Process for the refinement of essential oils by treatment with nitric and acetic acid

Abstract

The present invention relates to a method for modifying the odor profile of an essential oil or an extract thereof, to an essential oil or extract obtained or obtainable by such a method, to an aroma composition comprising such an essential oil and / or extract, to a perfumed product, preferably pharmaceutical preparation, cosmetic preparation or preparation serving for nutrition or pleasure, comprising such an essential oil and / or extract and to the use of a mixture of acetic acid and nitric acid for modifying the odor profile of an essential oil and / or extract thereof.

Description

[0001] Process for the Refinement of Essential Oils by Treatment with Nitric and Acetic Acid

[0002] The present invention relates to a method for modifying the odor profile of an essential oil or an extract thereof, to an essential oil or extract obtained or obtainable by such a method, to an aroma composition comprising such an essential oil and / or extract, to a perfumed product, preferably pharmaceutical preparation, cosmetic preparation or preparation serv- ing for nutrition or pleasure, comprising such an essential oil and / or extract and to the use of a mixture of acetic acid and nitric acid for modifying the odor profile of an essential oil and / or extract thereof.

[0003] Essential oils are liquids, often hydrophobic liquids, comprising volatile, aromatic substances in concentrated form. Typically, essential oils are obtained from plants as plant extracts, wherein such plant extracts contain the characteristic fragrance of the plant it is derived from.

[0004] However, for obtaining such essential oils, distillation and extraction processes are required. Such processes are often laborious and provide only a limited amount of essential oils. Yields as low as 0.01-0.05% are typical for several flowers such as rose and jasmin but typically do not reach more than 1-5% even for robust plant materials such as vetiver and guaiac. Thus, essential oils are rather expensive and accordingly valuable perfumery ingredients, and early on means have been searched to intensify their odors for price performance or to modify their olfactory profiles for generating inimitable signatures in perfume formulations. When applying essential oils e.g. in perfumes, perfumers have to invest a significant amount of money of a given brief into using essential oils, which shall make an accordingly significant contribution to the signature of the overall composition. However, the olfactory profiles of essential oils have basically been the same since ancient time. Thus, new essential oils do only rarely appear on the market. There is thus a big need for modified essential oils by intensifying one or more odor characteristics of the essential oil, shifting the odor character, and / or by increasing the complexity of its odor profile.

[0005] Furthermore, essential oils often comprise sterically congested terpenes and terpenoids that feature a poor biodegradability. Thus, it is also desired to increase the biodegradability of essential oils, since biodegradable materials are more and more in demand, and since the advantage of using renewable and sustainable perfumery raw materials and the oncost that goes with this, should not be immolated with non-biodegradability. Today 100 / 100 biodegradable and renewable perfumery materials are desired by consumers and clients of perfume houses, whereas having only a sustainable supply is not sufficient.

[0006] Furthermore, essential oils often comprise sterically complex alcohols. However, such alcohols often have a poor biodegradability. It is thus also desired to increase the biodegradability of essential oils.

[0007] One of the oldest and most common modifications to intensify the odor profile and increase its character is by transforming the alcohols contained into esters, most commonly acetates. Thereby, the proton-donorating hydroxy function is exchanged for a proton-acepting carbonyl osmophoric group, in a distance ca. 2.3 A away, which is the distance of the so- called bifunctional unit (G. Ohloff, W. Pickenhagen, P. Kraft, F. Grau, Scent and Chemistry - The Molecular World of Odors, Wiley-VCH, Weinheim, 2022, pp. 94-106), allowing for internal hydrogen bonds. Thus, a stronger binding of the molecule with the odorant receptor is generally achieved and the compounds intensify. Accordingly, vetiver oil which is hydrodistilled from the dried roots of the tufted perennial grass Chrysopogon zizanioides (L.) Roberty, is fractionated by further fine-distillation, and the alcohol fraction thus obtained is acetylated by reaction with, for instance, acetic anhydride. The smelling principle of vetiver oil, 2-ep / -ziza-6(13)-en-3-one, responsible for its characteristic transparent suave and sweet woody-ambery, earthy odor, has only been established in 2021 by total synthesis by P. Kraft, B. List and co-workers (Angew. Chem. Int. Ed. 2021 , 60, 5666-5672), which corroborated an earlier Aroma Extract Dilution Analysis (AEDA) by Belhassen et al. (Chem. Biodivers. 2014, 11, 1821-1842).

[0008] 2-e / -ziza-6(13)-en-3-one norziza-2a-yl acetate ziza-6(13)-en-3a-ol intense vetiver, woody-ambery woody-ambery, vetiver typical vetiver, but th 29 pg / L air, th 4 pg / L air, significantly weaker not biodegradable not biodegradable than 2-e / -ziza-6(13)-en-3-one

[0009] It is a trace constituent only, and only thanks to its extremely low threshold of 29 pg / L air contributes to the overall odor of vetiver oil. 2-ep / -Ziza-6(13)-en-3-one is neither biodegradable nor synthetically accessible from renewable sources, but it does satisfy a vetiver rule postulated in 2008 (P. Kraft, Chem. Biodivers. 2008, 5, 970-999) stating that a vetiver odorant should possess 13-16 carbon atoms and a carbonyl osmophore in a distance 5.0 ± 0.5 A to a carbonyl osmophore as hydrogen-bond acceptor. The smelling principle of the vetiveryl acetate, norziza-2a-yl acetate (L. Tissand, H. Brevard, E. Belhassen, M. Alberola, U. Meierhenrich, J. -J. Filippi, J. Chromatogr. A 2018, 1573, 125-150) with a free rotating acetyl moiety also satisfies the vetiver rule in many conformers with distances of 4.4-4.6 A and possesses an odor threshold as low as 4 pg / L air, and a biotechnological production process for such vetiveryl esters was described in WO2016 / 193208 A1 . If we look at corresponding alcohols, such as ziza-6(13)-en-3alpha-ol, while still somewhat vetiver in smell, they are weaker by several orders of magnitude. So, the acetylation is a means to increase strength and character of the compounds.

[0010] Another such means to increase the strengths and character of terpene alcohols is that of oxidation, which also transforms compounds with hydroxy osmophoric groups to carbonyl osmophores. A prominent such example is the oxidation of a-guaiene to rotundol and of the latter further to rotundone. EP 2402301 A1 teaches such an oxidation of patchouli oil fractions with laccase, which leads to the formation of rotundol by allylic oxidation possessing a peppery, woody, rosy odor (N. Armanino, J. Charpentier, F. Flachsmann, A. Goeke, M. Liniger, P. Kraft, Angew. Chem. Int. Ed. 2020, 59, 16310-16344). The smell of the resulting mixture marketed as captive under the name Akigalawood is, however, determined by the minor amounts of rotundone with a >1000 x lower threshold, which is also formed by further oxidation. Thus, these oxidized sequiterpenoids intensify the odor and change the character of patchouli oil into woody, peppery direction, eliminating campho- raceous aspects. oc-guaiene rotundol rotundone woody, balsamic, peppery, woody, rosy peppery rather weak (1 / ?): th 0.47 ng / l air th 0.0003 ng / l air

[0011] (1S): th 6.26 ng / l air

[0012] Changes in the odor character by oxidation / acetylation are also very characteristic for one of the major alcoholic constituents of vetiver oil, the bicyclic primary alcohol isovalencenol as found by S. Takahashi, Chem. Pharm. Bull. 1968, 16 (12 2447-2450 (doi.org / 10.1248 / cpb.16.2447). Weyerstahl, Marschall, Splittgerber, D. Wolf and H. Sur- burg, (Flavour Fragr. J. 2000, 15, 395-412) ascribed it as key character of the base note, together with vetiselinol and khusimol. The oxidation product (E)-eremophila-1 (10),7(11)- dien-12-al and its corresponding acetate both naturally occur in Haitian vetiver oil as well though in smaller quantities and they possess odors in direction of Iso E Super, the smelling principle of which is arborone. A certain structural similarity might explain this olfactory resemblance.

