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EXTRACTING OF NON-VOLATILE COMPOUNDS

 PROCESS FOR EXTRACTING NON-VOLATILE COMPOUNDS

The present invention relates to a process for extracting nonvolatile natural clean compounds contained in a solid raw material of natural origin using a natural fatty substance, like a vegetable oil, without the use of organic solvent and most importantly without chemical transformation.

Natural extracts including the plant extracts are widely used in many areas including food, pharmacy and cosmetics. These areas have very specific regulations regarding its toxicity of extracts.

There are many methods of extracting natural compounds from natural raw materials. In most cases, the solvents used are mostly polar like water, glycerin, alcohol, or in part apolar (hexane, acetone, vegetable oil, triglycerides with saturated fatty acids). Among these clean solvents, vegetable oils have a special main place because of natural origin and can be surely considered as “active” solvents that are widely used in food and cosmetics.

Among the methods for extracting natural compounds derived from plants, mention may be made of cold or hot maceration methods using a simple phenomenon of static diffusion, sometimes assisted by mechanical pressure or the case of the use of a fatty substance as an extraction solvent, the maceration method is both inefficient in yield of extracted molecules and poorly or not controlled at the level of oxidative degradation of the fatty substance. It is particularly unsuitable for the case of polyunsaturated oils sensitive to oxidation, hence the recommendation to use saturated oils or triglycerides of saturated fatty acids, especially if the extraction is done hot.

Methods of maceration in an oil-type solvent are a process of extracting natural compounds from a plant in a fish oil, by cold maceration, under an inert atmosphere, protected from light, without volatile solvent and at room temperature. Such a process has the disadvantage of being long, the maceration time being of the order of twenty days, which can result in oxidative alteration of the oil without otherwise obtaining a high concentration of molecules mined. Another way is by  extracting of natural compounds by a mineral or vegetable oil, by maceration at a temperature between 20 and 60 1 C. The algae may contain a fraction of water or be lyophilized, the extraction solvent may be the water and the atmosphere is not controlled. However, this type of process also requires large volumes of oil (1 kg of biological material per 20 liters of oil) and can be relatively long, hence the same limits as in the previous case. Different method is the  extraction of antioxidants in an oily solvent by hot maceration. The heat treatment being carried out by dielectric heating under microwave frequency. This document recommends working between 0 and 100 ° C. and the duration of the treatment is preferably between 15 minutes and 14 hours The authors suggest working with an oxygen-free atmosphere, under atmospheric or reduced pressure.

Microwave-assisted extraction methods of natural compounds from plants have been described. These processes include extractions involving a polar organic solvent (water, alcohol, glycerin) or apolar (hexane). Thus, the extraction of natural products combining microwave irradiation and organic solvent (hexane, alcohol …) without control of the atmosphere. However, such processes consume large amounts of solvents. This document recommends working with a high humidity (from about 40% to 90%) to limit the duration of microwave irradiation (about 10 to 100 seconds). However, the use of an organic solvent is restrictive for the use of the extracts thus obtained in the food, pharmaceutical or cosmetic field. There is also a method of extraction in a non-aqueous oily solvent under microwave radiation. Microwave radiation is produced to heat mainly the aqueous parts of plants rather than the components of the substrate. The heating time is of the order of 4 to 6 minutes and the treatment is carried out in the presence of air. This method is intended for an aromatization of an oil for food applications, without it being specified the oxidative deterioration of the oil and the yield of extracted molecules.

microwave extraction
Microwave Plant Extraction

Methods for extracting natural compounds derived from plants under ultrasonic activation have also been described. The solvent used is generally a polar solvent (water, glycerol, alcohol), more rarely apolar or oily. The treatment is carried out in the presence of air, with or without heating. Thus, the extraction of natural flavors of fresh truffles at a temperature of 12O for 3 hours. The atmosphere is not controlled in this process which is intended to aromatize an oil for food applications.

A fatty substance sees its solubilization power increase when heated. Fatty substances, including vegetable oils, however, have the disadvantage of being sensitive to oxidation, a process increased by heat. This is mainly due to the presence of double bonds on their constituent fatty acids, which tend to oxidize. This limits their use or limits the extraction yields, users being reluctant to use relatively high temperatures.

