Table of Contents
The Production of Coconut Oil from Coconut Milk by Fermentation
UKAN SUKANDAR*
Chemical Engineering Research Group on Product Design and Development, Faculty of Industrial
Technology, Institut Teknologi Bandung, Jalan Ganesa 10 Bandung 40132
Phone: +6222 2500989 ext. 323, Fax: +6222 2501438, E-mail: [email protected]
ABSTRACT
Coconut oil contains lauric acid which increases body endurance and reduces the risk of cholesterol
accumulation in blood. One of the techniques to produce coconut oil is fermentation. Coconut oil production by
fermentation is able to be applied in small industry because the process is simple and easy. Fermentation uses
microorganism which produces protease enzyme for breaking the lypoprotein chain in coconut milk. The
research used batch scale fermentation in a 1 litre Erlenmeyer flask as a fermentor in microaerophylic condition.
The parameter of success are the highest yield and the fastest breaking time of emulsion. Fermentation used
Saccharomyces cerevisiae having the highest coconut oil yield. Variables of this research were the formulation
of inoculum medium, the amount of inoculum, optimum temperature, pH, and oxygen content. There were four
experiment variations for every variable. The optimum formulation of inoculum medium was at the
composition of coconut water to coconut skim equals to 1 to 9, the optimum amount of inoculum was at the
composition of inoculum to coconut cream equals to 1 to 3, optimum temperature was 35oC, optimum pH range
equals to 6.58-6.68, and oxygen content was at range of 60-90% operation volume/fermentor volume.
The analysis of physical and chemical properties of coconut oil were density, refractive index, acid value, iodine
value, saponification value, peroxide value, and the composition of fatty acids. Coconut oil obtained by this
research fulfilled quality standard of coconut oil by Codex Standard 210-1999 with lauric acid content equals to
49.18 %.
Key words: coconut oil, lauric acid, Saccharomyces cerevisiae, protease enzyme
PREFACE
centrifugation, and drying. Every process has its
advantages and disadvantages.
Coconut is a plant which can grow well in tropical
area. Indonesia is one of the biggest coconut
producers in the world. Unfortunately, Indonesia is
still behind some Phillipines in managing coconut.
Coconut can be made into food sources or daily
equipments. Coconut oil is the most important
coconut product. Coconut oil can be used as raw
material of food, pharmaceutical, and cosmetics
industry. Coconut oil is believed to cure some
disease such as diabetes and reduce the risk of
cholesterol accumulation in blood.
Heating is a common applied process because the
equipments used are simple and need less money.
This process heats coconut milk until 100-110oC to
vaporize water and break protein in coconut milk.
Unfortunately, this process has some disadvantages
such as the low percentage of lauric acid and
damaged fatty acid contents in coconut oil.
Second process is centrfugation. This method is
often applied in big scale industry. Drying process
needs a lot of energy. This technique has its own
advantages which are fast and high percentage lauric
acid obtained. Unfortunately, it needs big place and
capital. It also can’t be applied in small industry.
Coconut oil can be carried out by dry process and
wet process. Coconut oil made by dry process
usually contains high percentage oil. Unfortunately,
oil produced by dry process has some disadvantages
such as oxidized and putrided easily. Wet process
can be made by traditional heating, fermentation,
Other process is trawling. This process has some
advantages in yield and good energy efficiency.
Unfortunately, this method is seldom applied
because it needs good separation technique so that
oil can’t mix with water. Process applied in this
*Research report submitted by Ukan Sukandar, a
participant in the 7th International Post-Graduate
University Course in Microbiology (1979-1980).
925
research is fermentation. The advantages of
fermentation are no oxidation risk, high yield, and
can be applied in small scale. Its disadvantages is it
takes longer time than other processes.
Coconut (Cocos nucifera) is a monokotil plants
which is from the Cocos genus, Palmae family, and
Arecales order. Coconut trees height can be 25 to 30
m heights and grow well in tropical climate. The
local coconuts that grow in Indonesia are yellow
coconuts (Cocos nucifera) and green coconut (Cocos
nucifera Linn).
This research in general intends to examine the
production of coconut oil using fermentation. In
particular, it heads for examining some variable
influencing the yield of coconut oil includes the
formulation of inoculum medium, determining
amount of inoculum, temperature, pH, and oxygen
limitation. The fermentation process is expected to
be applied in small industry in Indonesia.
