Medicinal & Aromatic Plants

Medicinal & Aromatic Plants
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Research Article - (2023)Volume 12, Issue 1

Essential Oil Composition of Turmeric Cultivated in Ethiopia

Sileshi Abera Ayele* and Belay Gezahegn Gebreyes
 
*Correspondence: Sileshi Abera Ayele, Department of Food Science and Nutrition, Ethiopian Institute of Agricultural Research, Teppi, Ethiopia, Tel: 920443883, Email:

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Abstract

The current study based on quantification of physicochemical composition of turmeric dame variety and its physicochemical compositions of the turmeric were determined using standard methods. The results of the analysis shows that it contains 13% moisture content, 6.78% ash, 6.119% crude protein, 8.89% oleoresin, 3% essential oil and 65.211 total carbohydrate. Composition of the essential oil obtained from the rhizome of turmeric was analyzed by GC/MS technique. More than 50 compounds were detected and 50 of them were identified. They accounted for 99.129% of essential oil. The major constituents of rhizome essential oil were tumeron (30.843%), aR-turmerone (28.378%), curlone (17.351%), α-curcumene (2.639%), zingiberene (2.528%), (-)-β-sesquiphellandrene (2.449%), bergamotol.Z-alpha.-trans- (1.8455%), α-phellandrene (1.374%). The study proved that the physicochemical and essential chemical composition of Ethiopian turmeric was comparable to values reported in literature from different parts of the world and it has good total carbohydrate (%).

Keywords

Essential oil; Ethiopian turmeric; Tumerone; aR-Turmerone; Turmeric quality

Introduction

Spices and herbs, are an important group of agricultural commodities being used by many civilizations all over the world to add flavor, taste, nutritional values and increase shelf life to food as well as to heal various physical, mental, emotional problems and to restore human health [1]. Turmeric (Curcuma longa L.) is a rhizomatous herbaceous perennial plant of the ginger family, Zingiberaceae. It is native to tropical South Asia but is now widely cultivated in the tropical and subtropical regions of the world. The deep orange-yellow powder known as turmeric is prepared from boiled and dried rhizomes of the plant. It has been commonly used as spice and medicine (Rhizome Curcumae longae), particularly in Asia. In Ayurveda medicine, turmeric is primarily used as a treatment for inflammatory conditions and in traditional Chinese medicine, it is used as stimulant, aspirant, carminative, cordeal, emenagogue, astringent, detergent, diuretic and martinet [2-4].

Turmeric is an important economic crop cultivated for its underground rhizomes which are widely used in drugs, cosmetic industries, condiments, curry stuffs and in religious and auspicious occasions. Due to its easy digestibility, turmeric has been used in industry to prepare special food and children's foods. Turmeric has long been known in India and many other countries as an important dietary source in addition to their use in traditional medicine for wound healing to cure inflammation and stomach acidity [5-7]. Moreover, nutrients found in turmeric do more than just prevent deficiency diseases. It has a high nutritional status that can be exploited. The curcumin contain vitamins or vitamin precursor.

Which produces vitamin C, beta-carotene as well as polyphenol coupled with fatty acid and essential oil. Turmeric is a good source of spice compared with other spices. Though consumed in Africa and some sub - Saharan countries. It is also major Spice in Ethiopia that enhances the flavor of other spices and foods and is the base of most Ethiopian curries which is domesticated from Indian.

Research has shown that the quantitative composition is widely influenced by the genotype, ontogenic development, and environmental and growing conditions [8-10]. It also implies the possibility of different medicinal uses of the same plant species grown in different regions [11]. This paper reports the chemical constitution of the turmeric grown in the southern part of Ethiopia. Therefore, the present study was lunched to determine the physicochemical compositions improved and released turmeric variety Deme.

Materials and Methods

Sample collection and preparation

Fresh turmeric dame variety used in this study was collected from the filled site of Teppi National Spice Research Center (TNSRC), Ethiopia. The samples were cleaned manually to remove all foreign matter, dust and dirty and immature rhizomes. The required plant materials were air dried for two week. After air drying, the samples were ground to fine powder using electrical mill and stored in airtight bottles till required for analysis.

