System and method for extracting volatile molecules from plant raw materials

Abstract

The invention relates to the field of producing natural plant extracts, and more particularly to the field of capturing volatile compounds and molecules from plant raw materials, and in particular from fresh flowers, including mute flowers. More specifically, the invention relates to a system and to a method for capturing the odorous substances of plants, and for making these substances available (in particular in the form of an extract on a carrier) with a view to their use, for example in the composition of a perfume. The invention also relates to such an extract.

Description

[0001] System and method for extracting volatile molecules from plant raw material

[0002] Technical field

[0003] The invention relates to the field of manufacturing natural plant extracts, and more particularly to the field of capturing volatile compounds and molecules from plant raw materials, and in particular from flowers, including mute flowers. The invention relates more specifically to a system and a method for capturing odorous substances from plants, and making these substances available (in particular in the form of an extract on a support) for use, for example in the composition of a perfume. The invention also relates to such an extract.

[0004] Background of the invention

[0005] There are various known extraction processes for concentrating plant fragrances, some of which are very ancient.

[0006] The oldest process is called enfleurage, and involves placing freshly picked flowers on a fatty substance such as animal fat, then allowing the fatty substance to absorb the scent of the flowers. After this step, the fat is used as is or treated before use.

[0007] Processes are also known that use hydrodistillation or steam distillation techniques, whereby natural plant extracts are entrained by steam to obtain essential oils and hydrosols. These processes are widely used today but have the disadvantage of degrading the plants used, and, in addition, do not always allow a fragrance to be obtained that is representative of the original odor of the fresh raw material. Distillation processes also have the disadvantage of having very low yields, i.e., a very large quantity of raw material is required for a small quantity of final product. In addition, these processes are particularly energy-intensive and require large quantities of water. Solvent extraction processes are also known.These processes involve leaving the plants in a tank filled with a solvent, usually a petrochemical solvent, until the solvent is impregnated with the plants' odors. The solvent is then removed by evaporation. These processes have the disadvantage of being time-consuming to implement, and also of requiring large quantities of a petrochemical solvent, which is often polluting and dangerous, and whose presence in finished products is regulated.

[0008] Processes using supercritical CO2 are also known. In the supercritical state, CO2 acts as a solvent to extract odor molecules. Processes using supercritical CO2 generally produce extracts whose odor is more faithful to that of the raw material than the processes mentioned above. However, these processes are expensive to implement. In addition, these processes are generally not compatible with the use of fresh raw materials.

[0009] Finally, document EP 2 644 039 describes a device for extracting fragrant ingredients from a plant, constituting an alternative to the enfleurage technique. This device comprises an extraction chamber, which contains a container for the plants, such as flowers (jasmine, rose, tuberose, etc.) and is crossed by a gas stream. The gas is then guided via a compressor into a collection chamber where the odorous substances it contains are trapped by a solvent which may be a vegetable oil.

[0010] The invention is based on the observation that there is currently no known method for capturing volatile molecules that would make it possible to obtain a product whose odor is exactly representative of the odor of the plant, in particular its top notes. In addition, existing methods do not make it possible to capture the odors of certain plants, including in particular so-called "mute" flowers such as lily of the valley, hyacinth, lilac, freesia, etc. A flower is generally considered to be mute if it meets at least one of the following conditions:

[0011] - a very low extraction yield of its compounds of interest via known processes; and the obtaining via known processes of a final extract of poor olfactory quality.

[0012] Summary of the invention

[0013] The present invention aims to overcome the drawbacks of the state of the art, and in particular those described above, by proposing a system and a method for extracting natural plant extracts which make it possible to obtain an extract representative of the odor of the raw material. The invention also aims to propose an extraction system and method which do not use polluting or dangerous substances, and which have an energy efficiency possibly higher than known extraction methods.

[0014] To this end, the invention relates to a system for extracting volatile molecules from a plant raw material, comprising:

[0015] - at least one enclosure comprising a plurality of receptacles, configured to receive a plant raw material, the enclosure being gas-tight and comprising an inlet and an outlet arranged at two ends of the enclosure, the enclosure being configured to generate a circulation of gas within the enclosure at the level of each receptacle, with a gas flow rate close to or equal to the level of each receptacle;

[0016] - a compression device, configured to adjust the pressure of the air or gas flowing from the enclosure to a capture system to a relative pressure greater than or equal to 2 bars; the capture system comprising:

[0017] - a first capture device, at least partially filled with a first solvent, so as to allow an exchange between the first solvent and the compressed gas driven by the compression device; and

[0018] - a second capture device, comprising an inlet connected to a pipe making it possible to bring the air evacuated from the first capture device into the second capture device, the second capture device being at least partially filled with a second solvent, so as to allow an exchange between the second solvent and the compressed gas having passed through the first capture device.

[0019] The invention also relates to a method for extracting volatile molecules from a plant raw material, such as flowers, the extraction method comprising the following steps:

[0020] - distributing plant material into several portions, in an enclosure supplied with a gas such as air and configured to generate a circulation of said gas through each portion of plant material, with a gas flow rate close to or equal to the level of each portion,

[0021] - extract the gas having circulated over all the portions of plant material and compress it to a relative pressure greater than or equal to 2 bars,

[0022] - capturing the compressed gas in a first organic solvent having a solubility in water of less than or equal to 20% by weight, and separating by condensation the water vapor contained in the gas, to obtain a depleted gas, a first organic phase and a first aqueous phase,

[0023] - capturing the depleted gas in a second organic solvent having a solubility in water of less than or equal to 20% by weight, preferably identical to the first organic solvent, and separating by condensation the water vapor contained in the gas, to obtain a second organic phase, a second aqueous phase and a still depleted gas which is optionally recirculated in step (a),

[0024] - combine the two organic phases and possibly the organic compounds present in the two aqueous phases, to obtain a plant extract.

[0025] It also relates to a plant extract that can be obtained using this process, in particular an extract from plant material consisting of mute flowers. Detailed description

[0026] The invention relates to a method and a device for extracting aromatic compounds from plant material, as well as the extract thus obtained.

[0027] Plant material means fresh plant material, possibly washed, or plant material that has undergone at least one mechanical (e.g. blown), chemical (e.g. oxidized) and / or thermal (in particular dried, grilled or roasted) treatment after harvesting and from which odorous molecules can be extracted. It is preferably fresh plant material, i.e. all types of freshly picked or cut plants, and not dried. Plant material can be any part of any plant and in particular be made up of leaves, flowers, fruits, stems, flowering tops, needles, roots or mixtures thereof.Flowers are used in particular, especially jasmine, rose, tuberose, all perfume flowers as well as flowers described as mute in the field of perfumery, notably lily of the valley, hyacinth, lily, honeysuckle, lilac, gardenia, violet, carnation, sweet pea, buddleia or peony.

