Supercritical carbon dioxide extraction of Angelica archangelica L. root oil

ELSEVIER

Journal

of Supercritical

Fluids 12 (1998) 59-67

Supercritical carbon dioxide extraction of Angelica archangelica L. root oil Catalin Doneanu a, Gheorghe Anitescu b,* a Department of Organic Chemistry, Faculty of Pharmacy, 6 Traian Vuia Str., Bucharest, Romania b Department of Chemical Engineering and Materials Science, Syracuse University, Syracuse, NY 13244, USA Received 5 May 1997; received in revised form 19 August 1997; accepted 26 August 1997

Abstract Angelica (var. Angelica archangelica L.) oil was isolated from grated fresh roots of the plant by supercritical fluid extraction using carbon dioxide and a two-stage fractional separation system. Throughout the extraction process the pressure and temperature were maintained at 120 bar and 40°C respectively. A 1 h static extraction step was followed by a 2 h dynamic extraction conducted at a flow rate of 0.5 kg h-‘. The extracted material was characterized by capillary gas chromatography-mass spectrometry using three different mass spectra libraries. More than 200 compounds were found in the extracted oil, of which 118 compounds were positively identified and four other compounds tentatively identified. 0 1998 Elsevier Science B.V. Keywords: Angelica archangelica L.; Carbon dioxide; Capillary GC-MS;

1. Introduction Angelica (var. Angelica archangelica L.) is a herbaceous biennial or perennial plant of the umbel family, with tall stalks and large divided leaves. The roots and fruits are used in flavoring, perfumes, medicine, etc. It is specific to European flora, and it is cultivated mostly in France, Germany, Belgium, and the Netherlands. Essential oil of angelica is usually obtained from the rhizomes and roots by steam distillation. This method yields O.l-1.0% of essential oil related to the angelica root material. A preliminary drying of the rhizomes and roots is not recommended

* Corresponding author. Tel.: (+ 1) 315 443 191; fax: (+ 1) 315 443 1243; e-mail: [email protected] 0896-8446/98/$19.00 0 1998 Elsevier Science B.V. All rights reserved. PII SO896-8446(97)00040-5

Essential oil; Supercritical fluid extraction

because of the partial loss of the most volatile compounds. Further, by drying, some terpenes (especially a-phelandrene) become resinous. Therefore, the top fragrance notes of the oil, usually fresh and gently pungent, may be altered. Essential oil obtained from rhizomes and roots of angelica is a yellow liquid having a fresh, herbaceous, and gently pungent aroma on an earthly and woody background. There are many studies on the extraction and composition of angelica root oil [l-9]. In the early investigations, reviewed by Gildemeister and Hoffmann [ 11, only a small number of constituents were identified. The essential oil composition of angelica roots has been investigated by Klouwen and ter Heide [ 21, Taskinen and Nyktinen [ 31, For& [4], Srinivas [ 51, Kallio et al. [ 61, Nykgnen

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C. Doneanu, G. Anitescu / Journal of Supercritical Fluids I2 (1998) 59-67

et al. [7], Kerrola and Kallio [8], and Kerrola et al. [9]. However, the detailed effects of both the plant’s environmental conditions and extraction parameters on the yield and composition of the extract of angelica flavor have not yet been elucidated. A large variability in the relative amounts of the compounds was found to depend on the stage of plant development and the kind of strains and freshness of the roots at the time of extraction [9]. Throughout the investigations, angelica root oil was found to have a very complex composition. The bouquet aroma of this oil is the result of the combination of the aromas of a very large number of components. Thus, it is very important that the native natural proportion of the components is maintained during any extraction procedure. Unfortunately, the traditional extraction techniques based on liquid solvents or steam distillation were found to present some disadvantages. For example, the steam distillation procedure cannot recover the pungent compounds because these are thermally degraded to produce volatile aldehydes or ketones. Some of the aromatic compounds are also known to be affected by heat. The essential oil when extracted with liquid solvents lacks a strong aroma due to the loss of volatile compounds during the evaporation process of the solvents. Further, the alcohol extraction of the flavors was found to produce artifacts by esterification, etherification, and/or acetal formation [ 31. Supercritical fluid extraction (SFE), mainly by supercritical carbon dioxide (SC-C02), can be used to extract volatile oils from natural products and does not produce substantial thermal degradation or solvent pollution/alteration of the extracts [lo]. Nevertheless, a high density of supercritical fluid (SCF) and one-stage subcritical separation is unsuitable due to the simultaneous extraction of many undesired compounds, such as fatty acids and their esters, cuticular waxes, coumarins, etc. [ 111. SFE performed in multiple steps by increasing the SCF density and a multistage separation technique give superior quality products compared with those obtained by the traditional techniques [ 12,131. However, there are many parameters that must be considered in the SFE procedure. These include the type of solvent/cosolvent, raw