Physicochemical analysis

Turmeric powder moisture content determination: The dried turmeric seed samples were analyzed for the contents of moisture, according to the AOAC (925.10) methods. The amount of water found in a food sample is influenced by the type of food, age or maturity, variety and geographical location. The moisture content determination gives an indication of the amount of water found in the food substance and thus suggests the keeping characteristics of such foods. A clean weighing Aluminum tin was placed in an oven and dried at 130°C for about 30 minutes, cooled in a dessicator and weighed (W). About 2 g of each turmeric sample was weighed into the aluminum tin and re-weighed (b). The aluminum tin with the sample was dried to a constant weight (c) at 130°C. The determination for each sample was done in duplicate and the means were calculated.

Oleoresin determination: Ten (10) gm of sample were taken into a thimble and placed in a Soxhlet apparatus 250 ml of hexane was added and extracted according to their boiling point for six hours. After completion of extraction the dark brown extract was then cooled, concentrated using rotary evaporator get a crude dried extract which was black orange in colour and yield was calculated. The experiments were made in duplicate, and then the means were calculated.

Essential oil determination: Essential oil content of cardamom seed were analyzed by hydro-distillation according to ES ISO (6571:2012). The experiments were made in duplicate, and then the means were calculated.

Determination of % ash: Ash was determined by incineration of known weights of the samples in a muffle furnace at 550°C until a white ash was obtained. Organic matter was burned off and the inorganic material remaining is cooled and weighed. Heating was carried out in stages, first to derive the water, then to char the product thoroughly and finally to ash at 550°C in a muffle furnace. The ashing dishes (made of porcelain) were placed into a muffle furnace for 30 min at 550°C. The dishes were removed and cooled in desiccators for about 30 min at room temperature; each dish was weighed to the nearest g. About 4 g of flour sample was added into each dish. The dishes were placed on a hot plate under a fume-hood and the temperature was slowly increased until smoking ceases and the samples become thoroughly charred. The dishes were placed inside the muffle furnace at 550°C for 6 h, and removed from 30 the muffle and then placed in desiccators for 1h to cool. The ash was clean and which in appearance. When cooled to room temperature, each dish+ash was reweighed. Weight of total ash was calculated by difference and expressed as percentage of the fresh sample. The experiments were made in duplicate, and then the means were calculated.

Determination of crude protein content: Protein content was determined using kjeldahl method. The sample was digested by concentrated sulfuric acid with mixed tablet catalyst (7 g K2SO4+0.210 g CuSO4 × 5H2O+0.210 g TiO2) using FOSS fully automated 2520 digester for an hour. Foss kjeltec 8400 was used for percent protein determination. Boric acid was used as ammonia trapping agent. The experiments were made in duplicate, and then the means were calculated.

Determination of total carbohydrate: Total carbohydrate contents of turmeric was calculated by the following equations Total Carbohydrate (%)=100-(% moisture+% crude protein+% crude fat+% ash). As it seen from in the Table 1 the total carbohydrate% for the turmeric dame variety is 65.211.

GC analysis: The essential oils were analyzed by Gas Cheromatography (GC) and Gas Chromatography coupled with Mass Spectroscopy (GC-MS). GC analysis was carried out on Agilent 7890B gas chromatography with 5977A MS detector and DB-5MS capillary colimn (30 m × 0.25 mm × 0.25 μm). Helium was used as carrier gas with a flow rate of 1 mL/min and the sample was injected in splitless mode. The oven temperature was initially set at 60°C hold for 3 minutes and then increased at arte of 4°C/min to 80°C for 7 min, increased at arte of 7°C/min to 140°C for 1 min increased at 2°C/min to 145°C for 25 min then increased at arte of 20°C/ min to 280°C. Injector and detector temperatures were set at 280°C.

GC-MS analysis: The mass spectra were recorded using Agilent 5977A MS detector with EI source, coupled with Agilent 7890 B gas chromatography equipped with DB-5MS capillary column (30 m × 0.25 mm; film thickness 0.25 μm). The GC conditions were set as described above for GC analysis. The mass spectrometer conditions were as follows: ionization potential 70 eV. Source temperature 230°C. Identification was based on retention date and computer matching with the NIST 2014 Library as well as by comparison of electron-impact-mass spectra with those of relevant reference materials and literature.