[0013] (E)-isovalencenol (E)-eremophila-1 (10), (E)-eremophila-1 (10), arborone woody, creamy, 7(11)-dien-12-al 7(11 )-dien-12-yl acetate transparent, woody-ambery, sandalwood, cedar [(E)-isovalencenal] [(E)-isovalencenyl acetatel] th 5 pg / l air (rac) woody-ambery, Iso E Super-like woody-ambery, Iso E Super smelling principle of Iso E The primary object of the present invention is to modify the odor profile of an essential oil and / or extract thereof, preferably while increasing its biodegradability and bioavailability.

[0014] Thus, the primary object of the present invention was to modify the odor profile of an essential oil and / or extract thereof, preferably while increasing its biodegradability. The primary object of the present invention is solved by a method for modifying the odor profile of an essential oil and / or an extract thereof, comprising the steps i) providing one or more essential oil(s) and / or one or more extracts) thereof, wherein the oil(s) or extracts) comprise one or more compounds selected from the group consisting of primary alcohols, secondary alcohols, unsaturated terpenes and terpenoids, ii) providing a mixture of acetic acid and nitric acid, iii) mixing the essential oil(s) and / or extracts) provided in step i) and the mixture provided in step ii) to obtain a reaction mixture, iv) reacting the reaction mixture obtained in step iii) at conditions allowing an oxidation of the, one, two, three or more or all of the one or more primary or secondary alcohols, unsaturated terpenes or unsaturated terpenoids in the essential oil(s) and / or extract(s), and an acetylation of the, one, two, three or more or all of the one or more primary or secondary alcohols, unsaturated terpenes or unsaturated terpenoids in the essential oil(s) and / or extract(s), to obtain a mixture comprising at least one aldehyde or ketone, and at least one acetate, v) optionally: providing a substance allowing the enolization of ketones, preferably providing an acid or a base, preferably a base, preferably wherein the substance (preferably acid or base) is selected from the group consisting of potassium methoxide, potassium hydroxide, sodium hydroxide, potassium tert-butoxide, sodium methoxide, lithium diisopropylamide, sodium bicarbonate (NaHCOs), potassium bicarbonate (KHCO3), potassium carbonate (K2CO3), or mixtures thereof, vi) optionally: mixing the base provided in step v) with the mixture obtained after step iv), vii) optionally: reacting the mixture obtained after step vi) at conditions allowing an partial or complete isomerization of the, one, two, three or more of the ketones in the mixture obtained after step iv), preferably into the thermodynamic favorable isomers and / or allowing a partial or complete saponification of the, one, two, three or more of the acetates in the mixture, preferably to provide a characteristic acetate fingerprint, to obtain a modified essential oil and / or extract comprising the one or more compounds selected from the group consisting of primary alcohols, secondary alcohols, unsaturated terpenes and terpenoids as defined in step i), at least one aldehyde or ketone as defined in step iv) and optionally at least one isomer thereof as defined in step v), and at least one acetate as defined in step iv).

[0015] It was surprisingly found that the oxidation and the acetylation with acetic acid and nitric acid enriched characteristic aromatic compounds in the obtained product. The use of acetic acid, particularly the combination with nitric acid, was not known to provide such characteristic aromatic compounds, particularly by its specific oxidation potential.

[0016] Furthermore, it was found that the combination of the oxidation and the acetylation with an optional isomerization in the method according to the invention led to the formation of further characteristic odoriferous compounds in the obtained product.

[0017] For the oxidation, we found that a mixture of (preferably glacial) acetic acid and nitrous acid has ideal properties, also in being close to food-grade ingredients. It was further found that the formed ketones isomerize by enolate formation in the a-posi- tion, and acetates that are inadvertently formed in the oxidation reaction with nitrous and acetic acid are again saponifier. These acetates in result thus may act here also as protection group of the free alcohols not reacted in the oxidation. A specific change in the composition of especially the fragrant alcohols is observed, which while generally sensorially preferred, is however optional.

[0018] Biodegradation is an oxidative process, and partial oxidation of the substrate does introduce additional biodegradation anchor groups for further oxidation. In addition, acetate functions can act as leaving groups in eliminations, and the resulting unsaturated materials are more prone to further oxidative processes. So, both transformations, acylation and oxidation, aid biodegradation.

[0019] Several essential oils were processed with a method according to the invention and were tested by sensorial evaluation with a fascinating result.

[0020] The term “unsaturated terpenes and terpenoids” includes unsaturated terpenes and unsaturated terpenoids. Preferably, the term further includes unsaturated nor-terpenes. Particularly preferably, the number of carbon atoms in the terpenes and / or terpenoids and / or nor-terpenes is in a range of from 5 to 20, preferably 10 to 17 carbon atoms, particularly preferably 13 to 15 carbon atoms.

[0021] The term “mixture of acetic acid and nitric acid” refers to a mixture comprising or consisting of acetic acid (preferably glacial acetic acid) and nitric acid (preferably concentrated nitric acid). Preferably, the molar ratio of acetic acid to nitric acid in said mixture is in a range of from 1 :1 to 100:1 , particularly preferably in a range of from 10:1 to 3:1 , preferably with acetic acid being in excess.

[0022] Preferably, the amount of acetic acid in the reaction mixture obtained in step iii) of the method according to the invention is in a range of from 10 to 90 wt.-%, particularly preferably in a range of from 60 to 80 wt.-%, based on the total weight of the reaction mixture. Preferably, the amount of the acetic acid in the reaction mixture can be determined by measuring the weight of the acetic acid provided in step i) and by measuring the weight of the provided further components, which are then mixed to obtain the reaction mixture in step iii). Preferably, the amount of nitric acid in the reaction mixture obtained in step iii) of the method according to the invention is in a range of from 1 to 30 wt.-%, particularly preferably in a range of from 10 to 20 wt.-%, based on the total weight of the reaction mixture. Preferably, the amount of the nitric acid in the reaction mixture can be determined by measuring the weight of the nitric acid provided in step i) and by measuring the weight of the provided further components, which are then mixed to obtain the reaction mixture in step iii).

[0023] Preferably, the amount of the essential oil(s) and / or extracts thereof in the reaction mixture obtained in step iii) of the method according to the invention is in a range of from 5 to 95 wt.-%, particularly preferably in a range of from 10 to 60 wt.-%, based on the total weight of the reaction mixture. Preferably, the amount of the essential oil(s) and / or extracts thereof in the reaction mixture can be determined by measuring the weight of the essential oil(s) and / or extracts thereof provided in step i) and by measuring the weight of the provided further components, which are then mixed to obtain the reaction mixture in step iii).

