Ultrasound-assisted extraction method using plant sap

Abstract

A method for ultrasound-assisted extraction of at least one compound from a biological material, comprising the following steps: a. provision of the biological material and an extraction solvent represented by at least one plant sap; b. bringing of said biological material into contact, in the presence of ultrasound and for a predetermined period, with said at least one plant sap so as to obtain a suspension; c. solid-liquid separation of the suspension so as to obtain a liquid extract comprising the at least one compound, and a solid residue; and d. recovery of the liquid extract.

Description

Ultrasonically assisted extraction process using plant saps FIELD OF THE INVENTION

[0001] The technical field of the present invention relates to methods for the ultrasound-assisted extraction of compounds from biological material. The invention relates in particular to an ultrasound-assisted extraction method using a natural extraction solvent represented by one or more plant saps. STATE OF THE ART

[0002] Ultrasound-assisted extraction is a technique for recovering compounds of interest from various matrices such as biological material using a suitable liquid medium as a solvent. The selection of the solvent depends on the compound to be extracted and the specific extraction conditions, such as polarity, temperature, and pressure.

[0003] This technique is assisted by ultrasonic waves with a frequency generally above 20 kHz, which propagate through liquid media. It can be used for any extraction involving a liquid, including liquid-liquid extraction and solid-liquid extraction.

[0004] In the case of solid-liquid extraction, the application of ultrasound results in an increase in the diffusion of dissolved compounds from inside the matrix into the extraction solvent as well as an improvement in the penetration of the extraction solvent into the matrix.

[0005] In addition, ultrasound-assisted extraction allows, compared to conventional extractions, to reduce extraction time, increase extraction yield and reduce extraction temperature.

[0006] It is common to use organic solvents such as alcohols, hexane, and ethyl acetate for the ultrasound-assisted extraction of compounds of interest from biological materials. However, these solvents can be toxic, flammable, explosive, poorly biodegradable, and are found in varying quantities in the final extract. In addition, additional steps are required after obtaining the liquid extract to remove traces of organic solvent, which involves energy consumption and additional costs. The same treatment should be applied to raw material residues to make them, if possible, biocompatible and recover them in recycling channels.

[0007] Faced with these challenges, researchers have naturally considered the use of water as a solvent for the extraction of compounds of interest from biological material. However, due to the highly polar nature of water, its ability to dissolve low-polar and non-polar compounds is limited, which limits its effectiveness as an extraction solvent. In addition, the extraction of compounds of interest from biological materials is often compromised by the poor diffusion of water in the material. Indeed, in the case of biological materials containing lipids or polar or intermediate polarity molecules, the material is difficult to wet by water, which hinders the penetration of water into the material and limits the extraction capacity of compounds of interest.The use of water as an extraction solvent is therefore not optimal for the ultrasound-assisted extraction process in the sense that the extraction yield is not significantly higher than conventional extraction methods.

[0008] There is therefore a constant need to formulate and use new natural solvents with high extraction yield, allowing the extraction of all types of compounds of interest and reducing the ecological impact of ultrasound-assisted extraction processes.

[0009] The invention therefore relates to a method for the ultrasound-assisted extraction of at least one compound from a biological material comprising the following steps: providing the biological material and an extraction solvent represented by at least one plant sap; bringing said biological material into contact, in the presence of ultrasound and for a predetermined period, with said at least one plant sap so as to obtain a suspension; solid-liquid separation of the suspension so as to obtain, on the one hand, a liquid extract comprising the at least one compound and, on the other hand, a solid residue; and recovering the liquid extract.

[0010] The inventors have discovered that using at least one plant sap as a solvent in an ultrasound-assisted extraction process improves the extraction yield by 4% to 700% compared to an ultrasound-assisted extraction process using water as a solvent. In addition to being natural and biodegradable, plant sap has a compound solubilizing power that increases the amount of compounds extracted from a biological material. The wide choice of plant saps existing in nature makes it possible to extract a large number of compounds by working on the affinity of a plant sap or a mixture of plant saps with one or more compounds of interest from a biological material. Thus, it is possible to extract one or more types of compounds from a biological material by choosing a plant sap or a mixture of plant sap.

[0011] In addition, the products directly obtained by the process, the liquid extract and the solid residue are free from any organic contaminants and are biodegradable.

[0012] The liquid extract contains the compound(s) extracted from the biological material as well as the sap(s) used as extraction solvent. The process according to the invention makes it possible to produce products having a specific and controlled activity by combining the biological activities specific to the plant sap(s) with those of the compounds extracted from the biological material.

[0013] Furthermore, no processing of the liquid extract is necessary. It can be used directly as a cosmetic, pharmaceutical and / or dietary supplement active ingredient.

[0014] The combination of ultrasound and plant sap improves extraction yield while limiting the ecological impact of the process, as it requires less energy to operate. The contact time is reduced and it is possible to carry out the extraction both hot and cold.

[0015] According to one embodiment of the invention, the method comprises a step e) of concentrating the liquid extract.

[0016] This embodiment makes it possible to obtain a concentrated liquid extract having a higher concentration of extracted compound. This may be necessary depending on the final use of the liquid extract obtained at the end of the process according to the invention.

[0017] According to another embodiment of the invention, the method comprises a step f) of purification of the liquid extract.

[0018] This step allows the isolation of a particular compound from other extracted compounds present in the liquid extract. It can be carried out on the liquid extract or on the concentrated liquid extract.

[0019] According to yet another embodiment of the invention, the method comprises a step of adding at least one preservative to the liquid extract.

