Method for extracting antioxidants in their liquid form by cold filtration from plants of the lamiaceae family

Abstract

The present invention relates to a method for extracting antioxidants in their liquid form (carnosic acid and carnosol) by cold filtration in a filter press and falling film evaporator, from natural material of the Lamiaceae family, including rosemary (Rosmarinus officinalis), without the addition of emulsifier or other additives. The method according to the invention comprises a series of evaporation and filtration steps, including a vacuum evaporation step in an evaporation device referred to as a falling film evaporation device, wherein the device enables the separation of carnosic acid by virtue of the design of the evaporator and its stirring system.

Description

[0001]Process for extracting antioxidants in their liquid form by cold filtration from plants of the Lamiaceae family.Technical fieldThe present invention relates to the field of natural extracts. It relates in particular to a process for extracting antioxidants in their liquid form (carnosic acid and carnosol) by cold filtration from natural material of the Lamiaceae family, without adding emulsifiers or other additives.Prior artPlant extracts play an important role in various fields. In particular, antioxidants of natural origin such as carnosic acid and carnosol extracted from rosemary are of great use in various fields such as food, pharmaceuticals, etc. Rosemary and other plants of the Lamiaceae family are widely used by manufacturers and various processes have been developed to extract antioxidants therefrom. Various processes relating toThe extraction of antioxidants from plant material is known from the state of the art. Patent application US6450935 (KEMIN IND INC) relates to a process for extracting antioxidants and essential oils from plants of the Lamiaceae species. An increase in the specific antioxidant activity of rosemary (Rosmarinus officinalis) extracts is achieved by using a mixture of tetrafluoroethane and an organic solvent in the extraction process. A mixture of tetrafluoroethane, acetone and methanol improves the total yield. A mixture of tetrafluoroethane and acetone has a higher efficiency. The processes yield an antioxidant extract is produced only with the aid of a surfactant to improve the physical appearance of the extract and avoid atomization of the product at the inlet of the evaporator. The finished product is a liquid and oily product that is mixed with a liquid product such as soybean oil to be added to animal feed and human food.processes simultaneously produce pharmaceutical-grade essential oils in high yields. The process comprises the steps of: a. using an organic solvent to obtain an extract containing compounds including antioxidants and essential oils from plant material of a plant of the species Lamiaceae; b. removing the organic solvent to create an extract product; c. treating the extracted product in an evaporator operated at a temperature and pressure that evaporates the essential oil fraction of the extracted product while leaving the antioxidant compounds in a residue; and d. condensing the essential oils into a distillate. The organic solvent according to this document comprises a mixture of tetrafluoroethane (TFE) and at least one organic solvent selected from the group consisting of acetone, ethanol, methanol, butane, propane, and hexane. Patent application WO9634534A1 (HAUSER CHEMICAL RES INC)relates to a process for extracting and isolating a carnosic acid concentrate from a carnosic acid-containing plant material (e.g., rosemary) comprising: contacting the carnosic acid-containing plant material with a water-miscible solvent to form a carnosic acid-containing plant extract; adjusting the pH of the plant extract to a level between about 7 and less than 10; adding water to the plant extract in an amount sufficient to cause precipitation of impurities while retaining the carnosic acid salt in solution; separating the impurities from the carnosic acid solution; acidifying the aqueous solution to precipitate a highly purified carnosic acid concentrate; and removing the carnosic acid concentrate from the solution. The Process comprises the following additional steps: - dissolving the carnosic acid concentrate in a volatile, moderately polar aprotic solvent to form asolution; - mixing this solution with sufficient non-polar alkane solvent to form insoluble impurities; - reducing the volume of the solution; - removing the insoluble impurities from the solution; and - cooling the solution to crystallize pure carnosic acid. The pH adjustment step is accomplished by adding sufficient sodium carbonate, ammonium hydroxide, sodium bicarbonate, or mixtures thereof, to deprotonate the carnosic acid and produce the carnosic acid salt. The