Coconut has an oval-round shape with the diameter
of 80 to 130 mm and 100-160 mm length. Husk is
the outer part of coconut which has 2 layers; the
outside layer epicarp and inside layer mesocarp.
When the fruit is not ripe, the mesocarp is white and
turns into brown when ripens. Coconut husk can be
made into broom, car seater, bag, doormat, and plant
media in powder shape. Coconut shell or endocarp
layer is located under the coconut husk. At the
beginning, the coconut shell is soft and white and
then turns into brown color and hard. Coconut shell
is usually made for handycraft products, bricket, and
raw material of active carbon. Coconut water is
located inside of coconut under the coconut meat.
Coconut water is made in the first trimester and
reaches their maximum volume by the age of 8th
month. The main chemical compounds of coconut
water are sugar, mineral, fat, and nitrogen compound.
The
research
uses
batch
process.
The
microorganisms come from culture collection in
Microbiology
and
Bioprocess
Technology
Laboratory, Department of Chemical Engineering,
Faculty of Industrial Technology, Institut Teknologi
Bandung. Coconuts used in this research come from
Balubur Market, Bandung. This process is carried
out in microaerophylic condition. The variation
includes formulation of inoculum medium with the
variations of coconut skim to coconut water are 1 to
5, 1 to 7, 1 to 9, and 1 to 11, the amount of inoculum
with the variations of inoculum to coconut cream are
1 to 2, 1 to 3, 1 to 4, and 1 to 5, the variations of
operating temperature are 25, 30, 35, and 40 °C, and
the variations of acidity level (pH) are 5.5; 5.78; 6.68
and 7.36. The evaluated parameter are yield,
emulsion breaking time, density, refractive index,
acid value, iodine value, saponification value, and
the contents of fatty acid in coconut oil.
Coconut meat is also named as endosperm layer and
begins to form in 6th to 7th months after the fruit is
formed. The outside part of coconut meat is covered
by a thin brown layer called testa. Up until now,
coconut meat is dried to produce copra then ground
to produce coconut milk. Copra and coconut milk is
used as a raw material to produce coconut oil.
Composition of a fresh ripe coconut is shown in
Table 1.
This research is approached with research carried out
by Puertollano in 1970 using Lactobacillus
plantarum and Lactobacillus delbrueckii. The
variation includes are pH, dilution in extraction of
coconut milk, microorganism used, temperature, pH,
oxygen contents, grinding, and nutrient as
microorganism growth media. That research obtains
two factors which influence emulsion breaking that
are the reduction of fermented sugar as emulsifier
and the precipitation of dissolved protein as acid
obtained during fermentation process. Unfortunately,
that research can’t explain why coconut milk
emulsion without inoculum addition can’t break
itself.
Table 1 Chemical contents inside coconut meat
Composition (in 100 g
Component
coconut meat)
36.3 ml
Water
4.5 g
Protein
41.6 g
Fat
13 g
Carbohydrate
3.6 g
Fiber
1g
Mineral (Ca, P, Fe)
Source : Caballero, 2003
Coconut oil is the most important coconut product.
Coconut oil contains high percentage of saturated
fatty acid (C6-C20) and unsaturated fatty acid (oleic
and linoleic acid). The high percentage of saturated
fatty acid makes coconut oil resistant to oxidation so
it isn’t easily rotten and can be stored in long time
(Setiaji,2006). Composition of saturated fatty acid in
coconut oil is dominated by lauric acid which is
medium-chain trigliserida (MCT). MCT metabolic
process is different from long chain fatty acids. MCT
is easily oxidized, digested, and absorbed by human
THEORY
Coconut is one of the agricultural plants which their
whole parts such as husk, coconut shell, coconut
water, and coconut meat, can be used. The part of
coconut containing oil-fat is coconut meat. Coconut
meat used for oil producing is usually 11 to 12
months age.