[0028] The extraction system according to the invention uses a circulation of gas, in particular air, at a temperature advantageously close to, or equal to, ambient temperature, to drive the volatile molecules emitted by the raw material stored in the enclosure towards a solvent. By avoiding heating the enclosure (or heating it to an excessive temperature), and by avoiding any premature contact between the raw material and a substance (such as water vapor, a solvent or other chemical product) likely to degrade some of the volatile molecules responsible for the original odor of the raw material, it is ensured that all of the volatile molecules emitted can be captured without alteration (or with negligible alteration) by the extraction system.By implementing a circulation of pressurized gas, the system according to the invention makes it possible to increase the exchanges between the compressed gas and the solvents contained in the capture devices, thus increasing the efficiency of the capture of volatile molecules by the solvent(s). This increases the efficiency and extraction yield of the extraction system, making it compatible in particular with industrial use. The system which is the subject of the invention also makes it possible to treat several successive quantities of raw material for the same quantity of solvent, and thus to obtain a higher concentration of volatile molecules in the solvent. The system according to the invention is particularly suitable for solvents of non-petrochemical origin.The extraction system according to the invention is thus more environmentally friendly than known systems and processes, and facilitates compliance of finished products with legislation, in particular concerning the presence of residual solvents. Finally, the system according to the invention is compatible with so-called mute flowers.

[0029] These objectives are achieved in particular because the enclosure is configured to generate a circulation of gas within the enclosure at the level of each receptacle, with a gas flow rate close to or equal to the level of each receptacle. To achieve this, several types of configurations are possible.

[0030] In a first embodiment, the enclosure comprises an inlet and an outlet arranged respectively at two opposite ends of the enclosure and the inlet of the enclosure is connected to a gas or air distribution column passing through the enclosure, the distribution column comprising a tubular body, the tubular body comprising a plurality of perforated longitudinal sections comprising distribution orifices at each receptacle, each perforated section being arranged between two adjacent receptacles, the cumulative surface area of ​​the orifices of each successive perforated section decreasing from the inlet towards the outlet of the enclosure.

[0031] In one embodiment, the orifices are of identical shape and size, the number of orifices in each successive openwork section decreasing from the inlet to the outlet of the enclosure.

[0032] In another embodiment, the enclosure comprises an outer casing and an inner casing, the inner casing comprising a plurality of perforated longitudinal sections comprising distribution orifices at each receptacle, each perforated section being arranged between two adjacent receptacles, the cumulative surface area of ​​the orifices of each successive perforated section decreasing from the inlet to the outlet of the enclosure.

[0033] In a first variant of this embodiment, the enclosure comprises a gas or air distribution column provided with longitudinal sections perforated at each receptacle and the distribution column is connected to the outlet of the enclosure.

[0034] In a second variant of this embodiment, the receptacles comprise perforated lower and upper walls.

[0035] In another embodiment, the enclosure comprises a plurality of receptacles arranged side by side and the inlet of the enclosure is connected to a gas or air distribution column comprising a tubular body, the tubular body comprising a plurality of perforated longitudinal sections comprising distribution orifices at each receptacle, the cumulative surface area of ​​the orifices of each successive perforated section decreasing along the distribution column, from the inlet of the enclosure. In yet another embodiment, the enclosure comprises a plurality of removable receptacles around a horizontal axis, the inlet of each receptacle comprising gas or air distribution orifices.

[0036] The additional embodiments below are compatible with each of the previously described enclosure embodiments.

[0037] In one embodiment, the compression device comprises an inlet connected to the outlet of the enclosure so as to suck the gas contained in the enclosure, and comprises an outlet connected to an inlet of the first capture device.

[0038] In one embodiment, the compression device is configured to provide a pressure greater than 2 bars, and for example greater than 4 bars.

[0039] In one embodiment, the compression device is configured to provide a pressure of between 4 and 6 bars.

[0040] In one embodiment, the compression device is configured so that the flow rate of gas circulating at the outlet of the enclosure, when the volume of the enclosure is between 100 and 200 liters, is greater than 20 liters per minute, or preferably less than 100 liters per minute, and is for example between 30 and 80 liters per minute.

[0041] In one embodiment, the compression device is an oil-free type compressor.

[0042] In one embodiment, the extraction system comprises two enclosures, the outlet of each enclosure being connected to the inlet of the compression device. In one embodiment, the extraction system comprises a selection device making it possible, for each enclosure, to activate or deactivate the circulation of gas, the selection device making it possible to activate the circulation of gas, either selectively in one or the other of the two enclosures, or in both enclosures simultaneously, the selection device comprising for example one or more valves.

[0043] In one embodiment, the selection device is controlled automatically, for example via a timer device.

[0044] In another embodiment, the extraction system comprises two or more enclosures disposed within a container, each of the enclosures comprising one or more gas inlets and one or more gas outlets connected to a single gas outlet of the container.

[0045] In one embodiment, the receptacles are superimposed, each receptacle having a bottom wall and, preferably, a peripheral side wall.

[0046] In one embodiment, the bottom wall and / or the side wall of each receptacle comprises a plurality of gas circulation orifices.

[0047] In one embodiment, the first solvent has a solubility in water of less than or equal to 20%, and preferably less than or equal to 10%.

[0048] In one embodiment, the second solvent is the same as the first solvent, or different from the first solvent, the second solvent then being miscible with the first solvent.

[0049] In one embodiment, the second solvent has a solubility in water of less than or equal to 20%, and preferably less than or equal to 10%.

[0050] In one embodiment, the first capture device and / or the second capture device comprises means for generating bubbles in the first and / or the second solvent, respectively, such as a turbine, a sintered filter, a nebulization system or an ultrasonic probe. This is preferably a porous metal filter, for example a metal sintered type filter, such that gas entering the first capture device is forced to pass through the filter before contacting the first solvent and / or gas entering the second capture device is forced to pass through the filter before contacting the second solvent.

[0051] In one embodiment, the first capture device and / or the second capture device comprises a portion forming a container for condensation water resulting from condensation occurring during the circulation of gas in the extraction system.

[0052] In one embodiment, the first capture device and / or the second capture device comprises a condensation water emptying device, the emptying device being able to be controlled automatically.

[0053] As indicated above, the invention also relates to an extraction method implementing the extraction system defined above.