[0020] This embodiment makes it possible to preserve the liquid extract from degradation, putrefaction, autolysis and / or to slow down its chemical, microbiological and / or enzymatic deterioration. Thus, depending on the destination of the liquid extract, one or more preservatives can be added.

[0021] According to yet another embodiment of the invention, the solid-liquid separation comprises at least one step of centrifugation and / or filtration and / or decantation and / or pressing of the suspension.

[0022] According to yet another embodiment of the invention, the biological material has a particle size of between 1 mm and 5 mm.

[0023] This embodiment makes it possible to optimize the extraction process according to the invention, because it makes it possible to increase the contact surface between the biological material and the plant sap(s), which facilitates the extraction of the compound(s) of interest. In addition, this makes it possible to increase the extraction yield for the same contact time, but also to reduce the contact time for the same extraction yield. A particle size of less than 1 mm is not preferential, because combined with ultrasound, the liquid extract obtained would contain too many solid microparticles.

[0024] According to yet another embodiment of the invention, the suspension is stirred throughout the duration of the contacting step.

[0025] This embodiment makes it possible to homogenize the suspension and thus facilitate the extraction of the compound(s) from the biological material. Agitation of the suspension makes it possible to maintain the biological material in suspension in the plant sap(s) during the contacting step. In addition, agitation makes it possible to reduce the contacting time and therefore the total duration of the process according to the invention. Agitation of the suspension during the contacting time can be carried out before, after or at the same time as the application of ultrasound.

[0026] According to yet another embodiment of the invention, one or more natural additives intended to modify its pH and / or its affinity with the at least one compound are previously added to the at least one plant sap.

[0027] This embodiment makes it possible to modulate the pH of the plant sap(s) and / or its affinity with the compound(s) to be extracted so as to promote extraction and increase the extraction yield of the process according to the invention. In the same way, this makes it possible to control the quantity of extracted compounds in the liquid extract and / or the pH of the liquid extract obtained. The modification of the pH of the sap is done by adding inputs compatible with cosmetic, pharmaceutical or food use, such as organic acids or salts, or bases.

[0028] According to yet another embodiment of the invention, the biological material represents between 0.5% and 30% by weight of the total mass of the suspension.

[0029] The amount of biological material suspended in the plant sap(s) depends on the amount of compounds to be extracted and the particle size of the biological material used. The desired biological effect and the cytotoxicity of the liquid extract must also be taken into consideration. In addition, the use of plant sap as an extraction solvent allows the extraction of a sufficient amount of compounds from a small amount of biological material. The inventors have found that a mass percentage of biological material relative to the total weight of the suspension of between 0.5% and 5% is a good compromise between the amount of compound extracted and the cytotoxicity of the liquid extract obtained.

[0030] According to yet another embodiment of the invention, the ultrasound has a frequency of between 20 kHz and 30 kHz.

[0031] The choice of ultrasound frequency depends on several factors such as the biological material, the nature of the compounds of interest, the temperature and the duration of contact. The method according to the invention operates with ultrasound having a frequency between 5 kHz and 100 kHz, for example 7 kHz, 10 kHz, 15 kHz, 20 kHz, 21 kHz, 22 kHz, 23 kHz, 24 kHz, 25 kHz, 26 kHz, 27 kHz, 28 kHz, 29 kHz, 30 kHz, 35 kHz, 40 kHz, 45 kHz, 50 kHz, 60 kHz, 70 kHz, 80 kHz, 90 kHz, 95 kHz.

[0032] Lower frequency ultrasound has a greater amplitude, which can cause damage to biological material and lead to a decrease in the quality of extracted compounds. Higher frequency ultrasound has a smaller amplitude, which reduces damage to biological material, but its extraction efficiency is also reduced. The inventors found that frequencies between 20 kHz and 30 kHz yielded undegraded compounds and higher extraction yields than frequencies below 20 kHz or above 30 kHz.

[0033] Throughout the contact period, it is possible to vary the ultrasound frequency. This allows for maximizing the extraction efficiency depending on the biological material, the compounds of interest, and the tree saps used. By varying the frequency, it is possible to optimize the release of different compounds based on their polarity, size, and molecular structure. In addition, varying the frequency helps reduce damage to the biological material, improving the quality of the liquid extract. Finally, by varying the ultrasound frequency, it is possible to control the temperature of the suspension throughout the contact period, which helps preserve heat-sensitive compounds.

[0034] According to yet another embodiment of the invention, the contacting step is carried out for a predetermined duration of between 5 min and 60 min.

[0035] The duration of contact depends on several factors such as the temperature of the suspension, the frequency of the ultrasounds, the biological material, the nature of the compounds and the nature of the plant sap(s) used. The inventors therefore adapt the duration of contact according to these factors while trying to reduce it as much as possible to limit the ecological and energy impact of the process. In addition, the inventors have found that a duration of contact between 5 min and 60 min is optimal given the frequency of the ultrasounds and the nature of the plant sap(s) used.However, the method according to the invention operates for contact times of between 1 min and 4320 min, for example 3 min, 6 min, 10 min, 15 min, 20 min, 25 min, 30 min, 35 min, 40 min, 45 min, 50 min, 55 min, 60 min, 70 min, 80 min, 90 min, 100 min, 2 h, 2 h 30 min, 3 h, 4 h, 5 h, 6 h, 8 h, 10 h, 12 h, 14 h, 16 h, 18 h, 20 h, 22 h, 24 h, 36 h, 48 h, 60 h, 70 h.

