Supercritical gas extraction of essential oil from pepper is carried out at four different conditions ..... was obtaIned from Mysore Sandalwood Factory, Mysore. The.
Quality Evaluation of Supercritical Carbondioxide
Extracted Essential Oils of Pepper by GC
Finger Printing And Sensory Analysis
K. Udaya Sankar and Shanthi Narasimhan (Central
Food Technological
Research
Institute,
Mysore-570013)
ABSTRACT
Supercritical gas extraction of essential oil from pepper is carried out at four different conditions of extraction selected on the basis of lower density of carbondioxide at near critical conditions. Quality evaluation of these extracts as compared to conventional steam distilled oils is reported. Standardized GC finger printing with integration and odour profile evaluations by a trained panel was carried out on these extracts. Physicochemical parameters of oils were also recorded. Extracts of 10M Pa and 6rP C were found to show a classical resolution of the GC finger printing and was close to the pictures of steam distilled oil. However, the odour impact was more complete, balanced and typical of fresh pepper In the suoercriticst gas extracted oil. KEY WORDS
Supercritical carbondioxide. extraction, pepper oils, sensory analysis.
lntroduction : P~Dper, the black qold has attracted many countries, far and wide trorn the early time both for medical use and as a aromatic ingredient in food. They have long been traded as whole berries either in conventional black or white form or more recently in green form either after bringing or dehydration. Newer buff coloured pepper is also a possible mode of handling the valuable spice. Developments in post harvest handling methods have been towards either for saving the quality of the valuable crop or reducing the bulk, thus lowering the shipping cost. Oleoresin manufacture with chlorinated solvent is a major development and used extensively, unfortunately often at the cost of loss to the growers (Govindrajan and Shanti Narasimhan, 1986). Because of the impending ban on chlorinated solvents for extraction of oleoresin for considerations of carcinogenicity or toxicity, technolo~ically two developments are foreseen. One is the use of acetone or ethyl alcohol and the other, carbon dioxide extraction. Acetone has the problem of traces of mesityl oxide formation in the preparation of pepper oleoresin, which, reacting with hydrogen sulphide produces 4-methyl-4-mercapto pentan-3-one in the subsequent meat preparation resulting in offensive catty odour (Pagington, 1983).
Pafai Journal,
Oct.-Dec., 1991
Ethyl alcohol is equally effective in extraction as acetone and has no residue problems. Supercritical carbondioxide extraction has much flexibility of operation because of variable solvation power and selectivity in holding the solutes, resulting from small changes in temperature and pressure, just above the critical temperature of the gas. The process also gives 'nature identical' product extracted at low temperature and there is no residue problem. However, the consideration for any technology to become viable, yield and economics involved are important. A detailed study of this process in pepper is reported (CFTRI Annual report, 1986). The present paper discusses the quality of oil, at selected conditions of extraction using supercritical carbondioxide and compares it to steam distilled volatile oil,
Materials and Methods (i) Malabar ungarbled black pepper from local market was ground to BS Sieve 22 before extraction. (ii) Methods of extraction: (a) Steam distillation of oil was carried out with Clevenger distillation apparatus using AOAC Method. (b) SCF carbondioxide extraction was carried out on 1.2 Kg of ground pepper under four different conditions as described (Udaya Sankar, 1988) at 8 M Pa at 40°C and 60°C, 10M Pa at 40°C and 60°C. 35
(III) Gas crvomstoqreotw Gas chromatographic analysis in duplicate IfJZ1S carrie.: out tor each sample under standardised condition" ClS detailed below.
Sn.maoz., GC S,\,
Coiurrr: -83, :.3 rnrn ID, 3 r,.'leters, SE 30 (5:];,'
cnrornosorb support 60'80 particle siz :
Sample size 4ul cr 1D":'·,~ SOlution of ('Iii In e!hyl acetate,
Det':xw r F:anle kJ'l'zatio~ delect,.,r
Injection oo t. 80 0 ( _,.
