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Characteristics Variation of Lavender Oil Produced by Different Hydrodistillation Techniques

Authors:
  • CSIR - Central Institute of Medicinal and Aromatic Plants

Abstract

Lavender (Lavandula angustifolia Mill.) grown in the agro-climatic conditions of western Himalaya was processed for extraction of volatile oil by different hydrodistillation techniques which revealed that water distillation of the herb produced higher yield (1.6%) than that of water-steam distillation (1.1%) and steam distillation methods (0.9%). The samples were analysed by GC and GC-MS to study and compare the essential oil composition and observed that the highest monoterpene hydrocarbon (10.05 %) and sesquiterpenoid (10.28%) content was observed in the oil produced by steam distillation method followed by water-steam distillation (6.31% and 7.73%) and water distillation (5.62% and 3.18%, respectively) methods. Higher ester content (50.44%) was observed in the oil produced by water-steam distillation followed by steam distillation (41.29%) and water distillation (35.52%). Linalyl acetate, one of the quality determining constituents of lavender oil, was recovered in higher amount from the oil produced by water-steam distillation (47.1%). The lowest linalyl acetate (30.01%) was recovered in the oil produced by water distillation method followed by steam distillation method (35.28%). On the contrary, the total alcohol content was found in higher quantities in the oil produced by water distillation method (52.32%) followed by steam distillation method (35.58%) and lowest in water steam distillation method (31.86%). These variations in the quality of lavender oil produced by different hydrodistillation methods could be due to the thermal degradations during the process and number of other chemical reactions such as allylic rearrangements, hydrolysis, elimination etc. Based on the present experimental condition, it is recommended that the lavender oil, on commercial scale, may be produced preferably by water-steam distillation method to reduce the by-product formation by various chemical reactions and to get better oil recoveries. Furthermore, the capital investment for the water-steam distillation unit will be much lower than the steam distillation system, as it wouldn’t require a separate boiler.
Comp. of Bio. Nat. Pro., Vol. 8 – Quality Control & Standardization122
7
Characteristics Variation of Lavender Oil
Produced by Different Hydrodistillation
Techniques
G.D. KIRAN BABU AND BIKRAM SINGH
Natural Plant Products Division, Institute of Himalayan Bioresource Technology
(CSIR), P.O. Box No. 6, Palampur – 176 061, Himachal Pradesh, India
Corresponding author : E-mail : gdkiran@ihbt.res.in
IHBT Communication Number: 0838.
ABSTRACT
Lavender (Lavandula angustifolia Mill.) grown in the agro-climatic
conditions of western Himalaya was processed for extraction of volatile
oil by different hydrodistillation techniques which revealed that water
distillation of the herb produced higher yield (1.6%) than that of
water-steam distillation (1.1%) and steam distillation methods (0.9%).
The samples were analysed by GC and GC-MS to study and compare
the essential oil composition and observed that the highest
monoterpene hydrocarbon (10.05 %) and sesquiterpenoid (10.28%)
content was observed in the oil produced by steam distillation method
followed by water-steam distillation (6.31% and 7.73%) and water
distillation (5.62% and 3.18%, respectively) methods. Higher ester
content (50.44%) was observed in the oil produced by water-steam
distillation followed by steam distillation (41.29%) and water
distillation (35.52%). Linalyl acetate, one of the quality determining
constituents of lavender oil, was recovered in higher amount from
the oil produced by water-steam distillation (47.1%). The lowest
linalyl acetate (30.01%) was recovered in the oil produced by water
distillation method followed by steam distillation method (35.28%).
On the contrary, the total alcohol content was found in higher
quantities in the oil produced by water distillation method (52.32%)
followed by steam distillation method (35.58%) and lowest in water-
Characteristics Variation of Lavender Oil produced by Different
Hydrodistillation Techniques
123
INTRODUCTION
True lavender (Lavandula angustifolia Mill. Syn. L. officinalis Chainx.)
is distributed in the mountainous districts of southern Europe,
bordering of western half of Mediterranean and extending from the
eastern coast of Spain, France, Switzerland, North Italy, Corsica and
north Africa. About twenty years back, an effort was made to cultivate
this plant on large scale in Kashmir valley in India to meet the
requirements of Indian market. However, commercial production did
not increase due to political disturbances (Vaze, 2000). India imports
100 tons lavender oil annually (Shawl et al., 2005). In this regard,
Institute of Himalayan Bioresource Technology, Palampur, initiated
the extension of the plantation and commissioned distillation units
in district Chamba, Himachal Pradesh, India with an objective to
produce sufficient quantities for meeting the industry requirement.
Lavender oil, obtained from the flowering tips, is used in
aromatherapy and has calmative, anti-flatulence, and anti-colic
properties (Lis-Balchin and Hart, 1999). The primary use of lavender
oils, however, is as raw ingredients in industrial perfume and
fragrance materials, with the bulk of this market filled by lavandin
oil. (McGimpsey & Porter, 1999). Lavender oil is characterized by
high levels of linalool and linalyl acetate, moderate levels of lavandulyl
acetate, terpinen-4-ol and lavandulol.
Inadequacy in Hydrodistillation
Hydrodistillation of essential oils suffer several limitations in isolating
and preserving the composition of natural fragrances. It produces
the degradation of thermo labile compounds and hydrolysis of water
steam distillation method (31.86%). These variations in the quality of
lavender oil produced by different hydrodistillation methods could be
due to the thermal degradations during the process and number of
other chemical reactions such as allylic rearrangements, hydrolysis,
elimination etc. Based on the present experimental condition, it is
recommended that the lavender oil, on commercial scale, may be
produced preferably by water-steam distillation method to reduce the
by-product formation by various chemical reactions and to get better
oil recoveries. Furthermore, the capital investment for the water-
steam distillation unit will be much lower than the steam distillation
system, as it wouldn’t require a separate boiler.