926
body so it is not accumulated or preserved as fat in a
human body so it can reduce the risk of cholesterol
accumulation in blood.
copra cake in which the proteins have largerly
denatured and insolubilized. The residue of pressing
copra still contains about 6-7 % oil and can be
extracted using extraction with solvent. Oil contents
in extraction residue is less than 0.1 % (Soerawidjaja,
2005). However, Crude coconut oil after extraction
process usually still contains residues so it needs oil
refinery steps. Dry process is carried out in medium
and big scale plant.
Lauric acid and capric acid can improve stamina.
Lauric acid is converted to monolaurine which have
antiviral, antibacterial, and antiprotozoa inside body.
Monolaurine can kill viruses which cell membrane is
covered with fat (lipid-coated viruses) such as
Human Immuno Virus (HIV) (Caballero, 2003).
Capric acid in coconut oil is converted to
monocaprine which has strong antimicrobial activity.
The wet process consists of some technique such as
traditional process by heating, centrifugation,
trawling, and fermentation. Basically, wet process
separates oil from water with emulsion breaking in
coconut milk. Emulsifier is a substance which
possibly two phase undissolved mix and form an
emulsion. Emulsion stability depends on emulsifier.
So, emulsion is broken by damaging or leaving out
emulsifier (Bikerman,1958). Emulsifier in coconut
milk is protein which is dispersed in phase boundary
oil-water (Puertollano et.al.,1970). Protein and fat
existed in coconut milk bind each other to make
lypoprotein bond. Oil is obtained by breaking this
bond.
Coconut oil is also used as frying oil and as fat
components in biscuit making, cookies, chocolate,
ice-cream, and margarine. Other than that, coconut
oil is also used as main and additional raw material
for pharmaceutical industry such as in tea tree oil
making, and in cosmetics industry such as the
making of moisturizer lotion for face and skin.
Coconut oil produced by different processes will
have different taste, colour, and odor. A quality
standard was decided to standardize the quality of
coconut oil by a few like-minded foundations. One
of the quality standards of coconut oil based on
Codex Standard is shown at Table 2.
In traditional way, the fresh coconut is grated and
pressed to yield a coconut milk. The fat-rich fraction
separates as a cream, and the cream is then heated
until 100-110oC in order that water in coconut milk
vaporizes. It makes protein bounds with water will
be broken so oil will be separated from water. Oil
produced by heating process is called klentik oil.
Byproduct of this process is coconut cake (protein
fraction) which can be made into bakery raw
material and fodder. Traditional way is applied
because the equipment and process is simple.
However, heating makes antioxiandt compound and
fatty acid are decomposed, oil is easily to be rotten,
waste of energy, and low yield.
Table 2. Quality standard of coconut oil product
Characteristics
0
Value
o
Relative density (40 C/air 20 C)
0.908-0.921
Refractive density (400C)
1.448-1.450
Acid value (mg KOH/gr oil)
<4
Saponification value (mg KOH/gr oil)
248 - 265
Iodine value
6 – 10.6
Peroxide value
< 10
Free fatty acid (as lauric acid)
< 0.2
In centrifugation technique, the emulsion is broken
using centrifugation (spinning). Due to the low
density of oil compared to water, then the coconut oil
will be separated from water by itself. Producing oil
using centrifugation technique has its own
advantages which are longer storage time, very little
change in the antioxiandt and fatty acid content. The
production process does not need a lot of time.
However, the equipment used is so expensive and
waste of energy so that this technique is only
applicable in big scale industry.
Coconut milk is main raw material for production of
coconut oil. Coconut milk is oil in water emulsion
extracted from coconut meat containing sugar,
protein, and mineral salt. When it is calmed, coconut
milk is divided into 2 layers : cream and skim.
Cream layer is at the top because it contains more oil.
Skim layer is at the bottom because it contains more
water. Coconut cream contains fat as much as 4070% (Ohler, 1999).
The extraction of oil from coconut meat can be
carried out in two ways. Coconut oil production from
copra is dry process, meanwhile coconut oil
production from coconut milk is wet process. Oil
extraction is done by pressing copra directly.
Unfortunately, copra produced by traditional drying
methods is often moldy and contaminated by insects
and rodents. Furthermore, if the copra is pressed to
remove the oil, the high temperatures used result in a
Basically the trawling technique was meant to
change the emulsion form of water-oil into oil-oil
emulsion. The way to do this is to let the coconut
milk to deposit itself for 2 hours until it will be
divided into two layers which are water and the oil
containing part. the oil containing liquid is parted
and coconut oil is added (trawling). The trawling
927
process is done with 3 parts of the oil containing
liquid with 1 part of coconut oil. Afterwards, stir the
mixture for 20 minutes and leave it for 6-7 hours.
