Method for Obtaining Etheric Oils and/or Constituents of Etheric Oils from Moist Extraction Material

Abstract

The invention relates to a method for obtaining etheric oils and/or constituents of etheric oils from the peel of citrus fruit and/or herbs that have a high residual moisture content comprising the steps a) extraction of the moist extraction material with an extraction agent mixture comprising at least one polar and at least one non-polar solvent for obtaining a miscella, wherein the extraction material is selected from citrus fruit peel and/or residues from the juice production from citrus fruits and/or herbs, wherein the extraction material has a residual moisture content of 5 to 95% by mass, measured on the total mass of the extraction material, wherein the extraction agent mixture contains at least one non-polar solvent in a proportion of 45 to 95% by volume, measured on the total volume of the extraction agent mixture, wherein the extraction agent mixture has a temperature above ambient temperature but below the boiling point of the lowest boiling-point solvent or of the lowest boiling-point azeotrope of the extraction agent mixture; b) separating the miscella from the extraction material; c) distillative separation of the miscella or distillative separation of the extraction agent mixture from the etheric oil and/or the constituents of the etheric oils.

Claims

1. A method for obtaining etheric oils and/or constituents of etheric oils from moist extraction material containing etheric oils and/or constituents of etheric oils comprising the following steps: a) extraction of the moist extraction material with an extraction agent mixture comprising at least one polar and at least one non-polar solvent for obtaining a miscella, wherein the extraction material is selected from citrus fruit peel and/or residues from the juice production from citrus fruits and/or herbs, wherein the extraction material has a residual moisture content of 5 to 95% by mass, measured on the total mass of the extraction material, wherein the extraction agent mixture contains at least one non-polar solvent in a proportion of 45 to 95% by volume, measured on the total volume of the extraction agent mixture, wherein the extraction agent mixture has a temperature above ambient temperature but below the boiling point of the lowest boiling-point solvent or of the lowest boiling-point azeotrope of the extraction agent mixture, b) separating the miscella from the extraction material, c) Distillative separation of the miscella.

2. The method according to claim 1, characterized in that the extraction material contains terpenes, terpenoids, sesquiterpenes and aromatic compounds.

3. The method according to claim 1, characterized in that the extraction material has a content of etheric oils and/or the constituents of etheric oils from 0.005 to 10% by mass, measured on the total dry mass of the extraction agent mixture.

4. The method according to claim 1, characterized in that hexane, benzene, kerosene, toluene and/or at least one alkane with 5 to 25 carbon atoms and/or a mixture of these is used as the non- polar solvent.

5. The method according to claim 1, characterized in that the extraction agent mixture contains at least one polar solvent in a proportion of 5 to 55% by volume, measured on the total mass of the extraction agent mixture.

6. The method according to claim 1, characterized in that at least one alcohol containing 1 to 10 carbon atoms or a mixture of these alcohols is used as the polar solvent.

7. The method according to claim 1, characterized in that the extraction agent mixture contains additional polar and/or non-polar solvents in a total volumetric proportion of 0.5 to 40% by volume measured on the total volume of the extraction agent mixture.

8. The method according to claim 1, characterized in that the extraction material is conditioned to an average particle size of from 0.001 to 10 mm.

9. The method according to claim 1, characterized in that the distillative separation of the non-polar solvent out of the separated miscella takes place first and then the separation of the separating non-polar constituents of the etheric oil.

Description

EXAMPLE 1

Moist Extraction of Peels of Navel Pranges (Juice Oranges), Bitter Oranges (Seville Oranges), Lemons or Citrons

[0119] Navel oranges were washed and rinsed and peeled. The peels were comminuted into 1-2 mm-sized pieces. The comminuted peels were separated into batches of 102.8 g to 104.3 g.

[0120] In order to determine the oil content of the peels to be extracted, a batch weighing 102.8 g was first dried for 3 h at 100 C. until no further weight loss could be observed. The dried batch weighed 21.3 g. The water content of the peels in this batch was therefore 79.3%. The dried peels were extracted for 3 hours with 150 ml hexane in a Soxhlet. The resulting extract was weighed and the hexane evaporated at 90 C. In total, 1.04 g of orange oil was obtained from the extract in this manner. This corresponds to an oil content of 0.97% of the moist mass and 4.88% of the dry mass.

[0121] In order to determine the optional composition of the extraction agent mixture, additional batches between 102.8 g and 104.3 g of orange peels were each added to 108.5 g extraction agent mixture that were each heated to 65 C. The composition of the extraction agent mixture was a volumetric ratio of n-hexane and 2-propanol between 45:55 and 85:15. The peels were stirred gently and left in the extraction solvent for 15 min. The extraction solvent laden with etheric oil and the peels were next separated via filtration. Remaining extraction solvent was removed from the peels via 30-second centrifugation at 180 rpm. The solvent mixture was removed from the extract obtained via evaporation at 90 C. and ambient pressure.