material-solvent ratio, the method of feeding the solvent, conditions of extraction (pressure, temperature, time, flow rate), preparation of raw material and separation conditions, etc. Analysis of the oils’ composition revealed that oils extracted under different SFE conditions possessed widely different percentage compositions. Qualitative aroma tests showed that the oil obtained at optimum SFE conditions had a fragrance that better resembled the flavor profile of the starting material. Angelica root oil has been isolated by SFE (12 MPa/SO”C) into three fractions with distinctly different compositions by three successive extraction steps and by using a single separator [9]. Obviously, each of the fractions was found to present a composition which did not resemble that of the natural aroma composition. To perform that requirement, the fractions must be mixed after completing the extraction process and the removal of undesired compounds. The aims of this study were to use an appropriate extraction procedure to obtain a more detailed knowledge of the proportion of fragrant constituents of angelica roots and to elucidate the actual aroma composition of a fresh root extract. Therefore, this study reports an SFE technique to isolate the volatile oil, consisting of two successive extraction stages (static and dynamic), and a twostage separation process. Approximately 200 compounds were separated from extracted oil by a gas chromatography-mass spectrometry (GC-MS) analytical method, and more than half have been identified. Throughout the extraction process, neither coumarins nor psoralens were detected in the GC traces of the extracted material, except for a small amount of osthol. Also, neither waxes, nor large amounts of long-chain fatty acid esters, nor ethers were found. Furthermore, extracts with a high resemblance to the native aroma of angelica roots were obtained.

2. Experimental section 2.1. Materials

Fresh angelica roots of var. Angelica archangelica L. cultivated in Romania were used 1 day after

C. Doneanu, G. Anitescu / Journal of Supercritical Fluids 12 (1998) 59-67

harvesting. Grated samples of 500 g each were placed in a stainless steel sieve basket to prevent carryover of particulates. Particle size was nonuniform because of the particular procedure of grating a fresh root material. Although grated material was passed through 1 mm diameter grater holes, the length of the plant fibers was variable (N l-4 mm). Carbon dioxide of 99.5% purity was used by passing through a filter filled with ZSM-20 molecular sieves for a further purification. The molecular sieves were conditioned before using a new cylinder with carbon dioxide by heating in an oven at 200°C for 7 h.

61

performed at various densities of carbon dioxide showed that an extraction at 12.0 MPa and 40°C (1 h static process followed by 2 h dynamic process) was optimum in order to have an acceptable yield and a composition containing a minimum of unwanted co-extracted compounds. Using these conditions, the undesired compounds, co-extracted during the designated extraction time, were precipitated selectively in the first separator, and the essential oil was recovered in the second separator. The water collected in the second separator was removed by addition of sodium sulfate. 2.3. GC-MS

