The present invention concerns a process and a plant for the production of lycopene from rejects of tomato processing.

More specifically the invention concerns a process and a plant of the said kind, wherein lycopene is extracted from tomato peels by means of ultrasound assisted solvent extraction . As known, lycopene is an open-insaturated chain carotenoid having red colour (it is the pigment responsible for the colouring of ripe tomatoes) which is present in tomato and in some other red vegetables (in particular watermelon and pink grapefruit). From tomato (botanical classification Solanum lycopersicon), lycopene also derives its name. The lycopene is one of the most effective antioxidant in nature, and its capacity of protection against degenerative diseases is known. In fact, this compound is able to efficacely contrast the action of free radicals and the consequent cell damages. Moreover, lycopene seems to have an important role in the prophylaxis of cardiovascular diseases and some kinds of epithelial tumor such as, in particular, prostate cancer.

The amount of lycopene in tomatoes is influenced by their degree of ripening; in fact it was calculated that in red and ripe tomatoes 50mg/kg of lycopene are present, whereas the concentration decreases down to 5mg/kg in yellow variety. Moreover, in some varieties forming object of genetic improvement concentrations up to 200mg/kg are reached. The concentration of lycopene varies in the fruit and the highest concentrations are present in the peel.

Due to its pharmacological properties, it can be understood why the lycopene became a substance more and more requested by the market and why, since at present a process economically convenient for its chemical synthesis does not exist, research is more and more concentrated on the identification of a convenient process for its production by means of extraction from natural vegetal matrixes containing an appreciable amount of it (and in particular from tomato and by-products of tomato processing, i.e tomato peels).

At present, the known process for the extraction of lycopene from tomato and/or by-products of tomato processing provide for the use of chemical solvents. This processes implies the contact of the vegetable material with a liquid at boling temperature. The choice of solvent is made on the base of the chemical-physical features of the substance to be extracted. In particular, stability at temperature changes and substance polarity have a decisive importance. The first negative consequence of the use of chemical solvents is the increase of costs due to the cost of solvent. The second negative consequence is that solvent used can sometime be toxic and in any case after the treatment must be removed from the finished product, but they can not always be completely recycled. A further consequence is that the vegetable material becomes a special waste with further costs increases for the overall process of lycopene production. After, in any case, due to the need for solvents in the step of exreaction, the known extractive processes can not be used in a large scale.

A more updated solvent extraction provides for the simultaneous use of electromagnetic waves (ultrasounds or microwaves) in order to increase the extraction yeld and reduce the volume of solvent used and the time of contact.

In particular, the ultrasound assisted extraction provides for the use of sound waves having frequencies higher than 20 kHz, which can increase the extraction yeld because they alternatively cause expansions and compressions of the matrix, with the formation of microbubbles. In this way, ultrasounds casue a deeper penetration of solvent into the cells of the matrix, improving the mass transfer.

The most important parameter to be controlled according to this kind of process in the frequency of waves. Little frequency changes can have an important effect on the extraction yeld.

At last, according to a recently proposed process for the production of lycopene from by-products of tomato processing, an alternative step of solid-liquid extraction is provided, based on the technology named Naviglio Extractor (Naviglio D et al, Extraction of pure lycopene from industrial tomato by-products in water using a new high- pressure process, Journal of Science of Food and Agriculture, vol. 88, 2008, pag. 2414 - 2420). This technology bases its extractive efficiency upon the pressure difference of the extraction liquid between the interior and the exterior of the solid matrix. The extraction chamber is filled with the solid matrix to be subjected to extraction and the circuit is completely filled with solvent. A static step starts consisting in raising the liquid pressure up to values comprised between 8 and 9 bar. The system is left under pressure for the time needed for the liquid to efficacely penetrate inside the solid matrix. After, the liquid pressure is quickly removed; thus the liquid fastly reaches the atmospheric pressure, but for an instant the liquid inside the solid matrix is still at the value of 8-9 bar. In such a way, a pressure difference originates between the interior and the exterior of the solid matrix, forcing the liquid to quickly exit from inside the solid. The fast movement of liquid from the inside to the outside helps the coming out of substances that are not chemically bound to the solid matrix. At this point a dynamic step starts consisting in a mixing of the liquid all overthe extraction system. An extraction cycle is constituted by a static step followed by a dynamic step; in order to obtain the exhaustion of the solid matrix more extraction cycles are needed. In this extraction technique the main effect of the extraction is due to the generation of a pressure gradient causing the quick deplacement of liquid from the inside to the outside of the solid matrix giving raise to the extraction of the substances contained in the solid matrix.

