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RRJFDT | Volume 1 | Issue 1 | July – September, 2013 22
Research and Reviews: Journal of Food and Dairy Technology
Extraction and Characterization of
Moringa oleifera
Seed Oil
Orhevba BA1, Sunmonu MO2*, and Iwunze HI1
1Department of Agricultural and Bioresources Engineering, Federal University of Technology, Minna, Nigeria.
2Department of Agricultural and Biosystems Engineering, University of Ilorin, Nigeria.
Research Article
Received: 24/03/2013
Revised: 18/05/2013
Accepted: 12/06/2013
*For Correspondence
Department of Agricultural and
Biosystems Engineering, University of
Ilorin, Nigeria.
Keywords:
Moringa oleifera,
seed oil,
proximate
ABSTRACT
Moringa Oleifera
seed oil was extracted using the solvent extraction method.
The proximate analysis of the oil was carried out. The physicochemical properties of the
oil were also determined. The parameters determined were: moisture content, ash, crude
protein, crude fat and carbohydrate for proximate analysis; and pH, saponification value,
iodine value, free fatty acid and specific gravity for physicochemical properties. The
values of moisture content, ash, crude protein, crude fat and carbohydrate were 0.60%,
1.50%, 2.19%, 39.3% and 56.42% respectively. While the values obtained for pH,
saponification value, iodine value, free fatty acid and specific gravity were 5.96,
164.09mg/g, 68.23g/mol, 8.27mgKOH/g and 0.86 respectively. The results showed
that
Moringa oleifera
seed oil is a good source of Carbohydrate, also the saponification
values and iodine values obtained shows that it is a good raw material for both home
and industrial consumption.
INTRODUCTION
Moringa oleifera
, commonly referred to as "
Moringa
" (from Tamil: Muringa and Malayalam: Murunggi,) is the most widely
cultivated species of the genus
Moringa
, which is the only genus in the family
Moringaceae
.
Moringa
, which is the only genus in the family
Moringaceae
, is an exceptionally nutritious vegetable tree with a variety of potential uses. Every part of
Moringa oleifera
such as the seed,
root and stem are useful. The tree itself is rather slender, with drooping branches that grow to approximately 10m in height [1].
Moringa
oleifera
is called different names worldwide [2].
Moringa oleifera
is now grown widely throughout the tropics of which Nigeria is a part. It is sometimes known as the ‘drumstick’ or
‘horseradish’ tree. Ranging in height from 5 to 12m with an open, umbrella-shaped crown, straight trunk and corky, whitish bark, the tree
produces a tuberous tap root. The evergreen or deciduous foliage (depending on climate) has leaflets 1 to 2 cm in diameter; the flowers
are white or cream coloured. The fruits (pods) are initially light green, slim and tender, eventually becoming dark green, firm and up to
120cm long, depending on the variety. Fully mature, dried seeds are round or triangular, the kernel being surrounded by a lightly wooded
shell with three papery wings [3].
In the tropics, it is used as forage for livestock; in many countries,
Moringa
is used as a micronutrient powder to treat diseases. The
green pods, fresh and dried leaves are used as vegetable. The seeds contain up to 40% of oil by weight which is used for cooking, soap
manufacture, cosmetic base and in lamps. All parts of the plant are used in a variety of traditional medicines. The press cake, obtained
following oil extraction, is useful as a soil conditioner; the plants are grown as live fences and windbreaks. It is also used as fuel wood
source after coppicing (cutting back the main stem to encourage side shoots); as an intercrop with other crops and the wood pulp may be
used for paper-making. In the tropics, it is used as forage for livestock; in many countries,
Moringa
is used as a micronutrient powder to
treat diseases. The green pods, fresh and dried leaves are used as vegetable [3,4].
Moringa
trees have been used to combat malnutrition, especially among infants and nursing mothers. The leaves can be eaten
fresh, cooked, or stored as dried powder for many months without refrigeration, and reportedly without loss of nutritional value.
Moringa
RRJFDT | Volume 1 | Issue 1 | July – September, 2013 23
is especially promising as a food source in the tropics because the tree is in full leaf at the end of the dry season when other foods are
typically scarce [5,6]. It is commonly said that
Moringa
leaves contain more Vitamin A than carrots, more calcium than milk, more iron than
spinach, more Vitamin C than oranges, and more potassium than bananas,” and that the protein quality of
Moringa
leaves rivals that of
milk and eggs. However, the leaves and stem of
M. oleifera
are known to have large amounts of their calcium bound in calcium oxalate
crystals [7].
The tree's bark, roots, fruit, flowers, leaves, seeds, and gum are also used medicinally. The uses include as an antiseptic and in
treating rheumatism, venomous bites, and other conditions. The flowers, leaves and roots are widely used as remedies for several
ailments. The bark of the
moringa
root should be scraped off because of its toxicity and the flesh of the root should be eaten sparingly [8].
