From Moringa (Moringa oleifera) Seeds - University of ...

In the name of Allah, Most Gracious, Most Merciful

Physicochemical Properties of Oil Extracted

From Moringa (Moringa oleifera) Seeds

BY

Rania Mohammed Salah eldeen Hassan Ali

B.Sc. (Agric). Honours

University of Khartoum

2001

A dissertation submitted in partial fulfillment for the requirements of

the degree of master of science in food science and technology

Supervisor

Dr. Babiker Elwasila Mohamed

Department of Food Sciences and Technology

Faculty of Agriculture

University of Khartoum

December, 2006

I

Dedication

For my family with love…

for my little baby Hamoody…

and for dear Eissa

II

AcknowledgementsAcknowledgementsAcknowledgementsAcknowledgements

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Special appreciation and deepest gratitude for my supervisor Special appreciation and deepest gratitude for my supervisor Special appreciation and deepest gratitude for my supervisor Special appreciation and deepest gratitude for my supervisor

Dr. Babiker Elwasila MohamedDr. Babiker Elwasila MohamedDr. Babiker Elwasila MohamedDr. Babiker Elwasila Mohamed for his kind encouragement, for his kind encouragement, for his kind encouragement, for his kind encouragement,

close and valuable supervision as well as his precious advices.close and valuable supervision as well as his precious advices.close and valuable supervision as well as his precious advices.close and valuable supervision as well as his precious advices.

Thanks are also given Thanks are also given Thanks are also given Thanks are also given to the members ofto the members ofto the members ofto the members of Food Research Center Food Research Center Food Research Center Food Research Center

(FRC), (FRC), (FRC), (FRC), for their helpfulfor their helpfulfor their helpfulfor their helpful advice. advice. advice. advice.

I am also I am also I am also I am also gratefulgratefulgratefulgrateful to all members of the to all members of the to all members of the to all members of the Department Department Department Department of of of of Food Food Food Food

Science Science Science Science and and and and TechnologyTechnologyTechnologyTechnology---- University University University University of Khartoum.of Khartoum.of Khartoum.of Khartoum.

III

Abstract

The potential of moringa (Moringa oleifera) as a source of

high-quality oil that can be used for cooking and other industrial

purposes was studied. Samples of moringa seeds were collected

from Damazin and their 100-seed weight was calculated. The

100-seed weight was found to be 206gm, a value which is

higher than the values reported for other oil-bearing seeds.

The chemical composition of the seeds was investigated

and the percent of each component was calculated. The

investigation showed that moringa seeds contained

approximately 5.5% moisture, 47.2% crude protein, 39.1% oil,

1.2% crude fiber, 3.6% ash and 3.4% carbohydrates.

The chemical composition indicated that moringa seeds

contained appreciable amount of oil that encouraged its

extraction and characterization. Two extraction procedures were

employed, namely solvent extraction and mechanical pressing.

Extraction by solvent yielded 39.1% while mechanical pressing

produced 26% oil. Therefore, the solvent extraction proved to be

suitable for the extraction of moringa oil, since it removed more

oil from the seeds.

The oil extracted from moringa was then evaluated for its

physicochemical properties. Oil extracted from groundnut, one

of the major oil source in Sudan, was used for comparison.

IV

Values obtained for physical characterization of moringa

oil were 1.464 refractive index, 0.9469 specific gravity, 45.82cp

viscosity and 6.3, 1.5 and 0.0 for yellow, red and blue colors

respectively. The values obtained for groundnut oil, used for

comparison, were 1.466 refractive index, 0.9525 specific

gravity, 62.28cp viscosity and 2.0, 1.1 and 0.4 for yellow, red

and blue respectively.

The chemical characteristics of moringa oil include iodine

value, saponification value, free fatty acids and peroxide value.

The results obtained were 88, 182, 1.972 and 9.0 respectively.

Values obtained for groundnut oil, used for comparison, were 86

iodine value, 191 saponification value, 1.972 free fatty acids and

13.5mille equiv. peroxide value.

The findings of the present investigation proved that the

oil extracted from moringa seeds has acceptable

physicochemical properties compared to groundnut oil and to

other commercial source used for oil production. Hence,

moringa can be considered a potential source for the production

of a high-quality oil.