[0024] Preferably the term “conditions allowing an oxidation and an acetylation to obtain a mixture comprising at least one aldehyde or ketone, and at least one acetate” is to be understood such that the obtained mixture comprises one or more aldehyde(s) and / or one or more ketone(s), as well as one or more acetate(s). Preferably, the, one or more or all aldehyde(s) and / or ketone(s) and / or acetate(s) may already be present in one or more of the components before the reaction in step iv). In this case, the term is understood such that the amount of this / these aldehyde(s) and / or ketone(s) and / or acetate(s) is / are increased by the oxidation and / or acetylation in step iv). Preferably, the, one or more or all aldehyde(s) and / or ketone(s) and / or acetate(s) has not been present in one or more of the components before the reaction in step iv). In this case, the term is understood such that this I these aldehyde(s) and / or ketone(s) and / or acetate(s) is / are produced by the oxidation and / or acetylation in step iv).

[0025] The presence of compounds in a component or mixture, as described herein above and below, can be determined by methods known to a skilled person, for example by mass spectrometry.

[0026] Preferably, the amount of the substance, preferably acid or base, preferably base, which is provided in step v), in the mixture obtained after step vi) is selected such that the mixture obtained after step vi), which includes the substance, preferably acid or base, preferably a base that has a conjugate acid with a pKaof the proton a to a carbonyl or equivalent electron-withdrawing function which is in the range of from 19 to 25, typically depending on the number of substituents. Accordingly, a pH >10, preferably a pH >12 is generally advantageous.

[0027] Advantageously, an addition of base in step v) also neutralizes non-reacted acetic acid, which may still be present in the mixture.

[0028] Preferably the term “conditions allowing an isomerization and / or a saponification to obtain a modified essential oil and / or extract” comprising the compounds as defined in step vii) of the method according to the invention is to be understood such that the essential oil and / or extract obtained after step vii) comprises these compounds.

[0029] Preferably, the, one or more or all compound(s) selected from the group consisting of primary alcohols, secondary alcohols, unsaturated terpenes, and unsaturated terpenoids as defined in step i), may already be present in the mixture obtained after step vi). In this case, the term is understood such that the amount of this / these compound(s) is / are increased by the isomerization and / or a saponification in step vii).

[0030] Preferably, the, one or more or all compound(s) selected from the group consisting of primary alcohols, secondary alcohols, unsaturated terpenes, and unsaturated terpenoids as defined in step i), has I have not been present in the mixture obtained after step vi). In this case, the term is understood such that this I these compound(s) is / are produced by the isomerization and / or a saponification in step vii).

[0031] Preferably, the, one or more or all isomer(s) as defined in step vii), may already be present in the mixture obtained after step vi). In this case, the term is understood such that the amount of this I these isomer(s) is / are increased by the isomerization in step vii).

[0032] Preferably, the, one or more or all isomer(s) as defined in step vii), has I have not been present in the mixture obtained after step vi). In this case, the term is understood such that this / these isomer(s) is / are produced by the isomerization in step vii).

[0033] It is preferred in the method according to the invention that in step i) one or more extracts) is / are provided and that the, one, two, three or more or all extract(s) provided in step i) is / are plant extract(s), preferably wherein the, one, two, three or more or all plant extract(s) is / are selected from the group consisting of extracts of blossoms, stems, leaves, fruits, fruit peels, roots, needles, branches and mixtures thereof.

[0034] The term “mixtures thereof’ preferably refers to a mixture of two or more of such extracts, e.g. a mixture of a blossom extract and a fruit extract. Preferably, the term “extracts of’ refers to extracts obtained from a material as described herein, wherein the extract may or may not include further components.

[0035] The method may further comprise a step viii), in which the obtained mixture is purified to remove undesired components from the obtained mixture, such as acetic acid, nitric acid, the base, and / or a reaction product thereof. Such a method may comprise or consist of one or both of washing and distillation.

[0036] Preferably, the, one, two, three or more or all essential oil(s) provided in step i) refers to oils obtained per steam distillation, hydrodistillation, and / or pressing peel, and / or to reworked essential oils such as rectified-, colour reduced-, furocoumarine reduced-, terpene fractions-, deterpened fraction-, allergen reduced-, allergen free-oils.

[0037] Preferably, the, one, two, three or more or all extract(s) provided in step i) refers to extracts) obtained by solvent extraction of a natural raw material. Preferably such extract(s) refer to concretes, absolutes, resinoides, tinctures, CO2 extracts, and / or rectified or re-ex- tracted versions thereof.

[0038] It is preferred in the method according to the invention that the, one, two, three or more or all essential oil(s) provided in step i) is / are selected from the group consisting of basil oil, caraway oil, carrot seed oil, celery seed oil, clary sage oil, dill weed oil, dill seed oil, estragon oil, fennel oil, galbanum oil, hyssop oil, marjoram oil, parsley seed oil, parsley leaf oil, star anise oil, star anise, teatree oil, cabreuva oil, geranium oil, ho leaf oil, jasmin, lavender oil, lavandin oil, magnolia flower oil, magnolia leaf oil, neroli oil, orange flower oil, orris butter, palmarosa oil, petit grain mandarine oil, petit grain orange oil, petit grain orange bitter oil, rose oil, rosewood oil, rosewood leaf oil, shiu oil, tagetes oil, ylang ylang oil, buchu leaf oil, carrot oil, davana oil, alpinia oil, bay oil, black pepper oil, cardamom oil, cascarilla oil, cassia oil, cinnamon leaf oil, cinnamon bark oil, coriander leaf oil, coriander seed oil, cumin oil, cumin seed oil, ginger oil, gingergrass oil, green pepper oil, longoza oil, lovage leaf oil, lovage root oil, mace oil, nutmeg oil, perilla oil, pimento berry oil, pink pepper oil, pink pep- per berries (Schinus molle L.) oil white pepper oil, schinus mole oil, turmeric oil, litsea cubeba oil, myrrh oil, olibanum oil, opoponax oil, peru balsam oil, styrax oil, tolu balsam oil, bergamote oil, cedrat oil, citronella oil, eucalyptus citriodora oil, grapefruit oil, lemon oil, lemongrass oil, litsea cubeba oil, lime oil, mandarin oil, orange oil, orange bitter oil, petit grain lemon oil, tangerine oil, allspices oil, artemisia oil, balsamite oil, calamus oil, catnip oil, cedar leaf oil, chamomile oil blue, chamomile oil roman, clove bud oil, clove leaf oil, clove stem oil, cornmint oil, cypress oil, elemi oil, eucalyptus oil, fir needle oil, fusel oil, helichrysum oil, hop oil, juniper berry oil, laurel leaf oil, mentha arvensis oil, mentha pip- perita oil, myrtle oil, oregano oil, pennyroyal oil, pimento leaf oil, pine needle oil, punida oil, rosemary oil, rosemary extact, sage oil, spearmint oil, spruce oil thyme oil, Wintergreen oil, wormwood oil, agarwood oil, amyris oil, boya oil, cedar-wood oil atlas, cedarwood oil china, cedarwood oil texas, cedarwood oil Virginia, copaiba oil, copaiba balm oil, cypriol oil, gaharu buaya oil, guaiac oil, gurjun balsam oil, nootka tree oil, patchouli oil, sandalwood oil, vetiver oil, cistus oil, ambrette seed oil, and mixtures thereof. The term “mixtures thereof’ preferably refers to a mixture of two or more of such oils, e.g. a mixture of vetiver oil and patchouli oil.

