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01005
Essential Oil Extraction from Orange and Lemon
Peel
Hemlata Karne*, Vedvati Kelkar, Apoorva Mundhe, Mitesh Ikar, Shantanu Betawar, Nikita
Chaudhari
Department of Chemical Engineering, Vishwakarma Institute of Technology, Pune, India
Abstract. The one-third of all food produced for human use is wasted each
year which has made food waste a serious problem all around the world.
Citrus juice manufacturing factories generate peel leftovers that can account
for 50-60% of the weight of the fruit, contributing significantly to food
waste. This study investigates the extraction of orange and lemon peel oils
using the Soxhlet process and their analysis via gas chromatography. The
aim is to identify and quantify key volatile compounds present in these oils,
thereby putting the leftover peels to use. Fresh orange and lemon peels were
transformed into zest and extracted using Hexane and Ethanol as solvent in
a Soxhlet apparatus. Gas chromatography with a specialized column and
detector unveiled major volatile compounds, including limonene, linalool,
citral. These compounds contribute to the characteristic aroma and potential
bioactivity of the oils. Orange peels displayed notably higher limonene
content compared to lemon peels. This approach illuminated the chemical
composition of the oils, offering opportunities in food, cosmetics, and
fragrance industries. Orange peels contained 70-90% limonene,
significantly more than lemon peels. The study concluded that peels harbor
28 volatile substances, with limonene responsible for their distinctive citrus
scent. In sum, this research underscores the effectiveness of Soxhlet
extraction, providing insights into orange and lemon peel oils' composition
using Gas chromatography and applications.
Keywords. Extraction, Aroma compounds, Lemon Peel, Orange Peel,
Extraction, Volatile Compounds.
* Hemlata Karne: hemlata.karne@vit.edu
© The Authors, published by EDP Sciences. This is an open access article distributed under the terms of the Creative Commons
Attribution License 4.0 (https://creativecommons.org/licenses/by/4.0/).
E3S Web of Conferences 455, 01005 (2023) https://doi.org/10.1051/e3sconf/202345501005
ICGEST 2023
Graphical Abstract
1. Introduction
The fact that one-third of all food produced for human use is wasted each year has made food
waste a serious problem all around the world. Citrus juice manufacturing factories generate
peel leftovers that can account for 50-60% of the weight of the fruit, contributing significantly
to food waste [1]. Fortunella, Eremocitrus, Clymendia, Poncirus, Microcitrus, and Citrus are
six citrus fruit genera that are native to Asia's tropical and subtropical regions. Citrus, on the
other hand, is the genus that contains the majority of commercially important fruits. Oranges,
mandarins, limes, lemons, and grapefruits are just a few of the important fruits of the Citrus
genus [2, 3]. The peel of the citrus fruit contains a high amount of the essential oil [4].
Essential Oils (EOs) are composite combinations of low-molecular-weight volatile
compounds extracted from plant parts such as flowers, leaves, seeds, fruits, and stems of
aromatic plants [5]. It is derived from plant material confined within a specific region of the
plant or a specific component of the plant cells. The majority of the volatile chemical
combination that makes up citrus essential oil is monoterpene hydrocarbon [4, 6]. The
majority of the citrus essential oil is found in the flavado part of the peel, with smaller
amounts found in the leaves, flowers, fruits, and seeds. Terpene hydrocarbons, oxygenated
compounds, and non-volatile compounds are three fractions that can be roughly split into the
more than a hundred different chemicals that comprise essential oils. The terpene fraction
can make up 50 to 95% of the oil. Germicidal, antioxidant, and antibacterial properties, and
anticarcinogenic activities are all present in the essential oil [7]. Some of the processes used
to obtain essential oil include hydro-distillation, solvent extraction, supercritical fluid
extraction, cold pressing, and microwave extraction. Recently, several advanced extraction
techniques, including ultrasound, microwave, enzymatic and supercritical fluid extraction,
were proposed by researchers to evaluate the relatively high volume of peels generated [8].
Some of the advantages of these advanced methods over conventional methods were less
time duration, low energy requirement, less solvent requirement, and low carbon dioxide
generation. The major constituent of citrus essential oil is limonene, a highly lipophilic cyclic
monoterpene that accounts for 68-98% of the oil's weight and up to 4% of the weight of citrus
peel waste. Limonene is a commonly used food preservation agent and is designated as a
generally recognised as safe ("GRAS") additive in the Code of Federal Regulations due to its
antioxidant properties and fragrance [1]. In actuality, limonene is essential to the global flavor
and fragrance industry. Numerous sectors have taken an interest in the existence of limonene,
a substantial component of the essential oils present in orange peel that has antibacterial,
antioxidant, biological, and herbal fragrance. C10H16 is the empirical formula for the
monoterpene limonene. It is a liquid when it is room temperature. Along with the racemic
mixture dipentene, it also exists as the optical isomers D- and L-limonene. As a precursor to
carvone or a-terpineol, limonene serves as an important industrial chemical [9].
The difficulties in disposing of trash from the juice business and fruits such as orange
peels generally caused environmental contamination. To address this issue, citrus fruit peels
can be utilized as raw material to extract essential oils for a number of residential and
industrial applications [10]. Because orange peel contains biomaterials such as essential oil,
pectin, and sugar, it may cause environmental problems if discarded, most notably water
contamination. If potentially marketable active substances, such as essential oil, could be
extracted, this concern may be transformed into a selling point [11]. Following extraction,
the peel might be used as a dry, high-protein stock feed, increasing the potential profit for the
orange juice industry. Essential oils are collected from fruit peels, flowers, leaves, stems,
roots, and seeds. They are extremely concentrated compounds. These oils are frequently
utilised in a variety of goods, including foods, pharmaceuticals, medicines, the fragrance
industry, and cosmetics, for their flavour and their medicinal or odiferous effects [12].
Essential oils are known to be subject to conversion and degradation reactions since they are
made up of a variety of various lipophilic and highly volatile components that come from a
wide range of distinct chemical families. A review of the literature on essential oil stability
found that oxidative changes and degradation reactions, which can result in changes that are
relevant to both sensory and pharmacological properties, have seldom ever been thoroughly
addressed [13]. Pires et al. reported that D-limonene can be obtained by extracting and
separating essential oils contained in citrus fruits. Essential oils are particularly abundant in
the peels of fruits, so it is efficient to extract essential oils from citrus peels. 70-90% limonene
pertains to, in fact, essential oil component extraction and d-limonene. Studies on the
separation of stimuli and evaluation and research on their physiological function activity are
being actively conducted, −D-limonene included in citrus fruits is obtainable to extract
essential oil as well as separate the oil ingredient [14].