[0054] The invention relates specifically to a method for extracting volatile molecules from a plant raw material, such as flowers, the method comprising the following steps:

[0055] - distributing plant material into several portions, in an enclosure supplied with a gas such as air and configured to generate a circulation of said gas through each portion of plant material, with a gas flow rate close to or equal to the level of each portion,

[0056] - extract the gas having circulated over all the portions of plant material and compress it to a relative pressure greater than or equal to 2 bars,

[0057] - capturing the compressed gas in a first organic solvent having a solubility in water of less than or equal to 20% by weight, and separating by condensation the water vapor contained in the gas, to obtain a depleted gas, a first organic phase and a first aqueous phase,

[0058] - capturing the depleted gas in a second organic solvent having a solubility in water of less than or equal to 20% by weight, preferably identical to the first organic solvent, and separating by condensation the water vapor contained in the gas, to obtain a second organic phase, a second aqueous phase and a still depleted gas which is optionally recirculated in step (a),

[0059] - combine the two organic phases and possibly the organic compounds present in the two aqueous phases, to obtain a plant extract.

[0060] "Depleted gas" means that the gas is devoid of some of the volatile compounds it contained before entering the first capture device. "Further depleted gas" means that the gas is devoid of some of the volatile compounds it contained before entering the second capture device.

[0061] In a preferred embodiment, the method according to the invention implements an extraction system as described previously and in the remainder of this description. The method then comprises the following steps:

[0062] - place a plant raw material in the enclosure;

[0063] - extract the gas contained in the enclosure, for example by suction via the enclosure outlet;

[0064] - compress the extracted gas to a relative pressure greater than or equal to 2 bars;

[0065] - circulate the compressed gas in the first capture device;

[0066] - circulating the gas leaving the first capture device into the second capture device.

[0067] In one embodiment, the steps of extraction, compression and circulation of gas are implemented in successive cycles, the extraction system being kept stopped between two successive operating cycles.

[0068] In one embodiment, the duration of each cycle corresponds to a first predetermined duration, in particular a duration greater than 15 minutes and for example equal to 30 minutes.

[0069] In one embodiment, the duration during which the extraction system is kept stopped corresponds to a second predetermined duration, the second predetermined duration being for example equal to the first predetermined duration.

[0070] In one embodiment, the duration of each cycle corresponds to the time required for the compressed gas to reach a predetermined relative pressure, for example a relative pressure of between 2 and 10 bars or between 4 and 6 bars.

[0071] In one embodiment, the time during which the extraction system is kept stopped corresponds to the time required for the relative pressure of the compressed gas to reach a zero value.

[0072] In one embodiment, the method implements an extraction system comprising at least two enclosures, in which method the extraction step is implemented alternately within each enclosure.

[0073] The present invention will be better understood from the following detailed description, given with reference to the accompanying drawings, in which:

[0074] Figure 1 is a schematic view of an extraction system according to the invention.

[0075] Figure 2 is a view of a gas distribution column.

[0076] Figure 3 is a schematic view of an extraction system according to the invention, comprising two enclosures.

[0077] Figure 4 represents the steps of an extraction method according to the invention.

[0078] Figure 5 illustrates a variant of the extraction system according to the invention.

[0079] Figure 6 illustrates a second variant of the extraction system according to the invention.

[0080] Figure 7 illustrates a third variant of the extraction system according to the invention.

[0081] Figure 8 is a chromatogram illustrating the composition of a rose absolute.

[0082] Figure 9 is a chromatogram illustrating the composition of rose flowers.

[0083] Figure 10 is a chromatogram illustrating the composition of a rose extract obtained according to the invention. Figure 11 is a chromatogram illustrating the composition of lily of the valley flowers.

[0084] Figure 12 is a chromatogram illustrating the composition of a lily of the valley extract obtained according to the invention.

[0085] Figure 1 is a schematic view of an example of an extraction system 1 according to the invention. The extraction system 1 comprises a storage enclosure 10, making it possible to store an odorous raw material 2, in particular a fresh plant raw material, such as flowers 2. The extraction system 1 further comprises a compression device 12 and a capture system 14, 16. The capture system comprises in the example a first capture device 14 and a second capture device 16. The extraction system 1 is configured to circulate a gas which may in particular be air through the enclosure 10 so as to entrain a mixture of gas (or air) and volatile molecules emitted by the raw material 2 stored in the enclosure 10 towards the capture system 14, 16.In the example, the compression device 12 is arranged between the enclosure 10 and the capture system 14, 16, so as to suck in the gas contained in the enclosure 10, this gas being air in the example. The sucked in air is compressed by the compression device 12 and driven towards the first capture device 14. The passage of the air in the first capture device 14 allows the capture of a portion of the volatile molecules mixed with the air. The air is then driven towards the second capture device 16. The second capture device 16 allows the capture of the portion of the volatile molecules not captured at the first capture device 14.