[0039] Additionally or alternatively, it is preferred in the method according to the invention that the, one, two, three or more or all extracts) provided in step i) is / are selected from the group consisting of basil extract, caraway extract, carrot seed extract, celery seed extract, celery extract, clary sage extract, estragon extract, flouve extract, galbanum extract, heather extract, hay extract, immortelle extract, lentisque extract, lin seed extract, mate extract, star anise extract, tobacco extract, violet leaf extract, wheat bran extract, broom extract, carnation extract, cassie extract, genet extract, geranium extract, hyacinthe extract, jasmin sambac extract, jasmin extract, jonquille extract, lavender extract, la- vandin extract, mimosa extract, narcisse extract, orange flower extract, orange leaf extract, orris extract, osmanthus extract, rose extract, tagetes extract, tuberose extract, ylang ylang extract, apple extract, beeswax extract, black currant bud extract, bran extract, buchu extract, black pepper extract, cardamom extract, fenugrec seed extract, ginger extract, nutmeg extract, pink pepper extract, schinus mole extract, sichuan pepper extract, tonka bean extract, turmeric extract, benzoin extract, myrrh extract, olibanum extract, opoponax extract, styrax extract, tolu balsam extract, vanilla extract, orange extract, clove bud extract, elemi extract, eucalyptus extract, fir balsam extract, gentiane extract, laurel leaf extract, mentha piperita extract, pine needle extract, thyme extract, castoreum extract, civet extract, moss a extract, moss c extract, patchouli extract, cistus extract, labdanum extract, ambrette seed extract, and mixtures thereof. It is further preferred in the method according to the invention that the, one, two, three or more or all essential oil(s) and / or extract(s) provided in step i) comprises a compound selected from ziza-6(13)-en-3-ol, khusimol, a-guaiene, rotundol, isovalencenol, p-caryo- phyllene, valencenol, 2-phenylethyl alcohol, geraniol and myrcene.

[0040] Ziza-6(13)-enol (preferably CAS-No. 28102-79-6) has been described as providing a weak woody, vetiver, and grapefruit aroma.

[0041] Khusimol (preferably CAS-No. 16223-63-5) has been described as a major component in essential oils such as vetiver oil, as well as in extracts thereof. a-Guaiene (preferably CAS-No. 3691-12-1) has been described as a major component in essential oils such as guaiac wood oil, as well as in extracts thereof. It has been described as providing a sweet, woody, balsam, peppery aroma.

[0042] Rotundol has been described as providing a pepper, woody, and rose aroma. Preferably, the term “Rotundol” refers to (1 R)-Rotundol and / or (1 S)-Rotundol. Isovalencenol has been described as providing a woody, creamy, sandalwood, and cedarwood scent. p-Caryophyllene has been described as providing a sweet, woody, spice, clove and dry smell.

[0043] 2-Phenylethyl alcohol has been described as providing a mild, warm floral rose scent with aspects of hyacinth.

[0044] Geraniol has been described as providing a fine sweet-floral rose scent with bready and sightly fruity facets.

[0045] Myrcene (preferably CAS-No. 123-35-3) has been described as providing a refreshing citrusy warm-balsamic resinous scent with fruity aspects recalling green mango.

[0046] Further preferably in the method according to the invention, the oxidation in step iv) provides one or more compounds selected from zizaenone, isovalencenal and rotundone ziza-6(13)-enone isovalencenal rotundone

[0047] Zizaenone has been described as providing a woody, amber, vetiver, and rooty scent.

[0048] Isovalencenal has been described as providing a woody, amber, and Iso E super-like smell.

[0049] Rotundone (preferably CAS-No. 18374-76-0) has been described as providing astrong intense peppery aroma.

[0050] Additionally or alternatively, it is preferred in the method according to the invention that the acetylation in step iv) provides one or more compounds selected from isovalencenyl acetate, guaiyl acetate, caryophyllene acetate, or myrcenyl acetate. isovalencenyl acetate a-guaiyl acetate p-caryophyllene acetate myrcenyl acetate

[0051] Isovalencenyl acetate has been described as providing a warm woody-ambery scent.

[0052] Guaiyl acetate (preferably CAS-No. 134-28-1) has been described as providing a tea, rose, woody, spicy, green, and somewhat fatty smell.

[0053] Caryophyllene acetate (preferably CAS-No. 57082-24-3) has been described as providing a woody, dry, earthy, amber, fruity, and spicy aroma.

[0054] Myrcenyl acetate (preferably CAS-No. 1118-39-4) has been described as providing a citrusy, bergamot, lavender, woody-floral, scent with spicy aspects in direction of nutmeg.

[0055] It is further preferred in the method according to the invention that modifying the odor profile refers to increasing the complexity of the odor profile and / or increasing the intensity of one or more odors, preferably selected from tea, rose, woody, spicy, green, fatty, pepper, dry, earthy, amber, fruity, flowery, vetiver, rooty, creamy, santal, and cedary.

[0056] Typically, a modification of an odor profile, such as increasing the complexity and / or increasing the intensity of an odor, may be determined by sensorial evaluation with a panel, preferably by a panel of trained perfumers skilled in the art of compounding.

[0057] Furthermore, it is preferred in the method according to the invention that the conditions allowing an oxidation and / or an acetylation as in step iv) of the method according to the invention include a) a reaction temperature in the range of from 0 to 80 °C, and / or b) a reaction time in the range of from 1 to 6 h, and / or c) stirring at a speed in the range of from 50 to 1200 rpm. Furthermore, it is preferred in the method according to the invention that the conditions allowing an isomerization and / or allowing a saponification as in step vii) of the method according to the invention include a) a reaction temperature in the range of from 10 to 50 °C, and / or b) a reaction time in the range of from 1 to 3 h, and / or c) stirring at a speed in the range of from 100 to 700 rpm.

[0058] It is particularly advantageous of the method according to the invention that the compound epi-zizaenone, which has been identified as the or one of the main aromatic substances for providing a vetiver scent, can be produced or enriched in an essential oil or extract thereof. In the prior art, ep / -zizaenone can only be produced via laborious, 11-step total synthetic process, which is far too complex and expensive to be applied on an industrial scale as it competes with natural vetiver oil. However, with the method according to the invention, the same compound can be produced or enriched in a sensorially significant, consumer-noticeable manner.

[0059] It is thus preferred that in step i) one or more essential oil(s) and / or extracts) comprising zizanol is / are provided, preferably wherein the or one essential oil is vetiver oil and / or wherein the or one extract is an extract of vetiver oil, wherein the oxidation in step iv) provides ziza-6(13)-en-3-one, and wherein the isomerization in step vii) provides 2-ep / -ziza-6(13)-en-3-one, one ep / -Zizaenone has been described as providing an intense vetiver aroma. Thus, the modified essential oil(s) and / or extracts) preferably comprise(s) 2-epi- ziza- 6(13)-en-3-one. Preferably, the modified essential oil(s) and / or extract(s) comprised) a mixture of ziza-6(13)-enol, ziza-6(13)-enone and 2-ep / -ziza-6(13)-enone.

[0060] It is further advantageous of the method according to the invention that the compounds rotundol and rotundone can be enriched in an essential oil and / or extract thereof.

[0061] It is thus preferred that in step i) one or more essential oil(s) and / or extracts) comprising a-guaiene is / are provided, preferably wherein the or one oil is patchouli oil and / or wherein the or one extract is an extract of patchouli oil, wherein the oxidation in step iv) provides rotundol and / or rotundone.

[0062] Thus, the modified essential oil(s) and / or extract(s) preferably comprise(s) a mixture of a- guaiene as well as rotundol and / or rotundone.