Moringa
seeds are effective against skin-infecting bacteria
Staphylococcus aureus
and
Pseudomonas aeruginosa
[8]. They contain the
potent antibiotic and fungicide terygospemin.
Moringa
seem to have most of the food nutrients required by the body to replenish its
defensive mechanisms. The Tonga people of Binga District in Zimbabwe use the root powder as an aphrodisiac and when it is mixed with
milk, it is considered useful against asthma, gout, rheumatism and enlarged spleen or liver. It also helps in the removal of wind from the
stomach and as a snuff and can be used to alleviate ear and toothache [8,9].
The leaf juice has a stabilizing effect on blood pressure. The leaf juice controls glucose levels in diabetic patients. Fresh leaves
and leaf powder are recommended for tuberculosis patients because of the availability of vitamin A that boosts the immune system. If leaf
juice is used as diuretic, it increases urine flow and cures gonorrhoea. Leaf juice mixed with honey treats diarrhoea, dysentery and colitis
(colon inflammation). Fresh leaves are good for pregnant and lactating mothers; they improve milk production and are prescribed for
anaemia. Paste made from bark treats boils. Paste from ground bark can be applied to relieve pain caused by snake, scorpion and insect
bites. Oil is sometimes applied externally for skin diseases [9].
Fully mature, dried seeds are round or triangular in shape, where the kernel is surrounded by light wooded shell with three
papery wings. When mature, the seeds from the pods can be extracted and treated like green peas and can be fried or roasted and eaten
like peanuts. It also contains oleic acid-type oil. The seeds contain up to 40% of oil by weight which is used for cooking, soap
manufacture, cosmetic base and in lamps. All parts of the plant are used in a variety of traditional medicines. The press cake, obtained
following oil extraction, is useful as a soil conditioner; the plants are grown as live fences and windbreaks. It is also used as fuelwood
source after coppicing (cutting back the main stem to encourage side shoots); as an intercrop with other crops and the wood pulp may be
used for paper-making [3].
Due to ever diminishing sources of fats and oils, there is the growing need for the search of new sources of oil as well as
exploiting sources that are currently unexploited in order to supplement the existing ones [1].
Moringa oleifera,
a very rapid growing tree
found growing in a varying range of climatic condition is a promising tree and has the potential to become a new source of oil for Nigeria.
It has been reported that some 3000 kg of seeds could be obtained from one hectare, equivalent to 900 kg oil/hectare, comparable to
soybean which also yields an average of 3000 kg seeds/hectare but with only 20% oil yield. The oil is edible, and closely resembles olive
oil in its fatty acids composition. According to Sengupta and Gupta [10],
M. oleifera
seeds contain between 33 and 41% w/w of vegetable
oil. Anwar
et al.,
[11] also investigated the composition of
M. oleifera
, including its fatty acid profile and showed that
M. oleifera
oil is high
in oleic acid (>70%).
M. oleifera
is commercially known as ‘‘ben oil” or ‘‘behen oil”, due to its content of behenic (docosanoic) acid, it
possesses significant resistance to oxidative degradation [12].
M. oleifera
has many medicinal uses and has significant nutritional value [11].
A recent survey conducted on 75 indigenous (India) plant-derived non-traditional oils concluded that
M. oleifera
oil, among others, has
good potential for biodiesel production [11].
Various extraction methods can be used in the extraction of oil and the method is normally dependent on what type of botanical
material is been used. These methods include mechanical, traditional and solvent extraction. Solvent extraction method involves the
counter – current flow of solvent and out bearing materials in the extraction vessel. It is usually used to recover a component from either a
solid or liquid. The sample is contacted with a solvent that will dissolve the solutes of interest. Solvent extraction is of major commercial
importance to the chemical and biochemical industries, as it is often the most efficient method of separation of valuable products from
complex feed stocks or reaction products. Some extraction techniques involve partition between two immiscible liquids; others involve
either continuous extractions or batch extractions. Because of environmental concerns, many common liquid/liquid processes have been
modified to either utilise benign solvents, or move to more frugal processes such as solid phase extraction. The solvent can be a vapour,
supercritical fluid, or liquid, and the sample can be a gas, liquid or solid [13]. The yield using this process is usually higher than that of
mechanical method; and the residue usually contains less than 2% oil. Common solvents used are hexane and benzene (hydrocarbons)
both of which are petroleum derivatives. Solvent extraction plants are becoming more as processing industries now aim to produce meals
with minimum oil contact for commercially acceptable production levels without impairing oil or meal quality.