2.2. Apparatus andprocedure SFE experiments were performed on an apparatus mainly consisting of a thermostatic extractor (1 1 internal volume) and two separators operated in series (100 ml and 300 ml). More details on the SFE apparatus were provided in a previous paper [ 131. No pump or compressor was used to deliver SC-CO,. The system is essentially maintenancefree, with virtually no moving parts. In the experimental runs, the extractor was charged with 500 g of grated roots of angelica plant, and carbon dioxide was delivered into the extractor by controlled heating of a siphon-type cylinder. In the first step, the extractor was loaded with carbon dioxide up to a desired pressure and thermostatically controlled at a given temperature during a 1 h period of time (a static period). In the second step, a carbon dioxide flow rate of 0.5 kg h-’ (measured at the outlet of the apparatus) was used during all the tests in a downflow mode. Downflow of SCF through the fixed bed of plant material is more effective than upflow, because in this mode any condensate is simply pushed out of the bottom of the extraction vessel, and the resultant oil content recovered [ 141. The pressure control valve at the outlet of the extractor is moderately warmed by heating tape to prevent plugging by freezing due to the Joule-Thomson effect produced by flowing carbon dioxide. Extracted fractions from the extractor were precipitated/condensed in two separators operated in series at pressures/temperatures of 6.0 MPa/lO”C and 3.0 MPa/O”C. Extractions

The GC-MS apparatus was a Fisons Instruments MD 800 gas chromatograph-mass spectrometer equipped with a split/splitless injector (maintained at 250°C) and with a fused silica SPB-5 column (50 m x 0.32 mm i.d. x 0.25 urn film thickness, Supelco, Bellefonte, PA, USA). Helium was used as the carrier gas, with an inlet pressure of 70 kPa, and the septum purge was 4 ml mini. The split ratio was 1:lOO and the volume of each of the injected samples was 0.1 ~1. The GC oven was programmed to operate from 60 to 240°C (20 min) at 3°C min- ‘. The ion source temperature was 200°C and the interface temperature was 250°C. Data acquisition was performed with MassLab software for the mass range from 35 to 480 a.m.u. with a scan rate of one scan per second. The ionization energy of electrons was 70 eV. The identification of compounds was based on a comparison of experimentally obtained mass spectra with NIST, WILEY-6 and TERPENE mass spectra libraries, using relative retention indices already established [ 151. In a second run, the oil was injected into the same column, using a flame ionization detector. The percentage composition was computed from peak areas without correction factors. Finally, by using the same temperature program, a mixture of n-alkanes from Ca to C& was analyzed. The retention times were then used for assigning Kovats retention indices of identified compounds in the angelica root oil extracts [ 16,171. In order to determine the ratio of the co-eluted compounds, limonene and P-phellandrene, the oil was solved in hexane

C. Doneanu, G. Anitescu /Journal of Supercritical Fluids 12 (1998) 59-67

62

Table 1 Identification and quantification of compounds contained in the Angelica archangelica L. root oil compared with literature data No.

Compound

Kovats index

Percentage composition C”

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51

Isobutyraldehyde 2-Methyl-3-buten-2-01 2-Methyl furane Isovaleraldehyde 2-Methyl 2-butanol Hexanal Isovaleric acid 2-Vinyl-5-methyl furane 2-Methyl butyric acid 2-Pentenoic acid 2-Heptanone Tricyclene a-Thujene 2-Methyl-5-isopropyl furane a-Pinene 2,CThujadiene a-Fenchene Camphene Verbenene Hexanoic acid o-Cymene Sabinene /+Pinene Myrcene 2-Carene a-Phellandrene 3-Carene a-Terpinene m-Cymene p-Cymene Limonene p-Phellandrene cis+Ocimene trm+Ocimene

y-Terpinene Benzyl formate Dimethyl styrene (isomer) a-Terpinolene a-p-Dimethyl styrene Camphen-6-one Linalool Perillene 1,3,8-p-Menthatriene cis-allo-Ocimene trans-Verbenol n-Amy1 benzene 6-Butyl- 1,4-cyclopentadiene a-Phellandren-8-01 (E,Z) 1,3,5-Undecatriene Terpinen-4-01 p-Cymen-7-ol(cuminylalcoho1)

591 611 615 649 659 798 819 826 830 873 886 925 928 933 936 945 949 951 956 969 972 975 980 990 1006 1008 1013 1018 1022 1026 1030 1030 1036 1043 1059 1076 1082 1090 1090 1098 1099 1101 1113 1129 1146 1158 1160 1167 1173 1179 1181