Four provenances of Citrus aurantium L. var amara (sour orange) were used to produce
peel, leaf, and flower oils, all of which were harvested from the identical pedoclimatic and
horticultural circumstances. The GC-FID and GC-MS methods were used to analyse their
chemical composition. The constituent percentages of the various provenances showed
striking variances. According to the research proposed by Park et al., linalool/linalyl acetate
was found in petitgrain, limonene was found in peel oils, and linalool/linalyl was linked to -
pinene in neroli oils, all of which were used to describe this chemical variability [4]. Pires et
al. reported that limonene was extracted from the tangerine peel using soxhlet extraction, a
kind of simultaneous steam distillation and solvent extraction (SDE). In order to quantify the
extracted d-limonene, a reversed-phase HPLC column was used in the HPLC study. The best
extraction period in any solvent, according to the HPLC analysis results, was 2 hours, and
the extracted levels of d-limonene from tangerine peel were 7.77 mg, 0.49 mg, and 0.28 mg
in ethyl alcohol, n-hexane, and ether, respectively, per g of tangerine peel. Because ethyl
alcohol produced the best yield when used as a solvent, polarity has a greater impact on
extraction yield than boiling point [14].
After reviewing earlier studies on the essential oils of the orange and lemon peels, it is
evident that limonene has anti-inflammatory characteristics. In fact, limonene inhibits the
2
E3S Web of Conferences 455, 01005 (2023) https://doi.org/10.1051/e3sconf/202345501005
ICGEST 2023
Graphical Abstract
1. Introduction
The fact that one-third of all food produced for human use is wasted each year has made food
waste a serious problem all around the world. Citrus juice manufacturing factories generate
peel leftovers that can account for 50-60% of the weight of the fruit, contributing significantly
to food waste [1]. Fortunella, Eremocitrus, Clymendia, Poncirus, Microcitrus, and Citrus are
six citrus fruit genera that are native to Asia's tropical and subtropical regions. Citrus, on the
other hand, is the genus that contains the majority of commercially important fruits. Oranges,
mandarins, limes, lemons, and grapefruits are just a few of the important fruits of the Citrus
genus [2, 3]. The peel of the citrus fruit contains a high amount of the essential oil [4].
Essential Oils (EOs) are composite combinations of low-molecular-weight volatile
compounds extracted from plant parts such as flowers, leaves, seeds, fruits, and stems of
aromatic plants [5]. It is derived from plant material confined within a specific region of the
plant or a specific component of the plant cells. The majority of the volatile chemical
combination that makes up citrus essential oil is monoterpene hydrocarbon [4, 6]. The
majority of the citrus essential oil is found in the flavado part of the peel, with smaller
amounts found in the leaves, flowers, fruits, and seeds. Terpene hydrocarbons, oxygenated
compounds, and non-volatile compounds are three fractions that can be roughly split into the
more than a hundred different chemicals that comprise essential oils. The terpene fraction
can make up 50 to 95% of the oil. Germicidal, antioxidant, and antibacterial properties, and
anticarcinogenic activities are all present in the essential oil [7]. Some of the processes used
to obtain essential oil include hydro-distillation, solvent extraction, supercritical fluid
extraction, cold pressing, and microwave extraction. Recently, several advanced extraction
techniques, including ultrasound, microwave, enzymatic and supercritical fluid extraction,
were proposed by researchers to evaluate the relatively high volume of peels generated [8].
Some of the advantages of these advanced methods over conventional methods were less
time duration, low energy requirement, less solvent requirement, and low carbon dioxide
generation. The major constituent of citrus essential oil is limonene, a highly lipophilic cyclic
monoterpene that accounts for 68-98% of the oil's weight and up to 4% of the weight of citrus
peel waste. Limonene is a commonly used food preservation agent and is designated as a
generally recognised as safe ("GRAS") additive in the Code of Federal Regulations due to its
antioxidant properties and fragrance [1]. In actuality, limonene is essential to the global flavor
and fragrance industry. Numerous sectors have taken an interest in the existence of limonene,
a substantial component of the essential oils present in orange peel that has antibacterial,
antioxidant, biological, and herbal fragrance. C10H16 is the empirical formula for the
monoterpene limonene. It is a liquid when it is room temperature. Along with the racemic
mixture dipentene, it also exists as the optical isomers D- and L-limonene. As a precursor to
carvone or a-terpineol, limonene serves as an important industrial chemical [9].
The difficulties in disposing of trash from the juice business and fruits such as orange
peels generally caused environmental contamination. To address this issue, citrus fruit peels
can be utilized as raw material to extract essential oils for a number of residential and
industrial applications [10]. Because orange peel contains biomaterials such as essential oil,
pectin, and sugar, it may cause environmental problems if discarded, most notably water
contamination. If potentially marketable active substances, such as essential oil, could be
extracted, this concern may be transformed into a selling point [11]. Following extraction,
the peel might be used as a dry, high-protein stock feed, increasing the potential profit for the
orange juice industry. Essential oils are collected from fruit peels, flowers, leaves, stems,
roots, and seeds. They are extremely concentrated compounds. These oils are frequently
utilised in a variety of goods, including foods, pharmaceuticals, medicines, the fragrance
industry, and cosmetics, for their flavour and their medicinal or odiferous effects [12].
Essential oils are known to be subject to conversion and degradation reactions since they are
made up of a variety of various lipophilic and highly volatile components that come from a
wide range of distinct chemical families. A review of the literature on essential oil stability
found that oxidative changes and degradation reactions, which can result in changes that are
relevant to both sensory and pharmacological properties, have seldom ever been thoroughly
addressed [13]. Pires et al. reported that D-limonene can be obtained by extracting and
separating essential oils contained in citrus fruits. Essential oils are particularly abundant in
the peels of fruits, so it is efficient to extract essential oils from citrus peels. 70-90% limonene
pertains to, in fact, essential oil component extraction and d-limonene. Studies on the
separation of stimuli and evaluation and research on their physiological function activity are
being actively conducted, −D-limonene included in citrus fruits is obtainable to extract
essential oil as well as separate the oil ingredient [14].
Four provenances of Citrus aurantium L. var amara (sour orange) were used to produce
peel, leaf, and flower oils, all of which were harvested from the identical pedoclimatic and
horticultural circumstances. The GC-FID and GC-MS methods were used to analyse their
chemical composition. The constituent percentages of the various provenances showed
striking variances. According to the research proposed by Park et al., linalool/linalyl acetate
was found in petitgrain, limonene was found in peel oils, and linalool/linalyl was linked to -
pinene in neroli oils, all of which were used to describe this chemical variability [4]. Pires et
al. reported that limonene was extracted from the tangerine peel using soxhlet extraction, a
kind of simultaneous steam distillation and solvent extraction (SDE). In order to quantify the
extracted d-limonene, a reversed-phase HPLC column was used in the HPLC study. The best
extraction period in any solvent, according to the HPLC analysis results, was 2 hours, and
the extracted levels of d-limonene from tangerine peel were 7.77 mg, 0.49 mg, and 0.28 mg
in ethyl alcohol, n-hexane, and ether, respectively, per g of tangerine peel. Because ethyl
alcohol produced the best yield when used as a solvent, polarity has a greater impact on
extraction yield than boiling point [14].
