WO1995003380A1

WO1995003380A1 - Process for extracting essential oils from plants through cold maceration and cold deterpenating

Info

Publication number: WO1995003380A1
Application number: PCT/FR1993/000748
Authority: WO
Inventors: Anne Guglielmone
Original assignee: Anne Guglielmone
Priority date: 1993-07-21
Filing date: 1993-07-21
Publication date: 1995-02-02
Also published as: AU4574993A

Abstract

Process for extracting essential oils in a substantially pure state from plants, through cold maceration of different plants in a solvent, whereby the essences are extracted, without prior grinding, concentrated and cold deterpenated, thus ensuring: a better stability of the resulting essential oils; a higher quality of the essential oils; increased cost-efficiency; whereafter the solvent is recovered through settling in a closed environment and the last traces of solvent being eliminated by evaporation. The separation of the terpenes (hydrogen carbides) from the essential oils by means of alcohol is also described, as well as the recovery of said terpenes. The separation of the essence-alcohol mixture through the action of a salt and the recovery of the solution used for separating the terpenes are further described.

Description

Process for the Extraction of Vegetable Essential Oils by Maceration

Cold and Cold Deterpenation

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I - The present invention relates to the extraction process in a substantially pure state of essential oils of plant origin, without their chemical properties being altered by cold maceration of flowers, plants, aromatic plants, herbs, citrus peel, wood, rizhon.es, leaves (from which vegetable fats are obtained | vegetable waxes), all of these plants being used fresh, without prior grinding (when a preliminary grinding is carried out, the impurities contained in the plants are entrained with and in the essence, disturbing the latter and altering its chemical properties). It should be noted that with this cold maceration process, all kinds of plants can be treated, including common plants (example of a common plant: the serpollet | thymus serpyllum |).

II - The method involved in the extraction process - object of the present invention - allows (in addition to extraction) the cold concentration and deterpenation of essential oils (or essences) obtained from plants (plants as defined in title I, lines 4, 5, 12); a solvent is used.

III - You should know that the essences, whether chemically defined under the classification of alcohols, phenols, aldehydes, ether oxides, ketones and that of esters, are all very volatile, very alterable in air, because they do not take long to be resignified (especially essences rich in terpenes) and not very stable, it is very difficult, with known extraction processes, to make a total synthesis of them in an economical way, without degrading their odor principle, which is not the case with the present extraction process which, for its part, retains in its entirety the odor principle of essences in addition to the conservation of their chemical properties.

The present extraction process allows the recovery of the solvent; to do this, a simple decantation operation of the solvent in a closed medium is carried out; then use a rotary vacuum evaporator fitted with a cold trap system allowing the concentration of the solvent (used in this method) having a very low boiling point (35º C); by this system, recovery of almost all of the solvent is possible. The rotary vacuum evaporator fitted with a cold trap also gives the ability to remove the last traces of the solvent. We then get the terpene essence; the evaporation of the last traces of the solvent allows the concentration of the gasoline.

The present extraction process, also, increases the production yield of essences drawn from plants (plants as defined in Title I, lines 4, 5, 12), by more than 25% by weight in more yield than usually obtained with known extraction processes

(percentage of variable increase depending on the plants used and the climatic conditions governing them, in particular the state of the atmosphere in general | example: humidity rate |); the essences are collected rigorously pure after purification.

For example, for 100 kilograms of essence of aurantiaceae (citrus in general) by distillation in a still, we obtain (depending on the fruits collected, the climatic conditions governing them and according to the manufacturers) 5 kilograms of deterpenated essence . The present extraction process allows us to obtain (always depending on the fruit, the climatic conditions) 25% more weight in terms of the terpene species collected.

IV - The present extraction process does not include prior grinding work on plants (plants as defined in title I, lines 4, 5, 12) which would allow the cells to burst. This bursting of the cells begins to occur during cold maceration spontaneously during the use of the solvent and this after approximately 5 to 10 minutes of maceration, without any recourse to a third aid. We then obtain the separation of two distinct liquids:

* one more dense (higher density) constituting the aqueous phase and which can be the object of recovery because this aqueous phase having absorbed some traces of odorous principle can be used for the preparation of toilet waters, or others, to scent of the same nature (example: the aqueous phase of the orange can be added in the manufacture of orange water which reinforces the scent of this water).

* the other less dense (lower density) constituting the organic phase (solvent containing the odorous principle of gasoline).