Cb

CC

Cd

0.01

0.01 trace 0.02 0.03 0.02 trace trace trace 0.01 trace 0.02 0.43 0.01 16.66 0.01 trace 1.09 0.57 0.02 0.04 0.62 1.12 3.91 0.13 11.27 8.69 0.31 0.09 5.56 13.12 8.92 2.05 5.43 0.64 0.02 0.07 0.78 0.78’ 0.05 0.09 0.03 0.01 0.07 0.22 0.02 0.19 0.20 0.10 0.14 0.12

0.60

0.90

0.55

0.05

24.0’

6.50

17.10

24.0’

0.38

0.45

1.30

6.98 0.73 1.83

20.20 1.30 5.35

0.76 1.25 7.6”

0.50 3.28

1.35 7.80

7.6” 10.1 0.07

0.86 2.85 8.45

0.65 4.40 6.75

0.43 0.75

3.10 0.55

9.8 13.2 10.0 1.25 2.68 0.11

0.30

0.55

0.16

0.01

0.64

0.40

0.50

0.45

trace 0.02

63

C. Doneanu, G. Anitescu 1 Journal of Supercritical Fluids 12 (1998) 59-67

Table 1 (continued) Identification and quantification of compounds contained in the Angelica archangelica L. root oil compared with literature data No.

52 53 54 55 56 51 58 59 60 61 62 63 64 65 66 67 68 69 70 71 12 13 14 15 16 II 78 19 80

81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102

Compound

p-Cymen-8-01 Sabina ketone a-Terpineol Tyrtenal Sabinol Thujol trans-Piperitol Verbenone Carve01 Chrysanthenyl acetate cis-3-Hexenyl isovalerate u-Phellandrene epoxide Cuminyl aldehyde Carvone Carvotanacetone Piperitone Isoascaridol (?) Phellandral Bornyl acetate Thymol trans-Verbenyl acetate Carvacrol cis-Pinocarvyl acetate trans-Carvyl acetate trans-Piperitol acetate Terpenyl acetate a-Cubebene Eucarvone cis-Carvyl acetate Longicyclene a-Copaene B-Elemene n-Tetradecane Sativene Piper&one oxide (?) l3-Cedrene 8Caryophyllene Octyl isovalerate Thujopsene (widdrene) a-Elemene (?) P-Famesene a-Humulene y-Muurolene Germacrene-D g-Selinene a-Zingiberene cl-Muurolene 8-Bisabolene &Cadinene cc-Copaen-l l-ol Elemol

Kovats index

1184 1187 1192 1198 1203 1206 1209 1211 1219 1223 1230 1238 1241 1245 1249 1255 1266 1217 1288 1289 1293 1299 1301 1337 1341 1351 1355 1358 1363 1376 1383 1397 1400 1404 1414 1424 1428 1434 1441 1446 1458 1463 1484 1491 1496 1499 1507 1513 1530 1549 1555

Percentage composition C”

Cb

CC

Cd

0.10 0.18 0.22 0.41 0.23 0.02 0.10 trace 0.03 0.01 trace 0.05 0.04 0.03 0.19 0.07 0.02 0.27 0.98 trace 0.16 0.34 0.02 0.06 0.14 1.23 0.03 0.01 0.01 0.11 1.16 0.21 0.01 0.02 0.07 0.11 0.14 0.01 0.05 0.01 0.16 1.20 0.05 1.13 0.03 0.16 0.59 1.13 0.31 0.45 0.17

1.28

0.25

0.31

trace 0.11 1.96

1.73

0.02

0.40 2.36

2.10

0.73 0.46 0.17 0.03

0.38

0.20 0.05

0.63 0.38

1.10 3.55

0.25 1.15

0.20 trace

1.91 0.9

0.40 trace

0.23 1.08 0.50 1.93 0.33

1.28 0.98 4.08 1.35

0.15 0.50 0.04 0.26 0.10

0.30

1.2 0.72 0.51 0.46 0.18

C. Doneanu, G. Anitescu / Journal of Supercritical Fluids I2 (1998) 59-67

64

Table 1 (continued) Identification and quantification of compounds contained in the Angelica archangelica L. root oil compared with literature data No.