After reviewing earlier studies on the essential oils of the orange and lemon peels, it is
evident that limonene has anti-inflammatory characteristics. In fact, limonene inhibits the
3
E3S Web of Conferences 455, 01005 (2023) https://doi.org/10.1051/e3sconf/202345501005
ICGEST 2023
activity of polysaccharides that drive excessive production of pro-inflammatory cytokines
(TNF-alpha) and nitrate oxide regulator of inflammation. Therefore, limonene appears to be
a potent anti-inflammatory, particularly in cases of skin irritation [15, 16]. Overall,
monoterpenes have a number of medicinal qualities, particularly insecticidal and anti-
diabetic ones. It was shown that the monoterpenes in orange essential oil exhibit larvicidal
activity against Aedes aegypti mosquito larvae in the fourth larval stage Culex pipiens [17,
18], which is the source of yellow fever [19]. Monoterpenes can imitate the qualities of
insulin, promote its secretion by repairing dead pancreatic beta cells, or even further boost its
secretion by living pancreatic beta cells in the case of type 1 diabetes, also known as insulin
dependent diabetes [20, 11]. The essential oil of Citrus sinensis epicarp has lately received
attention for its antioxidant properties, which were linked to the presence of phenolic
compounds [21].
Fruits peel from industrial or domestic waste caused contamination of the environment.
Extraction of essential oil from peel has several useful applications in industry. The purpose
of this study is to investigate the limonene content of various citrus fruits, specifically orange
and lemon. Limonene finds various applications as it is a popular additive in foods, cosmetics
and cleaning products. The oil was extracted from lemon and orange peels using the Soxhlet
technique and distilled to produce a concentrated combination of essential oil. The extracted
combination was then sent for GC - FID characterization. The limonene concentration of
orange and lemon peels was then established.
2. Materials and Methods
2.1 Materials
From different citrus fruit waste, lemon and orange peel were selected for this work. Hexane
and ethanol are commonly used solvents for essential oil extraction due to their specific
properties and advantages. Many essential oil constituents, like terpenes, are non-polar,
making hexane an efficient solvent for their extraction. Hexane tends to extract a relatively
narrow range of compounds, which can be advantageous when you want to target specific
components in the essential oil. It has a low boiling point, making it easy to remove from the
extract after the extraction process, leaving behind the essential oil. On the other hand,
Ethanol has good solvating power for a broad range of compounds, including both polar and
non-polar constituents present in essential oils. This allows for a more comprehensive
extraction of various components. Compared to some other solvents, ethanol is less toxic and
poses fewer risks when handled properly.
The chemicals used for this work were dilute nitric acid, n-hexane of laboratory grade,
ethanol of laboratory grade, along with distilled water, Whatman filter paper. All chemicals
were from Loba Chemicals. The glassware used for this work were round bottom flask,
basket heater, Soxhlet extractor (along with siphon arm), condenser, measuring cylinder,
beaker, funnel, specific gravity bottle, digital weighing scale.
2.2 Preparation of the Sample
Orange peels were cut into intermediate sized pieces (approximately 3*3 cm) and heated in
an oven at a temperature of 1000C for 20 min, 30 min and 40 min respectively. The oven was
not preheated. Orange and lemon peels were grated to obtain the zest of fresh skin. Zest of
fresh skin was ultimately used for the experimentation.
Fig. 1. Orange and Lemon Peels Zest
2.3 Extraction
The setup for Soxhlet extraction was arranged as shown in figure 2. Soxhlet extraction was
a continuous, automated extraction method used to extract compounds from a solid sample
with the helpe of a solvent. The apparatus used in Soxhlet extraction consisted of three main
parts: the extraction chamber, a round-bottom flask containing the solvent, and a condenser.
The solid sample, 50g orange zest, had been extracted and was placed in a porous thimble
made of materials such as cellulose or glass microfiber, which fits into the extraction
chamber. The appropriate solvent was chosen based on the nature of the compound that has
been extracted. For example, if non-polar compounds like essential oils were the target,
hexane might be used as the solvent. The round-bottom flask containing the solvent was
heated, causing it to evaporate and rose as vapor. The vapor was then condensed in the
condenser and dropped back into the solid sample in the extraction chamber. As the solvent
dropped back into the extraction chamber, it gradually dissolved the target compounds from
the solid sample. The dissolved compounds in the solvent gradually accumulated in the
round-bottom flask as the process continued. This accumulation leads to an increase in the
concentration of the target compounds in the solvent. The extraction process continued until
the concentration of the target compounds in the solvent reached a saturation point. At this
point, the process was considered completed. The solvent enriched with the extracted
compounds was collected in the round-bottom flask for further processing and analysis.
2.4 Distillation
The solvent and oil separated when the mixture was heated in distillation at a steady
temperature. The boiling points of the solvent was lowered than those of the majority of the
active components in the essential oil. For n-hexane the boiling point was 68.70 C, and for
ethanol it was 78.370 C. The simple distillation process continued in this manner until over
200 ml of the solvent was recovered in the beaker. The majority of the oil and a little amount
of the unseparated solvent was present in the mixture that was left behind in the rounded
bottom flask. Whatman filter paper was then used to filter the mixture to eliminate insoluble
solid particles and obtain pure oil.
4
E3S Web of Conferences 455, 01005 (2023) https://doi.org/10.1051/e3sconf/202345501005
ICGEST 2023
activity of polysaccharides that drive excessive production of pro-inflammatory cytokines
(TNF-alpha) and nitrate oxide regulator of inflammation. Therefore, limonene appears to be
a potent anti-inflammatory, particularly in cases of skin irritation [15, 16]. Overall,
monoterpenes have a number of medicinal qualities, particularly insecticidal and anti-
diabetic ones. It was shown that the monoterpenes in orange essential oil exhibit larvicidal
activity against Aedes aegypti mosquito larvae in the fourth larval stage Culex pipiens [17,
18], which is the source of yellow fever [19]. Monoterpenes can imitate the qualities of
insulin, promote its secretion by repairing dead pancreatic beta cells, or even further boost its
secretion by living pancreatic beta cells in the case of type 1 diabetes, also known as insulin
dependent diabetes [20, 11]. The essential oil of Citrus sinensis epicarp has lately received
attention for its antioxidant properties, which were linked to the presence of phenolic
compounds [21].
Fruits peel from industrial or domestic waste caused contamination of the environment.
Extraction of essential oil from peel has several useful applications in industry. The purpose
of this study is to investigate the limonene content of various citrus fruits, specifically orange
and lemon. Limonene finds various applications as it is a popular additive in foods, cosmetics
and cleaning products. The oil was extracted from lemon and orange peels using the Soxhlet
technique and distilled to produce a concentrated combination of essential oil. The extracted
combination was then sent for GC - FID characterization. The limonene concentration of
orange and lemon peels was then established.
2. Materials and Methods
2.1 Materials
From different citrus fruit waste, lemon and orange peel were selected for this work. Hexane
and ethanol are commonly used solvents for essential oil extraction due to their specific
properties and advantages. Many essential oil constituents, like terpenes, are non-polar,
making hexane an efficient solvent for their extraction. Hexane tends to extract a relatively
narrow range of compounds, which can be advantageous when you want to target specific
components in the essential oil. It has a low boiling point, making it easy to remove from the
extract after the extraction process, leaving behind the essential oil. On the other hand,
Ethanol has good solvating power for a broad range of compounds, including both polar and
non-polar constituents present in essential oils. This allows for a more comprehensive
extraction of various components. Compared to some other solvents, ethanol is less toxic and
poses fewer risks when handled properly.