[0086] The enclosure 10 comprises a gas-tight body 100, in the example a body 100 of generally straight cylindrical shape elongated along a vertical axis of symmetry. By "gas-tight" is meant that the enclosure 10 is in particular sealed against the surrounding air, except for the air entering the enclosure 10 via an inlet 102 formed in the body 100, in the example at a lower end 104 of the body 100, and an outlet 106 formed in the body 100, in the example at an upper end 108. The internal volume of the enclosure is in the example between 150 and 160 liters. The enclosure 10 comprises a plurality of receptacles 18 configured for the storage of the raw material, such as fresh flowers 2. The enclosure 10 further comprises a gas distribution column 20, arranged within the body 100.The distribution column 20, which is described in more detail below, comprises a hollow body 200 connected to the air inlet 102 and comprising one or more perforated sections 202. The perforated sections 202 allow gas / air to circulate between the inside and the outside of the body 200, and therefore between the inlet 102 and the interior space of the enclosure 10 located around the distribution column. Thus, when the compression device 12 sucks in the air contained in the enclosure 10, a circulation of air is generated from the inlet 102 to the outlet 106 of the enclosure, and the incoming air (see arrow F3) is forced to pass through the interior of the body 200 of the distribution column 20, then through the openwork sections 202 provided on the body 200, to then leave the enclosure 10 through the outlet 106. In the example, the distribution column 20 is arranged in the central part of the body 100, along the axis of symmetry of the body 100.Advantageously, the inlet 102 of the enclosure 10 is equipped with a filter, such as a carbon filter, making it possible to filter the air entering the enclosure 10 so that this air is free from any olfactory pollution. The compression device 12 comprises an inlet 120, which is connected to the outlet 106 of the enclosure 10 via a first pipe 22, and an outlet 122, which is connected to the first capture device 14 via a second pipe 24. The compression device 12 is configured to suck in the air contained in the enclosure 10 and to compress this air, which is loaded with volatile molecules from the raw material 2 stored in the enclosure 10. The compression device 12 is in the example a dry compressor (i.e. of the oil-free type), which makes it possible not to pollute the air circulating in the extraction system 1.Indeed, a lubricated compression device 12 would be likely to generate pollution in the extraction system, in particular by releasing lubricant particles into the gas / air circuit, which would be detrimental to the quality of the final product, which could contain lubricant particles (and furthermore the lubricant could be contaminated by volatile molecules from previous extractions). The compression device 12 is configured to generate at the output a relative pressure greater than or equal to 2 bars or 3 bars. Advantageously, the compression device 12 is capable of generating a relative pressure of between 4 and 5 bars or between 4 and 6 bars.Providing a compression device arranged downstream of the enclosure 10 makes it possible to generate an air circulation in the enclosure 10 by suction, which is better for entraining the volatile molecules of the flowers 2 arranged in the enclosure 10 compared to an air circulation generated by pressurizing the enclosure 10, which would also be more likely to generate turbulence harmful to the operation of the system and to the raw material contained in the enclosure 10. The compression device 12 is configured to generate an air (or gas) flow rate which is sufficient to ensure the entrainment of the air contained in the enclosure, and which remains sufficiently low so as not to generate excessive turbulence in the enclosure 10, and in particular so as not to generate turbulence likely to displace the raw material.For example, for an enclosure 10 having a volume of approximately 100 to 200 liters, a compression device 12 may be provided ensuring an air flow rate at the inlet of the device of between 30 and 100 liters per minute, and ensuring an air flow rate at the outlet of the device of between 10 and 50 liters per minute. For example again, for an enclosure 10 having a volume of approximately 160 liters, the compression device 12 will be provided to ensure an air flow rate at the inlet of 50 liters per minute and an air flow rate at the outlet of 20 liters per minute. Of course, the air flow rate that the compression device can generate at the inlet (and therefore at the outlet of the enclosure 10) will depend in particular on the internal volume of the enclosure 10.

[0087] The first capture device 14 comprises a body 140 forming a column-type container, and comprises an inlet 142 connected to the second pipe 24 and an outlet 144 connected to a third pipe 26 connecting the first and second capture devices 14, 16. The inlet 142 is arranged at a lower end of the body 140, and allows the admission of compressed air from the compression device 12, while the outlet 144 is arranged at a high end of the body 140, and allows the air to be evacuated towards the third pipe 26 and therefore towards the second capture device 16. The body 140 is partially filled with a first solvent S1, and comprises for this purpose a first part 141 forming a container for the first solvent S1. The first solvent is chosen from solvents suitable for the formulation of perfumes, and is preferably a solvent of natural and non-polluting origin.A porous metal filter 146, for example of the metal sintered type, is arranged at the inlet 142, so that the air entering the body 140 is forced to pass through the filter 146 before coming into contact with the first solvent. When the air coming from the compression device 12 is admitted into the first capture device 14, a bubbling phenomenon is generated thanks to the filter 146, allowing an exchange between the compressed air and the first solvent. This exchange results in a capture of at least a first part of the volatile molecules contained in the air by the first solvent. It is understood that another bubble generation system can be used instead of the filter 146. The efficiency of the capture carried out thanks to the passage of the air in the solvent is improved thanks to the pressurization of the air, the exchanges between the air and the solvent being increased by the air pressure.In order to optimize the exchanges between the compressed air and the first solvent, the filter 146 preferably has a porosity of between 10 and 100 microns, preferably between 20 and 60 microns, and for example equal to 20 microns. A fine porosity promotes the generation of fine air (or gas) bubbles and allows for a larger exchange surface between the first solvent and the air. In the example, the filter 146 is a sintered metal filter made of stainless steel. Advantageously, the volume of first solvent is greater than or equal to 400 ml, and in particular between 500 ml and 2000 ml, or between 500 ml and 1200 ml, or between 600 ml and 1100 ml, and for example equal to 900 ml. Of course, the volume of solvent will be determined according to the quantity of raw material that can be stored in the enclosure 10, and therefore according to the volume of the enclosure 10. As such, a volume of solvent greater than 2000 ml may of course be considered.

[0088] Advantageously, the body 140 of the first capture device 14 comprises a second part 148, located between the first part 141 and the outlet 144, forming a container for storing the condensation water EC, that is to say the water originating from the condensation of the water contained in the air entering the first capture device (water originating from the air entering the enclosure 10 and from the raw material 2). The second part 148 is of course in fluid communication with the first part 141. The respective volumes of these two parts will be determined so that the first part 141 can contain the entire quantity of first solvent desired, and so that the second part preferably has a volume sufficient to accommodate all of the condensation water, for example a volume of between 4 and 10 liters.

[0089] The air admitted into the first capture device 14 is discharged through the outlet 144 and entrained in the third pipe 26 towards the second capture device 16. The second capture device 16 comprises a body 160 forming a column-type container, and comprises an inlet 162 connected to the third pipe 26 and an outlet 164, which may be free or connected to a fourth pipe 28 connecting the second capture device to the inlet 102 of the enclosure 10. The inlet 162 is arranged at a lower end of the body 160, and allows the admission of compressed air having passed through the first capture device (14), while the outlet 164 is arranged at a high end of the body 160, and allows the air to be evacuated from the second capture device 16. The body 160 is partially filled with a second solvent S2, chosen from solvents suitable for the formulation of perfumes and is preferably a solvent of natural origin and non-polluting.Furthermore, the second solvent is chosen to be miscible in the first solvent. A porous metal filter 166, for example of the metal sintered type, is arranged at the inlet 162, so that the air entering the body 160 is forced to pass through the filter 166 before the second solvent. When the air coming from the first capture device 14 is admitted into the second capture device 16, a bubbling phenomenon is generated thanks to the filter 166. As for the first capture device, the passage of the air within the second solvent results in the capture of volatile molecules contained in the air by the second solvent and the bubbling system is not limited to a sintered filter. The passage of the compressed air in the second solvent thus makes it possible to capture a second part of the volatile molecules from the air and to recover these molecules in the second solvent.As for the first solvent, the efficiency of the capture carried out by passing air into the second solvent is improved by pressurizing the air, the exchanges between the air and the solvent being increased by the air pressure. In order to optimize the exchanges between the compressed air and the second solvent, the filter 166 preferably has a porosity of between 10 and 100 microns, preferably between 20 and 60 microns, and for example equal to 20 microns. In the example, the filter 166 is a sintered metal filter made of stainless steel. Advantageously, the volume of second solvent is greater than or equal to 50 ml, and in particular between 50 ml and 300 ml, or between 50 ml and 200 ml, and for example equal to 100 ml. Advantageously, the body 160 of the second capture device 16 comprises a compartment in the upper part, in which a condensation device 168 is arranged, comprising in the example Raschig rings.The condensation device 168 makes it possible to optimize the condensation of volatile molecules remaining mixed with the air and not having been captured by the solvents. Alternatively, the condensation device 168 may comprise a nebulization device.