By the use of this solvent, for the extraction of essential oils, the problem of separation of the organic and aqueous phases no longer arises. Indeed, the two liquids are immediately separated. It should not be forgotten that the first problem of the poor yield of species, during extraction, is due to the presence of water (example for orange / fruit: presence of water = more than 90/5) which tends to mask the odorous principle of the essence and to decrease the power of concentration of the essence. Indeed, the essence is found localized in very specific places of plants, in:

. the epidermal cells of the petals (example: pink)

. secretory hairs (example: mint). internal secretory cells (example: laurel)

. secreting pockets (example: orange zest)

. secretory channels (example: p pin)

V - The present extraction process makes it possible to act, by means of the solvent e) plied, on the fresh vegetables, part of the vegetable dye is absorbed by the solvent, the other part remaining in the essence, the proportions being depending on the nature of the essence: alcohol or aldehyde.

In plants, dyes are generally found in the form of glucosides. The coloring matters of flowers are anthocyanosides.

The color of anthocyanin (anthocyanoside) is a function of the reaction of the cell juice (at its pH). An example is given below for the rose which contains a dye called cyanidine, of structural formula:

isomer of luteolin or tetrahydroxyflavone - 5 - 7 - 3 '- 4', of structural formula:

Cyanidine, a dye containing auxochromes (OH) can be easily absorbed by solvents, which shows us that in some flowers, like the rose which can have different shades varying between red, yellow, pink, the nuances encountered are mainly due to the reaction of the cellular juice contained in the flower depending on the dye (cyanidine), variances involved in the concentration hydronium ions | H ₃ O ⁺ aq | (water absorbed by the plant, reacting with the cells containing the dyes) and the pH. Below, graph relating to the variation of pH as a function of the concentration of hydronium ions

| H ₃ O ⁺ aq | :

The essence of rose keeps part of the dye, essence whose main odorant body is an alcohol (phenylethyl alcohol / primary alcohol of crude formula C ₈ H ₁₀ O, of semi-developed formula:

C ₆ H ₅ - CH ₂ CH ₂ OH and structural formula

alcohol therefore having the free hydroxyl radical and, consequently, having the property of absorbing more color, which is not the case for the essence of lemon whose main odorant body is a diethylene aldehyde (citral, limonal or dimethyl 2 - 6 octanediene 2 - 6 OL - 8 of raw formula C ₁₀ H ₁₆ O of semi-developed formula:

(CH ₃ ) ₂ C = CH - CH ₂ - CH ₂ C (CH ₃ ) = CH - CHO and of formula

developed

The extraction of dyestuffs, thanks to the solvent used in the present extraction method, therefore allows the concentration of these dyestuffs without variation of the pH thereof in the petrol due to an oxidizing action.

VI - The solvent used in the extraction method, object of the present invention, is rectified ethyl ether (diethyl ether or diethyl ether) of crude formula C ₄ H ₁₀ O and of semi-developed formula: C ₂ H ₅ - O - C ₂ H ₅ . Ether used in industry perfumery requires, beforehand, a hot maceration of the plants in this solvent. The ethyl ether we use is used rectified, that is to say to a degree of purity which allows the almost instant burst of the cells of each plant, hence the easy absorption of the fragrant principle of flowers, plants, citrus fruits, etc. (plants as defined in title I, lines n ° 4, 5, 12) with this solvent.

The boiling point of rectified ethyl ether is 35 ° C. This very low boiling point of the extractor solvent, used in the method which is the subject of the present invention, compared to that of gasolines which is more than 100 ° C, allows the last traces of solvent to evaporate without the residual solution (gasoline) reaching the critical temperature causing its decomposition.

The operation of decanting the solvent in a closed medium, then the operation of evaporation of the solvent in order to separate it from the gasoline and the elimination of the last traces of this solvent by means of one rotary vacuum evaporator provided of a cold trap system avoid, on the one hand the distillation, because the ethyl ether is a very volatile body and the distillation leaves it lose, the simple decantation in closed environment, allows to recover the solvent in almost all and, on the other hand, the use of a gaseous stream of carbonic acid to entrain the last traces of the solvent; indeed, oxygen O ₂ | dioxygen: molar mass 32 g mol ^-1 | contained in this gaseous stream of carbonic acid would risk oxidizing the gasoline left as a residue; by evaporation, the essence is left stainless and perfectly concentrated.

Apart from the dye, other impurities are contained in the essence, namely: pectic matters, fats and, more particularly, hydrocarbons (non-oxygenated bodies).

After a period of rest serving to withdraw the materials contained in the gasoline, materials which the gasoline keeps in suspension, one proceeds to the distillation in a vacuum, this being the last precaution in order to eliminate all traces of impurities. Heat being an enemy of organic bodies, it is preferable to have recourse to vacuum distillation; a rigorously pure essence is then obtained after deterpenation. VII - Special attention is paid to terpenes of formula C _x H _y . Aside from the many foreign materials

(see title VI, page 6, lines nº 28, 29, 30) contained in the essence drawn from plants and which give an unpleasant appearance to essential oils, main impurities must be highlighted, namely the terpenes which communicate gasoline has an odor which is not always very fine. These heavy hydrocarbons have no aromatic value, are poorly soluble in diluted alcohol and in water, very exposed to rancidity and therefore unnecessarily clutter the species in which they are found.

