more reactors for radiating the olive paste with ultrasound, possibly associated upstream or downstream with a kneading device G.

Figure 3 shows a second system I2, according to the invention, for the treatment of freshly-pressed crude olive oil already produced, adapted to increase the quantity of turbidity, in other words to stabilize the turbidity of this olive oil (the term "increase the quantity of turbidity" means that, thanks to the treatment, the quantity of turbidity in suspension is greater, after a certain period of time, with respect to an untreated product; therefore, in this document, increasing the turbidity refers to stabilizing the turbidity over time). This system 12 comprises a pick-up zone Z1 for the freshly-pressed oil, pick-up means M1 comprising for example a pump, which take the oil from said pick-up zone and send it to an ultrasound reactor U which insonifies the oil according to the invention, followed by a storage zone Z2 for the treated oil.

Figure 4 shows a third system I3, according to the invention, for the treatment of freshly-pressed crude olive oil already produced, adapted to increase the quantity of turbidity, in other words to stabilize the turbidity of this olive oil. This system comprises a reactor formed of a container Z3 and a source of ultrasound Z4, for example a probe, located on the bottom of the container Z3, preferably on the exterior of the bottom.

Figure 9 shows a first embodiment of a reactor enabling ultrasound radiation of the product (olive paste or crude oil) to be used in the systems 11 or I2, according to the invention.

This reactor is indicated by the reference number 10'. It is formed by a cavity in the form of a conduit 11 in which the olive paste transits (or crude oil, depending on the type of treatment desired). In particular, the conduit 11 has a plurality of successive sections arranged so as to form portions of conduit with concave and/or convex forms, preferably lying on the same plane (in figure 9, the conduit 11 is shown in cross-section, with the cross-section plane lying along the axis of extension of the conduit itself; the conduit is symmetrical with respect to the cross-section plane).

For example, this conduit 11 comprises sections at right angles to one another, and in particular a straight inlet section 1A and a straight outlet section 11B, substantially aligned with one another, and a concave portion between the inlet and outlet sections 11A-11 B, with a substantially U shape, in other words formed by two parallel sections 11C and a joining section 11 D.

There are sources of ultrasound or ultrasound radiating elements 12 (these sources may be, for example, broad range ultrasound elements with a central frequency from around 20kHz to 40kHz), located on the external surface of the conduit, in other words on the outside of the body or case defining the conduit 11. In particular, in this example, these sources 12 are located on the side opposite the concavity of the reactor structure, and are preferably arranged on the intersections between orthogonal sections, in other words at the intersections of section 11 A with 11 C, 11 C with 11 D, 11 D with 11 C, and 11 C with 11 B. These sources are for example fixed to the case of the conduit 11 by means of screws 12A.

Advantageously, the intersection zones are chamfered, in other words they are inclined with respect to the directions of the respective sections, so as to form on the external surface an appropriate base for the sources 12.

Note how the reactor 10' is in reality a basic module, in other words the reactor may be formed of a plurality of structures such as that described, in series or in parallel to the inlet and outlet sections.

The conduit 11 has a quadrangular cross-section, but it could also be circular, oval or another appropriate shape.

Note also how the described structure is in practice formed by two symmetrical structures (in practice one with an S shape and one with a symmetrical S shape) connected in the central portion of the U (at the point on the axis marked by the letter K). The above-described structure may therefore be created by joining basic modules formed of S-shape structures.

The product transits in the conduit 11 and is "insonified". This conduit structure enables the optimum uniformity of the ultrasound field radiated towards the product. The position and input angle of the radiation beam of each insonifying element 12 have been designed to guarantee, through the reverberations in the walls, a particularly uniform acoustic field inside the reactor, so as to be able to treat all the product flowing in the conduit with the same power levels (for example, the total acoustic power emitted by the reactor is between 100W and 40kW, and more preferably between 250W and 2kW). The radiating elements 12 may have a vibrating frequency either in a relatively wide range band (i.e. in a range from around 20kHz to 200kHz with a band width ranging from a few dozen Hz to empty) or in a narrow band range (i.e. sonotrodes with a resonant frequency between 20kHz and 200kHz with a band width of a few Hz). The probes may also be wider band width elements and may also operate at higher central frequencies (in the order of MHz), particularly in the case of use on the end product in which there is less attenuation. Figure 10 shows another example of a reactor, shown schematically and indicated as a whole by the reference number 10". In this case, the reactor is a straight conduit 11 , for example with a quadrangular cross-section (but it may also be circular, oval, ellipsoidal, etc.), with the sources of ultrasound 12 arranged on the external surface of the conduit, as in the previous example. For example, these sources 12 are of the same type indicated above, and may be arranged on all or only some of the faces of the conduit. The distance of the sources 12 may be optimized based on the type of radiating elements used. If the ultrasound radiating elements have a relatively large band width (typically a few dozen Hz), the sources may be positioned in a helical manner (as shown in the figure) to ensure diffuse vibrations through the entire product, thereby preventing any drops in efficiency linked to destructive interference between the fields radiated by each source. In the case of insonification using narrow band sources (typically sonotrodes), optimal positioning of the sources is achieved by taking into consideration the overall resonance(s) of the reactor at the selected frequency or frequencies.

In this example, the product inlet 11A into the conduit is for example on a plane orthogonal to the axis of the conduit, as is the outlet 11 B. In other examples, the inlet and/or outlet may even be on the side of the container.