The mixture then will be divided into 3 layers which
are water in the bottom, coconut cake in the middle
part, and oil in the top layer (Syah, 2005). The oil
produced from trawling technique has its own
advantages which are clear in colour, quite long
storage time due to non-heating process. However,
this way depends on oil trawled so that the quality of
oil produced isn’t uniform.
Materials that were used in this research are ripe
coconut meat, ripe coconut water, and
microorganism strain in agar medium.
3.2 Equipments
Equipments that were used in this research are
Erlenmeyer flask 1 L, reaction tubes 200 mL, ose
needle, volume pipette 10 mL, measuring glass 50
mL, and separation funnel. Figure of Erlenmeyer
flask that was used as fermentor is shown in Fig. 1.
In fermentation technique, lipoprotein bond in
coconut milk is broken using protease enzyme or
with microorganism producing protease enzyme. If
the peptide chain in protein is broken, then the
protein-fat chain is also ruined therefore oil separates
from water and protein. Based on those facts, in the
process of breaking the lipoprotein chain in coconut
milk, we have to manipulate the protein and not the
fat. the composition and amount of fatty acid in the
lipoprotein chain must not change for it will affect
the benefit of the coconut oil produced from the
fermentation process. (Setiaji, 2006).
Fig. 1. Erlenmeyer 1 L
3.3 Experiments Procedures
Steps done in this research were raw material
preparation, inoculum preparation, and fermentation
process. Procedures which is done in raw material
preparations were as follows:
1. Ripe coconut meat was removed from its shell
and grinded.
2. Coconut meat was added with hot water, stirred
evenly, and shredded to take its coconut milk.
3. Add coconut milk into separation funnel, wait
for 30 minutes so that it makes two layers those
were skim and cream.
4. Those two layers were separated and added into
two different flasks.
Fermentation starts with develop seed water for
inoculum. Seed water used is the mixture of coconut
water and coconut skim. After inoculum
development, coconut milk is taken from grinded
coconut. It is mixed with water and pressed and then
wait for one hour to get coconut cream at the top
layer. Fermentation takes 10-15 hours in
microaerophylic condition and at optimum pH and
temperature. The assumption given is that enzyme
concentration will be at its maximum point. after
preparation of microorganism and substrate. After
the end of the process, three layers will be seen. Oil
is at the top layer, followed by protein fraction
(coconut cake), and water. Oil is filtered using fine
cloth. (Sastramihardja, 1984).
Procedures that are done in inoculum preparation are
as follows:
1. Strain was added with coconut water to make
seed water.
2. Take a little sample from seed water to count in
a counting chamber. By using some formula,
add some of seed water to fermentor.
3. Add skin and coconut water so that the
comparison of coconut water to skim became 1
to 9 in Erlenmeyer flask.
4. Inoculum was ready for fermentation process.
Oil produced by fermentation has its own advantages,
which are:
a. It has clear colour because it is not heated.
b. Antioxidant and fatty acid composition in oil does
not change.
c. It can be stored for a long time because it does not
easily oxidize.
d. It uses simple method and also simple tools.
e. High yield.
Procedures that were done in fermentation process
are as follows:
1. Inoculum added into fermentor with coconut
cream with the comparison of inoculum to
coconut cream is 1 to 3.
2. This fermentor was fermented at certain pH and
temperature for 12-16 hours.
3. Three layers were formed after fermentation
process. They were oil layers at the top, protein
Other than those advantages, fermentation also has
disadvantages such as the process takes a long time
and the coconut cake produces a sour taste.
(Soerawidjaja, 2005).
EXPERIMENT
3.1 Materials
928
fraction at the middle, and water at the bottom.
the volume of oil obtained was written.
4. Oil was decantted and separated from protein
and water.
5. Oil residue which couldn’t be separated was
centrifuged at 5000 rpm for 15 minutes. After
that, oil was separated from blondo (protein
fraction) and water.
6. Let oil containing flask for 2-3 days and then
moved the oil into another flask to get pure oil.