Results and Discussion

Physicochemical composition of turmeric dame variety presented in Table 1. The results of the analysis shows that the representative sample contains 13 % moisture content, 6.78 % ash, 6.119% crude protein, 8.89% oleoresin, 3.00% essential oil and 65.211% total carbohydrate. As it seen from different studies the physicochemical composition of turmeric rhizomes vary often with varieties, locations, sources, and cultivation conditions, while there are significant variations in composition of with turmeric rhizomes varieties and geographical locations [8-11]. The current physicochemical profiling study shows our released variety has its own characteristics, but it is comparable of other countries result. But crude protein content is higher as compared to some turmeric producing countries.

Types of parameter          Results
1st 2nd Average
Moister 12.95% 13.05% 13.00%
Oleoresin 8.75% 9.03% 8.89%
Essential oil 3.05% 2.95% 3.00%
Ash 6.72% 6.84% 6.78%
Protein 6.169% 6.069% 6.119%
Carbohydrate 65.411% 65.011% 65.211%

Table 1: Physicochemical composition of turmeric dame variety.

The essential oil obtained by the hydro distillation of turmeric powder was orang coloured a little viscous liquid with characteristic hot odour. The yield was 3.00% on dry weight basis. GC-MS analysis of turmeric essential oil showed more than 50 components and 50 0f them were identified on the basis of retention time and comparing with mass spectral database of standard compounds. Relative amounts of detected compounds were calculated on the basis of GC peak areas. They accounted for 99.129% of the essential oil. The essential oil contained monoterpenes, sesquiterpenes and non terpenic components. The major constituents were tumeron (30.843%), aR-turmerone (28.378%), curlone (17.351%), α-curcumene (2.639%), zingiberene (2.528%), (-)-β-sesquiphellandrene (2.449%), bergamotol,Z-alpha.-trans- (1.8455%), α-phellandrene (1.374%) and aR-tumerol (1.130%). The identified compound and their percentages are listed in Table 2. It is known that turmerone is principal flavouring compound of turmeric [12].

Thmerone and aR-turmerone imparts a camphory characteristic pungent smell. Many reports about the chemical constituent of turmeric essential oil are available. In the rhizome oil of turmeric from Brazil, the main components ware ar-turmerone (33.2%), a-turmerone (23.5%) and β- turmerone (22.7%) [13].

In Bangladesh, ar-turmerone (27.78%), tumerone (17.16%) and culone (13.82%) were the main constituents [14]. In lower Himalayan region of northern India a-turmerone (44.1%), β- turmerone (18.5%) and ar-turmerone (5.4%) were the main constituents [15]. ar-turmerone (45.8%) and zerumbone (3.5%) were the major component of Malaysia turmeric [16]. In contrast, bisabolene (13.9%), trans-ocimene (9.8%), myrcene (7.6%), 1,8-cineole (6.9%), thujene (6.7%) and thymol (6.4%) were the major component of Nigeria turmeric rhizome essential oil [17]. The main constituent from Sichuan Province, China were ar-turmerone (49.04%), humulene oxide (16.59%) and β- selinene (10.18%) [18]. However, in our Ethiopian turmeric rhizome essential oil sample, tumeron (30.843%) was found to be the major constituent. In Nepal turmeric essential oil 67 compound were identified and β-tumerone (17.74%), α- tumerone (8.19%), β-sesquiphellandrene (4.99%), 1,4- dimethyl-2-(methylpropyl)-benzene (4.40%), zingiberene (4.03%), 1-(1,5-dimethyl-4-hexenyl)-4methyl-benzene (3.80%), Epi-α- patschulene (3.67%) and (±)-dihydro-αr-turmerone (3.27%) were reported as a major compound [19].