V

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VI

List Of Contents

CONTENTS Page

Dedication I

Acknowledgment II

Abstract (English) III

Abstract (Arabic) V

List of contents VI

List of tables IX

List of figures X

Chapter One: Introduction 1

Chapter Two: Literature Review 3

2.1 Fats and oils in human diets 3

2.2 Production of oil 3

2.2.1 Mechanical pressing 4

2.2.2 Solvent extraction 5

2.3 Moringa tree 6

2.3.1 Historical background 6

2.3.2 Nomenclature and botany 7

2.3.3 Habitat 7

2.3.4 Uses 8

2.3.5 Distribution 8

2.3.6 Harvesting 9

2.4 Moringa seeds 9

2.5 Moringa oil 9

2.6 Groundnut 9

2.7 100-seeds weight of some oil-bearing seeds 10

2.8 Chemical composition of some oil-bearing seeds 11

2.8.1 Moisture content 11

2.8.2 Oil content 11

2.8.3 Protein content 12

VII

2.8.4 Ash content 12

2.8.5 Crude fiber 12

2.9 Physical characteristics of some oil-bearing seeds 13

2.9.1 Refractive index 13

2.9.2 Viscosity 13

2.9.3 Color 14

2.9.4 Specific gravity 14

2.10 Chemical characteristics of some oil-bearing seeds 14

2.10.1 Iodine value 14

2.10.2 Saponification value 15

2.10.3 Free fatty acids 15

2.10.4 Peroxide value 15

Chapter Three: Materials and Methods

3.1 Materials 17

3.2 Chemicals 17

3.3 Methods 17

3.3.1 Sample preparation 17

3.3.2 1 00-seed weight 17

3.3.3 Proximate composition of moringa seeds 17

3.3.4 Extraction of moringa oil 22

3.3.4.1 Mechanical pressing 22

3.3.4.2 Solvent extraction 22

3.3.5 Analytical procedures of moringa oil 22

3.3.5.1Oil Physical characteristics 22

3.3.5.1.1 Refractive index 22

3.3.5.1.2 Viscosity 24

3.3.5.1.3 Specific gravity 24

3.3.5.1.4 Color 25

3.3.5.2 Oil chemical characteristics 25

3.3.5.2.1 Iodine value 25

3.3.5.2.2 Saponification value 26

VIII

3.3.4.2.3 Free fatty acids 27

3.3.4.2.4 Peroxide value 27

Chapter Four: Results and Discussion

4.1 100-seed weight 29

4.2 Proximate chemical composition of moringa seeds 29

4.2.1 Moisture content 29

4.2.2 Oil content 30

4.2.3 Protein content 30

4.2.4 Crude fiber 31

4.2.5 Ash content 31

4.3 Extraction of moringa oil 31

4.4 Oil physical characteristics: 35

4.4.1 Refractive index: 35

4.4.2. Viscosity 36

4.3.3 Specific gravity 36

4.4.4 Color 37

4.5 Oil Chemical characteristic 41

4.5.1 Iodine value 41

4.5.2 Saponification value 41

4.5.3 Free fatty acids 42

4.5.4. Peroxide value 43

Conclusions and Recommendations

Conclusions 46

Recommendations 47

References 48

IX

List of tables

Table Page

Table (1): Proximate chemical composition of moringa seeds 33

Table (2): Physical characteristics of moringa and groundnut oils 38

Table (3): Color determination of moringa and groundnut oils 38

Table (4): Chemical characteristics of moringa and groundnut oils 44

X

List of figures

Figure Page

Figure (3.1): Moringa tree 18

Figure (3.2): Moringa pods 19

Figure (3.3): Moringa seeds 20

Figure (3.4): Moringa seeds powder 21

Figure (3.5): Moringa oil 23

Figure (4.1): Chemical composition of moringa seeds 34

Figure (4.2): Physical characteristics of moringa and groundnut oils 39

Figure (4.3): Physical characteristics of moringa and groundnut - color scale 40

Figure (4.4): Chemical characteristics of moringa and groundnut oils 45

CHAPTER ONE

INTRODUCTION

Fats and oils are essential components in the diets of human

and animal and as such play a remarkable role in various industries.