[0063] Depending on the amount and concentration of oxidizing agent(s), such as nitric acid, in the reaction in step iv), the ratio of rotundol to rotundone can be modified. In case of a higher amount and concentration of oxidizing agent(s), a higher proportion of rotundone is obtained.

[0064] It is further advantageous of the method according to the invention that the compounds isovalencenal and isovalencenyl acetate can be produced or enriched in a characteristic way in an essential oil and / or extract thereof.

[0065] It is thus preferred that in step i) one or more essential oil(s) and / or extracts) comprising isovalencenol is / are provided, preferably wherein the or one oil is vetiver oil and / or wherein the or one extract is an extract of vetiver oil, and wherein the oxidation in step iv) provides isovalencenal, and / or wherein the acetylation in step iv) provides isovalencenyl acetate.

[0066] Thus, the modified essential oil(s) and / or extracts) preferably comprise(s) a mixture of isovalencenol as well as isovalencenal and / or isovalencenyl. The present invention further relates to an essential oil or extract obtained or obtainable by a method according to the invention. The modified essential oil or extract according to the present invention mainly corresponds to the original essential oil or extract. However, several compounds, which have a characteristic fragrance, are now present or increased in the obtained essential oil or extract. The modified essential oil or extract thus provides a more pleasant, i.e. a more intense and / or a more complex fragrance. At the same time the amount of further components, such as undesired side-products, remaining solvents or remaining catalysts is reduced or such components are even avoided.

[0067] Furthermore, the present invention relates to an aroma composition comprising a modified essential oil and / or extract according to the present invention.

[0068] Preferably, the amount of the essential oil and / or extract according to the invention in the aroma composition is in a range of from 30 to 99 wt.-%, preferably in a range of from 40 to 95 wt.-%, particularly preferably in a range of from 50 to 90 wt.-%, based on the total weight of the aroma composition.

[0069] The present invention further relates to a perfumed product, preferably a pharmaceutical, cosmetic preparation or preparation serving for nutrition or pleasure comprising a modified essential oil and / or extract according to the invention or an aroma composition according to the invention.

[0070] Preferably, the amount of the essential oil and / or extract according to the invention in the is in a range of from 0.01 to 10 wt.-%, preferably in a range of from 0.05 to 7.5 wt.-%, further preferably in a range of from 0.1 to 5 wt.-%, particularly preferably in a range of from 0.5 to 2.5 wt.-%, based on the total weight of the product.

[0071] Preferably, a perfumed product is selected from the group consisting of washing and cleaning agents, hygiene or care products, preferably in the field of body and hair care, cosmetics and home care, preferably selected from the group consisting of perfume extracts, perfumes, eau de toilettes, aftershaves, eau de colognes, pre-shave-products, splash-colognes, perfumed refreshing tissues, acid, alkaline or neutral cleaning agents, textile refreshing agents, ironing aids, liquid washing agents, washing agents in powder form, laundry pre-treatment agents, fabric softeners, laundry soap, laundry tablets, disinfectants, surface disinfectants, air refreshers, aerosols, waxes and polishes, body care agents, hand creams and lotions, shower gels, foot creams and lotions, depilatory creams and lotions, aftershave creams and lotions, tanning creams and lotions, hair-care products, shampoos, deodorants, anti-perspirants, products of decorative cosmetics, candles, lamp oils, joss sticks, insecticides, repellents and propellants.

[0072] Preferably, pharmaceutical preparations according to the invention are in the form of capsules, tablets (uncoated and coated tablets, for example having coatings resistant to gastric juices), sugar-coated tablets, granules, pellets, mixtures of solids, dispersions in liquid phases, as emulsions, as powders, as solutions, as pastes or as other swallowable or chewable preparations and are preferably used as medicines only available by prescription, from pharmacies or other medicines or as food supplements.

[0073] Cosmetic preparations, as described herein, are in particular preparations, which are suitable for topical application to the skin of a human, in particular to achieve a cosmetic effect.

[0074] Cosmetic preparations or pharmaceutical preparations, as described herein, may further comprise one, two, three or more or all substances selected from the group consisting of odoriferous substances, perfume oils, fatty oils, fatty acids, ceramides, pseudoceramides, sterols, hydrocarbons phytosterols, anti-acne active ingredients, antidandruff active ingredients, antimicrobial active ingredients, preservatives, antiperspirants, anti-irritants, pruritus-relieving active ingredients, cooling active ingredients, antiaging active ingredients, skin-lightening and skin-tanning active ingredients, skin moisture regulators, osmolytes, insect repellents, enzyme inhibitors, odor absorbers, dyes, abrasives, anti-acne agents, anticellulitis agents, antidandruff agents, anti-inflammatory agents, irritation-preventing agents, irritation-inhibiting agents, antioxidants, astringents, perspiration-inhibiting agents, antiseptic agents, ant-statics, binders, buffers, carrier materials, chelating agents, cell stimulants, cleansing agents, care agents, depilatory agents, surface-active substances, deodorizing agents, antiperspirants, softeners, emulsifiers, enzymes, fibres, film-forming agents, fixatives, foam-forming agents, foam stabilizers, substances for preventing foaming, foam boosters, gelling agents, gel-forming agents, hair care agents, hair-setting agents, hairstraightening agents, moisture-donating agents, moisturizing substances, moisture-retaining substances, bleaching agents, strengthening agents, stain-removing agents, optically brightening agents, impregnating agents, dirtrepellent agents, friction-reducing agents, lubricants, moisturizing creams, ointments, opacifying agents, plasticizing agents, covering agents, polish, gloss agents, polymers, powders, proteins, re-oiling agents, abrading agents, silicones, skin-soothing agents, skin-cleansing agents, skin care agents, skin-healing agents, skin-lightening agents, skin-protecting agents, skin-softening agents, hair promotion agents, cooling agents, skin-cooling agents, warming agents, skin-warming agents, stabilizers, UV-absorbing agents, UV filters, detergents, fabric conditioning agents, suspending agents, skin-tanning agents, thickeners, vitamins, oils, waxes, fats, phospholipids, saturated fatty acids, mono- or polyunsaturated fatty acids, a-hydroxy acids, polyhydroxyfatty acids, liquefiers, dyestuffs, colour-protecting agents, pigments, anticorrosives, aromas, flavouring substances, odoriferous substances, polyols, surfactants, electrolytes, organic solvents, and silicone derivatives.