[0036] According to yet another embodiment of the invention, the at least one plant sap provided has a temperature of between 20°C and 80°C.

[0037] According to this embodiment, only the plant sap is optionally heated or cooled before contact with the biological material. This creates a temperature gradient within the suspension and thus accelerates the mass transfer of the compounds of interest from the biological material to the plant sap(s). In addition, this avoids thermal degradation of the compounds of interest that may be sensitive to low or high temperatures. In addition, selective heating of the plant sap(s) allows for better control of the temperature of the suspension, which is essential for preserving the stability and integrity of the heat-sensitive compounds. In short, heating only the plant sap(s) improves the efficiency and quality of the extraction according to the method while reducing the risks of degradation of the compounds of interest.

[0038] The inventors have observed optimal extraction yields for one or more saps having a temperature between 20°C and 80°C. However, the method according to the invention also works with one or more saps having a temperature between 1°C and 100°C, for example 3°C, 5°C, 10°C, 15°C, 20°C, 25°C, 30°C, 35°C, 40°C, 50°C, 60°C, 70°C, 80°C, 90°C.

[0039] According to yet another embodiment of the invention, the at least one plant sap is chosen from the group consisting of birch sap, maple sap, linden sap, pine sap, palm tree sap, ash sap, beech sap, fir sap, oak sap, cedar sap, walnut sap, plane tree sap, larch sap, chestnut sap, sequoia sap, cypress sap, vine sap, poplar sap, eucalyptus sap, cactus sap, baobab sap, willow sap, fig tree sap, mango tree sap, cherry tree sap, ginkgo biloba sap.

[0040] The invention also relates to the product directly obtained by the extraction process mentioned above.

[0041] The use of natural plant saps allows the production of products that are also natural and free from any synthetic residue or organic solvent. The resulting product contains not only the compounds extracted from the biological material, but also compounds derived from the plant sap(s) used. Thus, depending on the plant sap(s) used and the biological material used, the resulting product can include a wide variety of active ingredients.

[0042] The invention also relates to the use of a plant sap or a mixture of plant saps as an extraction solvent in an ultrasound-assisted extraction process.

[0043] An advantage of the present invention lies in the reduction of the cost of extraction of the compound(s) of interest.

[0044] Another advantage is the reduction in the time required to extract the compound(s) of interest.

[0045] Another advantage lies in the reduction of the ecological impact of the process according to the invention.

[0046] Another advantage lies in the presence in the final liquid extract of the compound(s) of interest, but also of the compounds initially present in the plant sap(s).

[0047] Yet another advantage of the present invention lies in the biocompatibility of the products resulting from the extraction.

[0048] Yet another advantage of the present invention lies in the increase in the extraction yield of the compound(s) of interest compared to known extraction techniques.

[0049] Yet another advantage of the present invention lies in the fact that there is no need to carry out decontamination steps for the liquid extract. Indeed, the liquid extract can be used for food, cosmetic and / or pharmaceutical purposes directly after the solid-liquid separation step.

[0050] Other characteristics, advantages and details of the invention will be better understood upon reading the additional description which follows.

[0051] As mentioned above, the invention relates to a method for the ultrasound-assisted extraction of at least one compound from a biological material comprising the following steps: providing the biological material and an extraction solvent represented by at least one plant sap; bringing said biological material into contact, in the presence of ultrasound and for a predetermined period, with at least one plant sap so as to obtain a suspension; solid-liquid separation of the suspension so as to obtain, on the one hand, a liquid extract comprising the at least one compound and, on the other hand, a solid residue; and recovering the liquid extract.

[0052] In the context of the present invention, biological material is understood to mean any material of a biological nature from which one or more compounds of interest are capable of being extracted. The biological material according to the invention may be plant, fungal, animal, or microbial material, alone or in a mixture. It may be used in whole or reduced form using suitable techniques, in dehydrated or fresh form. The method according to the invention is particularly suitable for the extraction of compounds from plant and / or fungal material.

[0053] Plant material means any material or substance of plant origin such as plants, trees, algae, fruits, vegetables, cereals, alone or in a mixture. The plant material used may be leaves of plants or trees, seeds, stems, roots, bark, bulbs, tubers, rhizomes, sap, flowers, sprouts, alone or in a mixture, previously reduced or not.

[0054] Fungal material means any matter or substance of fungal origin such as mushrooms, spores, mycelia, lichens, yeasts, alone or in mixture.

[0055] Animal material means any material of animal origin such as tissues, biological fluids, cells, proteins, DNA, RNA.

[0056] Microbial material means any matter or substance of microbial origin such as bacteria, viruses, protozoa, alone or in mixture.

[0057] Plant sap means the liquid that circulates in the vessels of woody plants, including trees, shrubs and vines. It is essentially composed of water, nutrients, sugars, growth hormones and other chemical substances necessary for the growth and survival of plants. The plant sap according to the invention can be composed of raw and / or elaborated sap. It is used as a natural extraction solvent to solubilize and facilitate the extraction of the compound(s) of interest from the biological material. Raw sap, also called ascending sap, is produced by the roots of plants and rises in the conductive vessels called xylem. It transports the water and nutrients absorbed by the roots and necessary for photosynthesis and plant growth. Elaborated sap, or descending sap, is produced in the leaves and green parts of the plant by photosynthesis.It is made up of sugars and other nutrients which are then transported to other parts of the plant by conducting vessels called phloem.