The chemicals used for this work were dilute nitric acid, n-hexane of laboratory grade,
ethanol of laboratory grade, along with distilled water, Whatman filter paper. All chemicals
were from Loba Chemicals. The glassware used for this work were round bottom flask,
basket heater, Soxhlet extractor (along with siphon arm), condenser, measuring cylinder,
beaker, funnel, specific gravity bottle, digital weighing scale.
2.2 Preparation of the Sample
Orange peels were cut into intermediate sized pieces (approximately 3*3 cm) and heated in
an oven at a temperature of 1000C for 20 min, 30 min and 40 min respectively. The oven was
not preheated. Orange and lemon peels were grated to obtain the zest of fresh skin. Zest of
fresh skin was ultimately used for the experimentation.
Fig. 1. Orange and Lemon Peels Zest
2.3 Extraction
The setup for Soxhlet extraction was arranged as shown in figure 2. Soxhlet extraction was
a continuous, automated extraction method used to extract compounds from a solid sample
with the helpe of a solvent. The apparatus used in Soxhlet extraction consisted of three main
parts: the extraction chamber, a round-bottom flask containing the solvent, and a condenser.
The solid sample, 50g orange zest, had been extracted and was placed in a porous thimble
made of materials such as cellulose or glass microfiber, which fits into the extraction
chamber. The appropriate solvent was chosen based on the nature of the compound that has
been extracted. For example, if non-polar compounds like essential oils were the target,
hexane might be used as the solvent. The round-bottom flask containing the solvent was
heated, causing it to evaporate and rose as vapor. The vapor was then condensed in the
condenser and dropped back into the solid sample in the extraction chamber. As the solvent
dropped back into the extraction chamber, it gradually dissolved the target compounds from
the solid sample. The dissolved compounds in the solvent gradually accumulated in the
round-bottom flask as the process continued. This accumulation leads to an increase in the
concentration of the target compounds in the solvent. The extraction process continued until
the concentration of the target compounds in the solvent reached a saturation point. At this
point, the process was considered completed. The solvent enriched with the extracted
compounds was collected in the round-bottom flask for further processing and analysis.
2.4 Distillation
The solvent and oil separated when the mixture was heated in distillation at a steady
temperature. The boiling points of the solvent was lowered than those of the majority of the
active components in the essential oil. For n-hexane the boiling point was 68.70 C, and for
ethanol it was 78.370 C. The simple distillation process continued in this manner until over
200 ml of the solvent was recovered in the beaker. The majority of the oil and a little amount
of the unseparated solvent was present in the mixture that was left behind in the rounded
bottom flask. Whatman filter paper was then used to filter the mixture to eliminate insoluble
solid particles and obtain pure oil.
5
E3S Web of Conferences 455, 01005 (2023) https://doi.org/10.1051/e3sconf/202345501005
ICGEST 2023
Fig. 2. Soxhlet Extraction
2.5 Characterization
The characterization of the distilled mixture was done by GC - FID process. The GC -FID
analysis process was conducted in Wellia Labs, Pune, Maharashtra, India where the samples
were provided and the lab after running the tests provided the results which are mentioned in
the paper further.
By injecting 1.0 L of an essential oil and hexane solution into a chromatograph (HP Agilent
7890A), the chemical analysis of the produced essential oil was carried out. At a flow rate of
30 mL/min, nitrogen served as the carrier gas. The column is an HP 5 capillary column with
a length of 30 m and an internal diameter of 0.32 mm. The stationary phase had a 0.25 m
thickness. The oven's temperature was programmed to be 120 °C for 6 minutes before
increasing by 10 °C/min to 260 °C in 5 minutes. The flame ionisation detector (FID) was
employed in this work. Everything there was managed by a computer using the National
Institute of Standards and Technology (NIST) database which allowed the identification of
compounds.
3. Result and Discussion
The extracted essential oils were clear, orange yellow in colour for oranges and pale yellow
green for lemons. Orange peel essential oil had a sweet, fruity aroma, while lemon essential
oil had a fresh, beautiful lemon aroma as well as distinct pinene and terpinene aromas. Seven
runs were conducted using various combinations of feed and solvent. The combination giving
the best results was selected and a final run was performed.
3.1 Orange Peel Essential Oil
Table 1 presents a comparison of all the runs performed with orange peels zest.
Table 1. Comparison Table of Orange Peels Runs
RUN 1
RUN 2
RUN 3
RUN 4
RUN 7
SOXHLET EXTRACTION
Feed
30 g
Orange Zest
50 g
Orange Zest
50 g
Dried Orange
50 g
Orange Zest
50 g
Orange Zest
Solvent (mL)
300
Hexane
300
Hexane
300
Hexane
300
Hexane
300
Ethanol
Time (min)
60
120
120
60
60
Temperature
(degree C)
70
80
80
70
75
Density of Extract
(g/mL)
0.84
0.85
0.99
0.90
0.72
DISTILLATION
Time (min)
60
60
60
70
60
Temperature
(degree C)
70
80
80
70
70
Separated Hexane
(mL)
200
200
221
200
200
Density of Hexane
(g/mL)
0.85
0.85
0.98
0.85
0.79
Density of Oil
(g/mL)
0.89
0.97
0.62
0.96
0.89
Amount of Oil
Extracted (g)
30
32
28
36.27
33
Yield of Extraction
(%)
100
64
56
72.54
66
Fig. 3 Amount of Oil Extracted from Orange Peel (g) in Different Runs
6
E3S Web of Conferences 455, 01005 (2023) https://doi.org/10.1051/e3sconf/202345501005
ICGEST 2023
Fig. 2. Soxhlet Extraction
2.5 Characterization
The characterization of the distilled mixture was done by GC - FID process. The GC -FID
analysis process was conducted in Wellia Labs, Pune, Maharashtra, India where the samples
were provided and the lab after running the tests provided the results which are mentioned in
the paper further.
By injecting 1.0 L of an essential oil and hexane solution into a chromatograph (HP Agilent
7890A), the chemical analysis of the produced essential oil was carried out. At a flow rate of
30 mL/min, nitrogen served as the carrier gas. The column is an HP 5 capillary column with
a length of 30 m and an internal diameter of 0.32 mm. The stationary phase had a 0.25 m
thickness. The oven's temperature was programmed to be 120 °C for 6 minutes before
increasing by 10 °C/min to 260 °C in 5 minutes. The flame ionisation detector (FID) was
employed in this work. Everything there was managed by a computer using the National
Institute of Standards and Technology (NIST) database which allowed the identification of
compounds.
3. Result and Discussion
The extracted essential oils were clear, orange yellow in colour for oranges and pale yellow
green for lemons. Orange peel essential oil had a sweet, fruity aroma, while lemon essential
oil had a fresh, beautiful lemon aroma as well as distinct pinene and terpinene aromas. Seven
runs were conducted using various combinations of feed and solvent. The combination giving
the best results was selected and a final run was performed.
3.1 Orange Peel Essential Oil
Table 1 presents a comparison of all the runs performed with orange peels zest.