Key words : Essential oil, hydrodistillation, Labiatae, Lavandula
angustifolia Mill., lavender oil, linalool, linalyl acetate,
steam distillation
Comp. of Bio. Nat. Pro., Vol. 8 – Quality Control & Standardization124
sensitive compounds. During hydrodistillation, esters present in
essential oils are generally hydrolyzed by the release of H+ ions from
water. In the presence of water, at about its boiling point, esters
hydrolyze to the corresponding acids and alcohols.
at higher
temperatures
Esters + water Corresponding acids and alcohols
The hydrolysis of esters in the geranium oils during
hydrodistillation has been discussed extensively by Babu and Kaul
(2005). Major ester present in the lavender oil is linalyl acetate, an
important quality determining constituent (Wiesenfeld, 1997). Due
to high temperatures and unfavorable conditions prevailing during
the hydrodistillation process, esters undergo molecular
rearrangements and elimination reactions leading to degradation of
molecules. Pickett et al. (1975a) examined a model system in which
pure linalyl acetate was subjected to steam distillation with pH 4.
The composition of the steam distillate was found to contain myrcene
(3.7%), limonene (1%), cis-ocimene (1.7%), trans-ocimene (3.3%), a-
terpineol (19.7%), neryl acetate (4.3%), geranyl acetate (5.3%), nerol
(1.7%) and geraniol (7%). Linalyl acetate has been found to readily
rearrange in vitro even when hops are distilled at pH 7. Linalyl
acetate was undetectable in oil obtained by steam distillation of hops
whereas; it can be easily detected in oil distilled by vacuum steam
distillation carried out at room temperature (Pickett et al., 1975b).
Linalyl acetate undergoes thermal degradation during steam
distillation, leading to linalyl, geranyl, and neryl carbocation, which
induces considerable rearrangement reactions (Fig 1). Hydration of
previously formed hydrocarbons yields corresponding alcohols (Morin
& Richard, 1985). In plants containing high proportions of linalyl
acetate, it is not surprising to encounter recemization of linalool
produced during ester thermal degradation in the steam distilled oil
(Casabianca et al., 1998). During hydrodistillation, acidic conditions
(pH=5.5-6.5) promote the decomposition of linalyl acetate and linalool
(Boelens & Sindreu, 1998). For example, linalyl acetate can be
converted by allylic rearrangement into geranyl acetate and neryl
acetate and by elimination into acyclic monoterpene hydrocarbons
such as myrcene, cis- and trans-b-ocimenes (Fig 2). Linalyl acetate
is hydrolyzed in considerable amounts during prolonged steam
distillation and under the same conditions also produces monocyclic
monoterpenes hydrocarbon – terpinolene – as the main product from
linalyl acetate via the a-terpinyl cation and terpinen-4-yl cation (Fig
3). a-Terpineol and then 1,8-cineole can be formed by hydration of
Characteristics Variation of Lavender Oil produced by Different
Hydrodistillation Techniques
125
the a-terpinyl cation. So also terpinene-4-ol can be formed by the
hydration of the terpinene-4-yl cation. Linalool also shows similar
rearrangement and elimination reactions under such conditions. As
mentioned earlier, esters are hydrolyzed to their corresponding
alcohols and carboxylic acid. Hydrolysis is catalyzed by carboxyl
esterases or esterases (Satoh, 1987) (Fig 4).
Conventionally lavender oil is being produced by steam distillation
on commercial scale. However, there is no report which compares
variations in the lavender oil yields and its chemical composition
produced by different methods of hydrodistillation viz., water
distillation, water-steam distillation and steam distillation.
Theoretically, there is no fundamental difference between these three
methods. However, there are certain variations in practice and the
practical results obtained, in some cases have considerable variations
because of above discussed chemical reactions occurring during
distillation and the same are reported in the present investigation.
This paper presents the variations in the qualitative and quantitative
characteristics of the lavender oils by different hydrodistillation
techniques.
MATERIALS AND METHODS
Plant Material
A plantation of L. angustifolia is maintained at Mountain Agriculture
Research and Extension Station, Choudhary Sarvan Kumar Himachal
Pradesh Krishi Vishwavidhyalaya (CSKHPKV), Salooni, district
Chamba, Himachal Pradesh, India. The shoot or flower biomass was
harvested in the month of June 2003 from one year old plantation.
The experimental location experiences a cold-dry climate, at an
altitude of 1800 m above mean sea level (amsl) in the western
Himalayas.
Distillation
Water distillation: Two kg flowering tops (spikes) of L. angustifolia
were charged into the vessel of Clevenger-type apparatus along with
4 l of water to distil by water distillation method. This method
involves distilling the essential oil yielding herbs by keeping the
biomass in direct contact with the water. The spikes were distilled
for 3 h to isolate the essential oil completely. The oil isolated was
measured, dried over anh. Na2SO4, filtered and analyzed.
Water-Steam distillation: The design and operating procedure of
HerboStillTM used for distilling the lavender spikes were described
in earlier communications (Babu et al., 2002, 2004, 2005, 2007; Rawat
Comp. of Bio. Nat. Pro., Vol. 8 – Quality Control & Standardization126
et al., 2007; Babu & Kaul, 2007). Eight kilograms lavender spikes
were charged over a false bottom/perforated grid in the HerboStillTM,
which was adjusted to accommodate 8 l of water at the bottom of the
vessel to distil the spikes by water-steam distillation method. This
method involves, distilling the plant material which was not in direct
contact with the water. A distance of 50 mm was maintained between
the plant charge and the water. The water vapor generated below
the false bottom was always in the form of saturated steam and
never superheated. This saturated steam was used to distil the
plant material. The vessel of the apparatus was heated on liquefied
petroleum gas (LPG) to commence the distillation. The vapors started
forming after 15-20 min., were condensed in a condenser and the
distillate along with oil was collected in a glass receiver. This process
was continued for 3 h. The oil was separated, measured, dried over
anh. Na2SO4, filtered and then used for analysis.