In the case of using this reactor 10" with olive paste, one-directional bleed valves may be used (not shown here) to allow any pockets of air trapped inside the reactor to escape.

Inspection or opening windows may also be inserted, as can nozzles for introducing water, which can allow easier washing of the reactor.

In the case shown in figure 10, the overall acoustic power emitted by the reactor is for example between 200W and 8kW, and more preferably between 400W and 2.4kW, based on the dimensions and cross-section of the pipe.

Figure 11 shows an example of a reactor 10"' formed of a straight conduit 11 , as in the previous example, but with a circular cross-section, in which the sources of ultrasound 2 are for example sonotrodes (narrow band sources, i.e. with a band width of a few Hz) fixed in line on one side of the external surface of the conduit. The overall acoustic power emitted by the reactor is for example between 800W and 40kW, and more preferably between 1 kW and 16kW, based on the dimensions and cross-section of the pipe.

Figure 12 shows a reactor 10^I with a conduit 11 similar to that shown in figure 11 , on the inside of which there is a mixing blade assembly 14 enabling the product being treated to be mixed. In this example, the blade assembly is static, in other words fixed with respect to the body of the conduit 1. For example, this blade assembly has a helical shape.

The blade assembly 14, mixing the product as it advances under the thrust of the inlet pumping devices, ensures better distribution of the acoustic radiation through all the elementary volumes of the product. The pitch, shape, inclination, number of sections and other helix parameters in the static mixer must be optimized based on the fluid one intends to treat, whether it is olive paste or end product. The acoustic radiation may be obtained, for example, in four different ways, which differ in terms of the type of acoustic radiation used and its mode of transfer. As far as the transfer of the acoustic radiation is concerned, it can be achieved from the outside according to the methods described in the previous examples (i.e. by means of sources located on the external surface of the conduit), or it can be transferred to the product through the mixing blade assembly 14, which can be vibrated by at least one source of ultrasound (not shown in the figure), and preferably two sources located at its ends, in other words at the points 14A and 14B, capable of transmitting a longitudinal vibration to the entire mixing blade assembly through its axis. There are four possible combinations since the sources used in the two methods described can either be relatively wide band or narrow band elements (i.e. with the above-mentioned intervals). The overall acoustic power emitted by the reactor is for example between 800W and 40kW, and more preferably between kW and 16kW, based on the dimensions and cross-section of the pipe and on the surface of the blade assembly (the larger the surface, the more power is applied so as not to exceed the limitations on radiated power per square cm).

Also in this case, the conduit 11 may be fitted with one-directional bleed valves to allow any pockets of air trapped inside the reactor to escape, or with inspection windows, etc. Figure 13 shows a reactor 10^v similar to that described in the previous case, wherein inside the conduit 11 there is a rotating mixing blade assembly 14. For example, this blade assembly has a rotation axis X coincident with the axis of the conduit 11 and may have a helical shape, for example. The inlet 11 A is located for example on the side of the conduit, while the outlet 11 B can be on a base of the conduit. During treatment, the blade assembly can be static or can rotate, in the same or in the opposite direction with respect to the direction of the fluid, so as to guarantee more pronounced mixing. Insonification can be carried out either from the outside (with sources located on the external surface of the conduit, as described above), or from the inside by means of transmission of the oscillation through the blade assembly (as described in the previous example), and can be achieved both with relatively wide band sources and with narrow band sources. Also in this case, one-directional bleed valves may be used to allow any pockets of air trapped inside the reactor to escape.

This solution makes it possible to agitate the paste while is it being insoni- fied, and this guarantees more efficient breakage of the cell walls where the oil is trapped, thereby guaranteeing more efficient separation. The overall acoustic power emitted by the reactor show in figure 13, for example, is between 200W and 40kW, and more preferably between 400W and 4kW, based on the dimensions and cross-section of the pipe and on the surface of the blade assembly (larger the surface, the more power is applied so as not to exceed the radiated power limits per square cm).

Figure 14 shows a reactor 10^VI similar to that described in the previous case, comprising a conduit 11 with an oval or ellipsoidal cross section, containing two rotating mixing blade assemblies 14 (with a helical shape, for example), placed parallel to one another. In this example, the sources of ultrasound are not visible, but can be arranged, for example, in a linear fashion on two opposing parts of the conduit.

The two blade assemblies 14 may, for example, be arranged and synchronized so that in their axial development the blade assemblies a common volume in the central part of the conduit. Inlet 11A and outlet 11 B are arranged, for example, on opposite sides of the conduit, at opposite ends, preferably cen- tered in the central part of the conduit.

Also in this case, insonification can be achieved by vibrating one or both of the blade assemblies to which one or more sources are associated, or by means of the sources placed on the external surface of the container, or by means of both systems.

Since this reactor can easily be scaled up to large dimensions, the overall acoustic power emitted by the reactor may be decided based on the dimensions of the external surface and the surface of the helixes until large values are reached, without exceeding the limitations on radiated power per square cm.

In the examples described, each reactor described can be seen as a basic module and therefore a final reactor may be formed of a plurality of basic module reactors arranged in series and/or in parallel.