Terpenes are contained in species in different proportions. These proportions of terpenes existing in essential oils, are subject to considerable variations; the latter are due, for each harvest or each provenance, to the difference in humidity and lighting conditions, etc. The most common terpenes are of the formula: a) C ₁₀ H ₁₆ and b) C ₁₅ H ₂₄ . Certain essences (bergamot, lavender, geranium, etc.) contain about 40 to 70%; others (lemon, orange, etc.) have more than about 90% of their weight.

Terpenes are characterized by a low boiling point, low density, complete insolubility in diluted alcohol, a weak aroma and a strong tendency to oxidize while resignifying under the influence of light, air and water.

Terpenes have great similarities in smell and taste, so that they cannot be used to determine the character of an essence. This is how we find:

- the | + | pinene with crude formula C ₁₀ H ₁₆ and structural formula:

in the essences of therebentine from America and Australia, camphor, coriander, fennel, star anise, etc. - the | + | limonene with gross formula C ₁₀ H ₁₆ and structural formula

in the essences of bergamot, fennel, in that of the Scots pine of palmarosa.

- the | - | phellandrene of structural formula:

in the species of bay, star anise, pine, etc.

Terpenes are not very aromatic and mask the characteristic aroma of the oxygenated compounds which they dilute; they are essentially oxidizable.

With sparse essences, nothing similar is to be feared. The results are always the same, even several years apart.

One of the great advantages of using deterpened essences is their high solubility in very dilute alcohol. Indeed, terpene essential oils are practically no longer soluble at a certain degree of alcohol concentration (concentration from 20 ° to 70 ° and more) while deterpened essences, they are soluble in all proportions in diluted alcohol , this total solubility of deterpened essences makes it possible to prepare relatively powerful perfumes with low alcoholic degree.

In addition, all the essences gain much in finesse at elimination of hydrogen carbides.

Example: the essence of geranium, even of good quality, will benefit very little from the addition of essence of real rose, the herbaceous smell of geranium will remain predominant. On the contrary, a very small proportion of the same essence of rose, in the essence of deterpenated geranium, will clearly communicate its particular aroma. The essence of Italian neroli has an unpleasant odor, it cannot be mixed with. the essence of neroli from France without diminishing it; but, relaxed, they can be mixed in equal parts, without giving rise to a reduction in finesse of the aroma.

The essence of aspic or large lavender (lavandula spica) deterpenée, is worth the essence of lavender (lavandula officinalis) frequently used in perfumery; the essence of Japanese mint which contains up to 75% menthol, deterpenated, is worth the essence of ordinary American mint.

VIII - The object of the present invention is to obtain essences obtained from plants (plants as defined in title I, lines n ° 4, 5, 12) without heating action and without having to resort to distillation in a still, according to the following procedure:

1st phase - extraction step by cold maceration in a solvent, without prior grinding of the plants (plants as defined in title I, lines n ° 4, 5, 12) to obtain essential oils.

2nd phase - recovery of the solvent by a simple decantation operation of the solvent containing the fragrant principle of the essential oil (separation of the aqueous and organic phases) and elimination of the last traces of solvent by means of a rotary vacuum evaporator with system cold trap; then obtain terpened essences.

3rd phase - cold deterpenation of the essences obtained in alcohol

diluted; recovery of terpenes; separation of the “vegetable essence-diluted alcohol” mixture by stirring this mixture with potassium acetate (very dry).

Recovery of the solution used to extract the terpenes.

Elimination of impurities in general, by vacuum distillation. Obtaining rigorously pure essences; economic yield greater than more than 25% by weight.

It was found, from the comparisons made,

a) - between a standard sample of lemon essential oil of unknown origin, but currently used in the flavor industry,

b) - between a standard sample of lemon essential oil obtained with our cold extraction method,

a retention time ranging from 0.49 min to 1.28 min for lemon essential oil of unknown provenance and a retention time ranging from 0.50 min to 2.68 min for lemon essential oil obtained with our cold extraction method (see Figure 1 (1/8) and Figure 2 (2/8) attached).