volatile, slightly aprotic solvent used in this process is selected from the group consisting of ether and acetone, and the alkane solvent is selected from the group consisting of pentane, hexane, heptane, and octane. These methods of extracting antioxidants from plants rely on processes that utilize chemical intermediates that pose both an environmental and health risk. The present invention ismain aim of providing a process free from the use of chemicals, in particular surfactants and / or emulsifiers, and economically viable compared to the complex processes of the state of the art.Disclosure of the inventionTo achieve the objectives of the invention, mainly the extraction of antioxidants from a plant of the Lamiaceae family, without the use of chemicals, a process has been proposed for extracting antioxidants in their liquid form (e.g. carnosic acid and carnosol) by cold filtration in a filter press and falling film evaporator without the use of emulsifiers. The process according to the invention comprises the following steps: - Introduction of leaves of a plant of the Lamiaceae family (e.g. Rosemary), and / or any other part of the plant, into an extraction reactor with a solvent without stirring under temperature conditions close to the boiling point of the solvent and under atmospheric pressure. The residence time is approximately40 min of boiling followed by 20 min of rest. The mass ratio "plant: solvent" is within the range [1: 5 - 1: 10]. - Then the Passage in a bag filter (or any other similar means) to separate the liquid from the plant material. - Passage in a vacuum evaporator to concentrate the extract to a dry extract between 12% and 20% in initial weight. The yield value of this step also depends on the residence time in the evaporator. The longer the duration, the higher the yield. - Followed by cooling in another tank to go from approximately a boiling temperature of the solvent (about 54 ° C - case of acetone) to ambient (25 ° C), preferably 5 ° C without stirring. - Then passage in a filter press (temperature between 17 and 22 ° C) and then storage in another tank. - The product resulting from the previous steps undergoes evaporation in a so-called falling film evaporation device, which allows the separation of carnosic acid thanks toto the design of the evaporator and its stirring system. - Then passage to the bag filter. - And finally the recovery in a container, the antioxidant content is between 1 and 20%, typically around 5%. The first step of the process involves a bioreactor equipped with means to control the extraction parameters, in particular the temperature of the plant-solvent mixture, the pressure. The natural material used can be any plant of the Lamiaceae family, and more broadly, any plant of the Lamiaceae family, which contains antioxidants mainly carnosic acid and carnosol. It is also expected that all parts of the plant containing the desired components can be extracted, as well as any form of plant material (for example, whole, ground, fresh or dried). The choice of solvent is decisive for the efficiency of the process. Therefore, the use of a solvent mixture is possible. The choice according toThe invention relates to acetone, ethanol, hexane or a mixture of the three solvents, preferably acetone. The solvent-plant interaction takes place without stirring and at atmospheric pressure. The temperature is preferably close to the boiling point of the solvent (e.g. 54 to 56°C for acetone). This parameter is adjusted using the bioreactor, preferably with a double jacket, to ensure heating of the mixture by the walls of the bioreactor. The solvent and the plant material are introduced into the bioreactor according to a mass ratio (plant: solvent) of between 1:5 and 1:10, preferably 1:8. After a stay of approximately 40 minutes in the bioreactor, followed by a rest period of approximately 20 minutes for cooling the extract, the latter passes through a filter to separate the liquid from the solid plant matter. This operation is carried out by a suitable filtration means, preferably a pocket filter. The filtrate from the previous step undergoes evaporation toconcentrate the extract to a dry extract of between 12% and 20% by initial weight. To remove the insoluble compounds from the concentrated extract, the latter is passed through a cooling tank, preferably at a temperature of 5°C without stirring, until precipitation occurs. Temperature is a critical parameter at this stage since molecules insoluble in cold acetone are soluble in hot acetone. The method for separating the solid compounds insoluble in cold acetone from the liquid extract is based on the use of a filter press or any other suitable separation process known to a person skilled in the art. The step after filtration, preferably by filter press, involves the