[0058] According to one embodiment of the invention, the plants whose sap is used for the extraction of compounds of interest from biological material are chosen from the non-exhaustive group consisting of: Acer saccharum (sugar maple), Acer nigrum (black maple), Acer rubrum (red maple), Acer saccharinum (silver maple), Adanosia digitata (baobab), Betula alleghaniensis (yellow birch), Betula alba (white birch), Betula lenta (sweet birch), Betula nigra (black birch), Carpinus caroliniana (Carolina hornbeam), Castanea dentata (American chestnut), Carya illinoinensis (pecan), Carya ovata (American black walnut), Carya tomentosa (wood walnut), Celtis occidentalis (western hackberry), Fagus grandifolia (American beech), Fraxinus americana (American ash), Fraxinus nigra (American ash), black), Ginkgo biloba (ginkgo biloba), Gleditsia triacanthos (American honeylocust), Juglans nigra (black walnut), Juniperus virginiana (Virginia juniper),Larix decidua (European honeysuckle), Liquidambar styraciflua (American copalm), Liriodendron tulipifera (Virginia tulip), Maclura pomifera (Orange osage), Morus alba (White wall), Nyssa sylvatica (Virginia tupélo), Ostryame (Virginia-houblonsa) (paulownia pubescent), Picea abies (common spruce), Pinus nigra (Austrian black pine), Pinus resinosa (red pine), Pinus strobus (white pine), Pinus sylvestris (sylvestre pine), Platanus occidentalis (American banana), Populus deltoides (peuplier deltoid), Populus deltoid false-tremble), Prunus serotina (black cherry), Quercus alba (white oak), Quercus bicolor (two-colored oak), Quercus coccinea (scarlet oak), Quercus falcata (swamp oak), Quercus palustris (swamp oak), Quercus rubrage (red giant cherry), Sequoia (giant redwood), Salix alba (white willow), Sassafras albidum (sassafras), Syringa reticulata (Japanese lilacs), Taxodium distichum (bald cypress),Tilia americana (American linden), Tilia cordata (small-leaved linden), Tilia platyphyllos (large-leaved linden), Tilia tomentosa (silver linden), Ulmus americana (American elm), Ulmus rubra (slippery elm), Vitis vinifera (grape vine) and Pinus pinea (umbrella pine).,

[0059] Ultrasound refers to vibratory waves that require an elastic medium for propagation. The main effects of ultrasound in a liquid medium are attributed to cavitation phenomena that are emitted from the physical processes that create, enlarge, and implode microbubbles of gas dissolved in the liquid. Ultrasonic waves produce longitudinal vibrations in the liquid, creating millions of microscopic bubbles that implode, producing extreme temperatures and pressures. In addition, ultrasound can rupture biological material through its production of microjets directed toward solid surfaces during the implosion of the cavitation microbubbles. The cumulative energy produced by this phenomenon is extremely high and produces intense shear forces that destroy the cell walls of the biological material, the contents of which are then released into the liquid medium.When ultrasound is combined with an extraction process, it is referred to as ultrasound-assisted extraction. According to one embodiment of the invention, the ultrasound is generated by one or more ultrasound probes and / or one or more ultrasound tanks. The ultrasound tank is particularly preferred because it avoids putting the biological material, the plant sap(s) and the enriched extract in direct contact with an ultrasound probe that could release microscopic metal particles resulting from its degradation, such as titanium and aluminum.

[0060] Preservative means any substance added to the liquid extract obtained at the end of the extraction process and intended to protect it from degradation, putrefaction, autolysis and / or slow down its chemical, microbiological and / or enzymatic deterioration.

[0061] According to one embodiment of the invention, the preservatives are chosen from the non-exhaustive group consisting of: sodium acetate, acetic acid, adipic acid, ascorbic acid, benzoic acid, citric acid, lactic acid, lactobionic acid, malic acid, sorbic acid, sodium alginate, benzyl alcohol, amylase, sulfur dioxide, antioxidants, artificial flavoring, nitrogen gas, benzyl benzoate, potassium benzoate, sodium benzoate, potassium bromate, butane, butylhydroxyanisole (BHA), butylhydroxytoluene (BHT), sodium butyrate, calcium propionate, calcium carbonate, sodium carbonate, calcium chloride, sodium chloride, calcium citrate, sodium citrate, dioxide sulfur, disodium diphosphate, EDTA (ethylenediaminetetraacetic acid), enzymes, sodium erythorbate, glycerol esters, ethoxyquin, ethylene glycol,sodium formate, sodium fumarate, monosodium glutamate, glycerol, gum arabic, hexamethylenetetramine, sodium hexametaphosphate, butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), disodium inosinate, potassium iodide, sodium laurate, lecithin, sodium malate, calcium metabisulfite, potassium metabisulfite, sodium metabisulfite, methylcellulose, potassium nitrate, sodium nitrate, potassium nitrite, octyl gallate, ascorbyl palmitate, panthenol, pectin, lactobacillus peristalsis, phenylalanine, calcium phosphate, potassium phosphate, sodium phosphate, polysorbate 20, polysorbate 80, propionate calcium, potassium propionate, sodium propionate, propylene glycol, ferric pyrophosphate, sodium pyrophosphate, tetrasodium pyrophosphate, yellow quinoline, licorice, benzyl salicylate,sodium silicate, silica, potassium sorbate, sodium sorbate, sorbitan monooleate, sucralose, aluminum sulfate, copper sulfate, iron sulfate, magnesium sulfate, zinc sulfate, sodium sulfite, xanthan.,

[0062] Additive means any substance or compound that can modify the pH of the plant sap(s) and / or the affinity of the plant sap(s) with the compound(s) of interest present in the biological material.