Oils are major dietary component and play important nutritional role

as concentrated source of energy and carriers of fat soluble vitamins.

They also impart flavor and taste to the foods, provide essential fatty

acids and are required for normal functions of the body

(Mohammed, 1996).

Vegetable oils are derived form the seeds and fruits of plants

which are grown in different parts of the world. Several hundred

varieties of plants were known to have oil-bearing seeds of fruits but

infact only eleven are commercially significant namely soybean,

cotton, groundnut, sunflower, line, olive, sesame, rape, caster,

coconut, and oil palm seeds (Ali, 2002).

Mustafa etal (1999) reported that moringa tree was brought

from Asia to Africa where it was used as a source of food and

medicinal purposes. like other vegetables, the leaves and the young

green pods can be eaten. When the pods turn brown, the seed can be

crushed to obtain high–grade oil, comparable to olive oil, which can

be used for many purposes such as soap making and cooking.

(Mustafa etal, 1999).

Moringa is therefore considered a potential source for

extraction of oil. The purpose of this research was to extend the

knowledge of moringa plant with special emphasis on extraction and

subsequent characterization of the oil obtained.

To attain this objective the following steps should be achieved:

(i) Determination of the proximate composition of moringa seeds.

(ii) Extraction of the oil from the seeds using two different methods.

(iii) Determination of the physical and chemical characteristics of the

oil extracted compared to groundnut oil, as a standard

CHAPTER TWO

Literature Review

2.1 Fats and oils in human diets:-

Fats and oils serve as rich sources of energy, yielding

approximately nine kilo calories/gram. They serve as carriers of the fat

soluble vitamins (A, D, E and K), while certain components of fats such

as unsaturated fatty acids are essential nutrients in the diet. Fats and oils

play a distinctive role in the natural flavor of a wide variety of food

commodities (Ali, 2002).

2.2 Production of oils

Crude vegetable oils and fats are obtained from oil-bearing seeds

and fruits etc, by either of two methods: mechanical pressure or

extraction by solvents. The effect of treatment by either method is to

separate the oil more or less completely from the solid matter naturally

associated with it. The residue latter is generally used for agricultural

purposes either for stock feeding or as fertilizer. Williams (1966) reported

that, the winning of the oil from the original materials is much more

nearly perfect by solvent extraction than by mechanical pressure, though

the difference varies greatly in different circumstances and with different

materials. When mechanical pressures employed, the residue contains

approximately from 4-8% of oil, where it is only from 1-2% when the

material is extracted by solvent. Eljack (1999) reported that the separation

of oils and fats from various oil-bearing seeds, nuts and fruits constitutes

a distinct and specialized branch of fat technology. There have been three

extraction processes namely hydraulic pressing, continuous screw

pressing and solvent extraction. According to Eljack (1999) these

extraction processes have the following common objectives :-

i. Hydraulic pressing: To obtain the fat or oil uninjured and as free

as possible from undesirable impurities;

ii. Continuous screw pressing: To obtain the fat or oil as high yield

as is consistent with the economy of the process; and

iii. Solvent extraction: To produce an oil cake or residue of the

greatest possible value.

Even after the most efficient pressing an oil cake will retains an

appreciable amount of absorbed oil, usually 2.5-5% by weight in the

case of seed or other materials initially high in oil and low in solids

contents. The unextracted residue will contain only a small fraction of

the total oil, however in seeds of low oil content such as soybeans, it may

contains as much as 15-20% of the total oil (Swern, 1979).

The residues from the processing of oil seeds are generally high in

protein content and are in good demand as animal feed stuff. They have a

limited use as sources of human food (e.g. soy bean or cotton seed flour),

or as a source of industrial proteins (e.g. for making glue). The residues

from castor beans are toxic unless specially treated, hence they are used

only as fertilizers (Eljack, 1999).

2.2.1 Mechanical pressing:-

In the world as whole there are many screw press mills being built

every year for the full extraction of the seeds (e.g. cotton, soy beans,

peanuts, sunflower seeds,…etc). In fact screw pressing is the preferred

process in many areas and most likely will be for decades to come

because of its basic simplicity. Indeed there are many seeds or fruits that

do not lend themselves to solvent extraction (Eljack, 1999).