recovery of carnosic acid first using a device called a falling film evaporator. The falling film device has several countercurrent tube exchangers for heating; they are equipped with a vacuum pump unit (withclosed refrigeration system) and a centrifugal pump to produce the forced circulation of the fluid to be treated. Thanks to this system, a layer of fluid is created which, by sliding on the internal surface of the exchanger, facilitates instantaneous evaporation, reduces fouling of the exchanger and eliminates foam formation. In addition, with the same pump, the concentrate is discharged. After this step, the concentrate passes through a pocket or multi-plate filter before being stored in a container. Brief description of the drawings Other characteristics and advantages of the invention will appear in the detailed description which follows and which refers to the appended figures, given solely by way of non-limiting example. - Figure 1 represents all the steps of the process for manufacturing the liquid extract of rosemary without emulsifier with an indication of the equipment used for each step. - Figure 2 represents the chromatogram of the presence of carnosic acid and carnosol inthe extract. - Figure 3 plots the evolution of viscosity as a function of temperature of the liquid rosemary extract without emulsifier. - Figure 4 is the operating principle diagram of the falling film evaporator (401). - Figure 5 plots the oxidative stability resulting from the application of the liquid rosemary extract without emulsifier in soybean oil.Detailed description of the inventionThe process for extracting antioxidants from plants of the Lamiaceae family without the use of emulsifiers comprises the following succession of steps: - Introduction of leaves of a plant of the Lamiaceae family (e.g. Rosemary), and / or any other part of the plant, into an extraction reactor (101) with a solvent without stirring under temperature conditions close to the boiling temperature of said solvent and under atmospheric pressure, the residence time is approximately 40 min of boiling followed by 20 min of rest; - Then the Passage in a pocket filter, orany other similar means, to separate the extract from the plant material; - Then the concentration of the filtrate from the previous step by evaporation in an evaporator (201) until a dry extract representing up to 20% by initial weight is obtained; - The concentrate from the previous step undergoes cooling in another tank (301), passing from a temperature of 26°C to 19°C, preferably down to 5°C, to precipitate the impurities; - Then passing through a filter press (701) at a temperature between 17 and 22°C, and then storing the filtrate in another tank (302); - The product stored in (302) undergoes vacuum evaporation in an evaporator (401) equipped with a falling-film separation device (501), which allows the separation of carnosic acid / carnosol thanks to the design of the separator and the stirring system of the evaporator (401); - Adjustment of the titration by progressive injection of a vegetable oil into the evaporator (401) during the process ofseparation in (501); - the product of the previous step is then filtered in a bag filter (602); - and finally the recovery of the finished product in a container where the final antioxidant content is between 1 and 20%, typically around 5%. According to a first aspect of the invention, the solvent is chosen from acetone, ethanol, hexane or a mixture of the three solvents, preferably acetone. This choice is motivated by the relatively low boiling point of acetone (56°C). According to a second aspect of the invention, the mass ratio [plant: solvent] is in the range [1: 5 – 1: 10], preferably 1: 8. According to another aspect of the invention, the temperature of the extraction in the extraction reactor (101) is between 33°C and 56°C, preferably 54.5°C. According to another aspect of the invention, the step of separating carnosic acid and carnosol is carried out under vacuum in a falling film evaporator (401) where the acetone and the essential oilis eliminated, said evaporator comprises a: - vertical exchanger (501) called falling film operating with steam; - a double jacket to allow heating of the tank (401) by conduction; - a double agitation agitator capable of mixing at the core by the agitator (1) and on the limits of the evaporator by the agitator (2); - a closed circuit recirculation pump for; - the horizontal exchangers for solvent recovery for its reuse; - the vacuum pump. The latter will be used for the introduction of the vegetable oil; According to another aspect of the invention, the selective process continues in a closed circuit thanks to the recirculation pump, establishing the impurity material in a vapor state while the antioxidant material is established in a non-polar