Also attached figures 3a (3/8) 3b (4/8) 3c (5/8) and figures 4a (6/8) 4b (7/8) 4c (8/8) relating to the chromatographic study in gas phase (ionization) of lemon essence: a) - from an unknown source

b) - obtained by the cold extraction process

Example of Yield

10 kilograms of ordinary fresh but very good quality lemon peel (citrus limonum), whole or cut into quarters, are macerated cold in the solvent. After 5 to 10 minutes of maceration, the secretive pockets of the lemon peel begin to burst spontaneously. After 2 to 3 hours of maceration, this bursting is complete. Said lemon peels are left in contact with the solvent for a period of 3 to 4 days. At the end of this time, the water contained in the lemon peels falls completely to the bottom of the container, the solvent containing the odorous principle, it floats. When this cold maceration operation comes to an end, a simple decantation operation of the solvent is carried out in a closed environment. The solvent and the gasoline left as residue are then recovered; the last traces of solvent (solvent which tends to impart its odor to petrol) are then removed by evaporation; then the deterpenation is carried out cold, in diluted alcohol, of the essences by agitation. The terpenes do not mix with the diluted alcohol, separate; we can thus recover them. Essences mixing, they, with the diluted alcohol, we proceed to the separation of the alcohol-essence mixture by stirring this mixture with potassium acetate. The potassium acetate dissolves with the diluted alcohol and the essence separates. The solution used to extract the terpenes is recovered. After standing, the impurities contained in the gasoline (secondary impurities) are removed by vacuum distillation. We then obtain the deterpenated lemon essence, i.e. 650 grams of deterpened essence for 10 kilograms of lemon peel and for 1 kilogram of lemon peel: 65 grams of deterpened essence (i.e. 75.41 cm ³ for 65 grams of lemon essence)

The rectified ethyl ether improves the extraction efficiency of the essences because it fulfills the functions of extractor with total exhaustion of the plants.

All the fatty (odorous) principle is removed.

Rectified ethyl ether also has the advantage of stabilizing the progression of terpenes in petrol because these, under the action of heating, increase their development leading to a very rapid rancid effect of petrol.

Claims

1) Process for the extraction, concentration and cold deterpenation of essential oils of plant origin, without prior grinding and without heating the plants, comprising a step of cold maceration in rectified ethyl ether, the latter having on the one hand a high degree of purity (allowing the beginning of the bursting of the cells of each plant after about 5 to 10 minutes of maceration! and, on the other hand, having a very low boiling point of 35 ° C , fulfilling the functions of extractor with total exhaustion of the plants, characterized in that a simple decantation of the solvent is carried out in a closed medium | separation of the aqueous and organic phases |, in that the residual solution is then concentrated using a rotary vacuum evaporator with cold trap system to recover essential oils and to remove the last traces of solvent without using a n gaseous stream of carbonic acid, and in that one then proceeds to the cold deterpenation of the residual solution in the diluted alcohol and to the recovery of terpenes, in that one treats, finally, said solution by adding a very dry potassium acetate to cause separation | separation by agitation | alcohol and essential oils which are then obtained in a strictly pure state after distillation in a vacuum for the elimination of dyes, pectic materials and fats, and in that the "alcohol" mixture is recovered / potassium acetate "and in that it is found that the retention time of the gasoline obtained by this cold extraction process is between 0.50 min and 2.68 min.

2) Method according to claim 1 characterized in that the rectified ethyl ether having a high degree of purity is the extractor solvent in which cold maceration takes place without prior grinding of the plants and without heating the plants and which fills the extractor function with total exhaustion of plants.

3) Method according to one of claims 1 to 2 characterized in that one proceeds to the cold maceration of the plants in rectified ethyl ether which, by its extracting properties, by its very low boiling point | 35 ° C | compared to that of gasolines | which is over 100 ° C | allows the concentration of essential oils and the evaporation of the last traces of solvent without the residual solution reaching the critical temperature causing its decomposition, and in that the significant degree of purity of the rectified ethyl ether, allows the beginning of the bursting of the cells of each plant after approximately 5 to 10 minutes.

4) Method according to claim 1 characterized in that one proceeds to a simple decanting operation of the solvent in a closed environment | separation of the aqueous and organic phases |, and in that the use of a rotary vacuum evaporator with cold trap system causes the last traces of solvent without resorting to a gaseous stream of carbonic acid, which leaves the stainless essential oils left as residue.

5) Method according to claim 1 characterized in that the cold deterpenation of essential oils is carried out in diluted alcohol, these being sparingly soluble in alcohol at a certain degree of concentration of the alcohol, in particular at a concentration of 20 degrees to 70 degrees and more.

6) Method according to one of claims 1 to 5 characterized in that one proceeds to the recovery of terpenes, these being miscible in any proportion in the diluted alcohol.

7) Method according to one of claims 1 to 6, characterized in that the alcoholic solution is treated by an addition of very dry potassium acetate, in that the potassium acetate causes the separation of the essential oil and diluted alcohol after stirring and, in that - following this separation - the "diluted alcohol / potassium acetate" mixture is recovered.

8) Method according to claim 1 characterized in that the retention time of the gasoline obtained by this cold extraction process is between 0.50 min and 2.68 min.

9) Method according to claim 1, characterized by a vacuum distillation in order to remove the various impurities.

10) Application of the method according to one of claims 1 to 9 to the extraction of essential oils contained in plants in general (flowers, roots, leaves, citrus peels, wood peels, plants, aromatic plants, common plants, herbs).