Steam Distillation
Two hundred kg flowering tops of the crop were charged over a
perforated grid (false bottom) in a commercial scale stainless steel
(SS) distillation tank which was connected to a steam boiler. The
herbage was steam distilled by feeding the steam at the bottom of
the false bottom in the tank. The steam, evolved through the plant
material consisting of water and essential oil, was condensed in a
water cooled shell and tube heat exchanger and collected in a
receiver/separator. The excess distillate (hydrosol) collected in the
receiver was removed continuously from the receiver/separator and
the whole process was continued for 4 h. At the end, 1800 mL oil
collected in the receiver was separated.
Gas Chromatography (GC)
GC analysis of essential oil samples was performed on Shimazdu Gas
Chromatograph GC-2010 fitted with BP-20 capillary column (SGE
International, Ringwood, Australia) length 30 m, internal diameter
0.25 mm, film thickness 0.25 mm using nitrogen as auxiliary carrier
gas with flow rate 4 ml/min, equipped with FID. Temperature was
programmed from 40-220oC at 4oC/min, held isothermally at 40 and
220oC for 5 min each. Sample injection volume, 2 µL; injector and
detector temperatures were kept at 220oC and 250oC, respectively.
Gas Chromatography-Mass Spectrometry (GC-MS)
GC-MS (70 eV) data were measured on MS-QP – 2010 series Shimadzu,
Tokyo, Japan equipped with MSD, AOC – 20i auto-sampler and BP-
20 capillary column (SGE International, Ringwood, Australia) 30 m
length, 0.25 mm i.d. and film thickness, 0.25 mm (polyethylene
glycol). The oven temperature was programmed as mentioned in
Characteristics Variation of Lavender Oil produced by Different
Hydrodistillation Techniques
127
GC. MS source temperature, 200oC; interface temperature, 220oC,
injector and detector temperatures, 220oC. Sample injection volume,
2 µl; split ratio, 1:50 and Mass Scan, 40 -600 amu. Helium was used
as a carrier gas with 1.1 mL/min flow rate.
Identification
A mixture of alkanes (C8-C32) was used as reference in calculation of
relative rention indices. Identification of constituents was carried
out with the help of retention indices and by comparison of mass
spectra with the data available in the literature (Adams, 1995;
Jennings & Shibamoto, 1980; MacLafferty, 1989), National Institute
of Standards and Technology (NIST) (Stein, 1990) and our own created
libraries.
RESULTS AND DISCUSSION
Variation in Lavender Oil Yields
Water distillation produced higher oil yield with 1.6% (32 ml from 2
kg) closely followed by water-steam distillation with 1.1% oil yields
(88 mL from 8 kg). However, steam distillation produced lowest oil
yields with 0.9% (1800 mL from 200 kg). This trend was also observed
earlier, in the case of geranium oil production (Babu & Kaul, 2005).
The lower oil yields in the steam distillation may be attributed to
the conditions prevailed during distillation such as lump formation
and agglutination of plant material and not recycling of hydrosol to
recover the dissolved oil, which caused incomplete recovery of the
oil.
Variation in Lavender Oil Composition
The major constituents characterized in the oil were myrcene, 1,8-
cineole, (Z) and (E)-b-ocimene, linalool, linalyl acetate, b-
caryophyllene, lavandulyl acetate, a-terpineol, neryl acetate, geranyl
acetate and geraniol. Lavender oil produced by water distillation
method was found to be richer in linalool (39.74%), a-terpineol (8.01%),
geraniol (2.78%), geranyl acetate (2.16%) and neryl acetate (1.25%).
The oil produced by water-steam distillation method contained higher
percentage of linalyl acetate (47.1%), 1,8-cineole (2.3%), a-pinene
(0.29%), d-3-carene (0.28%), b-pinene (0.2%) and sabinene (0.14%).
The oil produced by the steam distillation method contained higher
amounts of b-caryophyllene (6.27%), (E)-b-ocimene (3.03%), myrcene
(2.03%), (Z)-b-ocimene (2.28%). The composition of oil recovered
from the hydrosol collected during steam distillation was also analysed
and compared with direct oil and reported elsewhere (Babu & Singh,
2007).
Comp. of Bio. Nat. Pro., Vol. 8 – Quality Control & Standardization128
Fig 1. Thermal degradation of linalyl acetate
The highest monoterpene hydrocarbons (10.05%) and
sesquiterpenoids (10.28%) content were observed in the oil obtained
by steam distillation method followed by water-steam distillation
method (6.31% and 7.73%) and water distillation method (5.62% and
3.18%, respectively). This may be attributed to the non-polar nature
of the constituents possessing strong lipophillic bondages with the
fatty (oil) components (Koedam et al., 1979), which require higher
energy to break the bondage (Babu & Kaul, 2007). This energy can
be met by the higher enthalpy of the steam which is generated in a
separate boiler and delivered at a higher pressure in the distillation
tank during steam distillation method. This steam at higher pressure
also easily distills the higher boiling point constituents such as
sesquiterpene hydrocarbons. Hence, the steam distilled oil possessed
the higher monoterpene hydrocarbons and sesquiterpenoids. Contrary
to this, water and water-steam distillation methods produced oils
having lower monoterpene hydrocarbons and sesquiterpenoids, as
the steam generated in the still is always saturated and never be
superheated, which possess lower enthalpies. The highest
monoterpene cyclic ethers were found in the oil produced by water-
Characteristics Variation of Lavender Oil produced by Different
Hydrodistillation Techniques
129
steam distillation method (2.66%) closely followed by water distillation
method (2.29%) and steam distillation method (1.43%). Out of 2.66%
of monoterpene cyclic ethers (in the oil produced by water-steam
distillation method), 1,8-cineole was found to be the major component
(2.3%).