state. The duration of the process depends on the desired quality of the final product. According to another aspect, for the adjustment of the antioxidant titer, it can be dissolvedin a relatively high boiling point solvent such as vegetable oil (e.g. sunflower oil, soybean oil, canola oil). According to another aspect, the falling film evaporation device operates hot at temperatures close to 60°C, 70°C, preferably 80°C, the product in the evaporator (401) is hot-decanted to facilitate the filtration step (602) and the containerization of the finished product. For safety reasons, the extraction dregs undergo steam stripping of an appropriate duration to get rid of solvent residues. According to another particular aspect, the acetone removed by the evaporator (401) is recycled through a cold trap which is at a temperature allowing the solvent (e.g. acetone) to liquefy. The horizontal exchanger acts as a cooling source to recover the solvent.Examples of the inventionThe process was preferably tested using whole rosemary leavesdried. The chosen solvent is acetone. Table 1. Example Example Example Example Example Example 1 2 3 4 5 6 BATCH 2 BATCH 3 BATCH 4 BATCH 5 BATCH 6 BATCH 7 Extraction time - Minute 60 60 60 60 60 60 Temperature extraction -°C 54.5 54.5 54.5 54.5 54.5 54.5 Solvent density 0.792 0.793 0.794 0.794 0.795 0.794 Stripping - Minute 63 52 47 49 53 45 Final volume before transfer to D301 - L 8250 4500 4000 4400 5900 5800 Dry extract after end of concentration - % 6% 10% 9% 10% 8% 8% Temperature after transfer - °C 26 25 27 26 26 26 Filtration temperature -°C 19 17 22 19 17 20 Filtration time 1 -Minutes 35.0 158.3 70.5 102.5 78.3 103.3 Filtration 2 NA NA NA NA NA NA Filtrate appearance clear clear clear clear Clear clear Volume filtered - L 7200 4200 3500 3800 5100 4800 Oil addition - HH:MN 0:20 0:30 0:10 0:20 0:15 0:05 Concentration and drying temperature -°C 80 80 80 80 92 92 Concentration and drying - Minutes3920 2220 1680 1995 1155 930 Stripping + filtration - HH:MN 0:50 0:30 0:45 2:30 2:05 NA Yield - % 21.5 22.5 18.3 17.9 23.7 22.7 The natural material used in the tests can be any plant of the Lamiaceae family, and more broadly, any plant of the Lamiaceae family that contains antioxidants mainly carnosic acid and carnosol. It is also expected that all parts of the plant containing the desired components can be extracted, as well as any form of plant material (e.g., whole, ground, fresh, or dried). It was preferred in this trial to use whole dried rosemary leaves from Morocco (another region is possible). The solvent reagent used in this test is acetone which has a boiling point of 56°C. Acetone is used in a temperature range of 37°C, preferably above 40°C, preferably above 45°C, preferably above 55°C.It is known as a very good solvent for the extraction of carnosic acid in terms of yield and minimization of oxidative decomposition of antioxidants from rosemary or any other plant. The advantages of acetone show that it has a low boiling point. This point is acceptable from an environmental and health point of view (very low toxicity) and is easily handled. Acetone has proven to be an effective solvent, which has allowed obtaining a yield of approximately 50 to 86% of antioxidants from rosemary. The measurement of antioxidant content is determined by comparing the total amount of antioxidants obtained from the same type of rosemary using exclusively ethanol as a solvent.According to a preferred aspect, the natural material and the acetone solvent are added together in a ratio (plant:acetone) of 1:5 up to 1:10, preferably 1:8 on the natural material / solvent weight ratio to carry out the extraction step in any container (Extraction reactor. Fig.1) that will be compatible with the components. The container could withstand pressures ranging from atmospheric to high pressure for safety reasons. The extraction was carried out at >53°C, preferably between 37°C and 56°C (close to the boiling point of acetone). When the natural components have been extracted from the natural material after a sufficient time (Residence time), the mixture is passed through a filter to remove the natural material from the solution (Pouch filter. Fig.1). Any suitable separation method known to the person skilled in the art that does not interfere with the other process steps can be used.The concentration of the extract was carried out by evaporation in an evaporator (EV201. Fig.1) to a dry extract of an amount of 12% by weight, preferably greater than 16% by weight, more preferably greater than 17% by weight, more preferably greater than 18% by weight, more preferably greater than 19% by weight, more preferably greater than 20% by weight. To remove insoluble compounds from the concentrated extract, the latter (at 12% or 16% or 17% or 18% or 19% or 20% dry extract) remained