103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122

Compound

Germacrene-B Spathulenol June01 Caryophyllene oxide n-Hexadecane a-Copaen-S-01 Cedrol Humulene epoxide III Dehydroaromadendrene Isomethyl-a-damascone y-Eudesmol 13-Tridecanolide cc-Muurolol B-Eudesmol 3-Butylidene phthalide 12-Methyl-13-tridecanolide Pentadecanolide Dimyrcene Heptadecanolide Osthol Unidentified compounds (%)

Kovats index

1568 1587 1591 1594 1600 1605 1615 1620 1625 1629 1631 1636 1650 1661 1678 1692 1844 1958 2051 2144

Percentage composition C”

Cb

CC

0.10 0.03 0.14 0.02 0.03 0.01 0.01 0.11 0.01 0.01 0.02 0.82 0.02 0.17 0.04 0.33 0.49 0.02 0.06 0.23 2.17

1.15 1.10

trace

0.20 0.25

0.10 0.10

2.25

1.50

0.45

0.50

trace

0.21

0.50 4.30

0.65 2.90

0.37

7.60

1.60

Cd

trace

(?) Compounds tentatively identified. ’ This work, SFE method (12.0 MPa/40”C). b Kerrola et al. [9], Soxhlet extaction. c Kerrola et al. [9], SFE method (12.0 MPa/SO”C). d Taskinen and Nykanen [3]: extraction with ether-pentane followed by steam distillation. ’ The percentage represents the sum of two co-eluting peaks.

(l/100) and a GC run at 80°C (20 min) followed by a rate of 25”Cmin’ to 240°C (20min) was performed.

3. Experimental results and discussion The main goal of this study was to obtain the best quality and the maximum yield of the angelica oil by an optimal selection of SFE parameters. As expected, fresh root angelica oil was found to have a very complex composition. Its GC trace is shown in Fig. 1, with compound identifications reported in Table 1. A series of runs was performed to assess the optimal extraction conditions: 12.0 MPa and 40°C for the extractor (1 h static period of time and 2 h dynamic process) and 6.0 MPa/lO”C and 3.0 MPa/O”C for the separators.

These conditions precluded contamination of the liquid extract collected in the second separator. A yield of 0.18% was measured by weighing this fraction after water removal by anhydrous sodium sulfate and by weight of the fresh root sample charged in the extractor. When only a dynamic procedure was used, carbon dioxide left the extractor unsaturated with biocompounds in the first step of the extraction process. Therefore, a 1 h static step was completed before the dynamic step. The identification of the compounds constituting angelica root oil and their GC area percentages were reported in the first column of data in Table 1. In the next columns of data are reported the compositions of angelica oil extracted from dried roots by different techniques: Soxhlet extraction performed by Kerrola et al. [9]; SFE method (1.20 MPa/SO”C) performed by the same authors;

65

C. Doneanu, G. Anitescu / Journal of Supercritical Fluids 12 (1998) 59-67

lO(

18 23-34

82 93

%

C

Fig. 1. GC trace in Table 1).

of the angelica

(var. Angelica archnngelica) root

extraction with ether-pentane followed by steam distillation, performed by Taskinen and Nykanen [ 31. The second column of data shows averaged results reported for four various origins of angelica, while in the next column, results for the first two SFE fractions out of three were averaged. The results reveal a large variability in the relative amounts of the compounds, particularly between our results and those reported by Kerrola et al. The percentage composition for commonly identified compounds reported by Taskinen and Nykanen appears to be in a reasonable concordance with ours. The results also show a strong dependence of the oil composition on a number of parameters, such as variety of wild or cultivated angelica strains, stage of the plant development, freshness of the roots at the time of the extraction, environmental conditions during the plant develmethods, analytical proopment, extraction cedure, etc. The oil obtained from fresh roots of var. Angelica archangelica L. was examined in this study by capillary GC-MS using three mass spectra libraries: NIST, WILEY-6 and TERPENE. A total of approximately 200 compounds were