[0090] Advantageously, the first solvent has a hydrophobic character, in order to prevent the first solvent from being able to dissolve (or only in very limited quantities) in the water contained in the air circulating in the extraction system 1, or in the water condensed in the first capture device 14. Preferably, the first solvent has a solubility in water less than or equal to 20% by weight, preferably less than or equal to 10% by weight, or even less than or equal to 5% by weight. The first solvent is an organic solvent that a person skilled in the art can choose according to the plant material extracted and which advantageously comprises: at least one alkyl ester, at least one triglyceride (in particular C8 / C10 acid triglycerides); at least one fatty acid, for example a C12-C22 carboxylic acid; at least one fatty alcohol, for example C6-C20; and mixtures thereof.It is preferred to use an alkyl ester, in particular triethyl citrate (or TEC). If a quantity of solvent is dissolved in the condensed water EC in the reservoir 148 of the first capture device 14, it will be possible, at the end of the implementation of the extraction system 1, to recover the solvent dissolved in the water, the latter also comprising a portion of the captured volatile molecules.

[0091] Advantageously, the second solvent also has a hydrophobic character and preferably has a solubility in water of less than or equal to 20%, or less than or equal to 10% or even less than or equal to 5%. The second solvent is an organic solvent that a person skilled in the art can choose depending on the plant material extracted and which advantageously comprises: at least one alkyl ester, at least one triglyceride (in particular C8 / C10 acid triglycerides); at least one fatty acid, for example a C12-C22 carboxylic acid; at least one fatty alcohol, for example C6-C20; and mixtures thereof. It is preferred to use an alkyl ester, in particular triethyl citrate (or TEC). The second solvent may be identical to, or different from, the first solvent. It is preferred that the first and second solvents are identical.When the second solvent is different from the first solvent, it is, as mentioned above, chosen so as to be miscible with the first solvent, so that after capturing the molecules contained in the air circulating in the extraction system 1, the two solvents can be mixed and thus provide a product that can be directly used by the perfume manufacturing industries.

[0092] The extraction system 1 preferably comprises a device 13 for measuring the relative pressure, arranged in the example at the outlet of the compression device 12. Advantageously, the extraction system 1 comprises a device for adjusting the maximum pressure at the outlet of the compression device 12, such as a needle valve. The extraction system 1 may, alternatively or in addition, comprise a pressure regulating device.

[0093] When the extraction system 1 comprises a fourth pipe 28 at the outlet of the second capture device 16, the fourth pipe 28 is connected to the inlet 102 of the enclosure 10, via an intake device 30. The intake device 30 is configured to produce a mixture comprising a portion of air coming from the second capture device 16 and a portion of air coming from outside the extraction system 1. Advantageously, the proportion of air coming from the second capture device 16 can be adjusted, preferably in a range varying between 0% and 100%. Thus, the intake device 30 allows the air entering the enclosure 10 to be exclusively air coming from outside the extraction system 1, or for this incoming air to comprise a portion of air having already circulated through the extraction system 1.

[0094] An exemplary embodiment of the enclosure 10 and the suction column 20 is described below in relation to Figures 1 and 2. As described above, the enclosure 10 comprises a plurality of receptacles 18 for storing flowers 2. The receptacles 18 are in the example superimposed and each have a general shape adapted to the shape of the body 100 of the enclosure 10. Thus, in the example, the receptacles 18 have a general shape symmetrical in revolution, around the axis of symmetry of the body 100. Advantageously, as visible in Figure 1, the dimensions of the receptacles 18 are chosen so that a space is delimited between the periphery of each receptacle 18 and the internal side wall of the body 100 of the enclosure 10. Thus, a vertical circulation of air (or gas) can be generated along the internal wall of the body 100. during operation of extraction system 1 (see arrows Fi).

[0095] Each receptacle 18 comprises a bottom wall 180, forming a storage surface for the flowers. The bottom wall 180 may be a solid wall, or a perforated wall so as to allow air circulation through the bottom wall. Advantageously, the two end receptacles, that is to say the receptacles located in the immediate vicinity of the inlet 102 and the outlet 106 respectively, have a solid bottom wall 180, while all the receptacles located between the two end receptacles have a perforated bottom wall 180. Such a configuration makes it possible to promote the vertical air circulation mentioned above. The receptacles 18 may comprise a peripheral side wall 182 so that each receptacle forms a container.When the receptacles 18 comprise a side wall 182, the latter is preferably perforated, so as to comprise a plurality of orifices distributed over all or part of the periphery of the corresponding receptacle 18. Thus, whether or not the receptacles 18 comprise a side wall 182, these are configured to allow air circulation at the level of each receptacle which is oriented in a direction perpendicular to the axis of symmetry of the body 100, and therefore in a direction parallel to the corresponding bottom wall 180 (see arrows F2).

[0096] The distribution column 20 is, as mentioned above, arranged in the central part of the body 100. The distribution column 20 comprises a hollow body 200, in the example of tubular shape. The body 200 has a general shape symmetrical of revolution around the axis of symmetry of the body 100. The body 200 is open at a first end, or lower end 201, in order to be connected to the inlet 102 of the enclosure 10. The opposite end, or upper end 203 of the body 200 is closed. The body 200 comprises a plurality of perforated longitudinal sections 202, the adjacent perforated sections 202 being separated by a non-perforated section 205. Each perforated section 202 comprises a plurality of distribution orifices 204, each orifice 204 putting the interior and exterior of the body 200 into fluid communication. The distribution column 20 comprises as many perforated sections 202 as the enclosure 10 comprises receptacles 18.The distribution column 20 is configured so that each openwork section 202 is located above the level of the bottom wall 180 of the corresponding receptacle 18 (each bottom wall being located at the level of a non-openwork section 203). Thus, the orifices 204 of an openwork section 202 are arranged between the bottom walls 180 of two adjacent receptacles 18. The cumulative surface area of ​​the orifices 204 of each consecutive openwork section 202 decreases from the lower end 201 towards the upper end 203, and therefore from the inlet towards the outlet of the enclosure 10. Thus, the further an openwork section 202 is from the outlet 106 of the enclosure 10 (and therefore from the source of negative pressure), the easier it is for air to pass through the body 200. This configuration makes it possible to obtain an air flow passing through the distribution column 20 which is relatively homogeneous along the latter.In other words, an equivalent air flow rate is ensured at each receptacle 18. Preferably, the distribution orifices 204 are of identical shape and size, the orifices 204 having in the example a circular cross-section. The number of distribution orifices of each successive openwork section 202 decreases from the inlet to the outlet of the enclosure 10, i.e. from the lower end 201 to the upper end 203 of the distribution column 20.