in the cold in a condition preferably below 25°C, more preferably below 20°C, below 15°C, more preferably below 10°C and preferably at 5°C without stirring until precipitation occurred (301. Fig.1). Temperature is critical at this stage since molecules insoluble in cold acetone are soluble in hot acetone.The method for separating the solid compounds insoluble in cold acetone from the liquid extract is based on the use of a filter press (Filter press. Fig. 1) or any suitable separation process known to a person skilled in the art. The filtered extract is then passed through a falling film evaporator under vacuum (set (501) and EV401 of Fig. 1) at a temperature between about 33°C and 38°C where the acetone and the essential oil are removed. The evaporator is stirred. This step can be carried out at a temperature high enough to capture the antioxidant material as well as the solvent. In this case, the antioxidant substance can be condensed at a condensation location having a temperature suitable for deposition but higher than a condensation value of the solvent, in the case of acetone extraction, temperatures close to 60°C, 70°C, preferably 80°C.It is the falling film device as shown in Figure 4, which plays this decisive role in the process of extracting antioxidants without the use of emulsifiers. Indeed, said device (501) comprises an exchanger through which the product to be treated circulates. The product circulates by gravity in the tubes of the exchanger, creating a thin liquid film on the inner walls. By varying the liquid flow rate, it is possible to control the thickness of this liquid film, and thus reduce the residence time of the product. Since falling film technology is more sensitive to fouling, particularly compared to forced circulation evaporation, the device operates at high temperatures (temperatures close to 60°C, 70°C, preferably 80°C). The eliminated acetone is recycled through a cold trap which is at a temperature allowing the acetone to be liquefied.The selective process continues in a closed circuit for a period of time, establishing the impurity material in a vapor state while the antioxidant material is established in a non-polar state. Thus, for example, the antioxidant may be dissolved in a relatively high-boiling solvent such as vegetable oil. The residual solvent-free extract is a viscous product that contains many of the antioxidant compounds present in organic matter. Since most of the essential oils have been removed and most of the coloring molecules and other impurities have been removed by cold filtration, the residue is essentially odorless / low color impact and can therefore be used in applications as much as antioxidants. The residue contains a high percentage of antioxidant compounds. For example, the residue contains between approximately 1% and 20% carnosic acid, and typically 5% carnosic acid.This residue contains only rosemary extracts and vegetable oil and does not require any addition of emulsifiers or surfactants during the process to improve the physical properties of the extract. In addition, the final products flow easily through the evaporator and form a uniform and acceptable physical characteristic. The final product according to the invention is a liquid product and has a thixotropic property that manifests itself over time. A small disturbance such as shaking or stirring can change its consistency to liquid. If left to stand, it will return to its initial state. Examples of embodiments: Example 1: This invention identifies methods for extracting antioxidants in their liquid form without the use of emulsifiers. An extraction at a ratio of 1:8 dried rosemary leaves: acetone is carried out as described in Example 1, Table 1, for 60 minutes at a temperature of 54.5°C.The extract is concentrated under vacuum in EV201, in order to obtain a dry extract representing 6% of the total weight. The extract is cooled to a temperature of 19°C in the cooling tank (301) without stirring to precipitate the molecules insoluble in cold acetone. The filtration lasted 35 minutes, in order to obtain a purified solution, freed from impurities, clear and transparent, ready to be sent to the falling film evaporator 401 for the removal of the solvent and the essential oil. The concentration and drying step in the evaporator does not require any addition of emulsifier during the process to improve the physical properties of the extract thanks to the quantity of impurity eliminated by the cold in the filter press and which represents a yield that can reach 49% total dry matter.Examples 2 and 4: Examples 2 and 4 in Table 1 underwent the same extraction and purification parameters, 10% dry extract in first concentration and cooling to 18±1°C. The filtration time was changed to 158.3 minutes for a volume of 4200 L, and 102.5 minutes