In considering continuous screw pressing it is necessary to examine

fully a typical screw press oil mill. First, the seed to be extracted must be

accumulated and stored in sufficient volume to insure continuous runs,

second, it must be stored in such manner to insure that its quality is

preserved. and third, it must be clean from trash' sand and any

contaminants that will adversely affect the quality of the oil and material.

Balla (2001) reported that extraction of peanut oils with continuous

expellers or screw pressers consist of the following steps: kernel

pretreatment and size reduction, cooking and pressing.

2.2.2 Solvent extraction:-

Eljack (1999) reported that solvent extraction was developed and

preferred because it removes more oil, requires less energy, and normally

yields greater profits than do mechanical pressing. Nevertheless

mechanical pressing is still a growing business in the oil seed industries.

Solvent extraction was developed by the Germans after the second world

war. The Germans introduced several oil seed solvent extraction systems.

The two basic principles utilized were :

(i) Immersion extraction and (ii) Percolation extraction.

Solvent extraction process for oil seeds vary considerably depending

upon the raw materials to be processed, the type of meal products to be

produced, and the local governmental or other specifications for oil

products, the solvent used, the cost of utilities and local climatic

conditions (Eljack,., 1999).

In 1966 Williams reported that the extraction by solvent compared

with mechanical pressing methods is a comparatively new process and

though the improvements which have been made are very great. It is a

process in which there is still more scope for further improvement, not

only by the introduction of thoroughly satisfactory continuous process but

also in the improvement of the batch process commonly used.

The general principles of solvent extraction are very simple and

comprise the washing out of the oil from the ground seed by means of a

hot solvent and the subsequent evaporation of the solvent in order to

recover the dissolved oil, the solvent being used over again.

The extracted material is freed from solvent first by heating and

finally by steaming whereby the remaining traces are distilled from the

material until the latter is completely freed from any smell of solvent

(Williams,1966).

2.3 Moringa tree:-

2.3.1 Historical background:-

The history of natural flocculent was reviewed by Mohammed

Elshami (2002), he reported that cultivated beans such as Egyptian beans

and Sudanese beans were used as clarifying agent.

In the manufacture of jaggary, primitive sugar industry in India, the

cane juice is clarified with plant materials. In Africa has there was found

a Nile valley tradition of clarifying the high turbid water of river with

"cultivated beans" which spread from Egypt towards central Sudan. The

oldest records refer to the Nubian of upper Egypt and northern Sudan

who used full masri ( Vicia fuba). Neighboring arabized tribes in Merowi

district who also cultivated broad beans with the same materials. But

further in the Gezira Province, it was not available. Thus, substitute was

found in full Sudani ( Archis hypogaea).

There is a link between this "bean tradition" and discovery of

moringa seeds, which was considered being potent water coagulant of

plant origin used by Sudanese women.

Moringa oleifera trees were planted during British rule in public

gardens, and in the avenues along the Nile in small provincial towns.

Their only functions were decorative. Later the tree was called both in

Gezira Province and Kordofan "clarifier tree" Shagar al-rauwag (Jahn,

1977).

2.3.2 Nomenclature and botany:-

The Latin name of aloevera is Moringa oleifera. It is called "shagar

al rauwage" in Sudanese Arabic; a name indicates its importance as

clarifying agent. Moringa oleifera belongs to the family moringaceae.

The tree is fast growing with remarkable hardiness capable of surviving

periods of drought or wet conciliation. It can be easily propagated from

seeds and cuttings. The selection of variety and plant breeding methods

are important to produce rich–fruiting tree with lager seeds, as pods of

different varieties of moringa oleifera can vary from 15 cm to 120 cm.

Annual or short stem moringa oleifera, fertilized with cow dung and

crushed animals bones with special care in irrigation, soil drainage and

maturing can yield two harvests in one year. The first harvest of dry pods

occurs about nine months after sowing, with about 500 pods up to 50 cm

long with about 20 seeds per pod, and the second harvest about 13 moths

after sowing, yielding about 30- 40% less than the first harvest Perennial

moringa oleifera tends to decrease in yield as opposed to the annual

moringa oleifera and is more prone to diseases. ( Mohammed Elshami,

2002).