Furthermore, one or more basic modules from one example can be combined with one or more basic modules from one or more of the other examples. TESTS

Quality evaluation criteria

Quality evaluation was considered in terms of the quantity of polyphenols contained in the oil produced (P3 in fig. 2). The phenolic composition was evaluated using HPLC. Phenolic compounds are linked to four important factors relating to the quality of extra-virgin olive oils:

-They influence the oil's oxidation stability. Indeed, the link between phenolic content and the oxidation stability of extra-virgin olive oil has been widely demonstrated. A product with a higher oxidation stability also has a longer commercial life.

-Health value; for some of the phenolic compounds of extra-virgin olive oil, particularly hydroxytyrosol, tyrosol and derivatives of secoiridoids. These latter compounds include the dialdeidic form of decarboxime- thyl-elenolic acid linked to hydroxytyrosol, or tyrosol (3.4-DHPEA-EDA or p-HPEA-EDA), an isomer of oleuropein aglicone (3.4-DHPEA-EA). The European Community has accepted the health claim ( EU Regulation 432/2012) based on which the label may indicate that if the content of these compounds exceeds a certain threshold value, then the moderate consumption of oil containing them can reduce the occurrence of certain cardiovascular illnesses. For this reason, therefore, an elevated phenolic content in extra-virgin olive oils is an important parameter for evaluating the product's health properties.

-Sensory aspects. Phenolic compounds can influence the sensory properties of extra-virgin olive oils because they are linked to the "tangy" and "bitter" tastes that are an important marker for high-quality extra-virgin olive oils.

In addition to the nutritional aspects, there are also analytical parameters associated with sensory perception that can have a direct impact on the product's commercial value. Indeed, volatile substances with a sensory impact play an important role in defining the oil's aroma, and in particular are responsible for certain aromas that are considered desirable for high-quality extra-virgin olive oils, such as "fruity", "grassy" and "flowery". An adequate level of these substances is therefore an indicator of a product's high quality.

Evaluation criteria for turbidity stability

Turbidity stability was evaluated through visual analysis, in other words by observing the turbidity of samples of crude oil taken at points P4 and P5 of fig. 3 and observing the quantity of deposit decanted over time after pressing (the results were then confirmed by means of a turbidimeter).

Evaluation criteria for chemical-physical characteristics of olive oil

The chemical-physical characteristics of the end product were evaluated by means of analysis of the various parameters obtained from laboratory analysis of the oil produced (taken at point P3 of fig. 2 for yield increase tests and at points P4 and P5 of fig. 3 for the turbidity stability tests):

• Free acidity: evaluation of the free fatty acids (not associated with triglycerides) present in the oil, is the main parameter used to check whether the oil produced using the treatment displays significant differences with respect to untreated oil. The % of oleic acid contained in the oil is measured. The acidity limit for an extra-virgin olive oil is 0.8%.

• Number of peroxides: oxidative deterioration, synonymous with deg- radation and ageing, expressed in milliequivalents of oxygen per kilo of oil (meq 02/kg). The number of peroxides indicates the degree of primary oxidation of the oil, and therefore its tendency to turn rancid. Based on current standards, the limit for the number of peroxides is 20, above which the oil is considered lampante. A value below 10-12 is considered good.

• Spectrophotometric constants: the parameters K232, K270 and VK were determined by reading absorption levels at 232 and 270 nanometers. The limits for an extra-virgin olive oil are 2.5 for K232, 0.2 for K270 and 0.01 for VK.

• Ratio of unsaturated-saturated fatty acids: palmitic, stearic, oleic, lino- leic, linolenic. A good level of oleic acid content is also important from the nutritional point of view.

• Freshness: parameter 1.2DAG%, which represents the ratio "1.2- diglycerides/1.3-diglycerides". A fresh, good-quality extra-virgin olive oil has a total diglyceride content (DAG) in the range of 1 to 2.5% and a ratio between 1/2-DAG and 1/3-DAG (1.2DAG%) of not less than 80%. This means that there are more 1/2-DAG with respect to 1/3- DAG. With ageing and oxidation, the DAG in the oil increase to 3% and 1/3-DAG become more numerous than 1/2-DAG. Indicating the freshness of the product gives a quality parameter that has a direct impact on the commercial value of extra-virgin olive oil. As just mentioned, this parameter is very close to 100% in freshly produced oil obtained from pressing freshly-picked olives, and drops over time due to natural degenerative reactions in the olives picked and in the oil produced. This parameter is used in commercial negotiations between oil producers (presses) and oil mills (storage and bottling) for the certification of incoming goods by the latter, who need to guarantee that the oil acquired has been recently produced and is not from the previous year or obtained by mixing new oil with old oil.

Evaluation criteria for the chemical-physical characteristics of olive oil

The organoleptic characteristics of the end product (taken at point P3 of fig. 2), were evaluated by means of taste tests conducted by various tasters, who gave a value for the following attributes: fruity, mature, green, bitter, sweet, tangy, flowery and grassy. For each attribute, a score of 0 to 5 was given, and the median score was taken. At the end, the oil was given a final score from 0 to 10 by each taster, and once again the median of the individual scores given by each taster was taken.