[0075] Preferably, a composition serving for food or pleasure, as described herein, may be selected from the group consisting of (reduced-calorie) baked goods (e.g. bread, dry biscuits, cakes, other baked articles), confectionery (e.g. muesli bar products, chocolates, chocolate bars, other products in bar form, fruit gums, dragees, hard and soft caramels, chewing gum), non-alcoholic drinks (e.g. cocoa, coffee, green tea, black tea, (green, black) tea drinks enriched with (green, black) tea extracts, rooibos tea, other herbal teas, fruit-containing soft drinks, isotonic drinks, refreshing drinks, nectars, fruit and vegetable juices, fruit or vegetable juice preparations), instant drinks (e.g. instant cocoa drinks, instant tea drinks, instant coffee drinks), meat products (e.g. ham, fresh sausage or raw sausage preparations, spiced or marinated fresh or salt meat products), eggs or egg products (dried egg, egg white, egg yolk), cereal products (e.g. breakfast cereals, muesli bars, precooked ready- to-eat rice products), dairy products (e.g. full-fat or reduced-fat or fat-free milk drinks, rice pudding, yoghurt, kefir, cream cheese, soft cheese, hard cheese, dried milk powder, whey, butter, buttermilk, ice-cream, partially or completely hydrolysed milk-protein-containing products), products made from soy protein or other soybean fractions (e.g. soy milk and products produced therefrom, drinks containing isolated or enzymatically treated soy protein, drinks containing soy flour, preparations containing soy lecithin, fermented products such as tofu or tempeh or products produced therefrom and mixtures with fruit preparations and optionally flavours), dairy-like preparations (milk-type, yoghurt-type, dessert-type, ice cream) from protein rich plant materials (e.g. from seed materials of oat, almond, pea, lupine, lentils, faba beans, chickpea, rice, canola), plant protein-enriched non-dairy drinks, fruit preparations (e .g. jams, sorbets, fruit sauces, fruit fillings), vegetable preparations (e.g. ketchup, sauces, dried vegetables, frozen vegetables, precooked vegetables, boiled- down vegetables), snacks (e.g. baked or fried potato crisps or potato dough products, maize- or groundnut-based extrudates), fat- and oil-based products or emulsions thereof (e.g. mayonnaise, remoulade, dressings, in each case full-fat or reduced-fat), other readymade dishes and soups (e.g. dried soups, instant soups, precooked soups), spices, spice mixtures and in particular seasonings which are used, for example, in the snacks field, sweetener preparations, tablets or sachets, other preparations for sweetening or whitening drinks. Preferably, the composition according to the invention may be selected from the group consisting of toothpastes, toothpastes, tooth gels, mouthwashes, mouth rinses, liquids for gargling, oral or pharyngeal sprays (pump or aerosol spray), lozenges, lozenges, candies, chewing gums, chewy candies and dental care chewing gums. The present invention further relates to the use of a mixture of acetic acid and nitric acid for modifying the odor profile of an essential oil and / or extract thereof, preferably in a method according to the invention.

[0076] What was said above with regard to the method according to the invention, the modified essential oil or extract according to the invention, the aroma composition according to the invention or the perfumed product according to the invention applies accordingly to the use according to the invention.

[0077] Further aspects and advantages of the invention result from the subsequent description of preferred examples.

[0078] Examples

[0079] Example 1 : Modifying an essential oil

[0080] Example 1.1 : Lavender oil

[0081] 100.0 g of lavender oil and 40.0 g (666 mmol) glacial acetic acid were provided in a 1 literstirring apparatus with magnetic stirrer and dropping funnel. With stirring, 43.3 g (687 mmol) concentrated nitric acid and 86.6 g (1 .441 mol) glacial acetic acid were added dropwise with stirring into the mixture within a period of 1 h, which led to a slightly exothermic reaction. The temperature was maintained in the range of 25 to 30 °C by exterior cooling with an ice-water bath. Stirring of the reaction mixture was continued for 2 h at room temperature, prior to diluting with 50 ml methyl te / Y-butyl ether and 50 ml water. Subsequently, 40.0 g 377 mmol) of sodium carbonate was added in small portions with vigorous stirring under formation of CO2. After the gas formation ceased, the mixture was stirred a further 0.5 h at room temperature. Then the layers were separated (pH of the aqueous layer at pH 5-6), the organic layer was washed (50 ml 20% aq. soda solution to pH 5-6), followed by 50 ml 20% aq. soda solution (pH 8-9), followed by 50 ml 20% aq. soda solution (to pH 10), followed by 50 ml of water (to pH 7-8)) and concentrated on a rotary evaporator at 60 °C and 500 5 mbar. The yield was 90.0 g of crude oil.

[0082] The resulting product was divided into two parts and one part (40.0 g) was subsequently distilled in a Kugelrohr apparatus attemperature60-155 °C at a 0.9 mbar pressure for 45 min to afford32.0 g of distillate for direct evaluation.

[0083] The remaining 50.0 g of the product obtained above were placed in a 500 ml flask equipped with magnetic stirrer, water bath and reflux condenser and dissolved in a solvent mixture of 80.0 g methanol and 40.0 g water with 53.0 g (0.424 mol) 32% sodium hydroxide. After heating with reflux for 4 h (bath: 85 °C), the reaction mixture was allowed to cool to room temperature and most of the methanol was removed in a rotary evaporator at 60 °C at 400 200 mbar. The resulting residue was taken up with stirring in 80 ml water and 100 ml methyl te / Y-butyl ether and the resulting mixture was at 5-15 °C subsequently acidified with 115 g 20% sulfuric acid (pH 1). Then the layers were separated, and the organic one was washed (50 ml of 5% brine (pH 1), followed by 50 ml of 5% aq. sodium bicarbonate solution (pH 6-7), then 50 ml of 5% aq. sodium bicarbonate solution (pH 8-9), and finally 50 ml of 5% brine (pH 8-9)). The solvents were removed in a rotary evaporator at 60 °C and 10 mbar to afford 40.0 g of crude material, which was purified by Kugelrohr distillation at 60-160 °C and 0.9 mbar pressure, to furnish after 60 min. 31.0 g of the modified lavender oil.

[0084] Example 1.2: Patchouli oil

[0085] 100.0 g of patchouli oil and 40.0 g (666 mmol) of glacial acetic acid were placed in a 500 ml reaction flask equipped with magnetic stirrer and a dropping funnel. With stirring, 43.3 g (687 mmol) of cone, nitric acid and 86.6 g (1 .441 mol) of glacial acetic acid were added dropwise into the reaction flask within 1 h, upon which a slightly exothermic reaction was observed. By occasional cooling in an ice-water bath, the reaction temperature was maintained at 25-30 °C. After complete addition, the mixture was stirred for 2 h at room temperature. The mixture was then diluted with 50 ml methyl te / Y-butyl ether und 50 ml of water and subsequently 40.0 g (0.377 mol) of sodium carbonate was added portion wise with vigorous stirring under formation of CO2. The mixture was then allowed to stir at room temperature until no further gas evolved, and the layers were separated. The obtained phases were separated (aqueous phase pH 5-6), the organic phase was washed (first: 50 ml 20% soda-solution (pH 9), second: 50 ml 20% soda-solution (pH 11), third: 50 ml 10% sodium chloride solution (pH 7-8)). The organic layer was dried with sodium sulphate, filtered and concentrated in a rotary evaporator at 60 °C and 500 5 mbar, to provide 103.9 g of crude product, 53.5 g of which was purified by Kugelrohr distillation at 160 °C / 1.0 mbar pressure to afford 49.9 g of oxidatively modified essential oil.

[0086] 50.0 g of the remaining crude product as obtained above were placed in a 500-ml reaction vessel equipped with magnetic stirring bar, water bath and reflux condenser. The80.0 g of methanol, 40.0 g of water and 52.5 g (424 mmol) of 32% sodium hydroxide were added with stirring within 30 min. The mixture is refluxed for 4 h (bath temperature: 85 °C). The reaction mixture was allowed to cool to room temperature and 50 ml of water and 100 ml of methyl te / Y-butyl ether were added with stirring. Subsequently, the mixture was acidified by addition of 10% sulfuric acid (pH 1) and the resulting layers were separated. The aqueous layer was extracted twice with 100 ml MtBE (Methyl-te / Y-butylether) each, and the combined organic extracts were washed (first: 100 ml water, then: 100 ml concentrated sodium bicarbonate solution, followed by: 100 ml of concentrated sodium bicarbonate solution, and finally: 100 ml water (pH 7-8)). The resulting organic extract was dried with sodium sulphate, filtered and concentrated to dryness at the rotary evaporator at 60 °C and 5 mbar to furnish 48.9 g of crude product. The crude product obtained was subsequently purified by Kugelrohr distillation: (48.7 g crude product, temperature: 160 °C, pressure: 1.0 mbar), to afford 45.7 g of the modified essential oil as final product.