Higher total ester content (50.44%) was also observed in the oil
produced by water-steam distillation method followed by steam
distillation method (41.29%). The lowest total ester content was
observed in the oil produced by water distillation method (35.52%).
The major esters present in all the oil samples produced by these
different hydrodistillation techniques were linalyl, lavandulyl, neryl
and geranyl acetates. Linalyl acetate is one of the most important
ester which determines the quality of oil produced. The oil produced
by water-steam distillation method possessed highest linalyl acetate
(47.1%). The lowest linalyl acetate (30.01%) was found in the oil
produced by water distillation method followed by steam distillation
method (35.28%). On the contrary, neryl acetate and geranyl acetate
were found to be higher in the water distillation method (1.25% and
Fig 2. Rearrangement of linalyl acetate during distillation
Comp. of Bio. Nat. Pro., Vol. 8 – Quality Control & Standardization130
Fig 3. Hydrolysis of linalyl acetate
2.16%) and steam distillation (1.1% and 1.97%) than the water-steam
distillation method (0.51% and 0.8%, respectively). This can be
attributed to the fact that the linalyl acetate under acidic conditions
gets rearranged into neryl and geranyl acetates (Fig 2) (Mastelic,
2000).
Characteristics Variation of Lavender Oil produced by Different
Hydrodistillation Techniques
131
In addition to experiments described above, the spent water
(generally brown in color) discharged from the vessels was tested for
its acidity after completion of the distillation process and showed
pH=5 during water distillation and that of steam distillation tank
has pH=5.5. However, the spent water in the water-steam distillation
tank possessed pH=6.8. This variation in the pH can be correlated
to the extent of these chemical reactions that had taken place during
distillation. The water present in the still during water distillation
method was high as the plant material has to be dipped/immersed
into the water. Although, initially there was no water present in the
tank during steam distillation, as distillation proceeds, steam gets
condensed through heat losses and the level of water content
increases. Higher the water contents in the vessel, higher the
degraded product formation as suggested by the reversible reaction
presented in the introduction part. Hence, the pH of spent water in
water distillation and steam distillation methods possessed higher
acidity (pH is 5 and 5.5, respectively). However, in the case of water-
steam distillation method, the water was kept below the false bottom
and the level was maintained constant through out the process, which
helps in keeping the pH near neutral.
Contrary to the total ester content, the total alcohol content was
found to be the highest in the oil produced by water distillation
method (52.32%). The lowest total alcohol content was observed in
water-steam distillation method (31.88%) followed by steam distillation
method (35.58%). Similar trend was also observed in the distillation
of geranium oils and was due to the hydrolysis of esters discussed
elsewhere (Babu & Kaul, 2005). Therefore, it can be concluded that
the more water content in the distillation tank/vessel, the more
hydrolysis of esters takes place, thereby increasing the total alcohol
content and acidity as the reversible reaction carry forward (towards
right hand-side/product side) until the equilibrium is established.
The products formed during hydrolysis of esters, for example linalyl
Fig 4. Hydrolysis of linalyl acetate by carboxyl esterase
Comp. of Bio. Nat. Pro., Vol. 8 – Quality Control & Standardization132
Table 1. Lavender oil distilled by different hydrodistillation techniques
Compounds RI#Water Water-steam Steam
distillation distillation Distillation
a-Pinene 1011 0.19 0.29 0.16
Camphene 1049 0.20 0.31 0.35
b-Pinene 1114 0.13 0.20 0.14
Sabinene 1123 0.13 0.14 0.12
d-3-Carene 1149 0.19 0.28 0.16
Myrcene 1162 1.10 0.97 2.03
Limonene 1203 0.72 0.92 1.10
1,8-Cineole 1211 1.83 2.30 1.43
(Z)-b-Ocimene 1235 1.12 1.39 2.28
(E)-b-Oci mene 1252 1.47 1.50 3.03
p-Cymene 1269 0.14 0.17 0.30
a-Terpinolene 1283 0.23 0.14 0.38
1-Octen-3-yl acetate 1383 0.73 0.67 0.90
cis-Linalool oxide 1444 0.28 0.20
trans-Linalool oxide 1472 0.18 0.16
Camphor 1509 0.26 0.25 0.23
Linalool 1557 39.74 26.06 28.78
Linalyl acetate 1564 30.01 47.10 35.28
a-Santalene 1567 — 0.74
Bornyl acetate 1578 0.24 0.14 0.24
a-trans-Bergamotene 1584 — 0.16 0.25
b-Caryophyllene 1590 1.27 5.30 6.27
Terpinen-4-ol 1602 0.79 0.72 0.53
Lavandulyl acetate 1611 1.13 1.22 1.80
a-Humulene 1659 — 0.19 0.27
(E)-a-Farnesene 1666 1.02 1.38 1.64
Lavandulol 1682 — 0.42 0.47
a-Terpineol 1699 8.01 3.55 3.78
Neryl acetate 1730 1.25 0.51 1.10
ã-Cadinene 1747 — 0.13 0.19
Geranyl acetate 1760 2.16 0.80 1.97
Characteristics Variation of Lavender Oil produced by Different
Hydrodistillation Techniques
133
acetate, can be divided into two categories (i) oxygenated
monoterpenes and (ii) non-oxygenated monoterpenes. The oxygenated
monoterpenes for example 1,8-cineole, a-terpineol and terpinene-4-ol
are formed by hydration of the a-terpinyl cation and terpinene-4-yl
cation. Similarly, the non-oxygenated monoterpenes viz., terpinolene,
limonene and a-terpinene were formed through the same cations
(intermediates) but by eliminating the proton (Fig 3). Linalool also
shows similar reactions of rearrangement and elimination under the
same conditions as well (Mastelic et al., 2000). Therefore, linalool
by allylic rearrangement gives rise to geraniol and/or nerol and so
on.