S/N Name of compound   RT  %
1 α-Phellandrene 9.144 1.374
2 o-Cymene 9.91 0.496
3 D-Limonene 10.116 0.076
4 Eucalyptol 10.305 0.433
5 Cyclohexane, 1-methylene-4-(1methylethenyl) 11.535 0.052
6 2-Carene 13.109 0.112
7 α-Terpineol 19.397 0.028
8 Bicyclo[3,1,0]hexan-3-ol,4-methylene-1-(1-methyl)-,(1α, 3α, 5α)- 19.689 0.034
9 Thymol 22.556 0.061
10 2-methoxy-4-vinylphenol 22.979 0.031
11 Eugenol 24.067 0.044
12 Trans-8-tert-Butyl-bicyelo(4,3,0)non-3,7-diene 24.782 0.038
13 Trans-α-Bergamotene 25.463 0.078
14 Caryophyllene 26.001 0.396
15 2(1H)-Naphthalenone,7-ethyl-4a,5,6,7,8,8a-hexahydro-1,4a-dimethyl-,(1α,4aβ,7β,8aα)- 26.739 0.263
16 Cis-β-Farnesene 26.979 0.1
17 Humulene 27.111 0.099
18 (1S,5S)-2-Methyl-5-((R)-6-methylhept-5-en-2-yl)bicycle[3,1,0]hex-2-ene 27.38 0.035
19 1-Methyl-4-(6-methylhept-5-en-2-yl)cyclohexa-1,3-diene 27.82 0.092
20 α-Curcumene 27.94 2.639
21 α-Zingiberene 28.433 2.528
22 Dicumene 28.77 0.054
23 β-Bisabolene 28.925 0.561
24 (-)-β-Sesquiphellandrene 29.554 2.449
25 α-Bergamotene 29.657 0.243
26 Bicyclo[3,3,1]nona-2,6-diene 30.773 0.053
27 Humulene-1,2-epoxide 30.939 0.283
30 aR-Tumerol 32.089 1.13
31 Bicyclo[3.1.1]heptane, 6-methyl-2-methylene-6-(4-methyl-3-pentenyl)-,[1R- (1.alpha.,5.aalpha.,6.beta.)] 32.243 0.075
32 (.±.)-Dihydro-ar-turmerone 32.793 0.685
33 Megastigma-3,7(E), 9-triene 33.039 0.129
34 7-Methoxymethyl-2,7-dimethylcyclohepta-1,3,5-triene 33.313 1.091
36 Lanceol, cis 33.714 0.138
37 Zingiberenol 34.097 0.142
38 .(±)-trans-Nuciferol 34.515 0.665
39 Bergamotol, Z- α-trans- 35.391 1.845
41 Tetracyclo[5.2.1.0(2,6).0(3,5)decane, 4,4-dimethyl- 36.895 0.214
42 aR-Turmerone 37.382 28.38
43 Tumerone 37.777 30.84
44 Cis-Sesquisabinene hydrate 39.207 0.375
45 Curlone 40.374 17.35
46 (6R,7R)-Bisabolone 44.294 0.361
47 (Z)-gama-Atlantone 45.284 0.672
48 Cyclohexane, (2-nitro-2-propenyl)- 46.131 0.496
49 Tridecane,2-methyl-2-phenyl- 46.434 0.455
50 (E)-Atlantone 47.727 0.862
51 n-Hexadecanoic acid 52.328 0.497

Table 2: Chemical constituents of turmeric rhizome essential oil.

Conclusion

This study aimed to profile the physico-chemical composition of turmeric dame variety used for spice in Ethiopia. It focused on the physicochemical characterization of turmeric dame variety sample which was improved for low land agro-ecology. The turmeric dame variety was collected from national spices research center in Ethiopia and the physico-chemical parameters of one varieties powder was performed. The results of the analysis shows that it contains 13% moisture content, 6.78%ash, 6.119% crude protein, 8.89% oleoresin, 3% essential oil and 65.211 total carbohydrate. Tumeron (30.843%) was found to be the major constituent of rhizome essential oil. To conclude that the turmeric dame variety physicochemical composition and essential oil chemical composition are comparable and within the ranges of different turmeric producing country, the data will help the spices/turmeric breeders for further improvement of varieties.

References

Author Info

Sileshi Abera Ayele* and Belay Gezahegn Gebreyes
 
Department of Food Science and Nutrition, Ethiopian Institute of Agricultural Research, Teppi, Ethiopia
 

Citation: Ayele SA, Gebreyes BG (2022) Essential Oil Composition of Turmeric Cultivated in Ethiopia. Med Aromat Plant. 11:441.

Received: 23-Oct-2019, Manuscript No. MAP-19-2556; Editor assigned: 28-Oct-2019, Pre QC No. MAP-19-2556(PQ); Reviewed: 11-Nov-2019, QC No. MAP-19-2556; Revised: 28-Nov-2022, Manuscript No. MAP-19-2556(R); Published: 26-Dec-2022 , DOI: 10.35284/2471-9315.22.11.441

Copyright: © 2022 Ayele SA, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

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