Evaluation criteria for the yield of an olive oil production system

Three different approaches were used to evaluate the yield of the processes used:

-Ratio between the weight of the oil produced (taken at point P3 in fig.2) and the weight of the olives (as at point P1 in fig.2) used to produce it; -Quantity of residual oil in the pomace (taken at point P2 in fig.2) produced during the extraction process (referred to as oil from fresh); - Quantity of residual oil in the pomace (taken at point P2 in fig.2) produced during the extraction process after appropriate drying (referred to as oil from dry);

Preliminary operating tests with various insonification solutions

Samples of intermediate products from the olive oil production process were treated in small reactors in order to evaluate the effects of insonification. Laboratory tests were conducted to evaluate the maximum exposure of the extra-virgin olive oil to ultrasound. This was done by treating with different power levels and treatment times, in order to identify a maximum exposure value, per unit of volume, that does not lead to substantial damage to the substance treated. Indeed, although there are indications of a direct correlation between treatment power/time and production yield, observations during the experimentation showed a considerable reduction in some qualitative parameters in the event of over-exposure to ultrasonic radiation, since this radiation is able to accelerate the natural degenerative reactions that transform the triglycerides which freshly produced extra-virgin olive oil mostly consists of, into glycerides (due to the loss of one of the three fatty acids). One test in particular was conducted, involving the insonification of a sample of commercial oil with an amount of energy well above that proposed for the application of the invention, in order to guarantee an increase in yield, quality and turbidity stability while maintaining the chemical-physical and organoleptic characteristics of the oil. This test demonstrated that the introduction of excessive acoustic energy into the paste or end product can result in macroscopic alterations, and in particular an excessive increase in the free acidity (the acidity parameter) of the sample oil was noted, before and after treatment. This means that the treatment removed fatty acids from the triglycerides and converted them to a free form. Table 1 shows the results of laboratory analysis conducted on samples of the oil used for the experiment described above, before and after treatment. As can be seen, the acidity value goes from 0.29 [% Oleic acid] for the untreated oil to 0.42 [% Oleic acid] after the ultrasound treatment.

Table 1 Parameters relating to the oil used for the maximum insonification test conducted on a sample of commercial oil before and after treatment with ultrasound

Since over-exposure to acoustic radiation can transform a significant quantity of triglycerides into diglycerides, this type of treatment, although not affecting the healthiness of the product, risks causing a considerable reduction in the product's freshness, thereby greatly reducing its commercial value by degrading it to the level of refinery products (seed oils, palm oil, etc.). In general, it can be said that small increases (even of just a few percentage points) in acidity can lead not only to significant alterations to the product, but also that high acidity values tend to reduce the ability of the oil to retain its quality over time. It is therefore apparent that treatment systems for olive paste or crude oil that make use of ultrasound to increase the quality of the end product, cannot use elevated ultrasound power levels. This implies that the use of sources of ultrasound in direct contact with the product to be treated are not acceptable, since the power reverberated directly around the source is excessive, resulting in a degradation of the product treated.

Layout of an olive oil production system

Figure 5 shows a layout (also indicated as layout 2) of a production system for extra-virgin olive oil such as that shown in figure 1 or 2, wherein an ultrasound treatment reactor 10 has been inserted between the press F and the kneading machine G.

Figure 6 shows a layout (also indicated as layout 3) of a production system for extra-virgin olive oil such as that shown in figure 1 or 2, wherein an ultrasound treatment reactor 10 has been inserted between the kneading machine G and the decanter D.

Figure 7 shows a layout (also indicated as layout 5) of a production system for extra-virgin olive oil such as that shown in figure 1 or 2, wherein two ultrasound treatment reactors 10 have been inserted in series between the kneading machine G and the decanter D.

Figure 8 shows a layout (also indicated as layout 6) of a production system for extra-virgin olive oil such as that shown in figure 1 or 2, wherein two ultrasound treatment reactors 10 have been inserted in series in place of the kneading machine G.

It goes without saying that, in general, according to different embodiments of the invention, one or more ultrasound treatment reactors as presented above, may be arranged at different points of the production system.

System tests

Reactor 10' shown in figure 9 and reactor 10" shown in figure 10 were used for the tests, with a square cross-section and sources 12 arranged in a helical manner on the external surface of the conduit 1 1.

For each work session, specific samples were taken of olive (sample taken at point P1 of figure 1), of pomace (sample taken at point P2 of fig. 2), and of the end product (sample taken at point P3 of fig. 2) which were catalogued and analyzed by means of weighing analysis for the evaluation of the yield, and by means of chemical and organoleptic analysis for evaluation of the healthiness, nutritional quality and perceived quality based on taste and aroma, as described in detail at the start of this section. When possible, and depending on the quan- tity of olives available, the production layout configurations were tested in duplicate industrial production sessions, in other words using two quantities of raw material of the same weight and belonging to the same batch of olives. For each working day, the production plant was first run in a conventional operating session to fill the entire production line, so as to make even the first tests conducted meaningful. After this initial phase, specific blank tests were conducted (Layout shown in figure 1) for the production of untreated oil, in other words reference production sessions associated with a conventional production layout, in order to obtain samples that could provide analytical reference values. The tests were then conducted, including the use of ultrasound in various ways on 5 different types of layout, described respectively in fig. 5, fig.6, fig. 7 and fig. 8.