Therefore, depending upon the conditions prevailed in the
distillation tanks, the reactions progressed and different products of
varying quantities were formed. For example, neryl acetate (0.51%)
and geranyl acetates (0.8%) were found minimum in the water-steam
distillation and maximum content was found in water distillation
(1.25% and 2.16%, respectively). This excess amount of neryl and
geranyl acetates might have formed by the allylic rearrangement of
linalyl acetate (Fig 2). Hence, the conditions prevailing during water
Nerol 1805 1.00 0.29 0.56
Geraniol 1854 2.78 0.82 1.46
Caryophyllene oxide 1971 0.61 0.44 0.69
ô-Cadinol 2169 0.28 0.13 0.23
Total 99.19 99.25 98.86
Monoterpene 5.62 6.31 10.05
hydrocarbons
Monoterpene cyclic 2.29 2.66 1.43
ethers
Carbonyls 0.26 0.25 0.23
Esters 35.52 50.44 41.29
Alcohols 52.32 31.86 35.58
Sesquiterpenoids 3.18 7.73 10.28
Oil yields (%) 1.60 1.1 0.90
#RI = retention indices on BP-20 column; —, absent
Table 1. Contd.
Compounds RI#Water Water-steam Steam
distillation distillation Distillation
Comp. of Bio. Nat. Pro., Vol. 8 – Quality Control & Standardization134
distillation favored the formation of neryl and geranyl acetates.
Similarly, allylic rearrangement of linalool also more favored in water
distillation and steam distillation as higher nerol (1% and 0.56%,
respectively) and geraniol (2.78% and 1.46%, respectively) contents
were found than in the water-steam distillation (0.29% and 0.82%,
respectively). Similarly, elimination (of CH3COOH or CH3COO from
linalyl acetate and OH or O from linalool) reactions were also favored
in water distillation and steam distillation as the formation of
myrcene, a-terpinolene and a-terpineol were found in higher
concentration than in the oil produced by water–steam distillation.
The formation of acyclic monoterpene hydrocarbons viz., (Z) and (E)-
b-ocimene (2.28% and 3.03%, respectively) were very high in steam
distillation method whereas the conditions might not be favorable in
water distillation as they are in lower quantities (1.12% and 1.47%,
respectively). Similar trends were also observed in the case of
limonene. The formation of linalool from linalyl acetate is higher in
the water distillation method than in the water-stream distillation.
Hence, the oil produced by water distillation method contained higher
amount of linalool (39.74%) and lower content of linalyl acetate
(30.01%) in contrary to the higher content of linalyl acetate (47.1%)
and lower content of linalool (26.06%) in the water-steam distillation
method.
CONCLUSIONS
It is well-known that conventionally the lavender oil is steam distilled
on commercial scale. However, the present experimental findings
reveal that water-steam distillation method produced higher yields
and better quality lavender oil in terms of higher ester content than
the steam distillation method. In general, the by-products content
formed by different chemical reactions were higher in water distillation
and lower in water-steam distillation method followed by steam
distillation method. Therefore, it is recommended that the lavender
oil, on commercial scale, may be produced preferably by water-steam
distillation method to reduce the by-product formation by various
chemical reactions and to get better oil yields. Furthermore, the
production cost can be reduced as water-steam distillation doesn’t
require steam generator, skilled operator, small space for unit
installation etc.
ACKNOWLEDGEMENTS
The authors are grateful to the Director, IHBT Palampur for
continuous encouragement and for providing necessary facilities
during the course of this investigation. The authors also gratefully
Characteristics Variation of Lavender Oil produced by Different
Hydrodistillation Techniques
135
acknowledge the funding of this project by 11th International Congress
of Essential Oils Fragrances and Flavors-1989 (ICEOFF-89), New
Delhi. Thanks are also due to Mrs. Vijaylata Pathania for providing
chromatograms and Mr. Gian Chand for technical support services.
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... As can be seen, the largest amounts of ocimene are obtained by Bulgaria, the highest percentage of camphor is obtained by Italy, linalool and linalyl acetate were obtained in the highest amounts by France, the highest percentage of Terpinen-4-ol was recorded in France, and the most lavandulol and lavandulol acetate was obtained in France. Table 3. Classification of the main compounds in lavender essential oils (in percentages %) (compiled with data from [7,[92][93][94][95][96][97] In the case study by Danh et al., 2012, and the case study by G.D. Kiran Babu, the antioxidant and antimicrobial properties and the yields and chemical compositions of lavender essential oils were analysed via the supercritical fluid extraction method, hy-drodistillation method and steam distillation method [30,98]. The results obtained in these studies are shown in Table 4. Table 4. Yields, properties and main components (expressed in %) of lavender essential oils obtained using three extraction methods (compiled with data from [30,[91][92][93][94][95][96][98][99][100][101][102][103][104] Table 4 shows the conditions under which the three extraction methods of lavender essential oils are carried out, namely hydrodistillation, supercritical fluid extraction and steam distillation. ...
... Table 3. Classification of the main compounds in lavender essential oils (in percentages %) (compiled with data from [7,[92][93][94][95][96][97] In the case study by Danh et al., 2012, and the case study by G.D. Kiran Babu, the antioxidant and antimicrobial properties and the yields and chemical compositions of lavender essential oils were analysed via the supercritical fluid extraction method, hy-drodistillation method and steam distillation method [30,98]. The results obtained in these studies are shown in Table 4. Table 4. Yields, properties and main components (expressed in %) of lavender essential oils obtained using three extraction methods (compiled with data from [30,[91][92][93][94][95][96][98][99][100][101][102][103][104] Table 4 shows the conditions under which the three extraction methods of lavender essential oils are carried out, namely hydrodistillation, supercritical fluid extraction and steam distillation. Thus, it can be seen that hydrodistillation uses higher temperatures and takes more time than supercritical fluid extraction (100 • C, 300 min), while supercritical fluid extraction uses higher pressure and obtains higher yields (140 bar, 6.68 ± 0.57%) compared to the first method mentioned in Table 4. ...