[0097] Advantageously, in order to facilitate the loading of the enclosure with the raw material 2, the receptacles 18 are removable. Preferably, each receptacle is engaged around the body 200 of the distribution column 20 and for this purpose comprises an opening formed in the bottom wall 180, the opening having a shape complementary to the shape of the cross-section of the body 200, in the example a circular-shaped opening.

[0098] Figure 3 represents a variant of the extraction system 1 of Figure 1, in which the system comprises two similar enclosures 10. Providing two enclosures 10 makes it possible to store a double quantity of flowers. The extraction of the air contained in the enclosures 10 can be carried out simultaneously, or, advantageously, alternatively. Preferably, when the extraction system 1 comprises two enclosures 10, a selection device 32, comprising for example at least one valve, makes it possible to select from which enclosure 10 the air will be extracted during operation of the extraction system 1. Preferably, the selection device 32 makes it possible to provide an extraction of air in one or the other of the enclosures 10, or in both enclosures 10 simultaneously. The selection device 32 can be controlled automatically, for example by means of a timer device.Advantageously, when the extraction system comprises two enclosures, the air extraction can be carried out alternately within each enclosure, for example for a predetermined duration identical for each enclosure.

[0099] Figures 5 to 7 illustrate other embodiments of the extraction system according to the invention. The system shown in Figure 5 comprises an enclosure (10) provided with an air inlet (102) and an air outlet (106) and which contains a series (here five) of receptacles (40) arranged side by side. The inlet of the enclosure (10) is connected to a gas or air distribution column (20) comprising a tubular body, the tubular body comprising a plurality of perforated longitudinal sections comprising distribution orifices (not shown) at a bottom wall of each receptacle (40), such that an air flow of the same flow rate circulates (F3) in each receptacle. To do this, the cumulative surface area of ​​the orifices of each successive openwork section decreases along the distribution column, from the inlet (102) of the enclosure (10).

[0100] In the variant shown in Figure 6, the enclosure (10) comprises an outer casing corresponding to the body (100) and an inner casing (41), the inner casing (41) comprising a plurality of perforated longitudinal sections comprising distribution orifices (not shown) at the level of each receptacle (not shown), each perforated section being arranged between two adjacent receptacles, the cumulative surface area of ​​the orifices of each successive perforated section decreasing from the inlet (102) towards the outlet (106) of the enclosure (10).

[0101] In this variant, the air extraction can be carried out in two different ways. According to a first possibility, the enclosure can comprise a gas or air distribution column provided with perforated longitudinal sections at each receptacle and the distribution column is connected to the outlet of the enclosure. The air thus circulates in the distribution column, from the inlet to the outlet of the enclosure. According to another possibility, the receptacles comprise perforated lower and upper walls. The air or gas thus circulates from the bottom of the enclosure to the outlet by passing through the different receptacles.

[0102] In another variant illustrated in Figure 7, the enclosure (not shown) comprises a plurality of receptacles (42) movable around a horizontal axis (43), the inlet of each receptacle (42) comprising gas or air distribution orifices (not shown) arranged in one of its vertical walls and adapted to pass the gas or air (F3) through the receptacle (42). In this variant, the extraction of the air or gas can also be carried out in two different ways. According to a first possibility, the axis can constitute a gas or air distribution tube provided with perforated longitudinal sections and the distribution column is connected to the outlet of the receptacle. The air or gas having passed through the plant material thus enters the distribution column and circulates from the inlet to the outlet of the enclosure. According to another possibility, the receptacle comprises a second vertical wall opposite the first and perforated.

[0103] Figure 4 represents an extraction method in accordance with the invention, implementing an extraction system in accordance with the invention.

[0104] The method comprises a first step 200 during which a plant raw material, such as fresh flowers 2, is placed in the enclosure(s) 10.

[0105] The method then comprises a step 202 of extracting the gas or air contained in the enclosure 10. The extraction is carried out in the example by suction of the air via the outlet of the enclosure, using the compression device 12.

[0106] The method then comprises a step 204 of compressing the extracted air, to a relative pressure greater than or equal to 2 bars, and advantageously to a pressure of between 3 and 5 bars.

[0107] The method then comprises a step 206 of circulating the compressed air in the first capture device 14, a step during which the compressed air passes through the first solvent, which allows the capture by the first solvent of a portion of the volatile molecules mixed with the air.

[0108] The method then comprises a step 208 of circulating the air extracted from the first capture device 14 in the second capture device 16, a step during which the air passes through the second solvent, which allows the capture by the second solvent of a portion of the volatile molecules remaining mixed with the air.

[0109] Advantageously, the steps of extraction, compression and circulation of air (or gas) are implemented in successive cycles, a period of stopping the operation of the system being carried out between each cycle. Each cycle can be defined by a predetermined duration, for example a duration of 30 minutes. In this case, the method is implemented intermittently, the extraction system being in operation for the first predetermined duration, then stopped for a second determined duration, equal for example to 30 minutes. Alternatively, each cycle can be defined by the duration of obtaining a first predetermined pressure, the cycle being interrupted when the predetermined pressure is reached. The predetermined pressure can for example be between 4 and 5 bars. The extraction system is then kept stopped for a duration necessary for the relative pressure to reach a second predetermined pressure, for example equal to 0.

[0110] The system and method described above are particularly suitable for implementation in an industrial context, whether in terms of extraction yield (i.e. the quantity of product extracted for a given quantity of raw material), productivity (quantity of material that can be processed in a given time), processing capacity (i.e. the quantity of raw material that the system can accept in one use), and / or in terms of energy efficiency, since the system consumes little energy.