Since most of the production sessions were conducted in duplicate, it was possible to make a more precise analysis of the results by eliminating any disadvantages associated with production problems both of a macroscopic nature and of less importance. Since the degree of variability in the results of the various tests was always quite small, we can say with some confidence that the results are reliable in terms of repeatability. Furthermore, the presence of readings associated with the blank tests made it possible to establish reference analytical values for the conventional production layout, so as not to allow any variety in the raw material used to introduce spurious results that could have biased the indications relating to the effectiveness of the productive approach. Indeed, simply by way of example, a comparison of the polyphenols in the product in absolute terms would be erroneous for tests conducted on different days using the same batch of olives, and the same is true for analysis of the production yield. This is because olives that are pressed subsequently have a lower phenolic content than fresh olives due to the oxidative processes that begin to take place immediately once the olive has been picked from the plant. The same consideration can also be made for other parameters of interest linked both to qualitative aspects and to extraction yield. To this end, since the tests were conducted on 5 different days using two distinct batches of olives, table 2 shows the most significant parameters relating to the two batches of olives used, which were evaluated by means of laboratory analysis. It is important to evaluate the results obtained in terms of yield, taking these values into account and differentiating between the two batches of olives, since they were very different from one another. In particular, it should be noted how the quantity of oil contained in the first batch of olive is roughly half of that contained in the second batch. This is in line with the yield results, which we will comment upon later.

Table 2 Significant parameters characterizing the two distinct batches of olives used for the tests.

Table 3, 3bis and 3 ter show all the results produced during the 5 days of tests using the 6 layouts described in the above-mentioned figures for the two batches of olives. The data collected were divided into 4 main groups: yield data, quality data, chemical-physical parameters and organoleptic parameters. For the first batch of olives, chemical-physical analysis and organoleptic analysis (tables 3bis and 3ter) were omitted, however we did evaluate the acidity and the number of peroxides (inserted in the quality data), because they were sufficient to check whether the treated oil had undergone abrupt changes with respect to untreated oil. For the second batch of olives, given the positive result obtained with the first batch of olives, all the other parameters normally evaluated when analyzing an extra-virgin olive oil, and described in the introduction to this section, were analyzed.

Yield data Quality data

Test information

Weighing Laboratory analysis Laboratory analysis

Number

Oil from Oil from Total poly¬

Olives Oil Yield Acidity of perox¬

Olive dry fresh phenols

Day Layout ides batch

%. Oleic meq

kg kg % % % mg/kg acid 02/kg oil

LI 70 5.0 7.1% 11.9% 4.5% 0.26% 7.3 551.7

L2 70 5.6 8.0% 10.8% 4.0% 0.23% 5.3 530.9

V L2 70 6.0 8.6% 9.8% 3.9% 0.23% 4.8 604.1

1

L3 70 5.5 7.9% 9.4% 3.5% 0.23% 6.7 564.9

13 70 6.5 9.3% 9.9% 3.7% 0.20% 5.8 701.6

2° L4 70 5.0 7.1% 9.3% 3.8% 0.26% 5.6 646.4

LI 150 22.0 14.7% 18.2% 8.4% 0.46% 8.0 550.8

LI 150 20.2 13.5% 18.5% 8.2% 0.42% 8.7 547.6

3°

L3 150 23.6 15.7% 15.5% 6.9% 0.37% 7.4 694.4

L3 150 23.6 15.7% 14.7% 6.5% 0.39% 9.0 678.9

2 LI 150 17.2 11.5% 18.2% 8.6% 0.42% 8.3 477.5

4° L5 150 24.8 16.5% 16.8% 7.2% 0.41% 7.7 632.2

L5 150 24.3 16.2% 15.7% 6.8% 0.40% 8.2 665.6

L6 120 15.5 12.9% 20.4% 9.7% 0.38% 8.0 411.3

5°

L6 196 23.6 12.0% 21.8% 10.4% 0.37% 8.0 425.1

Table 3 Results obtained in the five days of tests, divided by layout, day and batch of olives used - Quality and yield

Table 3bis Results obtained on test days 3, 4 and 5, divided by layout, day and batch of olives used - Chemical- physical parameters Organoleptic parameters

Test information

Fruity Mature green Bitter Sweet Tang Flowery Grassy Score

Olive

Day Layout Median Median Median Median Median Median Median Median Median batch

LI 2.0 2.0 1.0 1.5 2.0 0.0 0.0 1.0 6.7

LI 2.0 1.0 1.0 1.5 2.0 0.0 0.0 1.0 6.9

3°

L3 2.0 0.0 1.0 2.0 1.0 0.0 0.0 2.0 6.7

13 2.0 0.0 2.0 2.0 2.0 1.0 0.0 2.0 6.8

2 LI 2.0 2.0 1.0 2.5 2.0 0.0 0.0 1.0 6.5

₄° L5 2.0 1.0 2.0 2.0 1.0 1.0 0.0 2.0 6.8

L5 2.0 1.0 2.0 2.5 1.0 1.0 0.0 2.0 6.9

L6 2.0 1.0 2.0 2.0 2.0 0.0 0.0 2.0 6.8

5°

L6 2.0 0.0 2.0 2.5 1.0 0.0 0.0 2.0 6.8

Table 3ter Results obtained on test days 3, 4 and 5, divided by layout, day and batch of olives used - Organoleptic parameters.

As can be seen from the results shown in tables 3 (3, 3bis, 3ter), for both batches of olives there is an increase in the quantity of polyphenols and yield for the treated oil (obtained with Layouts 2, 3 and 5) compared to untreated oil (obtained with Layout 1 shown in fig. 1). It can be asserted that the introduction of an ultrasound reactor according to the invention into the extraction line for the production of extra-virgin olive oil results in an improvement in terms of both quality and yield.