[0063] According to one embodiment of the invention, the additive(s) are chosen from the non-exhaustive group consisting of: citric acid, acetic acid, formic acid, hydrochloric acid, sodium hydroxide, ammonia, an anionic surfactant, a cationic surfactant.

[0064] Suspension means a solution comprising a solid suspended in a liquid. In the context of the present invention, the suspension is created upon contact between at least one plant sap and a biological material.

[0065] The following description relates to embodiments of the method according to the invention. Supply of biological material

[0066] This step consists of providing biological material which has optionally undergone pre-treatment to reduce its size, for example by grinding, and / or modify its water content, for example by hydration or dehydration.

[0067] Biological matter is preferably plant, algal, bacterial and / or fungal matter. Supply of an extraction solvent

[0068] This step involves providing one or more plant saps and / or a mixture of plant saps intended to be used as an extraction solvent.

[0069] Optionally, the plant sap(s) and / or the mixture of plant sap are first brought to a temperature between 1°C and 100°C, preferably between 20°C and 80°C, even more preferably between 30°C and 50°C.

[0070] Optionally again and prior to contact, additives are added to the plant sap(s) or to the mixture of plant saps so as to modify the pH and / or the affinity of the plant sap(s) or of the mixture of plant saps with the compounds of interest to be extracted from the biological material. Contact

[0071] This step of bringing the biological material into contact with the plant sap(s) or the mixture of plant saps consists of bringing the biological material into contact with one or more plant saps so as to obtain a suspension. The mass percentage of biological material in the suspension is between 0.5% and 30% relative to the total mass of the suspension represented by the sum of the masses of the biological material and the plant sap(s). Preferably, the percentage of biological material is between 0.5% and 10%.

[0072] The contact is carried out in an ultrasonic tank capable of emitting ultrasound at a frequency between 20 kHz and 100 kHz. The contact time is between 1 min and 4320 min, preferably between 2 min and 1440 min, even more preferably between 5 min and 60 min.

[0073] Optionally, the suspension is heated or cooled during the contact time in order to control the extraction temperature.

[0074] Optionally, the suspension is continuously or periodically stirred for the duration of the contacting. The stirring speed may be constant or variable for the duration of the contacting. The stirring speed is preferably between 50 rpm and 200 rpm.

[0075] Optionally, additives are added to the suspension in order to modify its pH and / or the affinity of the plant sap(s) with the compounds of interest to be extracted from the biological material. Additives are, for example, bases, acids or surfactants.

[0076] It is possible to provide one or more probes to measure suspension parameters, for example temperature and pH. This allows the extraction parameters to be corrected, if necessary, during contact. Solid-liquid separation of suspension

[0077] This step involves performing a solid-liquid separation of the suspension. This step is carried out at the end of the predetermined time. This allows the liquid part of the suspension to be separated from the solid part.

[0078] The liquid part obtained corresponds to the liquid extract containing few or no solid particles. The liquid extract essentially comprises the compound(s) extracted from the biological material and the compounds derived from the plant sap(s). The process according to the invention allows a significant increase of the order of 5% to 50% in the extraction yield compared to an ultrasound-assisted extraction process using water as a solvent.

[0079] The solid part corresponds to the solid residues from the biological material and does not contain any organic residue. It is rapidly biodegradable and non-toxic to the environment. In the embodiment of the invention where the biological material is plant and / or fungal material, the solid part is directly compostable and can also be used as fertilizer.

[0080] The solid-liquid separation can be carried out by any means allowing a liquid to be separated from a solid, for example by pressing, centrifugation, filtration, decantation and / or sieving. According to one embodiment of the invention, the solid-liquid separation is initiated by one or more successive pressings of the suspension and then the liquid extract resulting from the pressing is centrifuged and / or filtered so as to eliminate any solid residues potentially still present. Recovery of the liquid extract

[0081] This step involves recovering the liquid extract obtained after solid-liquid separation. Once recovered, the liquid extract can be used directly in the cosmetic, pharmaceutical, or food industries. The liquid extract can also be packaged for future use.

[0082] Optionally, one or more preservatives are added to the liquid extract. Concentration of liquid extract

[0083] This step is optional and involves increasing the concentration of compounds present in the liquid extract. It can be performed directly after the liquid extract recovery step or after the possible addition of preservatives to the liquid extract. Concentration can be advantageous depending on the final use of the liquid extract.

[0084] Concentration is achieved, for example, by evaporation, and / or by ultrafiltration and / or by nanofiltration and / or by precipitation. Purification of the liquid extract

[0085] This step involves isolating one or more compounds from the liquid extract. Purification is carried out, for example, by stationary phase or liquid phase chromatography and / or by affinity and / or by decolorization and / or by adsorption on ion exchange resins.

[0086] The following description concerns examples of ultrasound-assisted extractions.

[0087] In Examples 1 to 4 which follow, the inventors compare the uses of different solvents for the ultrasound-assisted extraction of compounds from different plant materials.

[0088] The plant materials used are: Calendula officinalis; Morus Alba; Salix Alba; and Ginkgo Biloba.

[0089] The solvents compared are: distilled water; birch sap (Brix level = 1); maple sap (Brix level = 3.4); a mixture of plant saps comprising 50% birch sap and 50% maple sap (Brix level = 2.3).

[0090] Each solvent is first brought to a temperature of 40°C and the biological material is first ground to reach a particle size of between 1 mm and 5 mm.