Table 1. Comparison Table of Orange Peels Runs
RUN 1
RUN 2
RUN 3
RUN 4
RUN 7
SOXHLET EXTRACTION
Feed
30 g
Orange Zest
50 g
Orange Zest
50 g
Dried Orange
50 g
Orange Zest
50 g
Orange Zest
Solvent (mL)
300
Hexane
300
Hexane
300
Hexane
300
Hexane
300
Ethanol
Time (min)
60
120
120
60
60
Temperature
(degree C)
70
80
80
70
75
Density of Extract
(g/mL)
0.84
0.85
0.99
0.90
0.72
DISTILLATION
Time (min)
60
60
60
70
60
Temperature
(degree C)
70
80
80
70
70
Separated Hexane
(mL)
200
200
221
200
200
Density of Hexane
(g/mL)
0.85
0.85
0.98
0.85
0.79
Density of Oil
(g/mL)
0.89
0.97
0.62
0.96
0.89
Amount of Oil
Extracted (g)
30
32
28
36.27
33
Yield of Extraction
(%)
100
64
56
72.54
66
Fig. 3 Amount of Oil Extracted from Orange Peel (g) in Different Runs
7
E3S Web of Conferences 455, 01005 (2023) https://doi.org/10.1051/e3sconf/202345501005
ICGEST 2023
Fig. 4 Yield of Extraction of Orange Essential Oil (%) in Different Runs
The comparison between dried orange peel samples and orange peel zest samples shows how
much less oil was extracted when dried orange peel samples were used in run 3. In run 3 oil
obtained was 28 g. In run 1, 2, and 4 N-hexane was used as solvent and obtained 30, 32, and
36.27 g oil respectively as shown in figure 3. While in run 6, oil obtained was 33 g with
ethanol as the solvent. Run 4 yielded the highest amount of oil, 36.27 g. Figure 4 shows a
graph with the extraction yield shown on it. Since 100% yield is almost impossible after
extraction and distillation, Run 1's 100% yield suggests that the oil's n-hexane level was
exceptionally high.
In terms of output, runs 4 produces the best results for Orange Peels. In order to confirm the
accuracy of all runs, multiple runs were taken with the same feed, solvent, time and
temperature conditions. The following table 2 includes the results:
Table 2. Extraction Yield for Orange Peel (Run 4)
RUN 4
Feed + Solvent
50g Orange Zest + 300 mL
Hexane
Density of Oil
0.96 g/mL
Amount of Oil Extracted
36.27 g
Yield of Extraction (%)
72.54%
A percentage of the relative weight of the essential oil extracted from the peel weight was
used to measure the extraction yield. The yield of the extraction, which is extremely high in
proportion to the original weight collected, was 72.54% for orange zest as shown in Table 2.
For the GC-FID analysis, orange peel zest and n-hexane (RUN 4) was provided. The
chromatogram displayed in Fig. 5 has been generated by the GC-FID analysis.
Fig. 5 GC - FID of Orange Peels
Table 3. GC-FID Analysis and Output for Orange Essential Oil
Compounds
Peels
Content (%)
Retention Time
(minutes)
Limonene
(Both Dextrorotatory and
Levorotatory together)
Orange
80
7.370
Analyses have shown 28 volatile compounds in orange peel essential oil. Of them, 32% are
terpene compounds, 50% are alcohol, and 18% are formaldehyde. GC – FID chromatogram
of the orange peel oil extract displayed 16 identified peaks. The results, including the orders
of elution as well as the relative peak areas, are in accordance with the NF ISO 855 standard
where most of the components guarantee the quality of this essential oil, its origin and method
of production. Orange peels had a much higher percentage of Limonene. Although it is
expected that oranges will contain more than 90% limonene, due to water content in the
solvent and flaws in the equipment, this percentage for orange peels has almost been lowered
by 10%.
3.2 Lemon Peel Essential Oil
For Lemon Peels, Run 5 yields the best results in terms of output. Multiple runs were taken
keeping the feed, solvent, time and temperature same, and yet same output as that of Run 5
was observed every time. The outcomes are shown in table 4 below:
Table 4. Comparison Table of Lemon Peels Runs
RUN 5
RUN 6
SOXHLET EXTRACTION
Feed
50 g
Lemon
Zest
50 g
Lemon
Zest
Solvent (mL)
300
Hexane
300
Ethanol
Time (min)
60
60
Temperature
(degree C)
75
75
Density of Extract
(g/mL)
0.80
0.78
8
E3S Web of Conferences 455, 01005 (2023) https://doi.org/10.1051/e3sconf/202345501005
ICGEST 2023
Fig. 4 Yield of Extraction of Orange Essential Oil (%) in Different Runs
The comparison between dried orange peel samples and orange peel zest samples shows how
much less oil was extracted when dried orange peel samples were used in run 3. In run 3 oil
obtained was 28 g. In run 1, 2, and 4 N-hexane was used as solvent and obtained 30, 32, and
36.27 g oil respectively as shown in figure 3. While in run 6, oil obtained was 33 g with
ethanol as the solvent. Run 4 yielded the highest amount of oil, 36.27 g. Figure 4 shows a
graph with the extraction yield shown on it. Since 100% yield is almost impossible after
extraction and distillation, Run 1's 100% yield suggests that the oil's n-hexane level was
exceptionally high.
In terms of output, runs 4 produces the best results for Orange Peels. In order to confirm the
accuracy of all runs, multiple runs were taken with the same feed, solvent, time and
temperature conditions. The following table 2 includes the results:
Table 2. Extraction Yield for Orange Peel (Run 4)
RUN 4
Feed + Solvent
50g Orange Zest + 300 mL
Hexane
Density of Oil
0.96 g/mL
Amount of Oil Extracted
36.27 g
Yield of Extraction (%)
72.54%
A percentage of the relative weight of the essential oil extracted from the peel weight was
used to measure the extraction yield. The yield of the extraction, which is extremely high in
proportion to the original weight collected, was 72.54% for orange zest as shown in Table 2.
For the GC-FID analysis, orange peel zest and n-hexane (RUN 4) was provided. The
chromatogram displayed in Fig. 5 has been generated by the GC-FID analysis.
Fig. 5 GC - FID of Orange Peels
Table 3. GC-FID Analysis and Output for Orange Essential Oil
Compounds
Peels
Content (%)
Retention Time
(minutes)
Limonene
(Both Dextrorotatory and
Levorotatory together)
Orange
80
7.370
Analyses have shown 28 volatile compounds in orange peel essential oil. Of them, 32% are
terpene compounds, 50% are alcohol, and 18% are formaldehyde. GC – FID chromatogram
of the orange peel oil extract displayed 16 identified peaks. The results, including the orders
of elution as well as the relative peak areas, are in accordance with the NF ISO 855 standard
where most of the components guarantee the quality of this essential oil, its origin and method
of production. Orange peels had a much higher percentage of Limonene. Although it is
expected that oranges will contain more than 90% limonene, due to water content in the
solvent and flaws in the equipment, this percentage for orange peels has almost been lowered
by 10%.