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Lavender is among the medicinal and aromatic plants with high economic value in the food, pharmaceutical, cosmetic and aromatherapeutic industries, and in its composition has numerous compounds, such as tannins, anthocyanins, minerals, saponins, flavonoids, polyphenols, essential oil and others. The qualitative and quantitative characteristics of lavender are best highlighted by extraction techniques such as hydrodistillation, steam distillation and supercritical CO2 extraction. In the water distillation extraction method, the plants are soaked in water until boiling and steam is released, carrying the essential oils with it, which are then separated via cooling. Steam distillation is one of the most common methods used to extract essential oils from medicinal and aromatic plants. Unlike hydrodistillation, where the water is stored directly in a tank, in this method, the steam is transported into the tank from the outside and the oils are released from the plant components when the steam penetrates the structures that contain it. Essential oils contain essential compounds that have antioxidant, antimicrobial, anti-fungal, etc., properties. All the component parts of lavender contain essential oils, which are distributed as follows: in leaves at about 0.4%, in stems at about 0.2%, and in inflorescences at about 2–4.5%.
... Ranges for said compounds vary due to both geographic location and lavender cultivar [17,[22][23][24]. Many other factors have also been shown to influence the yield and volatile profile of lavender essential oil, including the developmental stage of the flower [25], weather conditions [25], time of harvest [26], drying and storing conditions of plant material [26][27][28], distillation time [29], and the distillation or extraction technique employed [30][31][32][33]. ...
... Understanding the contribution of each plant part to the essential oil of lavender provides insight into proper cultivation and harvesting practices, as well as a better understanding of authentication of natural lavender essential oil. Authentic lavender essential oil has low levels of camphor, typically lower than the upper limit established by the lavender ISO standard [17,22,24,28,30,31,35]. Elevated levels of camphor are an indicator of the addition of lavandin Grosso and/or spike lavender, which have camphor levels of 6-8.5% and 8-16%, respectively [2,[19][20][21]. ...
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Lavandula angustifolia Mill. (lavender) is an essential-oil-bearing plant in the Lamiaceae family. Volatile oil produced through the steam distillation of lavender was examined to establish the essential oil yield and aromatic profile from each portion of the plant—namely, the corolla, calyx, leaf, and whole flowering top. The resulting essential oils were analyzed by GC-FID and GC-MS. The different plant parts generally shared similar compounds but in varying relative percentages. Aromatic profiles of the whole flowering top and calyx were similar, with prominent compounds being linalool acetate (34.3%, 32.0%), linalool (26.5%, 32.9%), lavandulyl acetate (5.6%, 4.9%), terpinen-4-ol (5.3%, 7.0%), and (Z)-β-ocimene (4.5%, 5.4%), respectively. Aromatic profiles for the corolla and leaf were unique. Prominent aromatic compounds of the corolla included linalool acetate (18.4%), linalool (10.8%), epi-α-cadinol (10.0%), borneol (7.3%), and lavandulyl acetate (6.3%). Prominent aromatic compounds of the leaf included epi-α-cadinol (19.8%), γ-cadinene (11.0%), borneol (6.0%), caryophyllene oxide (4.9%), and bornyl acetate (4.8%). Complete profiles and essential oil yields of corolla, calyx, leaf, and whole flowering top were established. This study establishes the influence the corolla, calyx, and leaf exert on the aromatic profile of the whole flowering top and provides insight into authentication of lavender essential oil.
... Lower pHs often destruct cells to remove more compounds and interestingly stimulate the hydrolysis of some glycoside structures to obtain more volatile aglycones (Boudraa et al., 2021). The decrease in yield was also attributed to the hydrolysis of esters as the formation of alcohols and acids that are less volatile compared to the initial esters (Babu and Singh, 2010). When sodium chloride is added to boiling water it can have two effects. ...
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Introduction Spearmint essential oil is a valuable medical and food product. Spearmint essential oil is effective for the treatment of flatulence, indigestion, nausea, and colic along with Alzheimer, obesity, and fungal infections. Methods This study evaluated the quality and quantity of spearmint essential oil by examining some extraction strategies. The procedures were hydro-distillation, hydro-steam distillation, microwave-assisted hydro-distillation, and open hydro-distillation. The hydro-distillation had five pH levels (2, 4, 6, 8, and 10) and four NaCl concentrations (0.5, 1, 1.5, and 2%). microwave-assisted hydro-distillation at a power of 225 W was applied for 60, 90, and 120 minutes for process durations. The solvent extraction of herbal distillate obtained by an open hydro-distillation system was done using n-pentane and n-hexane to achieve a recovered essential oil by a rotary evaporator. Results and discussion The results showed that the lowest pH in the hydro-distillation process led to obtaining double yield compared to the control. Additionally, at 1 and 1.5% NaCl concentrations, the oil yield increased by 12.86 and 20.87%, respectively. Although the yield was reduced by microwave-assisted hydro-distillation, however within 120 minutes, carvone increased by 12.7% and limonene decreased by 42.3%. The best quality of spearmint oil belonged to solvent extraction followed by rotary evaporator.