[0091] The mass percentage of biological matter in relation to the total mass of the suspension is 1%.

[0092] The contact is carried out for a period of 10 minutes in a 3 L tank delivering ultrasound at a frequency equal to 24 kHz and with constant stirring of the suspension.

[0093] The liquid extract is then obtained by pressing on a 200 mesh sieve.

[0094] In order to compare the extraction yields associated with each solvent, the inventors measure the polyphenols present in each liquid extract using the Folin-Ciocalteu method and determine the percentage of dry matter in each liquid extract.

[0095] The amount of polyphenols is expressed in mg of gallic acid equivalent (GAE) / mL.

[0096] Regarding the determination of the percentage of dry matter, the percentage of dry matter provided by the solvent is subtracted from each liquid extract. The percentages of dry matter initially present in the solvents used are as follows: distilled water: 0%; birch sap: 0.56%; maple sap: 2%; and mixture of plant saps comprising 50% birch sap and 50% maple sap: 2%.

[0097] Example 1: Extraction of compounds from Calendula officinalis.

[0098] The quantity of polyphenols present in the liquid extracts from the different extractions is presented in the following table.

[0099] [Table 1]SolventTotal polyphenols(mg / mlEAG)Distilled water0.130Birch sap0.165Maple sap0.15950% Birch sap50% Maple sap0.167

[0100] Thus, the use of birch sap as an extraction solvent allows an improvement in the extraction yield of polyphenols from Calendula officinalis of 26.4% compared to the use of distilled water as an extraction solvent.

[0101] The use of maple sap as an extraction solvent allows an improvement in the extraction yield of polyphenols from Calendula officinalis of 22.9% compared to the use of distilled water as an extraction solvent.

[0102] The use of a mixture of plant saps comprising 50% birch sap and 50% maple sap as an extraction solvent allows an improvement in the extraction yield of polyphenols from Calendula officinalis by 28.6% compared to the use of distilled water as an extraction solvent.

[0103] The percentage of dry matter of each liquid extract from the different extractions is presented in the following table.

[0104] [Table 2]SolventPercentage of dry matter (%)Distilled water0.54Birch sap0.76Maple sap1.3950% Birch sap50% Maple sap1.03

[0105] Thus, the use of birch sap as an extraction solvent allows an improvement in the extraction yield of dry matter from Calendula officinalis of 40.7% compared to the use of distilled water as an extraction solvent.

[0106] The use of maple sap as an extraction solvent allows an improvement in the extraction yield of dry matter from Calendula officinalis of 157.4% compared to the use of distilled water as an extraction solvent.

[0107] The use of a mixture of plant saps comprising 50% birch sap and 50% maple sap as an extraction solvent allows an improvement in the extraction yield of Calendula officinalis dry matter by 90.1% compared to the use of distilled water as an extraction solvent.

[0108] Example 2: Extraction of compounds from Morus Alba.

[0109] The quantity of polyphenols present in the liquid extracts from the different extractions is presented in the following table.

[0110] [Table 3] Solvent Total polyphenols (mg / ml EAG) Distilled water 0.160 Birch sap 0.229 Maple sap 0.167 50% Birch sap 50% Maple sap 0.198

[0111] Thus, the use of birch sap as an extraction solvent allows an improvement in the extraction yield of polyphenols from Morus Alba of 43.3% compared to the use of distilled water as an extraction solvent.

[0112] The use of maple sap as an extraction solvent allows an improvement in the extraction yield of polyphenols from Morus Alba of 4.7% compared to the use of distilled water as an extraction solvent.

[0113] The use of a mixture of plant saps comprising 50% birch sap and 50% maple sap as an extraction solvent allows an improvement in the extraction yield of polyphenols from Morus Alba by 23.9% compared to the use of distilled water as an extraction solvent.

[0114] Example 3: Extraction of compounds from Salix Alba.

[0115] The quantity of polyphenols present in the liquid extracts from the different extractions is presented in the following table.

[0116] [Table 4] Solvent Total polyphenols (mg / ml EAG) Distilled water 0.470 Birch sap 0.539 Maple sap 0.635 50% Birch sap 50% Maple sap 0.548

[0117] Thus, the use of birch sap as an extraction solvent allows an improvement in the extraction yield of polyphenols from Salix Alba of 14.8% compared to the use of distilled water as an extraction solvent.

[0118] The use of maple sap as an extraction solvent allows an improvement in the extraction yield of polyphenols from Salix Alba of 35.3% compared to the use of distilled water as an extraction solvent.

[0119] The use of a mixture of plant saps comprising 50% birch sap and 50% maple sap as an extraction solvent allows an improvement in the extraction yield of polyphenols from Salix Alba by 16.8% compared to the use of distilled water as an extraction solvent.

[0120] The percentage of dry matter of each liquid extract from the different extractions is presented in the following table.

[0121] [Table 5]SolventPercentage of dry matter (%)Distilled water0.43Birch sap0.80Maple sap1.4350% Birch sap50% Maple sap1.12

[0122] Thus, the use of birch sap as an extraction solvent allows an improvement in the extraction yield of dry matter from Salix Alba of 86.0% compared to the use of distilled water as an extraction solvent.

[0123] The use of maple sap as an extraction solvent allows an improvement in the extraction yield of dry matter from Salix Alba of 232.6% compared to the use of distilled water as an extraction solvent.

[0124] The use of a mixture of plant saps comprising 50% birch sap and 50% maple sap as an extraction solvent allows an improvement in the extraction yield of Salix Alba dry matter by 160.5% compared to the use of distilled water as an extraction solvent.