Usually solvents are used to extract fats and oils. Solvents, however, are not environmentally friendly. Enzymes, on the other
hand, are green catalysts, and are often used to improve the efficiency of oil extraction. Rosenthal
et al
[14] have reviewed the use of
RRJFDT | Volume 1 | Issue 1 | July – September, 2013 24
enzymes in the extraction of oil, protein, and other components from oil-containing seeds and fruits. This technology has been developed
to extract oil on a laboratory and pilot scale from many oil-bearing materials.
The characterisation of essential oils through chemical analysis is a mandatory step in the production chain, to be carried put by
both researchers and quality control laboratories. Essential oils are primarily composed of terprenes and their oxygenated derivatives.
Conventionally, gas chromatography methods are used to perform overall analytical cycle of the essential oil due to its high performance
and high level of accuracy. The colour, viscosity, solubility and smell of the extract also can be tested to ascertain the quality of an
optimum grade of the extract [15]. The index of refraction is related to the physical structure of the medium through which light is passing.
For this reason, the index of refraction is a characteristic of substances that can be employed in identifying unknown compounds. The
higher the refractive index, the greater the amount of dispersion which increase the brilliance of a material .Acid value is measure of the
amount of free acid present in fat. Some of the deterioration that takes place during storage in the raw material from which th fat is
obtained results in hydrolysis of fatty acids. Fatty acids must be removed in the preparation of insecticides . Specific gravity is the density
of a substance divided by the density of water. Since water has a density of 1g/cm3, and since all of the units cancel, specific gravity is the
same number as density but without any units. For example, the specific gravity of leached solution (i.e. ethanol and the solute from
Moringa oleifera
) is a function of the specific gravity of the oil and that of the organic solvent i.e. ethanol. The specific gravity of the oil is
about 0.93 and that of the solids not fat is 1.5. Hence as the oil content of solution increases, the specific gravity decrases and, conervsely
as he solid (solute) increases, the specific gravity of the milk also increases . Iodine value is also called iodine number which is the
measure of the proportion of the unsaturated acid present. There is no iodine present in oils and fats, but the test measures the amount
of iodine which can be absorbed by the unsaturated acids. As the concentration and types of unsaturated acids present are fairly constant,
the iodine value will give a figure for the total degree of unsaturation [15].
Due to high dependency of humans on oil for both domestic and industrial uses. There is need to look for another source of oil
with better method of extraction to give a higher yield. This study focuses on the extraction and characterization of moringa oleifera seed
oil.
MATERIALS AND METHODS
Some samples of
Moringa
oleifera
were obtained from maizube farms at Garatu Village in Bosso LGA of Niger State. A Picture of
the seeds is shown below.
Plate 1:
Moringa
oleifera
seeds
Pre-treatment procedure
This is the initial stage of sample preparation and it includes the following:
Seed collection
This involves the collection of the fruits of
Moringa oleifera
and drying it. The drying process stimulates the opening of the fruits
to release seeds embedded inside. The seeds were separated from the chaffs and other impurities. This Preparation is very important
since any impurity in the seeds will eventually reflect on the oil extracted.
Drying
After the seeds had been cleaned thoroughly; they were dried in an electric oven to reduce the moisture content of the seeds.
RRJFDT | Volume 1 | Issue 1 | July – September, 2013 25
Size Reduction
Moringa oleifera
seeds were milled into a paste using thermal Willey mill. This operation ruptures the cell wall and releases the
solute for direct contact with the solvent during the contact equilibrium process.
Weighing
This was done before and after the seeds were dried. The weight was taken and recorded using electronic weighing balance.
Experimental Procedure
The samples collected were washed with distilled water .These were then air dried in the laboratory and grinded. 10.0g of this
was weighed and placed on a filter paper which was folded carefully. The filter paper containing the sample was then inserted into the
Soxhlet apparatus. The weight of the filter paper and sample was recorded 200ml of the solvent (hexane) was measured using a
measuring cylinder and then poured into a 500ml round bottom flask with the sample and heated at 60oC for 5 hours after which the
sample was removed and transferred into the air oven to dry at 105oc for 15 minutes. This sample was then weighed and the difference
was calculated as: weight of sample before extraction – weight of sample after extraction, divided by the initial weight of sample, and
multiplied by 100 to give the percentage yield oil. The oil was recovered by solvent evaporation. It was heated at a low temperature until
the solvent finally evaporates leaving behind the oil extracted. Figure 3.1 shows the flow chart for the solvent extraction of
Moringa
oleifera
oil from Moringa seeds.
Proximate Analysis
Proximate analysis was carried out at the Chemistry Laboratory, Federal Polytechnic, Bida, Niger State. Nigeria. The proximate
composition of the material was determined by the method described by the Association of Analytical Chemist [16]. The proximate
analyses carried out are moisture content, crude fat, ash, crude protein and carbohydrate.