The bigger advantage of this technique consists in the possibility of using even water as the extraction liquid for the obtaining of lycopene. Since lycopene does notsolvein water, it is collected because it is in a para-crystalline form and hence is mechanically removed by the action of the pressure increasing and decreasing generated insidethe Naviglio extractor.

Once it is obtained in an eterogeneous phase, lycopene is purified in a solid phase extraction colomn or SPE column (SPE standing for Solid Phase Extraction) using a minimal amount of organic solvents.

This technology, is particularly convenient on one hand because of the possibility to use water as asolvent, but presents important limitations as far as the extraction time is concerned and because it can not be applied to big industrial plants.

In this context is entered the solution according to the present invention, with the aim of providing for a process and a plant for the production of lycopene from by-products of tomato processing by means of ultrasound assisted solvent extraction. The process according to the present invention is particularly advantageous because, due to the optimisation of all the process parameters, it allows for using water as solvent, solving all the problems connected to the use of chemical solvents and the need of purifying the final product in order to remove traces of solvent that are still present.

Thus the process and the plant of the present invention allow for combining the advantages of solvent extraction and ultrasound systems with the advantages of the Naviglio technology, with importantly reduced extraction time and importantly higher amounts of treated material.

In fact, the process and the plant of the present invention allow for obtaining production volumes that are notably higher than those of any industrial process of a known kind for the same amount (mg) of lycopene contained in the raw material (by-products of tomato processing).

A purpose of the present invention is therefore that of proposing a process and a plant allowing for overcoming the limits of the solutions according to the prior art and obtaining the previously described technical results.

A further aim of the invention is tha said process and said plant can be realised with substantially limited costs, as far as both the production and the operative costs is concerned.

Not least aim of the invention is that of proposing a process and a plant that are substantially simple, safe and reliable.

It is therefore a first specific object of the present invention a process for the production of lycopene from by-products of tomato processing, comprising the following steps:

- extracting lycopene from the raw material using water as solvent and with the assistance of ultrasounds, obtaining an extraction liquid made of exhausted solid biomass and liquid extract made of water that contains lycopene and pectins;

- separating the solid biomass from the liquid extract by centrifugation of the extraction liquid; - separating lycopene and pectins from water by centrifugation of the liquid extract;

- separating lycopene from pectins.

Preferably, according to the invention, said step of extracting lycopene from the raw material is performed adding such an amount of water that the weight percentage is comprised in the range 85-95% of water and 5-15% of raw material (more preferably 90% of water and 10% of raw material), by means of ultrasound vibrations with a frequency comprised between 24000 and 40000 Hz (more preferably between 24000 and 26000 Hz) and a time varying between 40 and 80 minutes (morepreferably between 45 and 60 minutes).

Further, according to the present invention, said step of separating lycopene and pectins from water preferably occurs by supercentrifugation of the liquid extract.

Alternatively, according to the invention, said step of separating lycopene from pectins can occur by addition of a solvent and evaporation or by means of solid phase extraction followed by addition of a solvent and evaporation.

Preferably, following said step of separating lycopene from pectins a step of drying of the solution is provided by means of atomisation in order to obtain a dust of lycopene.

Moreover, it is also possible to provide, following said step of separating the solid biomass from the liquid extract by centrifugation of the extraction liquid and preceding said step of separating lycopene and pectins from water by centrifugation of the liquid extract, a step of concentration of the liquid extract.

It is further a second object of the present invention a plant for the production of lycopene from by-products of tomato processing comprising a section for solvent extraction of lycopene from raw material with the assistance of ultrasounds, obtaining an extraction liquid made of exhausted solid biomass and liquid extract made of water that contains lycopene and pectins; a section for separating the solid biomass from the liquid extract by centrifugation of the extraction liquid; a section for separating lycopene and pectins from water by centrifugation of the liquid extract; and a section for separating lycopene from pectins.

Preferably, according to the invention, said section for solvent extraction comprises a plurality of disintegrators and ultrasound tanks; said section for separating the solid biomass from the liquid extract is constituted by an horizontal screw centrifuge; said section for separating lycopene and pectins from water is constituted by a vertical plate supercentrifuge and said section for separating lycopene from pectins is constituted by an evaporator or, as an alternative, by a plurality of extraction columns for SPE (Solid phase extraction), more preferably followed by an evaporator. Last, always according to the invention, downstream said section for separating lycopene from pectins an atomiser is provided.