[0125] Example 4: Extraction of compounds from Ginkgo Biloba.

[0126] The quantity of polyphenols present in the liquid extracts from the different extractions is presented in the following table.

[0127] [Table 6] Solvent Total polyphenols (mg / ml EAG) Distilled water 0.090 Birch sap 0.097 Maple sap 0.112 50% Birch sap 50% Maple sap 0.096

[0128] Thus, the use of birch sap as an extraction solvent allows an improvement in the extraction yield of Ginkgo Biloba polyphenols by 7.4% compared to the use of distilled water as an extraction solvent.

[0129] The use of maple sap as an extraction solvent allows an improvement in the extraction yield of Ginkgo Biloba polyphenols by 24.4% compared to the use of distilled water as an extraction solvent.

[0130] The use of a mixture of plant saps comprising 50% birch sap and 50% maple sap as an extraction solvent allows an improvement in the extraction yield of Ginkgo Biloba polyphenols by 7.1% compared to the use of distilled water as an extraction solvent.

[0131] The percentage of dry matter of each liquid extract from the different extractions is presented in the following table.

[0132] [Table 7]SolventPercentage of dry matter (%)Distilled water0.16Birch sap0.61Maple sap1.2750% Birch sap50% Maple sap0.70

[0133] Thus, the use of birch sap as an extraction solvent allows an improvement in the extraction yield of Ginkgo Biloba dry matter by 281.2% compared to the use of distilled water as an extraction solvent.

[0134] The use of maple sap as an extraction solvent allows an improvement in the extraction yield of Ginkgo Biloba dry matter of 693.8% compared to the use of distilled water as an extraction solvent.

[0135] The use of a mixture of plant saps comprising 50% birch sap and 50% maple sap as an extraction solvent allows an improvement in the extraction yield of Ginkgo Biloba dry matter by 337.5% compared to the use of distilled water as an extraction solvent.

[0136] The inventors also compared the effects of extraction solvent temperature for ultrasound-assisted extraction of compounds from a biological material represented by flax seeds.

[0137] The solvents compared are: distilled water; and birch sap.

[0138] Each solvent is first brought to a temperature of 40°C or 70°C and the biological material is first ground to reach a particle size of between 1 mm and 5 mm.

[0139] The mass percentage of biological matter in relation to the total mass of the suspension is 10%.

[0140] The contact is carried out for a period of 20 minutes in a 3 L tank delivering ultrasound at a frequency equal to 24 kHz and with constant stirring of the suspension.

[0141] The liquid extract is then obtained by pressing on filter paper, 5 µm, 1.2 µm.

[0142] In order to compare the extraction yields associated with each solvent and temperature, the inventors determined the percentage of dry matter in each liquid extract. The percentage of dry matter provided by the solvent was subtracted from each liquid extract. The percentages of dry matter initially present in the solvents used were as follows: distilled water: 0%; and birch sap: 0.56%.

[0143] Example 5: Extraction of compounds from flax seeds — Effect of solvent temperature.

[0144] The percentage of dry matter of each liquid extract from the different extractions is presented in the following table.

[0145] [Table 8] Solvent Percentage of dry matter (%) Temperature = 40 ° C Temperature = 70 ° C Distilled water 0.351.01 Birch sap 1.091.46

[0146] Thus, whether at a temperature of 40°C or 70°C, the use of birch sap as an extraction solvent allows an improvement in the extraction yield of flax seed dry matter of 211.43% at 40°C and 44.55% at 70°C compared to the use of distilled water as an extraction solvent.

[0147] A solvent at a temperature of 70°C provides a better extraction yield than a solvent at 40°C. For birch sap, the improvement in extraction yield is 33.9% and for distilled water 188%.

[0148] The inventors also compared the effects of ultrasound on the extraction of compounds from biological material represented by flax seeds.

[0149] The solvents compared are: distilled water; and birch sap.

[0150] Each solvent is first heated to a temperature of 70°C and the biological material is not ground in order to target only the mucilage of the flax seeds and avoid extracting the starch contained inside the seeds.

[0151] The mass percentage of biological matter in relation to the total mass of the suspension is 5%.

[0152] The contact is carried out for a period of 40 minutes in a 3 L tank under the following two conditions: Condition 1: 40 min with stirring only; and Condition 2: 30 min of stirring then 10 min under ultrasound at a frequency equal to 24 kHz.

[0153] The liquid extract is then obtained by pressing on filter paper, 5 µm, 1.2 µm.

[0154] In order to compare the extraction yields associated with each solvent in the presence or absence of ultrasound, the inventors determine the percentage of dry matter in each liquid extract. The percentage of dry matter provided by the solvent is subtracted from each liquid extract. The percentages of dry matter initially present in the solvents used are as follows: distilled water: 0%; and birch sap: 0.56%.

[0155] Example 6: Extraction of compounds from flax seeds — Effect of ultrasound.

[0156] The percentage of dry matter of each liquid extract from the different extractions is presented in the following table.

[0157] [Table 9]SolventPercentage of dry matter (%)Condition 1Condition 2Distilled water0.911.01Birch sap1.191.46

[0158] Thus, the presence of ultrasound during the extraction process allows an improvement in the extraction yield of dry matter from flax seeds of 22.7% for birch sap and 10.9% for distilled water.

[0159] Birch sap was found to provide a greater improvement in extraction yield than distilled water. The combination of ultrasound and plant sap is therefore particularly effective in improving the extraction yield of compounds of interest from biological material compared to known conventional techniques using distilled water as the extraction solvent.