3.2 Lemon Peel Essential Oil
For Lemon Peels, Run 5 yields the best results in terms of output. Multiple runs were taken
keeping the feed, solvent, time and temperature same, and yet same output as that of Run 5
was observed every time. The outcomes are shown in table 4 below:
Table 4. Comparison Table of Lemon Peels Runs
RUN 5
RUN 6
SOXHLET EXTRACTION
Feed
50 g
Lemon
Zest
50 g
Lemon
Zest
Solvent (mL)
300
Hexane
300
Ethanol
Time (min)
60
60
Temperature
(degree C)
75
75
Density of Extract
(g/mL)
0.80
0.78
9
E3S Web of Conferences 455, 01005 (2023) https://doi.org/10.1051/e3sconf/202345501005
ICGEST 2023
DISTILLATION
Time (min)
60
60
Temperature
(degree C)
70
70
Separated Hexane
(mL)
200
200
Density of Hexane
(g/mL)
0.88
0.79
Density of Oil
(g/mL)
0.95
0.84
Amount of Oil
Extracted (g)
38
34
Yield of Extraction
(%)
76
68
Fig. 6 Graph Representing the Amount of Oil Fig. 7 Yield of Extraction of Lemon Essential Oil
Extracted from Lemon Peel (g) (%) in Different Runs
Table 5 shows that run 5 produced the most oil, 38 g and 76% yield, compared to any run.
Whereas, run 6 produced only 34 g of oil and yield was 68%. The extraction yield was
calculated as a fraction of the relative weight of the essential oil extracted from the peel
weight. For lemon zest, the extraction yield, which is incredibly high in comparison to the
initial weight gathered, was 76%. The main components of lemon peel essential oil, in
addition to limonene, were β-pinene and γ-terpinene, which were present in amounts of 5-
12% and 5- 10%, respectively. The lemon essential oil also contains the volatile substances
sabinene, linalool, terpinen-4-ol, α-terpineol, octanal, and myrcene.
For the GC-FID analysis, lemon peel zest and n-hexane (RUN 5) was provided. The
chromatogram displayed in Fig. 8 has been generated by the GC-FID analysis.
Fig. 8 GC -FID of Lemon Peels
Table 4. GC-FID Analysis and Output for Lemon Essential Oil
Compounds
Peels
Content (%)
Retention Time
(minutes)
Limonene (D and L)
Lemon
70
7.364
As a reference method for separating volatile chemicals, lemon essential oil derived using
the Soxhlet extraction process was analysed by GC. This is because the chemical composition
of essential oils varies based on the season, the place of origin, and the extraction method.
For a semi-quantitative method, the main chemicals were determined using a GC-FID
analysis. The lemon peel oil extract's GC-FID chromatogram showed 13 recognised peaks.
3.3Comparison of Orange and Lemon Peel Essential Oil
A comparative study between orange and lemon essential oils shows that orange peels yield
a better amount of extract and density of oil in comparison to the lemon peels. Orange peels
and lemon peels contain 80% and 70% of limonene, respectively. This is negligible in
comparison to the range of 90%+ and 70–90% limonene that a good essential oil extraction
should include [10]. This low proportion may be related to the extraction process, including
the presence of water and other contaminants in the solvent. Additionally, the locally
produced equipment's shortcomings are partly responsible for the lower amount of limonene
found in each of these essential oils.
Fig. 9 Graph Showing a Comparison between the Amount of Oil Extracted from Orange and lemon
Essential Oil
10
E3S Web of Conferences 455, 01005 (2023) https://doi.org/10.1051/e3sconf/202345501005
ICGEST 2023
DISTILLATION
Time (min)
60
60
Temperature
(degree C)
70
70
Separated Hexane
(mL)
200
200
Density of Hexane
(g/mL)
0.88
0.79
Density of Oil
(g/mL)
0.95
0.84
Amount of Oil
Extracted (g)
38
34
Yield of Extraction
(%)
76
68
Fig. 6 Graph Representing the Amount of Oil Fig. 7 Yield of Extraction of Lemon Essential Oil
Extracted from Lemon Peel (g) (%) in Different Runs
Table 4 shows that run 5 produced the most oil, 38 g and 76% yield, compared to any run.
Whereas, run 6 produced only 34 g of oil and yield was 68%. The extraction yield was
calculated as a fraction of the relative weight of the essential oil extracted from the peel
weight. For lemon zest, the extraction yield, which is incredibly high in comparison to the
initial weight gathered, was 76%. The main components of lemon peel essential oil, in
addition to limonene, were β-pinene and γ-terpinene, which were present in amounts of 5-
12% and 5-10%, respectively. The lemon essential oil also contains the volatile substances
sabinene, linalool, terpinen-4-ol, α-terpineol, octanal, and myrcene.
For the GC-FID analysis, lemon peel zest and n-hexane (RUN 5) was provided. The
chromatogram displayed in Fig. 8 has been generated by the GC-FID analysis.
Fig. 8 GC - FID of Lemon Peels
Table 5. GC-FID Analysis and Output for Lemon Essential Oil
Compounds
Peels
Content (%)
Retention Time
(minutes)
Limonene (D and L)
Lemon
70
7.364
As a reference method for separating volatile chemicals, lemon essential oil derived using
the Soxhlet extraction process was analysed by GC. This is because the chemical composition
of essential oils varies based on the season, the place of origin, and the extraction method.
For a semi-quantitative method, the main chemicals were determined using a GC-FID
analysis. The lemon peel oil extract's GC-FID chromatogram showed 13 recognised peaks.
3.3 Comparison of Orange and Lemon Peel Essential Oil
A comparative study between orange and lemon essential oils shows that orange peels yield
a better amount of extract and density of oil in comparison to the lemon peels. Orange peels
and lemon peels contain 80% and 70% of limonene, respectively. This is negligible in
comparison to the range of 90%+ and 70–90% limonene that a good essential oil extraction
should include [10]. This low proportion may be related to the extraction process, including
the presence of water and other contaminants in the solvent. Additionally, the locally
produced equipment's shortcomings are partly responsible for the lower amount of limonene
found in each of these essential oils.
Fig. 9 Graph Showing a Comparison between the Amount of Oil Extracted from Orange and lemon
Essential Oil
11
E3S Web of Conferences 455, 01005 (2023) https://doi.org/10.1051/e3sconf/202345501005
ICGEST 2023
Fig. 10 Graph Showing a Comparison between the Yield of Extraction of Orange and Lemon
Essential Oil (%)
Fig. 11 Run 4 and Run 5 Sample Bottles for Analysis
Santerre et al. studied detection of essential oils in citrus fruits peel and obtained 67% of the
limonene content in lemon peel extract [22]. While in this study we obtained 70% of
limonene from lemon peel with hexane solvent which was higher than reported values.