The present invention will be described, for illustrative non limitative purposes, according to its preferred embodiment, with particular reference to the enclosed drawings, wherein:

- figure 1 shows a plant for the production of lycopene from byproducts of tomato processing according to a first embodiment of the present invention, e

- figure 2 shows a plant for the production of lycopene from by- products of tomato processing according to a second embodiment of the present invention.

With reference to the figures, the optimal plant provided with ultrasounds for the industrial production of lycopene from by-products of tomato processing is constituted by a section for extraction, indicated as a whole with the number 10, comprising two disintegrators 11 , each of

2000L, and four ultrasound tanks 12, each of 1000L.

Raw material (by-products of tomato processing) is mixed with water, used as solvent, in a weight percentage of 90% water and 10% raw material. The ultrasound vibrations needed to crash the vegetal molecules and extract lycopene with the help of the solvent water have a house and a frequency of 24000/26000Hz.

The time duration of the extraction process of all the lycopene from disintegrated molecules is 45/60 minutes. In a whole working day (24 hours) from 10000kg of raw material about 90000L of extraction liquid are obtained, which is constituted by milliards of lycopene containing microscopical bubbles, exhausted biomass, pectins.

The process liquid is then conveyed by means of pumps (not shown) in a tank 13 of 10000L provided with a mixer to maintain the cavitation bubbles in suspension and acting as a buffer for the plant, i.e. ensures a certain continuity of production independently from non excessive changes of the feed. From the tank 13 the process liquid is sent to an horizontal screw centrifuge 14 with a flow of 9m ³ /h. The horizontal centrifuge 14 has the function of separating the exhausted vegetal biomass from water that contains lycopene exploiting the high difference of existing between the solid biomass and water that contains lycopene. In particular, the horizontal centrifuge allows for obtaining such a separation continously, being provided with a rotating hollow element called drum, provided with a cylindrical section and an adjacent frustoconical section, inside which a screw rotates with different speed, the form of the screw reproducing that of the drum, wherein the vegetable biomass and water that contains lycopene are entered into the drum and are rotated together with it. Due to the effect of the centrifugal force and the difference in density existing between the exhausted vegetal biomass (solid phase) and water that contains lycopene (liquid phase), the solids deposit on the wall of the cylindrical section of the drum and are transported by the screw, through the frustoconical section inside which they are further freed from residual liquids, to the outlet openings provided at the tapered end of the drum.

The water that contains lycopene, having a lower specific weight, forms a layer positioned above the solids of the cylindrical section of the drum. The water is not transported by the screw, and is picked-up from the outside through holes placed at the end of the drum, on the side of its cylindrical section.

The exhausted vegetal biomass exiting from the horizontal centrifuge 14 is conveyed to a screw conveyer 15 and is collected in order to be used to produce energy (electric energy, vapour) or even as a fertiliser.

The extract, containing lycopene as clarified by the horizontal centrifuge 14, is sent to a vertical plate supercentrifuge 16 for separating completely the water and lycopene.

The lycopene deposited on the plates of the supercentrifuge is discharged in a basin by an automated self-cleaning system of the supercentrifuge itself.

According to a first embodiment, shown with reference to figure 1 , the product obtained downstream of the vertical plate supercentrifuge 16, constituted by lycopene chrystals together with pectins, is further purified by separation through evaporation. In pratice, the outlet product of the supercentrifuge 16 is first solubilised with alcohol at a purity of 96%, or with another equivalent solvent, and subsequently sent to an evaporator 17, in particular a heat pump evaporator. Hence, the product 18 so obtained can be sent, pure or added with inerts, to a spray atomiser (not shown) in order to be transformed in a lycopene dust at a purity of 98% or any other percentage, depending on the amount of inert additives.

Alternatively, the lycopene obtained from the supercentrifuge 16 can be purified from pectins by means of extraction columns 27 of the SPE (Solid phase extraction) kind.

The product 18 obtained can be solubilised with alcohol with a purity of 96%, or with another equivalent solvent, and, suitably concentrated, is sent to a spray atomiser (not shown) to be transformed in lycopene dust at a purity degree of 98% or any other percentage by addition of inert additives.

Opzionally, before being sent to the supercentrifuge 16, the extract, containing lycopene clarified by the horizontal centrifuge 14 can be sent, after passing in a tank 19 of 10000L, to a system of low temperature concentrators 20. The forwarding of the extract coming from the horizontal centrifuge directly to the supercentrifuge 16 or to the system of concentrators 20 is controlledby means of interception valves 21.

The present invention was described for illustrative, non limitative purposes, according to its preferred embodiments, but it is to be understood that variations and/or modifications can be made by the skilled in the art without for this reason escaping the relative scope of protection, as defined by the enclosed claims.