[0111] Advantageously, the volume of the enclosure is greater than 100 or even 150 liters, and generally between 100 and 1000 liters, in particular between 100 and 500 liters and for example between 120 and 200 liters. The use of two or more enclosures also makes it possible to increase the total treatment capacity of the system, or to obtain a given treatment capacity with smaller enclosures.

[0112] Advantageously, it may be provided that the first capture device and / or the second capture device comprises a condensation water discharge device. Such a device will comprise, for example, a valve that can be controlled manually or automatically. An automatically controlled condensation water discharge device will allow condensation water to be discharged automatically, during operation of the extraction system. Thus, it will not be necessary to interrupt operation of the extraction system when the condensation water risks reaching too large a volume.

[0113] Advantageously, it may be provided that at least part of the enclosure 10 is translucent or transparent, so as to allow light to penetrate into the enclosure. Indeed, depending on the type of flowers that one wishes to treat with the extraction system, it may be useful for the flowers not to be in the dark (which can negatively influence the development of the flower and also the quantity and quality of the volatile molecules emitted by the flowers).

[0114] Advantageously, it may be provided that the enclosure 10 is equipped with a heating and / or temperature regulation system, for example to maintain the interior of the enclosure at a given temperature, for example a temperature between 10°C and 50°C, preferably between 10°C and 30°C, in particular between 20°C and 30°C.

[0115] The use of solvents of natural origin and non-polluting has been described above. However, it is specified that the system according to the invention is compatible with the use of petrochemical solvents and also with the use of adsorbents replacing the first and second solvents.

[0116] The use of the extraction system with air circulation has been described above, but consideration may be given to circulating other types of gas through the extraction system, including an inert gas such as nitrogen. If a gas other than air is used, the extraction system may be configured to operate either in a closed circuit or in an open circuit (in which case a continuous supply of gas must be provided).

[0117] The invention also relates to the plant extract obtained according to the method described above. This plant extract may constitute a food flavoring or preferably a perfume ingredient. The perfume ingredient may be used in particular in the manufacture of an accord, that is to say a combination of a few perfume ingredients, or in the manufacture of a perfume, which contains a more complex combination of perfume ingredients. Examples Flower extraction

[0118] An extraction system as illustrated in Figure 3 is used to obtain flower extracts in accordance with the invention.

[0119] Freshly harvested flowers are placed in two separate extraction cylinders. They are evenly distributed in the baskets and across the entire height of the cylinders.

[0120] The same extraction solvent is placed in both capture columns, at a weight ratio of 90:10.

[0121] The system is started so that a flow of air passes alternately through one or the other of the cylinders, for a period of 15 to 60 min, preferably 30 min.

[0122] The flowers are left in the cylinders for a time suitable for the proper preservation of the flowers, typically for 8 to 48 hours, preferably for 24 hours. After this time, the flowers are unloaded and replaced with new fresh flowers.

[0123] This step is repeated until a suitable flower / solvent weight ratio of 20 / 1 to 200 / 1 is reached depending on the olfactory strength of the treated flowers.

[0124] Once the ratio is reached, the solvent contained in the extraction columns is withdrawn with the condensation water. The two phases, respectively aqueous and organic, are separated by condensation and the aqueous phase undergoes a chemical (salt saturation) or physical (centrifugation) treatment in order to recover the part of the solvent dissolved in water, which is then combined with the organic phases. The mixture obtained is dried to obtain the extract according to the invention.

[0125] Example 2: Analysis of a rose extract An extract of Rosa centifolia flowers (Extract 1) was obtained as described in Example 1, using triethyl citrate as the first and second solvents. This extract was analyzed and compared to a rose absolute of the same species, commonly used in the field of perfumery, but also to the headspace fraction of the fresh flower.

[0126] 2 A- Chromatographic analysis

[0127] The comparative study of the chemical composition in VOCs (volatile organic compounds) between fresh flowers, the ingredient according to the invention, as well as the classic perfumery ingredient such as an absolute, was carried out by gas chromatography (GC) using an Agilent GC 7890B system coupled to an MSD 5977B mass spectrometer (MS). Sample preparation was carried out in Headspace using HiSorb technology (Markes International). A HiSorb probe consists of a 75 mm rod of inert stainless steel covered on a small surface with a sorptive phase composed of polydimethylsiloxane (PDMS). The extraction and / or desorption steps of the probe were automated on a Centri extraction and enrichment platform (Markes International).

[0128] In the case of flower analysis, VOC extraction was performed by introducing freshly cut flowers into a bottomless 11 transparent glass flask closed with a silicone septum stopper, outdoors in the sun for 2 hours after introducing the HiSorb probe.

[0129] Once the VOCs extraction was effective, thermal desorption of the probe was carried out at 270°C for 15 min, with 2.5% of the efferent gas flow sent to a trap in order to concentrate the analytes before injection into GC. This trap corresponds to a glass tube containing a porous polymer-based adsorbent (Tenax®). This trap was desorbed by rapid heating at 300°C for 5 min and the gas flow sent to the GC column to allow the analysis of the VOCs.

[0130] VOC extraction is automated using the Centri extraction and enrichment platform as a preliminary step to HiSorb probe desorption. 500 mg of sample is introduced into a 20 ml glass vial. This vial is first pre-incubated for 5 min at 40°C with 500 rpm shaking to equilibrate the vial to the extraction temperature. The device then introduces the HiSorb probe into the vial to extract VOCs for 15 min at 40°C with 500 rpm shaking. The HiSorb probe is then desorbed under the same conditions as those applied in the case of VOC capture from fresh flowers (15 min, 270°C).

[0131] Chromatographic separation was obtained on a DB1-MS (Agilent) 30 x 0.25 m (0.25 pm) apolar column, according to the following temperature gradient: isotherm 250°C, 5 min; gradient 3°C / min up to 120°C; gradient 5°C / min up to 250°C; isotherm 250°C, 5 min. The carrier gas used was helium with a constant flow rate of 1.6 ml / min. Concerning mass spectrometry detection, the temperature of the transfer line was set at 250°C, that of the ionization source at 230°C, and the temperature of the MS Quad at 150°C. The ion scanning range was carried out between m / z 35 and m / z 550.

[0132] The results of these tests are shown in Figures 8 to 10.

[0133] As shown in these Figures, the compounds present in the rose head fraction (Figure 8) are found in greater numbers in Extract 1 (Figure 9) than in the absolute (Figure 10), in particular sabinene, beta-pinene, myrcene, alpha-phellandrene and gamma-terpinene.

[0134] 2B- Sensory analysis

[0135] The analysis was carried out by a trained panel. The extract obtained according to the invention was described as fresher compared to conventional rose extracts, closer to the olfactory characteristics of the flower, with notes of lychee, and honeyed and powdery notes characteristic of the Rosa centifolia rose.