The result showed that the highest coconut yield was
achieved by S. cerevisiae is 30 % , followed by T.
famata and R. oligosporus with yield 27.5 % and
22.5% respectively. All microorganism produced
pured oil, protein and oil separate perfectly, and the
oil had fragrant smell. At microorganism selection
stage S. cerevisiae had been chosen according to
yield and physical characteristic of oil. Although
during fermentation process using S. cerevisiae
might produce alcohol because of microaerophylic
condition, the oil was safe to consume because
alcohol is not soluble into oil. Besides, fermentation
using yeast is easier to control than mold and
bacteria.
3.4 Researched Variable
Experiment was carried out by doing some variations
to some variables such as formulation of inoculum
medium, the amount of inoculum, temperature, pH,
and oxygen content. The variations of formulation
medium inoculum with the variations of coconut
skim to coconut water were 1 to 5, 1 to 7, 1 to 9, and
1 to 11. Variations of the amount of inoculum with
the variations of inoculum to coconut cream were 1
to 2, 1 to 3, 1 to 4, and 1 to 5. Variations of of
operating temperature were 25, 30, 35, and 40 °C.
Variations of pH were 5.5; 5.78 ; 6.68 and 7.36.
Variations of oxygen content were 10, 20, 30 and
40 % volume of empty fermentor/volume fermentor.
4.2 Formulation of Medium Inoculum
Optimum formulation of medium inoculum was
remarked with the largest number of S.cerevisae
cells for 16 hours fermentations. The counting of
S.cerevisae cells number is carried out in counting
chamber method. Cell concentration added into
medium for all variations are all same that are
100.000 cells/mL. The result of S.cerevisae growth
in all variations is shown in Fig. 2.
12
RESULT AND DISCUSSION
Cells x 10 (cell/mL)
10
6
4.1 Microorganism Selection
This stage used 9 strains of microorganisms. The
microorganism are Saccharomyces cerevisiae, Candida
tropicalis, Torulopsis famata, Lactobacillus plantarum,
Streptococcus lactis, Acetobacter aceti, Rhizopus
oligosporus, Aspergillus oryzae, and Beauveria bassiana.
8
6
4
Variation 1
Variation 2
2
Variation 3
Variation 4
0
Inoculum medium composition contained 2 mL
coconut water and 18 mL coconut skim. Biomass
concentration inoculated to inoculum medium was
one million cells/mL. Ten (10) mL inoculum
medium was added to 30 mL coconut cream so that
total volume fermentation became 40 mL. The result
could be seen at Table 3.
0
5
10
15
20
Time Growth (hours)
Fig. 2 Growth curve of S. cerevisiae
Third variations that its composition of coconut
water to coconut skim is 1 to 9 is the optimum
formulation of medium inoculum. This was shown in
S.cerevisae cells number per mL at the end of
logarithmic phase is the largest of all variations.
Tabel 3. Coconut yield for microorganism tested
Coconut volume (mL)
Total
yield
Microorganism
1st
2nd
3rd
4th
day day day
day (% -v/v)
S. cerevisiae
11.5
12
12
12
30
C. tropicalis
5
6
6
6
15
T. famata
11
11
11
11
27.5
L. plantarum
6
7
8
8
20
S. lactis
8
9
9
9
22.5
A.aceti
8
8
8
8
20
R.oligosporus
7.5
8
8
9
22.5
A. oryzae
6.5
6.5
6.5
7
17.5
B. bassiana
3.5
4
4
4
10
Coconut water which was used as medium is good
enough for fermentation process. This was shown in
Fig. 2 which every variation didn’t have adaptation
phase and directly enters logarithmic phase.
Logarithmic phase started from 4th hour until 8th hour
shown by fast growth rate.
Yeast growth entered stationer phase after 12th hours.
This showed that fermentation process happens for
12 hours. This result was likely to be the same as
literature. Literature stated that fermentation process
occurs during 10-14 hours (Sastramihardja, 1984).
929
During fermentation process, there was a decrease in
pH caused by formaton of organic acids. Acids
formation occured because coconut milk contains
glucose
compound
and
supported
by
microaerophylic condition. S.cerevisae could convert
glucose into organic acids such as lactic acid and
acetic acid. Glycolysis cycle also explained why acid
formation in fermentation occurs.
soluble protein. Soluble
precipitated is called blondo.