Detector ternper.nure 22C':: Programmed temperature trorn 60-200oC at 2°C P8r
min with initial and tina I Isothermal period 5 minutes
Integration of peak upto 25 min with CR3A integrator
.iv) Sensory analysIs: Odour protiles by strip technique was carr.so out following Heath's method (Heath, 1978) The panel consisting of 4·5 members were experiencea in evaluating pepper and other spices Descriptors were selected Irom earlier work and literature (Govindarajan V. S., et al 1973) The initial odour profile examinations was followed by testing after 12 hours Results and Discussions: (a) The quality of the oil extracted under different conditions was compared with conventional steam dislilled oils for varrous parameters and reported earlier (CFTRI Annual report, 1983-84, 1985-86, Udaya Sankar, 1989). Tabte 1 summarises the findings. The physical constants of specific gravity and refractive index does not indicate any diflerence among them. However, percentage recovery and optical rotation shows the differences. These are needed to be subtantialed with other parameters of quality. (b) Sensory profile: Odour profile of the samples recorded by the trained panel Indicates distinct differences. Table 2 gives the odour quality as il appears in the samples. It may be observed that steam distilled oil is distinctively different from others. being more flowery and the dry out note is more terpenic. Among the test samples, 10 M Pa and 0C 60 extracted sample was found to be best and tnue to pepper powder with distinct herbal. woody notes along with milder top notes. 8 M Pa and 0C 40 sample was the poorest with total lack of residual notes and the fade out notes were very taint.
.•
(c) GC tinqer printing: The gas chromatography ,tJad shown a resolution of about 44-46 peaks in steam distilled oil and also oil extracted with carbon dioxide at higher pressure. Lower pressure extracted oils showed 36-37 peaks. Fig 1 shows tr, finger printing of each sample. Distinct differences were not noticed between steam distilled and 10M Pa 0C and 60 carbon dioxide sample in GC tinger prints. 36
Both showed clear pre and post caryophyllene peak" at middl~ and high Ht. A capillary column w: ,.: better separation capabilities would perhaps show differences as they do have distinct variation in sensory properties. The lower pressure extracted samples showed .~horter and lewere high RI peaks. .noicar.no rower levels of high bOiling compounds 8 M Pa and 4,oC sample, the poorest of the sample showed oruv high early Ht peaks ane low pre-caryophyllene peak It has been cernonstratec earlier that the middle and late R! peaks under these conditions of resolution are indicative of good quality 01 basic pepper note (GOVindarajan and Snar,t Narasimhan. 1986). This study also confirm these findings Conclusions: The best yield and quality of pepper Oil is obtained to 10M Pa and 60°C with 6-7 hours of extraction It is also economical. Odour pronle both as fresh and dry out show excellent product and its GC finger printing matches closely wrth conventional steam distilled oil and is promising to sl.ow more de/inite peaks indicafive of good quality. References: Annual Report, (1983-84, Central Food Technological Research Institute, Mysore, p.30. Annual Report, (1985-86), Central Food Technological Research Institute, Mysore, p91-92 Govindarajan, VS, and Shanti Narasimhan, (1986). Black Pepper-Piper Nlgrum, presented at ACS spring meeling, New York. Govindarajan, VS., Dhanaraj, S., Shanti Narasimhan. (1973), Evaluation of spice oleoresins: III Evaluation of some horticultureal varieties and trade types of pepper. J. of Plantation Crops (India), 1, 8-16. Heath, H. B., (1976), Flavour Technology, Profiles, Products, Application AVI Publishing Co, Westport, Conn. (USA) Pagington, J. S., (1983), A review of oleoresin Black Pepper and its extraction solvents, Pert and Flavourist, 8, 29-36 Udaya Sankar, K., (1989), Studies on physico-chemical characteristics supercriticat carbondioxide extracted pepper oils using carbondioxide J. Sci Fd. and Aq., 28, 105-112
Pafai Journat,
Oct.-Dec., 1991
Table 1 Physico-chemical properties 01 pepper oil Extraction
Time
Conditions
taken
%Recovcry
Sp gr
Table 2
Odour profile 01 pepper oils
Optical
Refractive
Extraction
rotation
Index
condmons
(HI
Initia!