2.3.3 Habitat:-

The origin of moringa oleifera is South Africa. It is wide spread in

India, the east and West Indies, the other tropical countries and Europe.

This tree was introduced to Sudan during British rule as ornamental tree

in Gezira province and kordofan. ( Mohammed Elshami, 2002)

Moringa oliefera which is locally known as Rawag is the most widely

known and utilized species of the genus moringaceae (Wickens, 1988).

The moringa tree originated in India, people brought it to Africa from

Asia who used it as a source of food and for medicinal purposes.

The moringa tree likes sun shine and can grow best on dry sandy soil

and can withstand drought conditions. It grows quickly from seeds or

cuttings, can reach a height of twelve feet within the first year and

regenerates itself even after the most severe pruning (Mustaf , etal 1999).

Two harvests of seed pods can be produced in one year, and the

moringa leaves tend to appear toward the end of dry season when few

other sources of green leafy vegetables are available (Mustafa,etal, 1999).

2.3.4 Uses:-

Almost every part of the plant is of value as food. The seeds are

said to be eaten like peanut. Thickened root were used as substitute for

horse radish. Foliage was eaten as greens in salads. The leaves and young

green pods which are low in fats and carbohydrate, but rich in protein,

calcium, minerals, iron and vitamins can be eaten like other vegetables

(Mustafa,etal, 1999). In addition leaves pounded up and used for

scrubbing utensils. The seeds yield 38-40% of non drying oil known as

ben oil (Ducke, 1983).

Moringa trees are used to provide live fences and as wind breaker,

leaves are used as vegetable, the seeds as a source of edible oil and the

seeds cake for water purification. (Jahn, 1977).

In spite of these uses scientific tests on acute and chronic toxicity

were not carried out and until 1981 no evidence of acute toxicity has been

found, however, further investigations are continuing (Jahn, 1977).

2.3.5 Distribution:-

Moringa tree is naturally found in India, Arabia and possibly Africa

and the East India. It's widely cultivated and naturalized in tropical

Africa, Tropical America, Srilanka, India, Mexico, Malaysia and the

Philippine Island (Ducke, 1983).

2.3.6 Harvesting:-

Fruit or other part of the plant usually harvested as desired

according to some authors but in India fruiting may peak between March

and April and again in September and October. Seeds were gathered in

March and April to be used for oil extraction (Burkill, 1966).

2.4. Moringa seeds:-

Moringa seed kernels contain about 40% oil by weight .The oil can

be used for soap making and consumption. Beside the industrial uses such

as fine lubricant and perfumery, the fatty acids profile of the oil with its

very high content of oleic acid may make it an oil with potential for

further industrial application. (Machell, 1994). After pressing, the cake

can be dried, stored and be used for water purification or as fertilizer

(HDOM, 2000).

2.5. Moringa oil:-

Moringa oil can be extracted from moringa seed kernels by either

pressing methods or cold method process. It is the most stable natural oil

and it is found to be a good source of Behenic acid in nature. Perfume

manufacturers esteem the oil for its great power of absorbing and

retaining even the most fugitive odors. The filtered and pure oil is packed

in suitable containers as per our customers requirement. This oil can be

used as preservative in food industries and for cooking (Mustafa,etal

1999) .

2.6. Groundnut:-

Groundnut Arachis hypogaea is a very important oil seed in Sudan

beside cotton , sunflower and sesame seeds. Groundnut had a blend odor

and golden color most of the Sudanese people prefer the crude form,

which were used in many forms like butter (Dakoa), roasting in the shell,

snack food, in confections, cooking oil and the residue as animal feed

(Balla, 2001). Groundnut is grown annually throughout the Sudan, and

larger scale cultivation is contemplated in the Gezira and in the sandy soil

of kordofan in west central Sudan (Elshami, 2002).

It is no an important oil seed crop of the world in production after

soybean and cotton. It is high in oil content (52.5%) and rich source of

protein (26.17%), however it has small seeds (28-59 gram/100 seed) and

spherical shape. (Balla, 2001). The major groundnut producing countries

in the world are India, china, USA, Indonisia, Burma, Nigeria, Senegal,

Zaire, brazil and Argentina (FAO, 1988).