... Ranges for these compounds vary depending on cultivation process (spontaneous vs. clonal), cultivar, and country of origin (14). Other factors that influence the volatile profile and aroma of lavender essential oil include the developmental stage of the flower (15), environmental conditions (15), processing and storage conditions of the plant material (16)(17)(18), plant parts used in distillation (19), and the distillation or extraction technique employed (20)(21)(22)(23). Notwithstanding, the lavender ISO standard, as well as the ISO standards for lavandin Grosso and spike lavender (24,25), are reliable reference points when considering both the quality and authenticity of lavender and Lavandula spp. ...
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Authentic Lavandula angustifolia (lavender) essential oil samples (n = 41) were procured from six producing countries. Essential oils were analyzed to determine physical properties and to determine profiles and related data by GC/MS, GC/FID, enantioselective GC, and GC/IRMS. The current study identified 43 volatile compounds that were detected in all authentic lavender samples (n = 41), and which can be considered authentic markers. Enantiomeric ranges for 15 volatile compounds and stable isotope ranges for four prominent compounds were determined in authentic lavender. Authentic samples and associated data were used to assess the quality of commercially available lavender essential oil samples (n = 12). 75% of the commercial samples studied were adulterated, and 17 volatile compounds were detected in these samples which can be considered markers for adulteration. This study establishes the utility and importance of using a multifaceted analytical approach to differentiate quality and determine authenticity of lavender essential oil.
... Moreover, in the process of hydrodistillation, the degradation/hydrolysis of thermolabile compounds/water-sensitive compounds has been observed, and the esters are generally hydrolyzed by the release of H + ions from water to analogous acids and alcohols. The pH of water is often reduced during hydrodistillation and essential oil components like esters are sensitive to hydrolysis, while others like acyclic monoterpene hydrocarbons and aldehydes are susceptible to polymerization because of low pH [42]. As the terpenoids are volatile and thermolabile, they may be easily oxidized or hydrolyzed depending on their respective structure. ...
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The increase in the utilization of Lavandula essential oil in industries led to an impressive rise in the demand for quality essential oils. However, a post-harvest drying of Lavandula species can be a decisive factor to determine the quantity and quality of essential oil. The study was conducted in western Himalayan conditions to assess the essential oil content and composition of two Lavandula species viz., lavender (Lavandula angustifolia Mill.), and lavandin (Lavandula × intermedia Emeric ex Loisel), at four different drying duration (0 h, 24 h, 48 h and 72 h after the harvest). The higher growth attributes viz., plant height (71.7 cm), ear length (8.8 cm), number of spikes (18.1), and number of flowers per ear (47.5) were higher in lavandin, while the number of branches (17.1) was higher in lavender. Essential oil content (%) and moisture reduction (%) were significantly higher at 72 h than at 0 h. The major components of lavender and lavandin essential oil were linalool (33.6–40.5%), linalyl acetate (10.8–13.6%), lavandulyl acetate (2.8–14.5%), and linalyl propionate (5.3–14.1%) in both the Lavandula species. There was a decreasing trend in linalool and an increasing trend in linalyl acetate content in lavandin, with an increase in drying duration up to 72 h; while in lavender, no regular trend was observed in linalool and linalyl acetate content. It was observed that linalool and linalyl acetate levels were the highest at 24 and 0 h of drying in lavender and lavandin, respectively, and essential oil extraction can be done according to the desire of the constituent at varied drying duration.
... Furthermore, the results obtained in similar studies with other aromatic plants, such as the case of lavender EO [50], also revealed that the highest MH and SH contents were observed in the EO isolated using the SD method followed by the WSD and HD methods. According to the authors, this may be due to the non-polar nature of the components possessing strong lipophillic bondages with the fatty (oil) components, which require higher energy to break the bondage. ...
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This study mainly deals with the effect of hydrodistillation (HD) and water-steam distillation (WSD) methods on the color, yield, and chemical profile of the essential oil (EO) from Cryptomeria japonica fresh leaves from São Miguel Island (Azores Archipelago, Portugal). The yields of EO–HD (pale-yellowish) and EO–WSD (colorless) samples were 1.21% and 0.45% (v/w), respectively. The GC–FID, GC–MS, and 13C-NMR analyses of EO–HD vs. EO–WSD revealed (i) a high-content of monoterpenes (72.8% vs. 86.7%), mainly α-pinene (34.5% vs. 46.4%) and sabinene (20.2% vs. 11.6%), and oxygenated mono- and sesquiterpenes (20.2% vs. 9.6%); (ii) similar sesquiterpene (1.6% vs. 1.6%), β-myrcene (5.9% vs. 5.8%), and camphene (3.5% vs. 3.8%) contents; and (iii) significant differences in other classes/components: EO–HD is richer in oxygenated sesquiterpenes (17.1%, mainly elemol (10.4%) and α-eudesmol (3.4%)) and diterpenes (3%; mostly phyllocladene), while EO–WSD is richer in oxygenated monoterpenes (7.2%, mainly terpinen-4-ol (5.4%)), p-cymene (4.4%), and limonene (3.2%). Overall, the color, yield, and quantitative composition of the EO samples studied are strongly influenced by the distillation method. Nonetheless, this C. japonica leaf EO displayed a consistent α-pinene- and sabinene-rich composition. The same chemotype was found in a commercial Azorean C. japonica leaf EO sample, obtained by industrial steam distillation (SD), as well as in Corsica C. japonica leaf EO–HD. Furthermore, the bioactive composition of our EO samples revealed the potential to be used in green plant protection and in the medical, food, cosmetic, and household industries.
... The total yield of extracted substances and their composition depends mainly on the applied extraction techniques. Along with traditional methods of isolating volatile oils such as hydrodistillation [8] and steam distillation [9], innovative techniques such as supercritical fluid extraction (SFE) (with solvents like CO 2 , propane, butane etc.) [3] or the microwave-assisted extraction (MAE) are introduced into lab scale and industrial scale practice. The standard laboratory method used for comparison of extracts composition is still soxhlet extraction [10], having long duration and high consumption of solvent disadvantages. ...