In this respect, table 4 shows the mean results for yield obtained with the above-mentioned procedures, and for the quantities of polyphenols measured in the laboratory. The results for the untreated oil were obtained using the data collected during the tests conducted on Layout 1 (fig.1 ), while those for the treated oil were obtained using the results collected during the tests conducted on Layouts 2, 3 and 5. The data for the two batches of olives are shown separately, as being of different quality they produced different yields and phenolic quantities. Without loss of generality, it can be concluded from the results shown in table 4, that there has been an increase both in terms of yield (for all three procedures used, and in fact using the same amount of olives, there is an increase in oil produced of 14.4% for the first batch and 21.6% for the second batch, and a reduction in the amount of oil remaining in the pomace of 17.3% for the first batch and 14.3% for the second batch according to analysis conducted on the pomace that was allowed to dry, and a reduction of 16.0% for the first batch and 18.5% for the second batch according to analysis conducted on the fresh pomace, with respect to extraction from untreated oil), and in terms of the quantity of polyphenols (an increase of 10.5% in the quantity of polyphenols for the first batch of olives and 27.1 % for the second) in the case where ultrasound treatment is inserted into the production process, with respect to untreated oil. This result is also supported by the results for the chemical-physical and organoleptic parameters measured for the second batch of olives, which show that the treated oil retained these characteristics perfectly. Furthermore, as can be noted from the tables 3 (3, 3bis, 3ter), the treated oil was on average given a higher score for the organoleptic attributes "grassy" and "flowery", which, as mentioned previously, are linked to the phenolic components contained in the oil, and therefore associated with the quality and health aspects of extra-virgin olive oil.

Table 4 Quantitative comparison of resul s for yield and phenolic quantity be- tween untreated oil and treated oil

The results obtained in the tests conducted on the production line shown in Layout 6 (fig. 16), were not used in calculating the mean shown in table 4. In this layout, in fact, the kneading machine is missing. The kneading machine is the main and most important machine in an olive oil production line, since it is here that the enzymatic actions that lead to extraction of the oil are activated. The aim of this test was to demonstrate how the ultrasound machines created by us can replace the kneading machine. Naturally, the yield obtained is less than that obtained when using a kneading machine and ultrasound treatment together, but the result obtained is nevertheless on a par with that obtained using the standard procedure with a kneading machine described in fig 1.

The outcome of all the comparative analysis between oil produced in a conventional manner and oil already produced using the method proposed has demonstrated considerable benefits both in terms of production yield and various qualitative parameters. In particular, it has been observed that the proposed process innovation has the following effects on the analytic parameters described above:

I. No significant effects are observed relating to changes to product properties (free acidity, number of peroxides and spectrophotometric constants);

II. No changes are observed in the oil freshness indicators since the parameter 1.2DEG% shows no significant changes associated with the application of the proposed innovation to the pastes during the extra-virgin olive oil mechanical extraction process;

III. No significant changes are observed in the volatile compounds that have a sensory impact, with particular reference to the possible reduction in their content;

IV. Significant increases are observed in terms of the phenolic concentration associated with the application of the new technology to olive pastes, with particular reference to those phenolic compounds considered responsible for the health and sensory properties of extra-virgin olive oil, such as 3.4-DHPEA-EDA and 3.4-DHPEA-EA;

V. Significant increases are observed associated with the application of the new technology to olive pastes in terms of the yield from the extraction line, in other words a greater quantity of extra-virgin olive oil is produced with respect to the quantity produced using a conventional extraction line, for the same quantity and type of olives used.

It can be concluded from these tests that application of the new technology to olive pastes during the extra-virgin olive oil mechanical extraction process, and particularly before, immediately after or in place of the kneading phase and subsequent extraction of the oil by means of centrifugal separation, has an overall positive effect on the quality of oil produced and on its quantity.

Tests on crude oil

Among the various observations made, tests were conducted to determine whether, after a period of several months, an oil extracted using the innovative method described above, and an insonified crude oil, retain a uniform turbidity, as opposed to an untreated crude oil that tends to decant (separation of the water phase and hydro-soluble substances), becoming clear over time and displaying settling. The aim of these tests was therefore to determine the effectiveness of the ultrasound treatment on the turbidity stability of extra-virgin olive oil, in other words to prevent the process of settling on the bottom, which is typically manifested in freshly-pressed crude oil a few weeks after pressing. For these tests as for all the others, chemical-physical analysis was conducted to demonstrate the retention of these characteristics following treatment.