[0160] The inventors also compared the effects of different solvents on the extraction of compounds from a biological material represented by flax seeds. In this example, the inventors compare a plant sap, birch sap, to natural deep eutectic solvents (NADES) as mentioned in the table below:

[0161] [Table 10]SolventCompoundsMolar RatioWater(wt%)Density(g / ml)123LGH2Lactic AcidGlucoseWater6:1:613.051.2497GCHGlucoseChlorideCholineWater2:5:57.841.2069SuCHSucroseChlorideCholineWater1:4:47.41.2269

[0162] After preparation, the NADES solvents are diluted to obtain a Brix degree between 8 and 9. LGH2 is diluted 9 times and has a Brix degree equal to 8.23. GCH is diluted 12 times and has a Brix degree equal to 8.33. SuCH is diluted 13.5 times and has a Brix degree equal to 8.63.

[0163] Each solvent is first brought to a temperature of 40°C and the biological material is not crushed.

[0164] The mass percentage of biological matter in relation to the total mass of the suspension is 15%.

[0165] The contact is carried out for a period of 60 minutes in a 3 L tank delivering ultrasound at a frequency equal to 24 kHz and with constant stirring of the suspension.

[0166] The liquid extract is then obtained by pressing on filter paper, 5 µm, 1.2 µm.

[0167] In order to compare the extraction yields associated with each solvent, the inventors determine the percentage of dry matter in each liquid extract. The percentage of dry matter provided by the solvent is subtracted from each liquid extract. The percentages of dry matter initially present in the solvents used are as follows: Birch sap: 0.56%; LGH2: 6%; GCH: 8.34%; and SuCH: 8.84%.

[0168] Example 7: Extraction of compounds from flax seeds — Comparison with NADES.

[0169] The percentage of dry matter of each liquid extract from the different extractions is presented in the following table.

[0170] [Table 11]SolventPercentage of dry matter (%)Birch sap1.09LGH20.78GCH0.92SuCH0.84

[0171] Thus, the use of birch sap as an extraction solvent allows an improvement in the extraction yield of dry matter from flax seeds of: 39.7% compared to NADES LGH2; 18.4% compared to NADES GCH; and 29.8% compared to NADES SuCH.

[0172] Birch sap, although having a Brix degree of 1, proves to be more effective than NADES in extracting compounds from flax seeds by means of ultrasound-assisted extraction.

[0173] The use of plant saps as an extraction solvent in the ultrasound-assisted extraction process according to the invention makes it possible to modulate the various extraction parameters so as to obtain an optimal extraction yield. Thus, and depending on the desired result, the inventors vary the temperature of the solvent, the contact time, the ultrasound frequency, the particle size of the biological material, the mass percentage of the biological material, the nature of the plant sap(s) used and / or the addition or absence of additives.

[0174] The method according to the invention makes it possible to obtain a liquid extract combining the biological activities of the compounds extracted from the biological material as well as those derived from the plant sap(s) used. The liquid extract can be used directly as is or used for the manufacture of a nutraceutical composition, a dietary or food product, a food supplement, a pharmaceutical composition or a cosmetic composition, intended for oral or parenteral administration, or for topical, rectal, nasal, auricular, vaginal and / or ocular application.

Claims

A method for the ultrasound-assisted extraction of at least one compound from a biological material comprising the following steps: providing the biological material and an extraction solvent represented by at least one plant sap; bringing said biological material into contact, in the presence of ultrasound and for a predetermined period, with said at least one plant sap so as to obtain a suspension; solid-liquid separation of said suspension so as to obtain, on the one hand, a liquid extract comprising the at least one compound and, on the other hand, a solid residue; and recovering the liquid extract. Method according to claim 1, characterized in that it comprises a step e) of concentration of the liquid extract. Method according to claim 1 or 2, characterized in that it comprises a step f) of purification of the liquid extract. Method according to any one of the preceding claims, characterized in that it comprises a step of adding at least one preservative to the liquid extract. Method according to any one of the preceding claims, characterized in that the solid-liquid separation comprises at least one step of centrifugation and / or filtration and / or decantation and / or pressing of the suspension. Method according to any one of the preceding claims, characterized in that the biological material has a particle size of between 1 mm and 5 mm. Method according to any one of the preceding claims, characterized in that the suspension is stirred throughout the duration of the contacting step. Method according to any one of the preceding claims, characterized in that one or more natural additives intended to modify its pH and / or its affinity with the at least one compound are previously added to the at least one plant sap. Method according to any one of the preceding claims, characterized in that the biological material represents between 0.5% and 30% by weight of the total mass of the suspension. Method according to any one of the preceding claims, characterized in that the ultrasound has a frequency of between 20 kHz and 30 kHz. Method according to any one of the preceding claims, characterized in that the contacting step is carried out for a predetermined duration of between 5 min and 60 min. Method according to any one of the preceding claims, characterized in that the at least one plant sap provided has a temperature between 20°C and 80°C. Method according to any one of the preceding claims, characterized in that the at least one plant sap is chosen from the group consisting of birch sap, maple sap, linden sap, pine sap, palm sap, ash sap, beech sap, fir sap, oak sap, cedar sap, walnut sap, plane tree sap, larch sap, chestnut sap, sequoia sap, cypress sap, vine sap, poplar sap, eucalyptus sap, cactus sap, baobab sap, willow sap, fig tree sap, mango tree sap, cherry tree sap, ginkgo biloba sap.

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