Groundnut oil is easily refined to give a pale yellow oil of pleasant,

mild or bland flavor. The oil shows good resistance to oxidation, its fatty

acid profile consists of about 20%. saturated acids and 80% unsaturated

ones. Groundnut oil contains up to 30% linoleic acid, the essential fatty

acid which plays a major part in human diet (Ihekoronye and Ngoddy,

1985). Groundnut seeds are rich in oil (38-50%), which is used for

cooking, salads, manufacture of margarine, soap and as lubricant. The

high quality oil is used as well in pharmaceutical industry (Hitiggins,

1951).

In Sudan, groundnut is considered one of the major oil sources and

the crop continues to play an important role in the Sudan foreign trade

(AASYB, 2000).

2.7. 100 seed weight of some oil bearing seeds:

Elahmdi, et al., (1993) found the weight of 100 kernel of

groundnut to be 77.0g and 71.0g for kiriz cultivars grown in Wadmadeni

and New Half respectively, While in the same area the cultivar Ashford

weighed 48.0g and 46.8g. Eckay and Lawrence (1954) reported that the

weight per 100- kernels of Spanish peanut ranged from 26.4 to 54.0

grams, While weight of Virginia peanut varied between 55.2 to 85.0.g.

Balla (2001) reported that the 100 –seed weights of three groundnut

cultivars were 38.5, 76.3 and 50.8g for Barberton ,kiriz and Ashford

receptively.

2.8. Chemical composition of some oil –bearing seeds:

2.8.1 Moisture content:

Khalil and Chughtai (1983) reported moisture content in the range

4.7% to 5.1% for the four high yielding imported groundnut cultivars

grown in Pakistan. Cobb and Johnson (1973) reported that the moisture

content of the whole kernel of peanut varied between 3.9 and 13.2%

Ahmed (2001) reported 3% moisture content of sunflower

bearing –seed. The moisture content of the seed of three cultivars of

groundnut varied between 4.8 and 5.1% as reported by Balla (2001).

2.8.2 Oil content

Misra, et al., (1992) reported oil content for groundnut to range

between 42.5% and 54.5% while Nigam, et al., (1994) stated that the

average seed oil content of groundnut was 51% .Mortreail (1993)

reported that oil content of peanut cultivar, fastigiated varieties, ranged

between 50 and 51% Sanders, et al., (1982) reported that oil content in

peanut seed ranged from 36% to 56%. Ahmed (2001) reported that total

oil content of sunflower seeds was 44.3%. Oil content of three cultivars

of groundnut seeds varied from 49.7% to 52.5% were reported by Balla

(2001).Sekhon, etal,(1973) reported that the variation in oil content is

mainly due to the genetical characteristics of the cultivars.

2.8.3 Protein content:

Eckey and Lawrence (1954) reported that the average values of

protein content for Spanish and peanut kernels were 30.81% and 29.81%

respectively. Khalil and Chiughtai (1983) reported that there were

significant differences in protein content of five peanut cultivars grown in

Pakistan which ranged between 24.5 to 28.55. Kumari and Reddy (1993)

reported that the crude protein content of Peanut was 23.4%. Nigam, et

al., (1994) reported protein content of 22% in Virginia seed. Freeman, et

al., (1954) and Pancholy, et al., (1987) reported that protein content in

peanut kernels range from 16.2% to 36.5% .Ahmed (2001) reported

18.5% protein content of sunflower kernels which are comparable with

those (15-20 %) found by Weiss (1983). Balla (2001) reported that

protein contents of three cultivars of groundnut seeds to ranged between

20.1% and 26.1%.

2.8.4 Ash content

Ash content of groundnut seed ranged between 1.2% and 4.3 %

was reported by Freeman, et al., (1954) while values between 1.8% –

3.1% were reported by Cobb and Johnson (1973). Khalil and Chugtai

(1983) fond that the ash content of four groundnut cultivars grown in

Pakistan varied from 2.3% to 2.5 %. Ahmed (2001) reported that the ash

content of sunflower seeds was 3%. Balla (2001) reported that ash

content of three cultivars of groundnut ranged from 2.2% to 2.5%.