[0136] Example 3: Analysis of a lily of the valley extract

[0137] An extract of lily of the valley flowers was obtained as described in Example 1, using triethyl citrate as the first and second solvents. This extract was analyzed and compared to the headspace fraction of the fresh flower according to the method described in Example 2.

[0138] The comparative study of the chemical composition in VOCs (volatile organic compounds) between fresh flowers (Figure 11) and the ingredient according to the invention (Figure 12) shows that all the olfactory constituents of the flowers (except myrcene) are found in the extract according to the invention.

Claims

CLAIMS 1. Extraction system (1) of volatile molecules from a plant raw material, such as flowers, comprising: - at least one enclosure (10) comprising a plurality of receptacles (18), configured to receive a plant raw material, the enclosure (10) being gas-tight and comprising an inlet (102) and an outlet (106) arranged at two ends of the enclosure, the enclosure being configured to generate a circulation of gas within the enclosure at the level of each receptacle, with a gas flow rate close to or equal to the level of each receptacle; - a compression device (12), configured to adjust the pressure of the air or a gas circulating from the enclosure (10) to a capture system (14, 16) to a relative pressure greater than or equal to 2 bars; the capture system comprising: - a first capture device (14), at least partially filled with a first solvent so as to allow an exchange between the first solvent and the compressed gas driven by the compression device (12); and - a second capture device (16) comprising an inlet (162) connected to a pipe (26) making it possible to bring the air evacuated from the first capture device (14) into the second capture device (16), the second capture device being at least partially filled with a second solvent, so as to allow an exchange between the second solvent and the compressed gas having passed through the first capture device (14).

2. Extraction system (1) according to the preceding claim, in which the compression device (12) comprises an inlet (120) connected to the outlet (106) of the enclosure (10) so as to suck up the gas contained in the enclosure, and comprises an outlet (122) connected to an inlet of the first capture device (14).

3. Extraction system (1) according to claim 1 or 2, wherein the enclosure comprises an inlet (102) and an outlet (106) arranged respectively at two opposite ends of the enclosure, the inlet (102) being connected to a gas or air distribution column (20) passing through the enclosure, the distribution column (20) comprising a tubular body (200), the tubular body (200) comprising a plurality of perforated longitudinal sections (202) comprising distribution orifices (204) at each receptacle (18), each perforated section (202) being arranged between two adjacent receptacles (18), the cumulative surface area of ​​the orifices (204) of each successive perforated section (202) decreasing from the inlet towards the outlet of the enclosure (10).

4. Extraction system (1) according to claim 3, in which the orifices (204) are of identical shape and size, the number of orifices of each successive openwork section (202) decreasing from the inlet to the outlet of the enclosure (10).

5. Extraction system (1) according to one of the preceding claims, wherein the compression device (12) is configured to provide a pressure greater than 2 bars, and for example greater than 4 bars, preferably between 4 and 6 bars.

6. Extraction system (1) according to one of the preceding claims, the extraction system (1) comprising two enclosures (10), the outlet (106) of each enclosure being connected to the inlet of the compression device (12).

7. Extraction system (1) according to the preceding claim, comprising a selection device (32) making it possible, for each enclosure (10), to activate or deactivate the circulation of gas, the selection device making it possible to activate the circulation of gas, either selectively in one or the other of the two enclosures, or in both enclosures simultaneously, the selection device (32) comprising for example one or more valves.

8. Extraction system (1) according to one of the preceding claims, in which the receptacles (18) are superimposed, each receptacle comprising a bottom wall (180) and, preferably, a peripheral side wall (182).

9. Extraction system (1) according to the preceding claim, in which the bottom wall (180) and / or the side wall (182) of each receptacle (18) comprises a plurality of gas circulation orifices.

10. Extraction system (1) according to one of the preceding claims, in which the first solvent has a solubility in water of less than or equal to 20%, and preferably less than or equal to 10%.

11. Extraction system (1) according to one of the preceding claims, in which the second solvent is identical to the first solvent, or different from the first solvent, the second solvent then being miscible with the first solvent.

12. Extraction system (1) according to the preceding claim, in which the second solvent has a solubility in water of less than or equal to 20%, and preferably less than or equal to 10%.

13. Extraction system (1) according to one of the preceding claims, wherein the first capture device (14) and / or the second capture device (16) comprises means for generating bubbles in the first and / or the second solvent, such as a turbine, a sintered filter, a nebulization system or an ultrasonic probe, preferably a porous metal filter (146, 166), so that the gas entering the first capture device (14) is forced to pass through the filter (146) before coming into contact with the first solvent and / or the gas entering the second capture device (16) is forced to pass through the filter (166) before coming into contact with the second solvent.

14. Extraction system (1) according to one of the preceding claims, in which the first capture device (14) and / or the second capture device (16) comprises a part forming a container for the condensation water. resulting from condensation occurring during the circulation of gas in the extraction system.

15. Process for extracting volatile molecules from a plant raw material, such as flowers, comprising the following steps: - distributing plant material into several portions, in an enclosure supplied with a gas such as air and configured to generate a circulation of said gas through each portion of plant material, with a gas flow rate close to or equal to the level of each portion, - extract the gas having circulated over all the portions of plant material and compress it to a relative pressure greater than or equal to 2 bars, - capturing the compressed gas in a first organic solvent having a solubility in water of less than or equal to 20% by weight, and separating by condensation the water vapor contained in the gas, to obtain a depleted gas, a first organic phase and a first aqueous phase, - capturing the depleted gas in a second organic solvent having a solubility in water of less than or equal to 20% by weight, preferably identical to the first organic solvent, and separating by condensation the water vapor contained in the gas, to obtain a second organic phase, a second aqueous phase and a still depleted gas which is optionally recirculated in step (a), - combine the two organic phases and possibly the organic compounds present in the two aqueous phases, to obtain a plant extract.

16. Method according to claim 15, characterized in that it implements an extraction system (1) according to one of claims 1 to 14, the method comprising the following steps: - place (200) a plant raw material in the enclosure; - extracting (202) the gas contained in the enclosure, for example by suction via the enclosure outlet; - compress (204) the extracted gas to a relative pressure greater than or equal to 2 bars; - circulating (206) the compressed gas in the first capture device; - circulating (208) the gas leaving the first capture device into the second capture device.

17. Plant extract obtainable according to the process according to claim 15 or 16.

18. Plant extract according to claim 17, characterized in that the plant material consists of mute flowers.

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