To demonstrate the above, two types of test were conducted:

a. Insonification tests with treatment in "batch" (or discontinuous) mode b. Insonification tests with treatment in line

Insonification tests on crude oil with treatment in discontinuous mode for evaluation of turbidity stability

In this test, a quantity of 700ml of crude extra-virgin olive oil was insonified using the system 13 described in fig. 4. Various treatment tests were conducted, varying power and exposure times. Before starting the test, a sample of oil was taken to be used as an untreated sample for the purpose of comparison. Two power values were chosen, based on the preliminary tests described previously (critical values for the quality of the oil), and for each power value three treatments were carried out, each time increasing the exposure time of the sample to insonification, for a total of 6 tests, which were referred to as follows: PiTi , PiT₂, P1T3, P2T1 , P₂T₂, P2T3, where: Pi and P₂ represent the power values used in the test, with Pi > P₂; Ti , T₂ and T₃ represent the treatment times, with

Table 5 shows the chemical-physical parameters of the samples taken in the 6 tests described above, and of the untreated sample. Sample Power: Acidity Number of k232 k270 ΔΚ

peroxides

kWh/l % Oleic acid meq 02/kg oil

Untreated. Ο,ΟΟΕ. 0.26% 11.7 1.69 0.098 -0.001

PJl 2,00 E. 0.25% 12.7 X X X

PJ₂ 5,30E. 0.24% 13.1 1.76 0.103 -0.001

PJ₃ 9,30E. 0.25% 14.3 X X X

P2T1 1,00 E. 0.26% 12.6 X X X

P₂T₂ 2,70E. 0.26% 12.4 1.72 0.102 -0.002

P2T3 4,70E. 0.26% 12.8 X X X

Table 5 Results of treatment for turbidity stability in discontinuous mode

From an examination of these samples, it was noted that, after several months, while the untreated sample is already at an advanced stage of de- cantation, since it is clearer and displays rather marked settling, the sample treated with P1T3 has greater turbidity and displays much less settling than the untreated oil, while its quality has remained unchanged, as can be seen from the results obtained from the analysis and shown in table 5.

Table 5 can also be compared with Table 1 in order to establish the difference between the exposure values used for this type of treatment, which have proven to be able not to alter the acidity of the product and other factors linked to quality. Indeed, the maximum exposure of this class of test in terms of energy per liter is approximately one tenth of that which led to the structural changes to the product matrix as described in the previous section.

These exposure values were obtained with wide-band, unfocussed ultrasound probes, meaning fairly diffuse treatments with low dislocation values (in other words using acoustic radiation that caused moderate local movements in each point of the vibrating surface), rather than being concentrated with high local dislocation values such as would have been obtained with, for example, a sonotrode directly immersed in the product to be treated, which transmits localized, concentrated ultrasonic radiation. Therefore, exposure of the product to ultrasound can be increased if the ultrasonic radiation diffusion techniques used can make the radiation the least concentrated possible. For this reason, solutions were studied that enable the resonant vibration of the reactor with external excitation or that use immersion radiation diffusers with a shape that can come into contact with the greatest quantity of paste and that can also at the same time enable mixing of the paste and other useful functions.

Insonification tests with treatment in line for evaluation of turbidity stability

To conduct this test, the set-up described in fig. 3 was used, which is composed of a recipient Z1 containing the crude oil to be treated, connected by means of a hydraulic pump M1 fitted with an inverter so as to be able to precisely set the number of pump revs, and varying the length of time the crude oil spends inside the reactor 10' described above, positioned in cascade with the pump. The reactor outlet was connected to a second recipient Z2, from which the samples of crude oil treated for the 4 exposure times were taken. Table 6 shows the results of analysis conducted on the untreated oil and on the four samples of oil after treatment with four different exposure times, according to this procedure: Ti , T₂, T₃, T₄ exposure times of the crude oil to insonification in the reactor 10' with T₄ = 4TL T₃ = 3Ti , T₂ = 21 .

Table 6 Check of parameters after treatment in line for turbidity stabi ization

In conclusion, summing up, the invention relates to a reactor fitted with at least one source of ultrasound, preferably located on the exterior of the reaction cavity of the reactor, enabling olive paste to be treated in an olive oil production system, or olive oil produced to be treated directly. In the first case, the surprising effect of the treatment on the olive paste is that of increasing the quantity of polyphenols in the treated oil and its turbidity stability over time and, secondly, that of increasing the quantity of oil yielded. In the second case, the surprising effect is that of increasing turbidity stability over time.

The first case can be easily achieved in line, with a reactor that forms an ultrasound treatment conduit (with at least one associated source of ultrasound preferably on the exterior of the conduit) for the olive paste in transit through the conduit, and in particular olive paste being treated in an olive oil production system. The second case can also be easily achieved in line by means of an ultrasound treatment conduit (with at least one associated source of ultrasound preferably on the exterior of the conduit) through which oil already produced is sent. The second case, however, can also be achieved using a discontinuous treatment, in other words where the reactor comprises a recipient into which the olive oil already produced is poured and is then subjected to ultrasonic radiation (the oil being treated is still, and does not flow as in the case of the conduit).

The invention also relates to a system using said reactor. This system can therefore be an olive oil production system, in which case one or more reactors are inserted into the olive paste processing line, and in particular immediately before the kneading machine, or immediately after the kneading machine, or even in place of the kneading machine. This system may also be a system for increasing the turbidity stability of olive oil already produced and may therefore comprise, in line, an oil pick-up zone, an ultrasound treatment conduit and a zone for receiving the treated oil, or a "static", discontinuous system, as described above, or a recipient into which the oil already produced is poured and then insonified.

It is understood that the drawings only show possible non-limiting embodiments of the invention, which can vary in forms and arrangements without however departing from the scope of the concept on which the invention is based. Any reference numerals in the appended claims are provided purely to facilitate the reading thereof, in the light of the above description and accompanying drawings, and do not in any way limit the scope of protection.