Determination of Physicochemical Properties
The following physicochemical properties were determined;
Saponification Value
The sample was melted and filtered to remove any impurities and the last traces of moisture. 5g of the sample was weighed into
a conical flask. 50ml of alcohol KOH was added from burette by allowing it to drain for a definite period of time. A blank sample was
prepared using the same method. Then a reflux condenser was connected to the flask and it was boiled gently for about 1hr. The flask
and condenser were allowed to cool and rinsed with little distilled water and the condenser was removed. 1ml of indicator was added and
0.5M HCl was used for titration until the pink colour disappeared.
Iodine Value
0.5g of oil was weighed into iodine flask and it was dissolved into 10ml of chloroform. 25ml of Wiji’s iodine solution was added
to it using pipette for a certain period of time. The solution was mixed well and allowed to stand in a dark corner for exactly 30minutes
with occasional shaking. 50ml of 15% KI was added and shaked thoroughly. 100ml of freshly boiled and cooled water was used to wash
down free iodine on a stopper. It titrated against 60 normal sodium trioxothiosulphate (VI) until the yellow solution turned almost
colourless. Little starch was added as an indicator and titrated until blue colouration completely disappeared.
Free Fatty Acid
5g of oil or melted fat was dissolved in 50ml of the neutral solvent in 250ml conical flask. 3 – 4 drops of phenolphthalein
indicator was added. The sample was titrated against 0.1KOH and shaken constantly until it changed to pink colour.
Specific gravity
A stopper density bottle was filled with cold distilled water and kept in a water bath at 1000C for 30 minutes. The weight was
taken after losing away any water drops on the bottle. After drying the bottle was filled with the extracted oil and the process was
repeated to get the final weight.
RRJFDT | Volume 1 | Issue 1 | July – September, 2013 26
pH
2g of the sample was poured into a clean dry 25ml beaker and 13ml of hot distilled water was added to the sample in the beaker
and stirred slowly. It was then cooled in a cold water bath to 250C. The pH electrode was standard with buffer solution and the electrode
immersed into the sample and the pH value was read and recorded.
RESULTS AND DISCUSSIONS
The results of the proximate composition of
Moringa oleifera
oil are presented in Table 1.
Table 1: Proximate composition of
Moringa oleifera
Nutrient
Composition (%)
Moisture content
0.60± 0.07
Ash
1.50±0.01
Crude protein
2.19±0.21
Crude fat
39.30±1.00
Carbohydrate
56.42±0.72
Values are mean ±Standard deviation of triplicate determinations
The results of the physicochemical properties of
Moringa oleifera
oil are presented on Table 2.
Table 2: Physicochemical properties of
Moringa oleifera
oil
Characteristics
Moringa oleifera
pH
5.96±0.03
Saponification value
164.09±1.58mg/g
Iodine value
68.23±0.60g/mol
Free fatty acid
8.27±0.19mgKOH/g
Specific gravity
0.86±0.01
Values are mean ±Standard deviation of triplicate determinations
The oil yield was between 33 – 37% for the replicates, this was in agreement with Solade [17] which got 35 – 40% oil yield in palm
kernel. This is also in line with the results given by Abdulkarim
et al
that gave the value of oil yield from mature seeds of any plant to be
between 22 – 43%. Variation in oil yield may be due to differences in variety of plant, cultivation climate, ripening stage and the method of
extraction used. The value of 39.30% obtained for crude fat agrees with the 39.80% reported by Nzikou
et al.
[18] for crude fat. The high
potential of oil makes this seed a distinct potential for the oil industry. Jamieson reported 40% crude fat from castor oil seed which in
agreement or close to the value obtained in this research. The saponification value of 164.09mg/g and iodine value of 68.23g/mol agrees
slightly with the values of 166.0 09mg/g and 67.40g/mol obtained by Nzikou
et al.
However, the values obtained for moisture content,
ash content and crude protein were contrary to what Nzikou
et al.
reported. Nzikou
et al.
reported 5.3% for moisture, 37.6% for crude
protein, and 4.2% for ash content. Also, the value of 8.27mg/KOH/g obtained for fatty acid is contrary to the value of 1.08mgKOH/g
reported by Nzikou
et al.
The difference in value may be attributed to the different methods of extraction used [18].
CONCLUSIONS
Moringa oleifera
seed has the potential to become a new source of oil and its full potential should be exploited. It contains high
unsaturated to saturated fatty acids ratio due to its high iodine and saponification values and might be an acceptable substitute for high
saturated oil such as olive oil in diets. The production of useful oil from the seeds could be of economic importance of benefit to the areas
where the tree is cultivated.
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