for a volume of 3800 L respectively for Example 2 and 4. The appearances of both filtrates are clear, clear and transparent, directed to the falling film evaporator (401) for solvent removal. Example 3: For Example 3 in Table 1, the same extraction steps and parameters of Example 1 were maintained. The dry extract, after the end of concentration, reaches 9% of the total extract weight and is cooled to a temperature of 22°C. The cold extract is filtered through the filter press for 70.5 minutes, allowing the elimination of a quantity of insolubles of approximately 48% of total dry matter.This allows to obtain a purified solution, free of impurities, clear and transparent ready to be concentrated in the falling film evaporator (401). The vegetable oil chosen is sunflower and it is added to standardize the carnosic acid titer. This solution is concentrated and dried to remove any trace of residual solvent. The final product is decanted, filtered in only 45 minutes, and placed in a container. Examples 5 and 6: Examples 5 and 6 in Table 1 were subjected to the same extraction and purification parameters with the same plant: solvent ratio, 8% dry extract after the end of concentration and cooling to 18±1.8°C. The concentration and drying temperature and time were modified compared to the other examples mentioned in Table 1.Instead of 80°C for an average time of 2454 minutes, the temperature was 92°C for an average time of 1043 minutes, for Examples 1; 2; 3; 4 and Examples 5; 6 respectively. The increase in the concentration and drying temperature continues by establishing the impurity material (Solvent Residual) in a vapor state. Gas chromatography analyses reveal that the solvent residuals for Examples 5 and 6 are 14 ppm and 7 ppm respectively. In all extraction examples, the extraction grains underwent steam stripping for an average time of 52 minutes. Example 6 underwent a minimum time of 45 minutes of stripping to get rid of the solvent residues, as a safety measure (to eliminate residual acetone). In contrast, Example 1 underwent 63 minutes of stripping. Any suitable stripping schedule known to those skilled in the art that does not interfere with other steps of the process may be used.The extract followed the same production steps as described in Example 1, with modifications to the purification parameters as illustrated in Table 1. Analysis of antioxidants: carnosic acid and carn osol. A sample of each extraction example was analyzed by high-performance liquid chromatography with ultraviolet detection to qualify the presence as well as quantify the content of carnosic acid, carnosol, isorosmanol and 12-O-Methylcarnosic acid. Analysis of the different batches demonstrates that the final product contains carnosic acid and carnosol, two molecules of interest for their antioxidant properties. In addition, the presence of 12-O-Methylcarnosic acid, known for its ability to stabilize lipid chains, as illustrated in Figure 2 which represents the analysis chromatogram.Viscosity: Figure 3 plots the viscosity evolution of the antioxidant extract as a function of temperature for the liquid rosemary extract without emulsifier. A 50 g sample of product from Example 3 is subjected to different temperatures to evaluate the viscosity as a function of temperature. The product viscosity reflects the physical properties of the product, behavior during heating (solvent removal step) and product flow in the evaporator (container recovery and final filtration step). Figure 3 shows the viscosity evolution of the extract as a function of temperature without the presence of emulsifiers. With a carnosic acid content of 5% w. w, the viscosity increases with decreasing temperature, from 6500 (cp) at 50°C to 22000 (cp) at 10°C.which shows the need for hot decanting to facilitate the filtration and containerization step (saving in time for evacuating the product from tank 401). Oxidative stability: The soybean oil matrix was chosen for the application of the product from this manufacturing process. The oxidative stability of soybean oils enriched with the product from this process was evaluated by the Rancimat test. The latter allows the stability of fatty substances to be evaluated and is expressed as induction time in hours (IP). A blank and six samples of soybean oil enriched with rosemary extract 30, 35, 50, 60, 100 and 150 ppm were added to the test tube and placed in an electric heating block set at 100°C, each tube was boiled with a flow of filtered, clean and dry air of 0.9 ml / minute. Figure 5 plots the induction times as a function of antioxidant dosage.The application of rosemary extract from this manufacturing process extends the induction time to values ​​of 21, 21, 23, 24, 27 and 31 hours respectively for 30, 35, 50, 60, 100 and 150 ppm instead of 10 hours for the white.