In previous steps, fermentation was carried out in
temperature
based
on
literature.
30oC
(Sastramihardja,1984). Optimum temperature for
S.cerevisae growth was known in 30-40oC range.
(Jong, 1987). The result of experiment for every
variation is shown in Fig. 3.
250
Oil Volume (mL)
200
Table 4. The result of every inoculum variation
2
3
4
1:2
1:3
1:4
1:5
150
100
Variation 1 (T = 25 C)
Variation 2 (T = 30 C)
50
Variation 3 (T = 35 C)
Variation 4 (T = 40 C)
0
0
6,28
6,28
6,28
6,28
Day
Oil volume
(mL)
Oil volume
(mL)
Oil volume
(mL)
Oil volume
(mL)
1
150
225
235
200
2
175
250
250
225
3
175
250
250
225
Oil pH
6
6
6
6
Blondo
pH
4,5
4,5
4,5
4,5
Water pH
4
4
4
4
been
4.4.1 Temperature
Inoculum medium used a mixture of coconut water
and coconut skim with ratio 1:9. Inoculum medium
inoculated with S. cerevisiae was added to coconut
cream. Every variation used same total volume (800
mL) and was incubated at 30oC. The result of
observation coconut yield for every variation can be
seen at Table 4.
1
had
4.4 Optimum Fermentation Condition
4.3 The Amount of Inoculum
Variation
Inoculum
: cream
Initial pH
mixture
protein
1
2
3
4
5
6
7
8
9 10 11 12 13 14 15 16 17 18 19 20 21
-50
Fermentation Time (hours)
Fig. 3. Oil volume obtained in temperature variation
Optimum enzyme activity was marked with how
fast coconut milk was separated into three layers
those are oil, blondo, and water. From Figure 3, it
was found that in 7th hour, 3rd variation had the
highest yield which volume was 150 ml. In the end
of fermentation process, oil volume obtained in 3rd
and 4th variation were 225 mL. Meanwhile, 1st and
2nd variations produced less oil for about 200 mL.
Based on those data, it could be concluded that
optimum fermentation temperature is 35oC based on
yield and fastest time for producing oil.
The best variation was chosen according to highest
coconut yield. At this stage, 2nd variation which its
ratio of inoculum to coconut cream was 1 to 3, had
been chosen because of its efficiency.
First variation produced less oil than 2nd variation. It
showed that coconut oil yield increased because
coconut cream added was increased. In 1st variation,
substrate could still be added to give maximum
coconut oil yield. But, this couldn’t be done for 2nd,
3rd, and 4th variation. Second and third variation
produced the same oil volume, and the volume
decreased in 4th variation. It showed that highest
productivity was happened to 2nd variation because
the yield was the same although the cream in 2nd
variation is less than 3rd variation. Coconut oil yield
decreased at 4th variation because there might be a
substrate inhibition and inoculum limit to break
coconut milk emulsion to produce oil.
4.4.2 pH
Other condition which was optimized in this process
beside temperature was pH. The variation of pH at
6.58-6.68 was the pH of freshly extracted coconut
milk. The chosen variation for pH was the variation
which had the fastest time producing oil with high
yield. The result of this stage is shown by Fig. 4.
250
Oil Volume (mL)
200
Coconut protein (blondo) had pH 4.5 because during
emulsion breaking process, carbohydrate in coconut
cream was converted to organic acids. These acids
disturbed protein isoelectric pH so that organic acids
accumulation caused breaking and precipitation of
150
100
Variation 1 (pH = 5)
Variation 2 (pH = 5.78)
50
Variation 3 (pH = 6.68)
Variation 4 (pH = 7.36)
0
0
5
10
15
20
-50
Fermentation Time (hours)
Fig. 4. Oil volume obtained in pH variation
930
25
From Fig. 4, it was known that 3rd and 2nd variation
produced oil at 5th hour. However, 3rd variation
produced much more oil than 2nd variation. Whereas,
1st and 4th variation produce oil at 8th and 7th hour
respectively. It happened because S. cerevisiae in
inoculum needed to adapt with new pH condition. As
we known before, the pH of inoculum were the same
as pH of coconut cream so that S. cerevisiae directly
broke coconut milk emulsion to oil. But if pH of
coconut cream was changed, S. cerevisiae needed
more time to adapt. By using those statements, it can
be conclueded that at this stage, 3rd variation with pH
6.68 was optimum pH fermentation. In other words,
optimum pH fermentation was the pH of coconut
milk without acid or base addition.