The object of the present invention is to overcome the drawbacks of the prior extraction methods by proposing a high-efficiency extraction technique employing a natural fatty substance, especially a vegetable oil, under conditions that advantageously combine a high extraction ratio with controlled limitation. the oxidation of the oil.

Another objective is to propose a technique for preserving the extracted active ingredient, even if it is an oxidizable and / or photosensitive active agent. Yet another object of the invention is to provide a technique which makes it possible to preserve the beneficial properties of the vegetable extraction oil, in particular its native polyunsaturated fatty acids and its unsaponifiable compounds.

The inventor has found that it is possible to meet all these objectives by ignoring the sensitivity to oxidation of a natural fatty substance, in particular of a vegetable oil and of certain oxidizable active agents, and the problems of thermal degradation. – Oxidative of this oil by working on a dispersible raw material and exclusively in a free atmosphere or essentially free of oxygen and carrying out a high heating of very short duration combined with a microdispersion of the raw material and rupture of the cells in the case where the process is applied to plants.

The subject of the present invention is thus a process for extracting non-volatile natural compounds, contained in a solid raw material of natural origin, in particular a plant, in a dispersible form, using a natural fatty substance. or a mixture of natural fatty substances, especially a vegetable oil or a mixture of vegetable oils, characterized in that it comprises:

at least one step a) of mixing and impregnating the solid raw material with the natural fatty substance at a temperature above the melting point of the fatty substance and under an atmosphere that is free or substantially free of oxygen,

at least one step b) of heating the mixture at high temperature for a very short time and in an atmosphere which is free or substantially free of oxygen,

at least in a step c) of microdispersion of the material to be extracted with possible rupture of the cells of the raw material, in the natural fatty substance at a temperature above the melting point of the fatty substance and in an atmosphere which is devoid of or substantially free of oxygen, step c) can be performed before, during or after step b).

By dispersible is meant that the raw material is in dissociated form capable of being finely dispersed, and for example, the raw material is in particulate form and preferably pulverulent. According to an essential characteristic of the invention, the unitary steps a) b) c) are conducted in a free atmosphere or essentially free of oxygen. This means that one works under gas or inert atmosphere or under vacuum or partial vacuum. The residual oxygen content must be low enough not to cause oxidation reactions sensitive to the temperature of the heat treatment. These steps can therefore be carried out under an inert atmosphere, for example under nitrogen and preferably under a continuous nitrogen sweep, allowing the extraction of the oxygen present or likely to be formed. A closed reactor can be employed with continuous extraction of oxygen by nitrogen flow. Nitrogen sparging, associated with the nitrogen flow, can also be done at least at the beginning of the heat treatment. These steps can also be conducted under vacuum. Proceeding thus confers an additional advantage, namely the entrainment of volatile materials with a deodorizing effect of the mixture.

Plant Fatts

The process according to the invention is advantageously carried out on a mixture of natural fatty substances + raw material containing from 2 to 40% water by weight, in particular between 3 and 30%, preferably between 5 and 15%. Part of the water may come from the natural fat, the rest being provided by the raw material. A supply of water can be made to be placed in these intervals.

Among the natural fats, it is possible to use, in particular, refined vegetable oils comprising less than 0.1% water by weight or virgin or unrefined vegetable oils which may contain from 0.1 to 2% by weight of water, preferably 0.1 to 0.3% water by weight. Codex Alimentahus sets the water and volatile content of edible vegetable oils at 0.2% by weight.

Step a) is conducted at ambient temperature or at a temperature above the melting point of the fatty substance or mixture of fatty substances used. In one embodiment, the temperature is advantageously between this melting temperature and the melting temperature + 20 ° C., preferably + 10 ° C. The ambient temperature (20-25 ° C) is perfectly suitable for fats, especially oils, liquids at this temperature. The duration of step a) can be between 1 and 48 hours, preferably between 5 and 30 hours and more preferably between 12 and 24 hours, preferably the impregnation is between 8 and 16 hours, for example About 12 hours.

In a preferred embodiment, the temperature of step b) is between 80 and 200 ° C, preferably between 100 and 190 ° C and more preferably between 140 and 170 ° C.

The term “high temperature heating of very short duration” means a treatment carried out in a time of less than or equal to 10 minutes, preferably less than or equal to 5 minutes, preferably from 1 to 5 minutes, and more preferably from 1 to 3 minutes. , this duration corresponds to the time of maintenance of the treatment temperature once this temperature reached. The temperature rise time is also very short, especially less than or equal to 5 minutes, preferably

I to 5 min, and more preferably 1 to 3 minutes.