[0087] Example 2: Vetiver oil Vetiver oil was provided and modified as described in Example 1 . A sample of the provided vetiver oil (V1), of the modified oil before adding the base (V2), and of the modified oil (V3) was collected.

[0088] The collected samples were analysed for their contents by mass spectrometry.

[0089]

[0090] Interestingly, it was found that - among others - the following exemplary compounds were modified by the process, which resulted in an enhanced vetiver profile: Example 3: Patchouli oil

[0091] Patchouli oil was provided and modified as described in Example 1. A sample of the provided patchouli oil (P1) and of the modified oil (P3) was collected.

[0092] The collected samples were analysed fortheir contents by mass spectrometry.

[0093] Interestingly, it was found that - among others - the following exemplary compounds were modified by the process: Example 4: Gurjun balm oil

[0094] Gurjun balm oil was provided and modified as described in Example 1 . A sample of the provided gurjun balm oil (G1) and of the modified oil (G3) was collected.

[0095] The collected samples were analysed fortheir contents by mass spectrometry.

[0096]

[0097] Interestingly, it was found that - among others - the following exemplary compounds were modified by the process: Example 5: Olibanum oil

[0098] Olibanum oil was provided and modified as described in Example 1 . A sample of the provided olibanum oil (O1), of the modified oil before adding the base (02), and of the modified oil (03) was collected. The collected samples were analysed for their contents by mass spectrometry.

[0099] Interestingly, it was found that - among others - the following exemplary compounds were modified by the process: Example 6: Rose oil

[0100] Rose oil was provided and modified as described in Example 1 . A sample of the provided rose oil (R1), of the modified oil before adding the base (R2), and of the modified oil (R3) was collected.

[0101] The collected samples were analysed fortheir contents by mass spectrometry.

[0102] Interestingly, it was found that - among others - the following exemplary compounds were modified by the process: Example 7: Sensory evaluation

[0103] Cedarwood oil, guiakwood oil, patchouli oil, olibanum oil, and rose oil were provided and modified as described in Example 1 .

[0104] The respective modified oil was evaluated for its olfactory profile.

[0105] It was found that the cedarwood, pine, and creamy notes were stronger in the modified cedarwood oil.

[0106] Further, it was found that a fruity and animalic note was present and the peppery note was stronger in the modified Guaiac Wood oil.

[0107] It was further found that the peppery, spicy, woody and earthy notes were stronger in the modified patchouli oil. Moreover, it was found that the olfactory notes of the modified olibanum oil were very strong and very citrusy. The modified oil provided very powerful olfactory notes, a slight lime note and a little less of the woody and warm note. It was also found that the odor profile of the modified rose oil has a more floral, fresh flower and rose petals odor than the provided rose oil.

[0108] Example 8: Perfumery Example

[0109] A perfume was compounded according to following formula:

[0110] 830 g of composition A were mixed with 10 g vetiver oil as initially provided in Example 2 before the modification, to obtain Sample 1 . 830 g of composition A were mixed with 10 g vetiver oil as obtained in Example 2 after the modification, to obtain Sample 2. In a parallel approach, 830 g of composition A were mixed with 10 g vetiver oil as obtained in Example 2 after the modification, to obtain Sample 3.

[0111] The odor profiles of samples 1 , 2 and 3 were tested by a panel and compared to each other. It was surprisingly found that both Sample 2 and Sample 3 have a softer odor than Sample 1. Furthermore, Sample 2 and Sample 3 show a less burnt odor than Sample 1. Moreover, Sample 2 and Sample 3 show a very nice and creamy woody hazelnut facet.

[0112] Example 9: Perfumery example

[0113] A perfume was compounded according to following formula:

[0114] 950 g of composition B were mixed with 100 g patchouli oil as initially provided in Example 3 before the modification, to obtain Sample 4.

[0115] 950 g of composition B were mixed with 100 g patchouli oil as obtained in Example 3 after the modification, to obtain Sample 5.

[0116] The odor profiles of samples 4 and 5 were tested by a panel and compared to each other. It was surprisingly found that Sample 5 features a wet woody (humid wood) and salty aspect, and was described as very interesting and novel, and providing an algae / fucus effect, each of which was not described for Sample 4. Example 10: Perfumery example

[0117] A perfume was compounded according to following formula:

[0118] 750 g of composition C were mixed with 100 g gurjun balm oil as initially provided in Example 4 before the modification, to obtain Sample 6.

[0119] 750 g of composition C were mixed with 100 g gurjun balm oil as obtained in Example 4 after the modification, to obtain Sample 7.

[0120] The odor profiles of samples 6 and 7 were tested by a panel and compared to each other.

[0121] It was surprisingly found that the odor profile of Sample 7 was described as much more reminiscent of soft woods, creamier, warm woods, cashmere wood, when compared to Sample 6.

Claims

Claims1 . Method for modifying the odor profile of an essential oil and / or an extract thereof, comprising the steps i) providing one or more essential oil(s) and / or one or more extracts) thereof, wherein the oil(s) or extracts) comprise one or more compounds selected from the group consisting of primary alcohols, secondary alcohols, unsaturated terpenes and terpenoids, ii) providing a mixture of acetic acid and nitric acid, iii) mixing the essential oil(s) and / or extracts) provided in step i) and the mixture provided in step ii) to obtain a reaction mixture, iv) reacting the reaction mixture obtained in step iii) at conditions allowing an oxidation of the, one, two, three or more or all of the one or more primary or secondary alcohols, unsaturated terpenes or unsaturated terpenoids in the essential oil(s) and / or extract(s), and an acetylation of the, one, two, three or more or all of the one or more primary or secondary alcohols, unsaturated terpenes or unsaturated terpenoids in the essential oil(s) and / or extract(s), to obtain a mixture comprising at least one aldehyde or ketone, and at least one acetate, v) optionally: providing a substance allowing the enolization of ketones, preferably providing an acid or a base, preferably a base, preferably wherein the substance is selected from the group consisting of potassium methoxide, potassium hydroxide, sodium hydroxide, potassium tert- butoxide, sodium methoxide, lithium diisopropylamide, sodium bicarbonate, potassium bicarbonate, potassium carbonate, or mixtures thereof,vi) optionally: mixing the base provided in step v) with the mixture obtained after step iv), vii) optionally: reacting the mixture obtained after step vi) at conditions allowing an isomerization of the, one, two, three or more of the ketones in the mixture obtained after step iv) and / or allowing a saponification of the, one, two, three or more of the acetates in the mixture, to obtain a modified essential oil and / or extract comprising the one or more compounds selected from the group consisting of primary alcohols, secondary alcohols, unsaturated terpenes, and unsaturated terpenoids as defined in step i), at least one aldehyde or ketone as defined in step iv) and at least one isomer thereof as defined in step v), and at least one acetate as defined in step iv).

2. Method according to claim 1 , wherein in step i) one or more extract(s) is / are provided and wherein the, one, two, three or more or all extracts) is / are plant extract(s), preferably wherein the, one, two, three or more or all plant extract(s) is / are selected from the group consisting of extracts of blossoms, stems, leaves, fruits, fruit peels, roots, needles, branches and mixtures thereof.