Quality analysis included physical and chemical
properties analysis. Physical properties analyzed
were relative density and refractive index.
Meanwhile, chemical properties analyzed were acid
value, saponification value, iodine value, peroxide
value, and fatty acid composition. Quality standard
used as a comparison was Codex Standard 210-1999.
Result of oil sample analysis is shown in Table 5.
Tabel 5. Quality analysis of oil sample
Characteristics
Codex Stan.
Sample
Relative density (40oC/
0.908-0.921
0.931
air 20oC)
Refractive index
1.448-1.450
1.448
(40oC)
Acid value (mg KOH
<4
0.28
/gr oil)
Saponification value
248 - 265
248.08
(mg KOH/gr oil)
Iodin value
6 – 10.6
7.86
Peroxide value
< 10
9.18
Free Fatty Acid (as
< 0.2
0.16
lauric acid)
Fatty acid
Composition (%)
Caproic acid
0.05 – 0.7
ND*)
Caprylic acid
4.6 - 10
9.41
Capric acid
5.0 – 8.0
8.61
Lauric acid
45.1 – 53.2
49.18
Myristate acid
16.8 - 21
17.12
Palmythate acid
7.5 – 10.2
7.35
Steraic acid
2.0 – 4.0
4.06
Oleic acid
5.0 – 10.0
ND*)
Linoleic acid
1.0 – 2.5
ND*)
4.4.3 Oxygen content
Optimum oxygen supply was determined by
variation of operation volum/fermentor volum.
Selected variation is the fastest variation which
produced coconut oil at high yield. The result of this
stage is shown by Fig. 5.
300
Oil Volume (mL)
250
200
150
100
Variation 1 (60%-v)
Variation 2 (70%-v)
50
Variation 3 (80%-v)
Variation 4 (90%-v)
0
*)
0
5
10
15
20
25
-50
non detectable
Oil density based on experiment had greater value
than standard. This was probably caused by
unaccurate measurement. Besides, imperfect
separation of oil from blondo and water might allow
another compound which enlarged oil mass.
Refractive index based on experiment was in range
on standard value. Result of refractive index
measurement showed that oil sample had the same
purity as standard.
Fermentation Time (hours)
Fig. 5. Oil volume obtained in oxygen content variation
From Fig. 5, it was known that increasing operation
volum gave more oil produced because there was
more coconut cream which was converted to oil.
Separation oil from coconut cream in every variation
tended to happen at the same time (7th hour).
Coconut oil yield was expressed by percentage of oil
volum/operation volum for every variation was
almost at the same value that was at 27.78% – 29%
range.
According to Sudarmadji (1989), high acid value
showed the low quality of oil. Acid value of samplec
was 0.28. This number was far below standard. This
statement proved that oil sample had high quality.
This was shown by the low number of free fatty acid
(as lauric acid).
At this stage, the variation using 100% operating
volume was also carried out. In this experiment,
there was not almost any void fraction in fermentor
so that fermentation process was carried out in
anaerobic condition. The yield obtained by this
variation was just 22.5%. It showed that
fermentation should not be done at aerobic or
anaerobic condition, but microaerophylic condition.
The range of operating volume to fermentor volum
ratio which was used depended on amount of oil
demanded.
Saponification value of sample was in the lower
range of standard value. The lower saponification
value, the lower molecular weight of the oil. It
means the length of carbon chain of fatty acids in oil
was shorter. Based on this sentence, we could
assume that sample was dominated by medium chain
fatty acid.
4.5 Coconut Oil Quality Analysis
931
Table of Contents
Oil sample had low iodine value (7.86). The higher
iodine value, more double bond in fatty acid was
formed. It means that contents of unsaturated fatty
acid was higher. This statement was proved by
composition of unsaturated fatty acid such as oleic
acid and linoleic acid in sample was undetected.
1.
2.
3.