Golmohammadi, et al. studied limonene extraction from citrus fruits peel by steam explosion
method and obtained 77% of limonene from orange peel [23]. In this study we obtained 80%
of limonene from orange peel using hexane solvent which was higher than reported value. In
literature it was reported that the other major components of orange peel oil are linalool, β-
myrcene, and α-pinene and that of lemon peel oil are limonene, β-pinene, and γ-terpinene
[24]. Similar results we obtained in this work. Orange peels contain 28 volatile substances,
of which limonene is believed to be responsible for giving it its unique smell that
distinguishes it apart from other citrus fruits. Out of 28 volatile compounds present, 32% are
terpene compounds, 50% are alcohol, and 18% are formaldehyde. The main components of
lemon peel essential oil, in addition to limonene, were found to be β-pinene and γ-terpinene,
which were present in amounts of 5-12% and 5- 10%, respectively. The lemon essential oil
also contains the volatile substances sabinene, linalool, terpinen-4-ol, α-terpineol, octanal,
and myrcene.
4. Conclusion
The Soxhlet extraction method is effective in obtaining orange and lemon peel oils. From all
the runs conducted the 4th and 5th runs yielded the highest amounts of oil 36.27g and 38g
respectively. Dried orange peel samples yield less oil than orange peel zest samples as
limonene is a volatile component which gets vaporized on heating the peels. N-hexane is a
better solvent for extracting oil from orange and lemon peels than ethanol which is evident
by the multiple runs conducted. Limonene is the major component of both oils responsible
for the characteristic aroma, but it is present at a higher concentration in orange peel oil.
Through GC-FID characterization, it was evident that limonene content in orange peel oil
was 80% and that in lemon peel oil it was 70%. The combination of the Soxhlet extraction
method and GC-FID analysis has played a major role in unraveling the complicated chemical
composition of the essential oils derived from orange and lemon peels. The highest yield of
76.54% limonene was obtained from orange peel as compared to lemon peel with hexane
solvent. The significance of extraction parameters becomes clearly evident, with factors like
solvent selection and extraction duration over oil yield.
References
1. Ozturk, Baranse. "Green Processes for Deterpenation of Essential Oils and Extraction
of Bioactive Compounds from Orange Peel Waste", The University of Manchester
(United Kingdom), (2020)
2. Chanthaphon A., Chanthachum, S. and Hongpattarakere T. Antimicrobial Activities of
Essential Oils and Crude Extracts from Tropical Citrus spp. Food-Related
Microorganisms. Songklanakarin J. Sci. Technol. 30(1): 125-131 (2008)
3. Mohamed, N.A.B. Study on Important Parameters Affecting the Hydro-Distillation for
Ginger Oil Production. M. Eng. Thesis, UniversitiTeknologi, Malaysia (2005)
4. Park, Sang & Ko, Kwan & Kim, In. Optimization of d-limonene Extraction from
Tangerine Peel in Various Solvents by Using Soxhlet Extractor. Korean Chemical
Engineering Research. 53. 717-722. 10.9713/kcer.2015.53.6.717 (2015)
5. Kehinde Oluwakemi Fagbemi, Daniel Ayandiran Aina, and Olufunmiso Olusola
Olajuyigbe ‘Soxhlet Extraction versus Hydrodistillation Using the Clevenger
Apparatus: A Comparative Study on the Extraction of a Volatile Compound from
Tamarindus indica Seeds’ Volume 2021
6. Muhammad M. Effects of Different Extraction Methods on Yield of Essential Oil from
Orange Peels. Under graduate Thesis, Abubakar Tafawa Balewa University, Bauchi,
Nigeria (2017)
7. Kusuma, Heri & AFP, Putra. Comparison of Two Isolation Methods for Essential Oils
from Orange Peel (Citrus auranticum L) as a Growth Promoter for Fish: Microwave
Steam Distillation and Conventional Steam Distillation. Journal of Aquaculture
Research & Development. 7. 1-5. 10.4172/2155-9546.1000409 (2016)
8. Gavahian, M., Chu, Y.-H. and Mousavi Khaneghah, A, Recent advances in the orange
oil extraction: an opportunity for the valorization of orange peel waste a review. Int J
Food Sci Technol, 54: 925-932 (2019)
9. Mansour Golmohammadi, Alimohammad Borghei, Ali Zenouzi, Nariman Ashrafi,
Mohammad J.Taherzadeh. "Optimization of essential oil extraction from orange peels
using steam explosion", Heliyon, (2018)
10. Patricia, Kammegne & Oden Bella, Martial Gervais & Yvonne, Dongo. Phytochemical
Screening of Essential Oil of Citrus sinensis by Gas Chromatography-Flame Ionization
Detector. Journal of Agricultural Science and Technology B.5. 10.17265/2161-
6264/2015.03B.005 (2015)
11. Muhammad, N. O., Soji-Omoniwa, O., Usman, L. A., and Omoniwa, B. P.
“Antihyperglycemic Activity of Leaf Essential Oil of Citrus sinensis (L.) Osbeck on
Alloxan Induced Diabetic Rats.” Annual Review and Research in Biology 3 (4): 825-
34 (2013)
12
E3S Web of Conferences 455, 01005 (2023) https://doi.org/10.1051/e3sconf/202345501005
ICGEST 2023
Fig. 10 Graph Showing a Comparison between the Yield of Extraction of Orange and Lemon
Essential Oil (%)
Fig. 11 Run 4 and Run 5 Sample Bottles for Analysis
Santerre et al. studied detection of essential oils in citrus fruits peel and obtained 67% of the
limonene content in lemon peel extract [22]. While in this study we obtained 70% of
limonene from lemon peel with hexane solvent which was higher than reported values.
Golmohammadi, et al. studied limonene extraction from citrus fruits peel by steam explosion
method and obtained 77% of limonene from orange peel [23]. In this study we obtained 80%
of limonene from orange peel using hexane solvent which was higher than reported value. In
literature it was reported that the other major components of orange peel oil are linalool, β-
myrcene, and α-pinene and that of lemon peel oil are limonene, β-pinene, and γ-terpinene
[24]. Similar results we obtained in this work. Orange peels contain 28 volatile substances,
of which limonene is believed to be responsible for giving it its unique smell that
distinguishes it apart from other citrus fruits. Out of 28 volatile compounds present, 32% are
terpene compounds, 50% are alcohol, and 18% are formaldehyde. The main components of
lemon peel essential oil, in addition to limonene, were found to be β-pinene and γ-terpinene,
which were present in amounts of 5-12% and 5- 10%, respectively. The lemon essential oil
also contains the volatile substances sabinene, linalool, terpinen-4-ol, α-terpineol, octanal,
and myrcene.
4. Conclusion
The Soxhlet extraction method is effective in obtaining orange and lemon peel oils. From all
the runs conducted the 4th and 5th runs yielded the highest amounts of oil 36.27g and 38g
respectively. Dried orange peel samples yield less oil than orange peel zest samples as
limonene is a volatile component which gets vaporized on heating the peels. N-hexane is a
better solvent for extracting oil from orange and lemon peels than ethanol which is evident
by the multiple runs conducted. Limonene is the major component of both oils responsible
for the characteristic aroma, but it is present at a higher concentration in orange peel oil.
Through GC-FID characterization, it was evident that limonene content in orange peel oil
was 80% and that in lemon peel oil it was 70%. The combination of the Soxhlet extraction
method and GC-FID analysis has played a major role in unraveling the complicated chemical
composition of the essential oils derived from orange and lemon peels. The highest yield of
76.54% limonene was obtained from orange peel as compared to lemon peel with hexane
solvent. The significance of extraction parameters becomes clearly evident, with factors like
solvent selection and extraction duration over oil yield.