Any rapid thermal heating system can be used, in a preferred embodiment, the heat treatment is provided by microwaves.

The use of a microwave source in a closed reactor makes it possible to reach the desired temperatures in a short time and thus limit secondary oxidation phenomena, especially since the process is carried out in an atmosphere that is free or essentially free of heat. ‘oxygen.

The heating at high temperature makes it possible to increase the solubilization power of the oil and promotes the contact between the solvent and the product to be extracted as well as the diffusion of the solutes in the solvent. Thus, amphiphilic or partially polar molecules can be extracted by the heated oil, parallel to the solubilization of water molecules, the extraction efficiency is therefore high.

It is recommended the use of a microwave generator with high power output, preferably of the order of 10,000 Watts to 30,000 Watts per kilogram of mixture. Step c) allows both the microdispersion of the material to be extracted and on cell tissues, the rupture of the cells, which favors the dispersion of the molecules extracted in the natural fatty substance. This effect can be obtained by microwaves. According to one embodiment of the invention, step c) comprises a microwave treatment. According to a certain modality, steps b) and c) are carried out by applying microwaves in one or more passes.

By microdispersion is meant particles or solutes suspended in the fatty substance. The size of the particles or solutes is such that there is no decantation over time, it is in particular between 0.1 to 10 microns.

Step c) may also comprise or consist of treating the mixture by ultrasonic cavitation before, during or after step b).

The microwave treatment makes it possible to break the cell membranes allowing a better diffusion of the intracellular plant compounds in the oil. Ultrasonic treatment uses the cavitation phenomenon, which effectively breaks down cell membranes, breaks down solid particles and evenly disperses solutes in the oil.

Cavitation and dispersion under ultrasonic waves are preferably carried out in a closed reactor equipped with a low-frequency cavitation ultrasound generator, in particular less than 100 kHz and preferably of the order of 20 to 30 kHz.

The duration of the ultrasonic treatment is in particular between 2 and 30 min, preferably between 10 and 20 min.

Step c) can be carried out at ambient temperature or at a temperature above the melting point of the fatty substance or mixture of fatty substances used. The temperature is advantageously between this melting temperature and the melting temperature + 20 ° C., preferably + 10 ° C. The ambient temperature (20 ° C. 25 ° C) is perfectly suitable for fatty ,rps, especially liquid oils at this temperature.

Steps b) and c) can be conducted simultaneously.

The inventor has demonstrated a synergistic effect between a microwave treatment and an ultrasound treatment that makes it possible to improve the extraction yield in a shorter time and with a reduced quantity of fatty substances, which favors the final concentration of molecules. extracted.

According to an advantageous characteristic, during a step c) or just before, an oxygen scavenging or reducing compound is added, a compound making it possible to regenerate in reduced form the tocopherols of the oil as well as the phenolic compounds extracted from the oil by the process or a pro-oxidant metal chelator, these compounds contributing to improve the oxidative stability of the final product. It is thus possible to add vitamin C, in the form of pure ascorbic acid, salt such as ascorbyl ascorbate or ascorbate, citric acid or lactic acid in free form. or ester or lecithins, or a combination thereof. An individual amount of 0.01 to 1% by weight in the mixture will be added, preferably 0.1 to 0.5% by weight in the mixture.

A preferred embodiment is therefore the following:

at least one step a) of mixing and impregnating the solid raw material in dispersible form with the natural fatty substance at a temperature above the melting point of the fatty substance and under an atmosphere that is free or substantially free of oxygen,

at least one step b) of heating the mixture at high temperature for a very short time and in an atmosphere which is free or substantially free of oxygen, using microwaves; at least one step c) of microdifferentiation of the mixture; material for extracting and optionally breaking the cells of the raw material in the natural fatty substance at a temperature above the melting point of the fatty substance and in an atmosphere which is devoid of or substantially free of oxygen, using ultrasound, step c) can be performed before, during or after step b).

In this preferred embodiment, applied to plant material, the raw material is preferably milled at low temperature, for example between -20 and -80 ° C. For example this step can be carried out by freezing between -20 and -30 ° C. and grinding (for example using a knife mill) or by grinding under cryogenic conditions (for example between -70 and -80 ° C.). This material is in powder form.