Peroxide value of oil sample was quite high. (close
to the high range of maximum standard) The value is
9.18. This was probably caused by open place oil
storage. It was indirectly exposed by sun ray. This
condition might cause oxidation reaction. The length
time of storage was estimated for 2-3 weeks before
sample analysis. Besides that, it hadn’t been
pasteurized
before
stored.
According
to
Puertollano,et.al. (1970), pasteurization could kill
contaminant microorganism and maintained oil
stability to oxidation when stored.
4.
5.
Coconut oil should be pasteurized to kill
pathogen microorganism and to keep stability
from oxidation.
Coconut should be come from one place and
was processed directly after harvesting to get
uniform coconut oil quality.
Coconut meat should be extracted with hot
water to kill contaminan bacteria.
The parameter in microoganism selection should
not only consider yield but also time to break
coconut milk emulsion to oil.
Fermentation process should be undertaken
using other microoganisms like R. oligosporus
and T. famata which had almost as same
coconut oil yield as S. cerevisiae.
LITERATURE
Fatty acid compositions was analyzed using GCMS
(Gas Chromatography Mass Spectrometry). Lauric
acid contents in sample fulfilled standard value. It
means that coconut oil produced by fermentation
using S.cerevisae as microorganism had a good
quality. The higher lauric acid contents in coconut
oil, the better quality of oil produced.
[1] Bikerman, J.J, ”Surface Chemistry: Theory and
Applications”, 2nd Ed, Academic Press Inc, New
York, 1958.
[2] Caballero, B., “Encyclopedia of Food and
Sciences and Nutrition Vol. 3”, 2nd Ed,
Academic Press Inc, New York, 2003.
[3] Jong, S.C.; Gantt, M.J., “American Type Culture
Collection, Catalogue of Fungi/Yeasts”, 17th Ed,
1987.
[4] Ohler, J.G.,“Modern Coconut Management :
Palm Cultivation and Products”, 1999.
[5] Pradera, et al., “Coconut Products : Tender
Coconut Water”, 1992
(www.coconutboard.nic.in).
[6] Puertollano, C.L; Keith H.S.; Julian B,
“Separation of the Oil and Protein Fractions in
Coconut
(Cocos
nucifera
Linn.)
by
Fermentation”, J.Agr. Food Chem.18 (4), 1970,
579-584.
[7] Sastramihardja, I., “Minyak Kelapa”,
Laboratorium Mikrobiologi ITB, Bandung, 1984.
[8] Setiaji, B., ”Membuat VCO berkualitas Tinggi”,
Jakarta, Swadaya, 2006.
[9] SNI 01-2902-1992 (http://www.dprin.go.id/).
[10] Soerawidjaja, T.H., ”Diktat Kuliah Proses
Industri Kimia”,ITB, Bandung, 2005.
[11] Sudarmadji, S.; Bambang H.; Suhardi, “Analisa
Bahan Makanan and Pertanian”, Liberty
Yogyakarta, Yogyakarta, 1989.
[12] Syah, A.N.A, “Virgin Coconut Oil Minyak
Penakluk Aneka Penyakit”, Agromedia Pustaka,
Jakarta, 2005.
CONCLUSION AND SUGGESTION
5.1 Conclusion
According to results of this research, it could be
summarized things follow :
1. Coconut milk fermentation into coconut oil used
microorganism Saccharomyces cerevisiae gave
the highest coconut oil yield.
2. Inoculum medium which ratio of coconut water
to coconut skim was 1 to 9 gave the most cell
amount of S. cerevisiae.
3. Ratio inoculum to coconut cream which results
the highest coconut oil yield was 1 to 3.
4. The optimum temperature of coconut milk
fermentation to coconut oil was 35oC.
5. The optimum pH of coconut milk fermentation
to coconut oil was 6.5-7.
6. Fermentation
process
was
done
at
microaerophylic condition with oxygen content
was
expressed
by
fraction
operation
volum/fermentor volum was 60 – 90 % v/v.
7. Physical and chemical properties of coconut oil
resulted by this research fulfilled quality
standard of coconut oil by Codex Standard 2101999 with lauric acid content was 49.18 %-w.
5.2 Suggestion
Suggestion for furthest studies related to this
research are followed :
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