oil (numbering

of the peaks

corresponds

with the compounds

separated, of which 118 compounds were positively identified and another four were tentatively identified. To allow a comparison, the main families of compounds identified from Table 1 are summarized in Table 2. Besides the hydrocarbons (monoterpenes and sesquiterpenes) and their oxygenated compounds, Table 2 also presents the specific angelica macrocyclic lactones and total undesired coumarins co-extracted with the oils. Compounds collected in the first separator were identified qualitatively, but only a rough estimation of the percentage composition was made. The SFE process was optimized by quantification of the desired and undesired compounds in the second separator to obtain maximum and minimum percentages respectively. These data indicate reasonably good agreement between our results and those reported by Taskinen and Nykanen. Monoterpene hydrocarbons represent the larger fraction of the angelica root oil constituents (- 80%). It was previously reported that the main proportion of angelica root oil consists of monoterpene hydrocarbons (up to 88%) [4]. Considerably smaller proportions of monoterpenes were detected in the Soxhlet extracts of angelica roots by Kerrola

66

C. Doneanu, G. Anitescu / Journal ojSupercritical Fluids 12 (1998) 59-67

Table 2 Percentage comparison of main families of compounds extracted by different methods (as shown in Table 1) Compound family

Monoterpene hydrocarbons Sesquiterpene hydrocarbons Oxygenated compounds Lactones Others (Coumarins)

Percentage composition C”

Cb

c”

Cd

81.57 6.13 6.91 1.70 2.99 (0.23)

34.39 15.01 20.43 7.05 23.12 (8.40)

69.60 10.45 6.15 5.05 8.75 (2.05)

82.28 6.75 4.98 0.82 5.17

’ This work, SFE method (12.0 MPa/40”C). b Kerrola et al. [9], Soxhlet extaction. ’ Kerrola et al. [9], SFE method (12.0 MPa/SO”C). d Taskinen and NykZnen [3]: extraction with ether-pentane

followed by steam distillation.

et al. [9]: 24 to 46%. Nykanen et al. [7] reported 28% monoterpenes in an angelica root commercial oil. The main component in our fresh root angelica oil isolated by SFE is a-pinene (16.66%). Its isomer, S-pinene, is present at a lower percentage ( 1.12%). As pinene and limonene oxidize to produce citronellol, carvone, piperitone, and carvacrol [ lo], their high percentages in our oil composition show the lack of oxidation phenomenon. Note that a-phellandrene is also present in a high amount (11.27%), whereas its isomer, (3-phellandrene, was estimated quantitatively in a first step because of the co-elution with limonene (together they represent 22.04%). From a later GC analysis, limonene and B-phellandrene were found to represent 13.12% and 8.92% respectively. Other monoterpene hydrocarbons identified in a large amount were: 3-carene (8.69%), p-cymene (5.56%), truns-p-ocimene (5.43%) and its geometric isomer, ci,+ocimene (2.05%), myrcene (3.91%), and camphene (1.09%). The difference in odor of the angelica root oils can be attributed to the compositional differences of the volatiles, especially in the relative amounts of various monoterpene hydrocarbons [4]. It can be assumed that a high number of different monoterpene compounds indicates a high quality of the oil aroma [9]. Sesquiterpene hydrocarbons represented 6.73% of the angelica oil composition, in very good concordance with the percentage reported by Taskinen and Nykiinen (6.75%). The main compounds identified are: a-humulene (1.23%),

a-copaene ( 1.16%), germacrene-D ( 1.13%), and B-bisabolene (1.13%). Oxygenated compounds of terpene hydrocarbons confer special characteristics to the angelica root oil, such as particular odor notes and stability of the oil against alteration. The compounds extracted by SFE in significant amounts are: terpenyl acetate (1.23%), bornyl acetate a-copaen- 1l-01 (0.45%)) carvacrol (0.98%), (0.34%), and phellandral (0.27%). Macrocyclic lactones were found in a relatively low percentage (1.70%), but they are very important compounds in angelica root oil. The musklike odor of this oil is generally attributed to the lactone of 15-hydroxypentadecanoic acid. Besides pentadecanolide (0.49%), three other macrocyclic lactones were found in the oil isolated by SFE from fresh roots of angelica var. archangelica L.: 13-tridecanolide (0.82%), 12-methyl-13-tridecanolide (0.33%) and heptadecanolide (0.06%). Coumarins as undesired compounds were found in a very low concentration in our SFE oil (only osthol, 0.23%) compared with those found in the oils extracted by Kerrola et al. [9]: 2.05% in SFE oils and 8.40% in the oils extracted by the Soxhlet method. A qualitative sensory analysis of a number of fractions extracted at different SFE conditions showed that the fraction extracted under the above-mentioned conditions had the best quality compared with the other fractions and a commercially available sample of the essential oil.