According to an advantageous characteristic, it is added, as described above, during step c) or just before, a scavenger compound or oxygen reducing agent, a compound for regenerating in reduced form the tocopherols of the oil and the compounds phenolics extracted in the oil by the process or a pro-oxidant metal chelator, these compounds contributing to improve the oxidative stability of the final product. As described above it is possible to add vitamin C, in the form of pure ascorbic acid, salt such as ascorbyl ascorbate or ascorbate, citric acid or lactic acid under free form or ester or lecithins, or a combination of these compounds. An individual amount of 0.01 to 1% by weight in the mixture will be added, preferably 0.1 to 0.5% by weight in the mixture.

The steps a) b) c) are advantageously conducted in the absence of light or any oxidizing radiation such as UV to limit the risk of photo-oxidation and degradation of the photosensitive molecules.

Steps a) b) c) can be carried out with or without stirring the mixture and preferably with stirring.

According to one embodiment, the method consists of a combined sequence of steps a) b) and c), the order of steps b) and c) being indifferent, each step being performed at least once each. According to another embodiment and depending on the material to be extracted and the yield of desired extracted molecules, steps a) b) and c) are carried out several times.

According to a preferred embodiment, steps b) and c) are performed at least a second time; they then correspond to steps bn) and n), n corresponding to the total number of repetition of the cycle {step a) + step b)}, n is at least equal to 2, preferably n is equal to 2.

In one embodiment, a period of passive diffusion of the compounds extracted in the oil and of cooling may be carried out between each step, or after the last step, a period of gentle stirring in a closed system under an atmosphere which is devoid of or essentially free from ‘oxygen.

The duration of this step must be sufficient for a good diffusion of the assets in the oil. This duration may especially be between 1 h and 24 h hours, preferably between 1 h and 12 h.

The cooling can be carried out in any manner known per se, in particular by passive cooling or by means of cooling means. This cooling step is advantageously conducted in a free atmosphere or substantially free of oxygen, as steps a) b) and c). It is advantageously conducted in the absence of light or any oxidizing radiation such as UV.

The raw material of natural origin can be any type of raw material, preferably it is chosen from terrestrial plants, in particular the aerial vegetative parts: leaves, stems, flowers, whole plants, or the roots, tubers, seeds, fruits , cakes, flours and any co-product of plants … microscopic and macroscopic algae; the mushrooms ; lichens; the products of the hive; minerals, rocks, sands., or any mixture of these compounds.

Extraction of Plant Polar Glycerol Lipids

The nonvolatile natural compounds extracted can be any type of non-volatile compounds, in particular lipo-soluble, lipo-extractable or lipodispersible compounds. It may be apolar, polar or amphiphilic molecules, or any mixture of these compounds that may have synergistic actions, especially phenolic compounds (polyphenols type, flavonoids, phenolic acids, catechins, diterpenes, flavones, monophenols, flavonols glycosides ..), vitamins A 1 E 1 C. free or esters, tannins, waxes, fatty acids, essential oils, organic acids, hydrophobic proteins, pigments (carotenoids, xanthophylls, lutein, zeaxanthin, chlorophylls) ..), unsaponifiable compounds (free and esterified phytosterols, fatty alcohols, triterpenes, squalene ..), polar lipids (phospholipids, glycolipids, sphingolipids, etc.) enzymes and coenzymes, trace elements, minerals, organic salts, etc., or any mixture of these compounds.

According to one embodiment of the invention, the ratio between the raw material and the oil in the starting mixture used in step a) is between 1: 0.5 and 1: 10, preferably between 1: 1 and 1: 5 and more preferably between 1: 1 and 1: 3 expressed in mass / mass of oil or mass / volume of oil. The method according to the invention makes it possible to reduce the ratio between the raw material and the oil.

According to one characteristic of the invention, it is advantageous to start from a natural raw material ground at low temperature, for example between -20 and -80 ° C. For example this step can be carried out by freezing between -20 and -30 ° C. 0 C and grinding (for example using a knife mill) or by crushing in cryogenic conditions (for example between -70 and -80 0 C). This step makes it possible to increase the extraction yield synergistically with the action of heat, in particular under the microwaves, and that of the breaking of the cells, in particular by ultrasonic cavitation, by increasing the contact surface between the cells. oil and the product to be extracted.