Claims

Claims:

1. Process for extracting antioxidants in liquid form from a plant of the Lamiaceae family without the use of emulsifiers, and with improved yield, comprising the following steps: - Introduction of leaves of a plant of the Lamiaceae family (e.g. Rosemary), and / or any other part of the plant, into an extraction reactor (101) with a solvent without stirring under temperature conditions close to the boiling temperature of said solvent and under atmospheric pressure, the residence time is approximately 40 min of boiling followed by 20 min of rest; - Then Passage through a bag filter, or any other similar means, to separate the extract from the plant material; - Then concentration of the filtrate from the previous step by evaporation in an evaporator (201) until a dry extract representing up to 20% by initial weight is obtained; - The concentrate from the previous step is cooled in another tank ( 301), passant d’une température de 26°C à 19°C, de préférence jusqu’à 5°C,to precipitate the impurities; - Then pass through a filter press (701) at a temperature between 17 and 2 2°C, et puis stockage du filtrat dans une autre cu ve (302) ; - The product stored in (302) undergoes vacuum evaporation in an evaporator (401) equipped with a so-called falling film separation device (501), which allows the separation of carnosic acid / carnosol thanks to the design of the separator and the stirring system of the evaporator (401); - Adjustment of the titration by progressive injection of a vegetable oil into the evaporator (401) during the separation process in (501); - the product from the previous step is then filtered in a bag filter (602); - and finally the recovery of the finished product in a container where the final antioxidant content is between 1 and 20%, typically around 5%. 2 . Procédé selon la revendication 1, caractérisé en ce que le solvant est choisi among acetone, ethanol, hexane or a mixture of the three solvents, preferably acetone. 3 . Procédé selon la revendication 2, caractérisé en ce que le rapport massique[plant:solvent] is in the range [1:5 – 1:10], preferably 1:

8.

4. Procédé selon la revendication 3, caractérisé en ce que la température de the extraction in the extraction reactor (101) is between 33°C and 56°C, preferably 54.5°C.

5. Procédé selon la revendication 4, caractérisé en ce que l’évaporateur (201) operates under vacuum at boiling point temperature at the observed vacuum level.

6. Procédé selon la revendication 5, caractérisé en ce que l’étape de séparation carnosic acid and carnosol is carried out under vacuum in a falling film evaporator (401) where the solvent and the essential oil are removed, said evaporator comprises: - a vertical exchanger (501) called falling film operating with steam; - a double jacket; - a double agitation agitator (1, 2) capable of mixing at the heart and on the limits of the evaporator; - a recirculation pump; - horizontal solvent recovery exchangers; - a vacuum pump.

7. Procédé selon la revendication 6, caractérisé en ce que le processus sélectif secontinues in a closed circuit establishing the impurity material in a vapor state while the antioxidant material is established in a non-polar state.

8. Procédé selon la revendication 7, caractérisé en ce que l'antioxydant peut être dissolved in a relatively high boiling point solvent such as vegetable oil.

9. Procédé selon la revendication 8, caractérisé en ce que le dispositif falling film evaporator (401) operates hot at temperatures p roches de 60°C ou 70°C, préférablement 80°C, le pr oduit dans l’évaporateur (401) is hot-decanted to facilitate the filtration step (602) and the containerization of the finished product.

10. Procédé selon la revendication 9, caractérisé en ce que l'acétone éliminée par the evaporator (401) is recycled through a cold trap made up of horizontal exchangers which is at a temperature allowing the acetone to liquefy.

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