C. Doneanu, G. Anitescu / Journal ofSupercritica1 Fluids 12 (1998) 59-67

4. Conclusions A two-step SFE process (1 h static period at 12.0 MPa/40”C followed by 2 h dynamic period at 12.0 MPa/40”C and 0.5 kg CO2 h-‘) coupled with a two-stage separation process (6.0 MPa/lO”C and 3.0 MPa/O”C) was selected as an optimum procedure to extract a very complex oil from the fresh roots of Angelica archangelica L. By this procedure, approximately 200 compounds were separated by capillary GC-MS, of which 118 were conclusively identified and four were tentatively identified. The aroma provided by this composition was found to have the highest quality when compared with other fractions extracted under different conditions. The advantages of SC-CO, extraction over steam distillation or liquid solvent extraction include: no thermal degradation of most of the labile compounds; a minimum coextracted amount of undesired compounds; no production of artifacts; and no solvent contamination.

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6-l

[5] S.R. Srinivas, Atlas of Essential Oils, S.R. Srinivas, New York, 1986. [6] H. Kallio, R. Huopalahti, A. Nykanen, A. Ojala, Extraction of angelica root with liquid carbon dioxide, in: M. Martens, G.A. Dalen, H. Russwurm (Eds.), Flavor Science and Technology, Wiley, Brisbane, Australia, 1987, p. 111. [7] I. Nyklnen, L. Nykanen, M. Alkio, Composition of angelica root oils obtained by supercritical CO* extraction and steam distillation, J. Essent. Oil Res. 3 (1991) 229. [8] K. Kerrola, H. Kallio, Extraction of volatile compounds of angelica (Angelica archangelica L.) root by liquid carbon dioxide, J. Agric. Food Chem. 42 (1994) 2235. [9] K. Kerrola, B. Galambosi, H. Kallio, Characterization of volatile composition and odor of angelica (Angelica archangelica subsp. archangelica L.) root extracts, J. Agric. Food Chem. 42 (1994) 1979. [lo] D. Couchi, D. Barth, E. Reverchon, G. Della Porta, Supercritical CO, desorption of bergamot peel oil, Ind. Eng. Chem. Res. 34 (1995) 4508. [ 1l] E. Reverchon, A. Ambruosi, F. Senatore, Isolation of peppermint oil using supercritical COz extraction, Flavour Fragr. J. 9 (1994) 19. [ 121 E. Reverchon, G. Della Porta, D. Gorgoglione, Supercritical CO2 fractionation of jasmine concrete, J. Supercrit. Fluids 8 (1995) 60. [ 131 G. Anitescu, C. Doneanu, V. Radulescu, Isolation of coriander oil: comparison between steam distillation and supercritical CO, extraction, Flavour Fragr. J. 12 (1997) 173. [ 141 P. Barton, R.E. Hughes Jr.,, M.M. Hussein, Supercritical carbon dioxide extraction of peppermint and spearmint, J. Supercrit. Fluids 5 (1992) 157. [ 151 R.P. Adams, Identification of Essential Oils by Ion Trap Mass Spectroscopy, second edition, Academic Press, London, UK, 1994. [ 161 N.W. Davies, Gas chromatographic retention indices of monoterpenes and sesquiterpenes on methyl silicone and carbowax 20M phases, J. Chromatogr. 22 (503) (1990) 1. [17] W. Jennings, T. Shibamoto, Qualitative Analysis of Flavour and Fragrance Volatiles by Glass Capillary Column Gas Chromatography, Academic Press, New York, 1980.