(aher 12h)
Steam distilled
Steam
distilled
60
909
08834
~6.7 4
Flowery, spicy earthy
End earthy,
oxrdtscd terpenic, Good
herbal
intensity
1 479 SC carbondioxtde
Supercrmcal carbonoro ode
8 M Pa and 40°C
Tcrpeny rruldy spicy,
Soapy, dull
more balsamic
8 M Pa and
40°C
Dryout nate
193
791
0.8844
... 074
1483
B M Pa and 60°C
Spicy, flowery,
Mild spicy
carnphory. good mtenstty
80 M Pa and
60°C
11.8
846
08864
-1 11
1.475
10 M Pa and 40°C
10 M Pa and JODe
Mild cineol' rc. fairly good
imbalanced 63
1000
08859
+013
1483
10 M Pi':! and SO°C
10 M Pa and 60°C
Cineole like, camphory,
spicy, less t'owery.
59
982
08749
+-035
1483
Citrus, fresh herbal,
Green, herbal,
flowery, SPICY, woody. balanced Good intensity
roory, SPiCy note, good
-----------~
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38
Pafai Journal,
I Oct-Dec.. 1991
"
-'
I.:; ~-'=--'-
~
"0
~
,,
c ~
" r;
- ~-
, p.195. 7. Stahl, E. and Gerard, 1985, p. 29
!!.-,
Flavorlat,
p.
498.
Chemical Senses and
29.
Phys.
Chem.,88(4),1984,
p.887
QUALITY EVALUATION BY GC FINGER PRINTING OF SUPERCRITICAL CARBON DIOXIDE EXTRACTED ESSENTIAL OILS OF PEPPER
K.
UDAYA SANKAR and Shanthi Narasimhan
..• International Journal of (communicated) .
Food
Science
&
Technology
EXTRACTED EVALUATION OF SUPERCRITCAL CARBONDIOXIDE QUALITY ESSENTIAL OILS OF PEPPER BY GC FINGER PRINTING AND SENSORY ANALYSIS K. Udaya Sankar and Shanthi Narasimhan (Central Food Technological Research Institute, Mysore-570013)
SUMMARY Supercritical
gas extraction of essential oil from pepper is
carried out at four different on
conditions of e:{traction
selected
the basis of lower density of carbondioxide at near
critical
conditions.
Quality
conventional
evaluation of these extracts as compared to
steam distilled oils is reported.
Standardized
GC
finger printing with integration and odour profile evaluations by a
trained
panel was carried out
on
these
extracts.
Physico
chemcial parameters of oils were also recorded. Extracts classical
under
10 M Pa and 60 C was found to be showing
resolution of the GC finger printing and was close
the pictures of steam distilled oil. was
more complete,
However,
a to
the odour impact
balanced and typical of fresh pepper in
the
supercritical gas extracted oil.
,
KEY WORDS Supercritical sensory analysis.
carbondioxide,
extraction,
pepper
oils,
Introduction: Pepper, the black gold has attracted many countries, far and wide
from the early time both for medical use and as a
ingredient in food. either
in
green
They have long been traded as whole berries
conventional black or white form or more recently
form either after brining or in
buff
coloured
valuable
aromatic
pepper
spice.
dehydrated
form.
also is a possible mode of
Developments in post harvest
handling
been towards either for saving the quality of the
crop
or
reducing
Oleoresin
the bulk.
manufacture
with
thus lowering the chlorinated
Newer
handling
have
is
the
methods valuable
shipping
solvent
in
cost. major
a
development and used extensively, unfortunatley many times at the cost
of loss to the growers (Govindarajan and Shanti Narisimhan,
1986).