References
1. Ozturk, Baranse. "Green Processes for Deterpenation of Essential Oils and Extraction
of Bioactive Compounds from Orange Peel Waste", The University of Manchester
(United Kingdom), (2020)
2. Chanthaphon A., Chanthachum, S. and Hongpattarakere T. Antimicrobial Activities of
Essential Oils and Crude Extracts from Tropical Citrus spp. Food-Related
Microorganisms. Songklanakarin J. Sci. Technol. 30(1): 125-131 (2008)
3. Mohamed, N.A.B. Study on Important Parameters Affecting the Hydro-Distillation for
Ginger Oil Production. M. Eng. Thesis, UniversitiTeknologi, Malaysia (2005)
4. Park, Sang & Ko, Kwan & Kim, In. Optimization of d-limonene Extraction from
Tangerine Peel in Various Solvents by Using Soxhlet Extractor. Korean Chemical
Engineering Research. 53. 717-722. 10.9713/kcer.2015.53.6.717 (2015)
5. Kehinde Oluwakemi Fagbemi, Daniel Ayandiran Aina, and Olufunmiso Olusola
Olajuyigbe ‘Soxhlet Extraction versus Hydrodistillation Using the Clevenger
Apparatus: A Comparative Study on the Extraction of a Volatile Compound from
Tamarindus indica Seeds’ Volume 2021
6. Muhammad M. Effects of Different Extraction Methods on Yield of Essential Oil from
Orange Peels. Under graduate Thesis, Abubakar Tafawa Balewa University, Bauchi,
Nigeria (2017)
7. Kusuma, Heri & AFP, Putra. Comparison of Two Isolation Methods for Essential Oils
from Orange Peel (Citrus auranticum L) as a Growth Promoter for Fish: Microwave
Steam Distillation and Conventional Steam Distillation. Journal of Aquaculture
Research & Development. 7. 1-5. 10.4172/2155-9546.1000409 (2016)
8. Gavahian, M., Chu, Y.-H. and Mousavi Khaneghah, A, Recent advances in the orange
oil extraction: an opportunity for the valorization of orange peel waste a review. Int J
Food Sci Technol, 54: 925-932 (2019)
9. Mansour Golmohammadi, Alimohammad Borghei, Ali Zenouzi, Nariman Ashrafi,
Mohammad J.Taherzadeh. "Optimization of essential oil extraction from orange peels
using steam explosion", Heliyon, (2018)
10. Patricia, Kammegne & Oden Bella, Martial Gervais & Yvonne, Dongo. Phytochemical
Screening of Essential Oil of Citrus sinensis by Gas Chromatography-Flame Ionization
Detector. Journal of Agricultural Science and Technology B.5. 10.17265/2161-
6264/2015.03B.005 (2015)
11. Muhammad, N. O., Soji-Omoniwa, O., Usman, L. A., and Omoniwa, B. P.
“Antihyperglycemic Activity of Leaf Essential Oil of Citrus sinensis (L.) Osbeck on
Alloxan Induced Diabetic Rats.” Annual Review and Research in Biology 3 (4): 825-
34 (2013)
13
E3S Web of Conferences 455, 01005 (2023) https://doi.org/10.1051/e3sconf/202345501005
ICGEST 2023
12. Giwa, Saidat & Muhammad, Mahmood & GIWA, Abdulwahab. Utilizing orange peels
for essential oil production. Journal of Engineering and Applied Sciences. 13. (2018)
13. Tsegayefekadu, & Seifu, Tesfaye & Mitiku, Abambagade. Extraction of Essential Oil
from Orange Peel using Different Methods and Effect of Solvents, Time, and
Temperature to Maximize Yield (2020)
14. Sandra Félix, Joana Araújo, Ana Maria Pires, Ana Cláudia Sousa, Soap production: A
green perspective, Waste Management, Volume 66, Pages 190-195 (2017)
15. Chanthaphon A., Chanthachum, S. and Hongpattarakere T. Antimicrobial Activities of
Essential Oils and Crude Extracts from Tropical Citrus spp. Food-Related
Microorganisms. Songklanakarin J. Sci. Technol. 30(1): 125-131.
16. Yoon, W. J., Lee, N. H., and Hyun, C. G. “Limonene Suppresses Lipopolysaccharide-
Induced Production of Nitric Oxide Prostaglandin E2 and Pro-inflammatory Cytokines
in RAW 264.7 Macrophages.” J. Oleo Sci. 59 (8): 415-21 (2010)
17. Shalaby, A. A., Allam, K. A., Mostafa, A. A., and Fahmy, S. M. “Insecticidal
Properties of Citrus Oil against Culex pipiens and Musca domestica.” J. Egyptian Soc.
Parasitol. 28 (2): 595-606 (1998)
18. Zahran, H. E. D. M., and Abdelgaleil, S. A. M. “Insecticidal and Developmental
Inhibitory Properties of Monoterpenes on Culex pipiens L. (Diptera: Culicidae).” J.
Asia-Pacific Entomol. 14 (1): 46-51 (2010)
19. Amusan, A. A., Idowu, A. B., and Arowolo, F. S. “Comparative Toxicity Effect of Bush
Tea Leaves (Hyptis suaveolens) and Orange Peel (Citrus sinensis) Oil Extract on
Larval of the Yellow Fever Mosquito Aedes aegypti.” Tanz. Health Res Bull. 7 (3): 174-
8 (2005)
20. Tavafi, M., Ahmadvand, H., Tamjidipoor, A., Delfanc, B., and Khalatbarid, A. R.
“Satureja khozestanica Essential Oil Ameliorates Progression of Diabetic Nephropathy
in Uninephrectomized Diabetic Rats.” Tissue and Cell Journal 43 (1): 45-51 (2011)
21. Ghulam-Kamal, M., Yasinashraf, M., Izazhussain, A., Shahzadi, A., and Chughtai, M.
I. 2013. “Antioxidant Potential of Peel Essential Oils of Three Pakistani Citrus Species:
Citrus reticulata, Citrus sinensis and Citrus paradisii.” Pak. J. Bot. 45 (4): 1449-54.
22. Santerre, Cyrille & eldra, Delannay & Franco, Pilar & Nadine, Vallet & Touboul,
David. Comparison of Supercritical Fluid Chromatography Hyphenated to an
Ultraviolet Detector and Gas Chromatography Hyphenated to a Flame Ionization
Detector for Qualitative and Quantitative Analysis of Citrus Essential Oils. Separations.
9. 183. 10.3390/separations9070183 (2022)
23. Golmohammadi, Mansour & Borghei, Alimohammad & Zenouzi, Ali & Ashrafi,
Nariman & Taherzadeh, Mohammad. Optimization of essential oil extraction from
orange peels using steam explosion. Heliyon. 4. e00893.
10.1016/j.heliyon.2018.e00893 (2018)
24. Oil of Lemon (Citrus limon (L.) Burm. F.), Obtained by Expression, 2nd ed.;
International Organization for Standardization: Geneva, Switzerland, (2003)
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ICGEST 2023