[0122] The best results were achieved with the extraction mixtures that have a hexane proportion between 64 and 74% by volume. Using this composition, 0.99 g of orange oil was thus obtained from the 104.3 g batch, which corresponds to an extraction efficiency of 98% at a theoretic etheric oil content of 0.97% of the moist mass or a theoretic etheric oil amount of 1.01 g in the batch. Outside the indicated range, the extraction efficiency collapsed steeply into unacceptable and technically irrelevant values.

[0123] Similar extraction efficiencies could be achieved in the extraction of peels of bitter oranges, lemons and citrons, wherein here too the optimal extraction mixtures stood at a hexane proportion between 62 and 76% by volume of hexane.

EXAMPLE 2

Extraction of Etheric Oil from Fresh Peppermint

[0124] The oil content of the peppermint was determined via Soxhlet extraction at 0.7% by weight of the moist mass and 5% of the dry mass and the water content of the peppermint at 86% by weight.

[0125] The peppermint plants were coarsely comminuted and every 200 g were fed for 15 minutes into an extraction agent mixture of 65% by volume 5% hexane and 35% by volume 5% 2-propanol that was heated to 65 C. The extraction solvent laden with etheric oil and plant parts was next separated via filtration. Remaining extraction solvent was removed from the plant parts by 30-second centrifugation at 180 rpm. The solvent was removed from the extract obtained by evaporation at 90 C. and ambient pressure. Approximately 1.3 g of mint oil could be obtained in this manner, which corresponds to an extraction efficiency of 93% at a theoretic etheric oil content of 0.7% by weight of the moist mass or a theoretic etheric oil amount of 1.4 g per batch.

EXAMPLE 3

Extraction of Etheric Oil from Thyme

[0126] The oil content of the thyme was determined by Soxhlet extraction at 0.28% by weight of the moist mass and 1.65% of the dry mass and the water content of the thyme at 83% by weight.

[0127] The thyme was coarsely comminuted to pieces 1 mm in size and every 300 g were fed for 15 minutes into an extraction agent mixture of 67% by volume 5% hexane and 33% by volume 5% 2-propanol that was heated to 65 C.

[0128] The extraction solvent laden with etheric oil and the comminuted thyme was next separated via filtration. Remaining extraction solvent was removed from the comminuted thyme by 30-second centrifugation at 180 rpm. The solvent was removed from the extract obtained by evaporation at 90 C. and ambient pressure. Respectively 0.81 g of thyme oil from each batch could be obtained in this manner, which corresponds to an extraction efficiency of greater than 96% at a theoretic oil content of 0.28% by weight of the moist mass or a theoretic oil amount of 0.84 g per batch.

EXAMPLE 4

Extraction of Etheric Oil from Lavender Blossoms

[0129] The oil content of the lavender blossoms was determined via Soxhlet extraction at 1.6% by weight of the moist mass and 7.6% of the dry mass and the water content of the lavender blossoms at 79% by weight.

[0130] The blossoms were roughly comminuted to 1 cm-large pieces and every 100 g were fed for 15 minutes to a moist extraction solvent of 63% by volume 5% hexane and 37% by volume 5% 2-propanol, which was heated to 65 C. The extraction solvent laden with etheric oil and the blossoms were next separated via filtration. Remaining extraction solvent was removed from the blossoms by 30-second centrifugation at 180 rpm. The solvent was removed from the extract obtained by evaporation at 90 C. Approximately 1.5 g of lavender blossom oil could be obtained in this manner, which corresponds to an extraction efficiency of almost 94% at a theoretic oil content of 1.6% by weight of the moist mass or a theoretic oil amount of 1.6 g per batch.

TABLE-US-00001 TABLE 1 Solvent Dielectric constant at 25 C. Polarity n-hexane 1.9 Non-polar Benzene 2.3 Non-polar Diethylether 4.3 Non-polar Chloroform 4.8 Non-polar 2-propanol 18.2 Polar Ethanol 34.3 Polar Methanol 33.6 Polar Water 80.4 Very polar

TABLE-US-00002 TABLE 2 Typical compounds that occur in etheric oils (from https://de.wikipedia.org/wiki/%C3%84therische_%C3%96le) Substance group Acyclical Monocyclical Bicyclical Mono- Hydro- Ocimene, Limonene -pinene terpenes carbons myrcene -terpene Camphene Phellandrene Alcohols Linalool Menthol Sabinol Geraniol Borneol Aldehyde Neral citronellal Ketone Carvone Camphor Menthone Fenchone Ether Menthofurane Cineole Anethofurane Ester Geanyl Acetic-acid acetate bornyl ester Linalyl Iso bornyl acetate acetate Sesquiterpenes Farnesol -bisabolol Chamazulene Farnesene -caryophyllene -caryophyllene Substance group Examples Aromates Phenols Carveol Carvacrol Thymol Phenylpropanoids Apiole Zimataldehyde Anethole Dillapiol Estragole Furanocumarines Coriandrine