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This paper is aimed at evaluating the chemical aspects and marketing prospects of the extraction of Lavender (Lavandula int. Grosso) by Accelerated Solvent Extraction (ASE). The extraction was performed at three temperatures (100°C, 120°C and 140°C) and ethanol (96 %v/v) was selected as the polar solvent. The extraction yield was influenced only slightly by the extraction temperature (reaching 17.0 %, 16.5 % and 16.3 % at 140°C, 120°C and 100°C, respectively); its impact on a number and ratio of extractants was more pronounced. As for the chemical composition of the extracts, the major components at 100°C were methyl ursolate (30.50 %) and methyl oleanolate (7.27 %), while at 120°C and 140°C linalyl anthranilate (>31 %) and linalyl acetate (>17 %) dominated. Based on catalogue prices, and taking the costs connected to the extraction and separation of individual extractants into account, some of the components are worth considering also from a marketing viewpoint
... This could be related with thermal degradation of linalyl acetate during the drying and distillation processes. Linalyl acetate undergoes thermal degradation in the presence of water leading to linalyl, geranyl, and neryl carbocation, which induce considerable rearrangement reactions as Babu and Singh (2010) reported. Thus, the percentage of neryl acetate and geranyl acetate were dramatically higher in the microcapsules. ...
Article
Plant-based aroma chemicals, constituting the essential oils play a great role as the natural flavours and preservatives in the food industries. Many of these metabolites are susceptible to degradation under heat (i.e. thermolabile aroma chemicals) which may influence the organoleptic properties of the end-products e.g. essential oil, oleoresin, dry herb, tea and packaged juice. The current review identified in total 42 thermolabile aroma and/or flavour molecules belonging to monoterpenoids, sesquiterpenoids and phenolics. The probable pathway of their degradation and its promoting conditions were also described. Degradation pathways were categorized into five major classes including oxidation, C-C bond cleavage, elimination, hydrolysis and rearrangement. Numerous evidences were cited in support of the thermosensitivity of these phytochemicals under pyrolytic, thermal heating or gas chromatographic conditions. Various post-harvest processes involved in the manufacturing such as drying and distillation of the crops or thermal treatment of the food-products for storage were highlighted as the root cause of degradation. The influence of thermolabile aroma chemicals to maintain the sensory quality of the end-products such as citrus juices, floral oils and thermally cooked foods was discussed in detail. In the present article, detailed insight into the chemical and sensory aspects of thermosensitive aromas and flavours was provided, covering the period from 1990 up to 2020.
Article
Hydrodistillation in a Clevenger-type apparatus is a widely used technique for the extraction of essential oil from the aromatic plants. Many times, aroma chemicals have been reported to be thermolabile and hydrodistillation may possibly influence their half-life. In the current study, thermolability of furanodienone (a furanosesquiterpenoid with 1,5-diene system) was demonstrated during the hydrodistillation of black turmeric (Curcuma caesia Roxb.) rhizome. The formation of curzerenone through [3,3]- sigmatropic rearrangement of furanodienone was observed. ¹H Nuclear Magnetic Resonance spectroscopy-based profiling revealed a higher curzerenone versus furanodienone ratio in the essential oil in comparison to oil-enriched solvent extract. The ratio increased upon heating (40–80°C) the solvent-extract in an aqueous medium. Purified furanodienone also converted partially to curzerenone while incubating at 80°C in water. The rearrangement was found to be exclusively temperature-dependent which followed the first-order kinetics. This study confirmed curzerenone to be the major artefact in the essential oil of black turmeric.
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Free and glycosidically bound volatiles of surficial parts of Mentha citrata were investigated. Free volatile compounds were isolated from dried plant material by two methods: hydrodistillation and extraction with pentane used as control. Free volatile compounds as well as the aglycones obtained after enzymatic hydrolysis of glycosides were analyzed by gas chromatography-mass spectrometry (GC-MS). A significant difference in qualitative and quantitative composition of volatile compounds of the essential oil and pentane extract was found. The major components of the essential oil and pentane extract were linalyl acetate (21.46%; 42.02%), linalool(13.68%; 22.66%), 1,8-cineole (12.51%; 6.40%), beta -myrcene (8.10%; 2.87%), a-terpineol (7.38%; 0.73%) and geranyl acetate (8.66%; 1.76%). The major components of the volatile aglycones were 1-octen-3-ol (40.28%), eugenol(12.29%), 3-octanol(7.09%), linalool (4.59%), benzyl alcohol (3.71%), 2-phenylethanol (3.67%), S-hexene-l-ol (2.87%) and 1-heptene-3-ol (2.88%). Compared with free volatile compounds (essential oil: 1.56%; pentane extract: 1.64%), the glycosidically bound volatiles were present in a lower concentration, about 0.0068%.
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Adams, R. P. 2007. Identification of essential oil components by gas chromatography/ mass spectrometry, 4th Edition. Allured Publ., Carol Stream, IL Is out of print, but you can obtain a free pdf of it at www.juniperus.org
Article
extract was found. The major components of the essential oil and pentane extract were linalyl acetate (21.46%; 42.02%), linalool (13.68%; 22.66%), 1,8-cineole (12.51%; 6.40%), b-myrcene (8.10%; 2.87%), a-terpineol (7.38%; 0.73%) and geranyl acetate (8.66%; 1.76%). The major components of the volatile aglycones were 1-octen-3-ol (40.28%), eugenol (12.29%), 3-octanol (7.09%), linalool (4.59%), benzyl alcohol (3.71%), 2-phenylethanol (3.67%), 3-hexene-1-ol (2.87%) and 1-heptene- 3-ol (2.88%). Compared with free volatile compounds (essentia1 oil: 1.56%; pentane extract: 1.64% ), the glycosidically bound volatiles were present in a lower concentration, about 0.0068%.