Claims

1) Reactor for increasing the quantity of polyphenols and/or the turbidity stability of extra-virgin olive oil over time, comprising a cavity adapted to receive a product constituted of olive oil or olive paste from which to obtain extra-virgin olive oil, and at least one source of ultrasound adapted to vibrate the body of said cavity.

2) Reactor according to claim 1 , wherein said cavity is a conduit in which said product can transit; said at least one source of ultrasound being located on the external surface of said conduit.

3) Reactor according to claim 2, wherein said conduit has a plurality of successive sections arranged so as to form portions of the conduit with concave and/or convex forms, preferably lying on the same plane.

4) Reactor according to claim 3, comprising a straight inlet section and a straight outlet section substantially aligned with one another, and a concave portion between said inlet and outlet sections with a substantially U shape.

5) Reactor according to one or more of the claims from 2 to 4, wherein said conduit is substantially straight, preferably with a circular, quadrangular or oval cross-section, in which there is a plurality of said sources of ultrasound located on the external surface of said conduit.

6) Reactor according to one or more of the previous claims, wherein inside said cavity there is at least one mixing blade assembly.

7) Reactor according to claim 6, wherein said at least one mixing blade assembly is fixed with respect to the walls of said cavity.

8) Reactor according to claim 6, wherein said at least one blade assembly is adapted to rotate inside said cavity.

9) Reactor according to any of the claims from 6 to 8, wherein said at least one blade assembly is associated with at least one source of ultrasound adapted to vibrate said at least one blade assembly; preferably said at least one source is connected to one end of said rotating blade assembly; preferably said source is external to said cavity.

10) Reactor according to one or more of the previous claims, adapted to emit an acoustic power of between 1^*10^~12 kWh/l and 5 kWh/l and more preferably between 1^*10^"9 kWh/l and 5^*10^"2 kWh/l, and even more preferably between 1*10^"6 kWh/l and 5^*10^"3 kWh/l for the treatment of oil, and between 1* 0^" ² kWh/l and 15 kWh/l and more preferably between 1^*10^"9 kWh/l and 1.5 kWh/l, and even more preferably between 1^*10^~6 kWh/l and 5^*10^"1 kWh/l for the treatment of olive paste, at any point of the oil production chain.

11) Reactor according to one or more of the previous claims, adapted to emit a power density at the interface with the treated means of between 1*10^" ⁹ W/cm^A2 and 500W/cm^A2 and more preferably between 1^*10^"6 W/cm^A2 and 50W/cm^A2, and even more preferably between 1^*10^"3 W/cm^A2 and 5 W/cm^A2.

12) Reactor according to one or more of the previous claims, wherein said at least one source emits an ultrasonic radiation in the frequency range between 1 Hz and 50 MHz and more preferably between 10 KHz and 10 MHz, and even more preferably between 15kHz and 4MHz.

13) System for the production of extra-virgin olive oil, comprising at least one reactor according to one or more of the previous claims.

14) System according to claim 13, comprising, in succession, an olive insertion zone, a first treatment zone including a milling device, such as preferably an oil press, a second treatment zone preferably comprising at least one said reactor, a third treatment zone including a separation device, such as preferably a decanter or horizontal centrifuge, and a fourth treatment zone including a separator or vertical centrifuge.

15) Method for increasing the turbidity stability and/or the quantity of polyphenols in extra-virgin olive oil, involving the vibration by means of ultrasound of a reactor containing a product constituted of olive oil or of olive paste from which to obtain olive oil.

16) Method according to claim 14, wherein said ultrasound originates from at least one source on at least one portion of the reactor in which said product is housed; preferably the method involves the transit of said product along at least said reactor in the form of a conduit and the ultrasonic radiation of said product by means of ultrasound originating from at least one source on at least one portion of said at least one conduit against which said product slides; said source being preferably external to said conduit.

17) Method according to claim 15 or 16, wherein said ultrasonic radiation which strikes said product has an acoustic power of between 1^*10^"12 kWh/l and 5 kWh/l and more preferably between 1^*10^"9 kWh/l and 5^*10^"2 kWh/l, and even more preferably between Γ10^"6 kWh/l and 5^*10^"3 kWh/l for the treatment of oil, and between 1*10^~12 kWh/l and 15 kWh/l and more preferably between 1*1 Cr⁹ kWh/l and 1.5 kWh/l, and even more preferably between 1*10^"6 kWh/l and 5*10^"1 kWh/l for the treatment of olive paste, at any point of the olive oil production chain.

18) Method according to claim 15 or 16, wherein said ultrasonic radiation which strikes said product has a power density at the interface with the treated means of between 1^*10^~9 W/cm^A2 and 500W/cm^A2 and more preferably between 1*10^"6 W/cm^A2 and 50W/cm^A2, and even more preferably between 1 *1 rj³ W/cm^A2 and 5 W/cm^A2.

19) Method according to claim 15 or 16, wherein said ultrasonic radiation is in the frequency range between 1 Hz and 50 MHz and more preferably between 10 KHz and 10 MHz, and even more preferably between 15kHz and 4MHz.

20) The use of ultrasound to increase the turbidity stability or the quantity of polyphenols, or both, in olive oil, in a flow of preferably extra-virgin olive oil, or of olive paste from which to obtain extra-virgin olive oil, along at least one conduit, wherein said ultrasound originates from at least one source on at least one portion of said at least one conduit against which said product slides.