3. Method according to claims 1 or 2, wherein the, one, two, three or more or all essential oil (s) and / or extracts) provided in step i) is / are selected from the group consisting of basil oil, caraway oil, carrot seed oil, celery seed oil, clary sage oil, dill weed oil, dill seed oil, estragon oil, fennel oil, galbanum oil, hyssop oil, marjoram oil, parsley seed oil, parsley leaf oil, star anise oil, star anise, teatree oil, cabreuva oil, geranium oil, ho leaf oil, jasmin, lavender oil, lavandin oil, magnolia flower oil, magnolia leaf oil, neroli oil, orange flower oil, orris butter, palmarosa oil, petit grain mandarine oil, petit grain orange oil, petit grain orange bitter oil, rose oil, rosewood oil, rosewood leaf oil, shiu oil, tagetes oil, ylang ylang oil, buchu leaf oil, carrot oil, davana oil, alpinia oil, bay oil, black pepper oil, cardamom oil, cascarilla oil, cassia oil, cinnamon leaf oil, cinnamon bark oil, coriander leaf oil, coriander seed oil, cumin oil, cumin seed oil,ginger oil, gingergrass oil, green pepper oil, longoza oil, lovage leaf oil, lovage root oil, mace oil, nutmeg oil, perilla oil, pimento berry oil, pink pepper oil, pink pepper berries (Schinus molle L.) oil white pepper oil, schinus mole oil, turmeric oil, litsea cubeba oil, myrrh oil, olibanum oil, opoponax oil, peru balsam oil, styrax oil, tolu balsam oil, bergamote oil, cedrat oil, citronella oil, eucalyptus citriodora oil, grapefruit oil, lemon oil, lemongrass oil, litsea cubeba oil, lime oil, mandarin oil, orange oil, orange bitter oil, petit grain lemon oil, tangerine oil, allspices oil, artemisia oil, balsamite oil, calamus oil, catnip oil, cedar leaf oil, chamomile oil blue, chamomile oil roman, clove bud oil, clove leaf oil, clove stem oil, cornmint oil, cypress oil, elemi oil, eucalyptus oil, fir needle oil, fusel oil, helichrysum oil, hop oil, juniper berry oil, laurel leaf oil, mentha arvensis oil, mentha pipperita oil, myrtle oil, oregano oil, pennyroyal oil, pimento leaf oil, pine needle oil, punida oil, rosemary oil, rosemary extact, sage oil, spearmint oil, spruce oil thyme oil, Wintergreen oil, wormwood oil, agarwood oil, amyris oil, boya oil, cedar-wood oil atlas, cedarwood oil china, cedarwood oil texas, cedarwood oil Virginia, copaiba oil, copaiba balm oil, cypriol oil, gaharu buaya oil, guaiac oil, gurjun balsam oil, nootka tree oil, patchouli oil, sandalwood oil, vetiver oil, cistus oil, ambrette seed oil, basil extract, caraway extract, carrot seed extract, celery seed extract, celery extract, clary sage extract, estragon extract, flouve extract, galbanum extract, heather extract, hay extract, immortelle extract, len- tisque extract, lin seed extract, mate extract, star anise extract, tobacco extract, violet leaf extract, wheat bran extract, broom extract, carnation extract, cassie extract, genet extract, geranium extract, hyacinthe extract, jasmin sambac extract, jasmin extract, jonquille extract, lavender extract, lavandin extract, mimosa extract, narcisse extract, orange flower extract, orange leaf extract, orris extract, osman- thus extract, rose extract, tagetes extract, tuberose extract, ylang ylang extract, apple extract, beeswax extract, black currant bud extract, bran extract, buchu extract, black pepper extract, cardamom extract, fenugrec seed extract, ginger extract, nutmeg extract, pink pepper extract, schinus mole extract, sichuan pepper extract, tonka bean extract, turmeric extract, benzoin extract, myrrh extract, olibanum extract, opoponax extract, styrax extract, tolu balsam extract, vanilla extract, orange extract, clove bud extract, elemi extract, eucalyptus extract, fir balsam extract, gentiane extract, laurel leaf extract, mentha piperita extract, pine needle extract, thyme extract, castoreum extract, civet extract, moss a extract, moss c extract, patchouli extract, cistus extract, labdanum extract, ambrette seed extract, and mixtures thereof.

4. Method according to any one of the preceding claims, wherein the, one, two, three or more or all essential oil(s) and / or extract(s) provided in step i) comprises a compound selected from ziza-6(13)-enol, (+)-khusimol, a-guaiene, rotundol, isovalen- cenol, caryophyllene, valencenol, 2-phenylethyl alcohol, geraniol and myrcene.2-phenylethanol geraniol myrcene5. Method according to any one of the preceding claims, wherein the oxidation in step iv) provides one or more compounds selected from ziza-6(13)-enone, isovalencenal and rotundoneziza-6(13)-enone isovalencenal rotundone and / orwherein the acetylation in step iv) provides one or more compounds selected from isovalencenyl acetate, a-guaiyl acetate, p-caryophyllene acetate, and myrcenyl acetate.isovalencenyl acetate a-guaiyl acetate p-caryophyllene acetate myrcenyl acetate6. Method according to any one of the preceding claims, wherein modifying the odor profile refers to increasing the complexity of the odor profile and / or increasing the intensity of one or more odors, preferably selected from tea, rose, woody, spicy, green, fatty, pepper, dry, earthy, amber, fruity, flowery, vetiver, rooty, creamy, Sandal wood, cedar, citrus, bergamot, lavender, floral, and nutmeg.

7. Method according to any one of the preceding claims, wherein the conditions allowing an oxidation of step iv) include a) a reaction temperature in the range of from 0 to 80 °C, and / or b) a reaction time in the range of from 1 to 6 h, and / or c) stirring at a speed in the range of from 50 to 1200 rpm.

8. Method according to any one of the preceding claims, wherein in step i) one or more essential oil(s) and / or extract(s) comprising ziza-6(13)-enol is / are provided, preferably wherein the or one essential oil is vetiver oil and / or wherein the or one extract is an extract of vetiver oil, wherein the oxidation in step iv) provides ziza-6(13)-enone, and wherein the isomerization in step vii) provides 2-ep / -ziza-6(13)-en-3-one,2-e -ziza-6(13)-en-3-one9. Method according to any one of the preceding claims, wherein in step i) one or more essential oil(s) and / or extract(s) comprising a-guaiene is / are provided, preferably wherein the or one oil is patchouli oil and / or wherein the or one extract is an extract of patchouli oil, wherein the oxidation in step iv) provides rotundol and / or rotundone.

10. Method according to any one of the preceding claims, wherein in step i) one or more essential oil(s) and / or extract(s) comprising isovalencenol is / are provided, preferably wherein the or one oil is vetiver oil and / or wherein the or one extract is an extract of vetiver oil, and wherein the oxidation in step iv) provides isovalencenal, and / or wherein the acetylation in step iv) provides isovalencenyl acetate.11 . Modified essential oil or extract obtained or obtainable by a method according to any one of the previous claims.

12. Aroma composition comprising a modified essential oil and / or extract according to claim 1 1 .

13. Perfumed product, preferably pharmaceutical preparation, cosmetic preparation or preparation serving for nutrition or pleasure comprising a modified essential oil and / or extract according to claim 11 or an aroma composition according to claim 12.

14. Use of a mixture of acetic acid and nitric acid for modifying the odor profile of an essential oil and / or extract thereof, preferably in a method according to any one of claims 1 to 10.

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