According to another characteristic of the invention, the solid natural material is provided in the form of a dispersible product obtained by flash-expansion flash instantaneous flashing. This step will make it possible to break the cell membranes, to break up the solid particles and to ensure the dispersion of the resulting particles.

As a finishing, the process may comprise one or more oil clarification step (s). By clarification is meant all the mechanical separations known to those skilled in the art. They may for example be chosen between filtration, decantation, centrifugation, spinning, or a combination of these techniques. The clarification steps make it possible to obtain a product that is at the same time substantially clear to the eye and free of microparticles in suspension. The process according to the invention makes it possible to obtain an oily extract concentrated in active agents which may be in the form of an oily solution, an oily microdispersion, an oily microsilver or an oily microemulsion, which form is stable over time.

The invention is characterized in that it makes it possible simultaneously to obtain a vegetable fatty substance and in particular a vegetable oil with a low oxidation level and a high concentration of extracted active molecules, thanks to the simultaneous implementation of a process conducted under an atmosphere that is free of or substantially free of oxygen, in particular a nitrogen inerting, and a process that uses the synergistic action of a short treatment at high temperature, in particular under microwaves, and microdispersion and optionally rupture of the cells of the product to be extracted, in particular by ultrasonic cavitation.

The low level of oxidation of the oil can be evaluated from the measurement of the peroxide index which evaluates the concentration of hydroperoxides of fatty acids, so-called primary oxidation compounds, which can be formed in the oil in the presence of oxygen. This measurement is carried out according to a recognized and standardized analytical method (NF ISO 3960). The content of extracted compounds can be measured according to different assay methods which depend on the nature of these compounds, for example the content of total phenol compounds can be determined according to the colorimetric method of FoNn Ciocalteau. the mineral content by atomic absorption or plasma torch, the vitamin content by HPLC.

The invention is also characterized in that it makes it possible to obtain an oil enriched with antioxidant compounds among other compounds, which gives it a better oxidation stability during its storage and its uses. It is hereby used by the inventor the known synergistic effect between the antioxidant activity of the natural tocopherols of vegetable oils and that of phenolic compounds and other more or less polar antioxidant molecules extracted from the plant or the material. first natural. In the case of the extraction of antioxidant and / or anti-radical reducing compounds, it is possible to evaluate the total antioxidant capacity of the oily extract obtained by an in vitro method of the ORAC-Oxygen Radical Absorbance Capacity test type. – which is widely used and recognized for evaluate the ability of a plant extract to block the radical oxidative reactions.

The invention also relates to a product in the form of an oily solution, oily microparticle and oily microemulsion obtainable by the implementation of the process according to the invention.

The product obtained by the invention makes it possible to obtain oils containing less than 1% water by weight.

The invention makes it possible to obtain, from a natural raw material, in particular a plant, and using a natural fatty substance, in particular a vegetable oil, an oil or fatty substance which has a controlled oxidation state after application of the process. , a condition which can result in a peroxide number of less than 10 meqθ 2 per kg of product obtained, and which simultaneously has a content of phenolic antioxidant compounds at least 5 to 100 times greater in the product obtained compared to the natural fatty substance used taken as a reference, the concentration factor directly dependent on the raw material to extract.

The product may also comprise free ascorbic acid, salt or ester, free citric or lactic acid or ester or lecithins.

Another subject of the invention is the use of oily extracts, oily solutions, oily microemulsions, oily micro-suspensions and oily micro-dispersions, of 100% vegetable or natural or biological origin, obtained according to the process, in formulations , advantageously formulations in the form of emulsions [aqueous phase + oily phase] or 100% oily phase formulations, for applications in the food, nutritional, cosmetic, pharmaceutical or veterinary field.

The invention thus relates to a food, nutritional, cosmetic, pharmaceutical or veterinary formulation, containing a product according to the invention. The invention relates to a cosmetic formulation including oil, cream, soap, serum, milk, makeup, lotion, shampoo, etc.

The invention and its advantages, in particular in terms of the extraction yield and the absence of oxidative degradation of the oil, will be better understood on reading the following examples which must be considered in a nonlimiting manner and which concern the application from the process to the extraction of phenolic compounds from different plants.