Because of the impending ban on chlorinated solvents for
extraction of oleoresin for considerations of carcinogenicity
One is
technologically two developments are foreseen.
toxicity.
or
the use of acetone or ethyl alcohol and the other. carbon dioxide extraction.
Acetone
has the problems of traces of mesityl oxide
formation in the preparation of pepper oleoresin, which, with in
hydrogen suphide produces 4-methyl-4-mercapto the
preparation resulting
meat
1983).
(Pagington,
Ethyl
alcohol
in is
offensive equally
reacting
pentan-3-one catty
odour
effective
in
extraction as acetone and has no residue problems. Supercritical of
op~ration
•
carbondioxide extraction has much flexibility
because
of
considerable
selectivity in holding the solutes. in temperature and pressure. of
the gas.
solvation
power
and
resulting from sma(l changes
just above the critical temperature
The process also gives 'nature 2
identical'
product
extracted However,
at the
low temperature and there is no
The
problem.
consideration for any technology to become viable,
yield and economics involved are important. this
residue
A detailed study
process in pepper is reported (CFTRI Annual report, present
conditions
paper discusses the quality
of
oil,
at
of
1986).
selected
of extraction using supercritical carbondioxide
with
steam distilled volatile oil. Materials and Methods: (i)
Malabar
ungarbled black pepper from local
market
was
(a) Steam distillation of
oil
ground to BS Sieve 22 before extraction. (ii)
Methods of extraction:
was carried out with Clevenger distillation apparatus using
AOAC
Method. (b) of
ground
SCF carbondioxide extraction was carried out on 1.2 pepper under four different conditions
(Udaya Sankar, 1988) at 8 M Pa at 40 C and 60 C,
as
Kg
described
10 M Pa at 40 C
and 60 C. (iii) duplicate
Gas chromatography: was
Gas chromatographic analysis
carried out for each
sample
under
in
standardised
conditions as detailed below.
.
Shimadzu - GC 9A, Column -SS, 3 mm 10, 3 Meters, SE 30 (5%), chromosorb support, 60/80 particle size, Sample size 4ul of 10% solution of oil in ethyl acetate, Detector: Flame Ionization detector, Injection port, 80 C Detector temperature 220 C Programmed temperature from 60-200 C at 2 C per min with initial and final isothermal period 5 minutes, Integration of peak upto 2.5 min with CR3A integrator (iv)
Sensory
analysis:
Odour profiles by strip
3
technique
was
carried out following Heath's method ( Heath, consisting
The panel
of 4-5 members were experiellced ill evaluating
and
other spices.
and
literature
pepper
Descriptors were selected from earlier S.,et al 1973).
(Govindarajan,V.
profile
odour
1978).
examinations
was followed by
The
testing
work
initial 12
after
hours. Results and Discussions: (a)
The
conditions
quality
of
the
oil
extracted
was compared with conventional steam
under
different
distilled
oils
for various parameters and reported earlier (CFTRl Annual report, 1983-84,
Udaya Sankar,
1985-86,
findings.
The
refractive However,
index
physical
constants
of
Table 1 summarises the specific
does not indicate any difference
percentage
differences.
1988).
These
recovery are
and
gravity among
opticdl rotation
needed to be subtantiated
and them.
shows with
the other
parameters of quality. (b) by
Sensory profile:
Odour profile of the samples recorded
the trained panel indicates distinct
differences.
gives the odour quality as it appears in the samples.
Table
g
It may be
observed that steam distilled oil is distinctively different from others, being more flowery and the dry out note is more terpenic. Among
the
test samples,
found
to be best and true to pepper powder with distinct herbal,
10 M Pa and 60 C extracted sample
woody notes along with milder top notes. was
th~
-
was
8 M Pa and 40 C sample
poorest with total lack of residual notes and
the
fade
out notes were very faint. (c)
resolution
GC finger printing:
The gas chromatography had shown a
of about 44-46 peaks in steam distilled oil and
4
also
oil
extracted
pressure
with carbon dioxide at
extracted
noticed
between
steam
dioxide
sample.
Both
peaks
at
pressure. Fig 1
the
Distinct differences were
not
disttlTed and 10 M Pa and showed clear pre and
middle and high Rt.
Lower
shows
oils showed 36-37 peaks.
printing of each sample.
finger
higher
post
60
carbon
C
caryophyllene
A capillary column
with
better
separation capabilities would perhaps show differences as they do have distinct pattern in sensory properties. extracted
samples
showed
shorter
The lower
and fewere
high
indicating lower levIes of high boiling compounds. C
sample,
peaks
Rt
the poorest of the sample showed only high
and low pre-caryophyllene peak.
resolution
are
early
Rt
It has been demonstrated
indicative of good quality of
note( Govindarajan and Shanti Narasimhan,
peaks,
B M Pa and 40
earlier that the middle and late Rt peaks under these of
pressure
1986).
conditions
basic
pepper
This study also
confirm these findings. Conclusions: The best yield and quality of pepper oil is obtained at 10 M Pa and 60 C with 6-7 hours of extraction. Odour and
It is also economical.
profile both as fresh and dry out show its
GC
finger printing matches clsoely
excellent with
conventional
steam distilled oil and is promising to show more definite indicative,of good quality.
•
•
5
product
peaks
Table.1 Physico-chemical properties of pepper oil Ex t r a c t i o n
Time
conditions
taken
% Hecovery
!3p.
l.:Jr.
Optical rotation
Refractive i nde x
(h)
Steam distilled
6.0
90.9
0.8834
-6.74
1.479
8 M Pa and 40 C
·19.3
79. ·1
0.8844
+0.74
1.483
8 M Pa and 60 C
·1 ·1 .8
84.6
0.8864
-1. 11
1.475
·10 M Pa and 40 C
6.3
·100.0
0.8859
+0.13
1.483
·10 M Pa and 60 C
5.9
98.2
0.8749
+0.35
1.483
Supercritical car bondi o x i de
..
. 6
Table 2. Odour profile uf pepper oils
Extraction conditIons
InitIal
Dryout note (after 12h)
Flowery, spicy, earthy oxidised terpenic, Good intensity
End earthy, herbal
8 M Pa and 40 C
Terpeny, mildy more balsamic
Soapy, dull
8 M Pa and 60 C
Spicy, flowery, campho ry, good intensity
Mild spicy
10 M Pa and 40 C
Cineole like, camphory spicy, less flowery, imbalanced
Mild cineolic, fairly good
10 M Pa and 60 C
Citrus, fresh herbal flowery, spicy, woody, balanced,Good intensity
Green, herbal, rooty, spicy note, good
Steam distilled
SC carbondioxide
7
spicy,
REFERENCES:
Annual Report, Mysore, p.30.
(1983-84), Central Food Technological Research Institute,
Annual Report, (1985-86), Central Food Technological Research Institute, Mysore, p.9"1--92. Govind arajan, V.S., and Shanti Narasimhan, (1986), Black Pepper- Piper Nigrum, presented at ACS spring meeting, New York. Govindarajan, V.S., Dhanaraj, 5., Shanti Narasimhan, (1973), Evaluation of spice 01e6resins: III Evaluation of some horticultureal varieties and trade types of pepper. J. of Planatation Crops (India), 1,8-16. Heath, H. B., (1978), Flavour Technology, Profiles, Application. AVI Publishing Co., Westport, Conn. (USA)
Products,
Pagin.]ton, J. S., (·1983), A review of oleoresin Black Pepper and its extraction solvents, Perf and Flavourist, 8, 29-36. Udaya Sankar, K., (1989), Studies on physico-chemical characterstics supercritical carbondioxide extracted pepper oils using carbondioxide, J. Sci. Fd. and Ag., (in Press)
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