2.8.5 Crude fiber

Khalil and Chughtai (1983) reported that the crude fiber of four

groundnut cultivars varied between 4.6 to 4.8 %, whereas Cobb and

Johnson (1973) reported that peanut kernel contains 1.2% – 4.3 % crude

fiber. Ahmed (2001) reported that the crude fiber of sunflower kernels

was 17%. Balla (2001) reported that the crude fiber content of three

groundnut cultivars ranged from 1.3% to 1.5 %.

2.9 Physical characteristics of some oil seeds:

2.9.1 Refractive index

The refractive index was defined by Eckey and Lawrence (1954) as

the ratio of the velocity of light in vacuum to velocity in the medium

being measured. Jacob and Krishnamurthy (1990) reported that the

refractive index of groundnut oil at 40C ranged between 1.4620 to

1.4640. Allen,etal (1975) reported that the refractive index of groundnut

oil varied between 1.4605 to 1.4645 at 40C. In Codex Alimentarius

Commission (1993) the refractive index of peanut oil was mentioned as

1.4600 to 1.4650 at 40c. Balla (2001) reported that the refractive index

of three groundnut cultivars varied between 1.4638 to 1.4666 at 40c.

Balla (2001) reported from the work of other investigators ( Harry,

1951; Eckey and Lawrence, 1954; and Jahn, 1977) that the variation in

refractive indices could be due to specific gravity, molecular weight,

increase in saturation and linearly autoxidation stage.

2.9.2 Viscosity

Swern (1979) mentioned the ability of an oil to resist flow as its

viscosity. Eugene et al., (1991) defined the viscosity as measurement of

resistance to flow. Ahmed (200l) reported that the viscosity is a measure

of the internal friction in the oil. Viscosity is a useful criterion for

degradation or de-polymerization that occurs in the initial stage of

hydrolysis of fats and oils during storage. Balla (2001) reported that the

viscosity of an oil decreased with rise in temperature, while saturation

and larger molecules such as long –chain fatty acids or polymerized oil

increased viscosity.

Mohammed (1996) reported that viscosity of groundnut oil at

21.1C was 70.7 cp. Balla (2001) found that the viscosity of three

groundnut cultivars to range between 46.0 and 52.43 centistokes at 30C.

Prasad and dutt (1989) reported that the viscosity of groundnut ranged

from 16.22 to 76.67 cp.

2.9.3 Color:

Vanred and Cocks (1966) pointed that the determination of color of

oil was based on visual comparison with standard by using lovibond tint

meter. Allen ,etal (1975) reported that the yellow color appeared in crude

oil of peanut is due to presence of β-carotene and other pigments, while

in Codex Alimentariuas Commission (1993) the color of groundnut oil

was mentioned to depend on the characteristics of the designated

products. Cobb and Jonson (1973) indicated that the color of groundnuts

oil using lovibond as maximum yellow 16.0 to 25.0 and 2.0 for red scale.

2.9.4 Specific gravity:

Mohammed (1996) found that the specific gravity of groundnut oil at 21Cْ

was 0.915, while the relative density of groundnut oil was reported by

Codex Alimentarius Commission (1993) to vary from 0.914 to 0.917 ْat

20Cْ.

2.10 Chemical characteristics of some oil-bearing seeds:

2.10.1 Iodine value

Ali (2002) reported that the measurement of iodine value (IV) was

found to be one of the most convenient and simple methods to determine

fat and oil deterioration. The initial iodine values for cotton , sesame and

groundnut oils were reported to be 106.7, 103.5 and 97.5cmg

/iodine/100g/fat respectively.

Jacob and Krishnamurthy (1990) found that the iodine value of

groundnut oil ranged between 85 and 95. Norden, et al., (1987) stated that

iodine value of the Florida breeding lines varied from 74 to 107. Cobb

and Johnson (1973) reported that the iodine valve of peanut oil ranged

from 82 to 107. Codex Alimentariuas Commission (1993) reported that

the iodine value for groundnut oil ranged from 80 to 106. Robertson

(1972) observed that the iodine value of cotton seed and sunflower oils

decreased when these oils were subjected to heat.

2.10.2 Saponifcation value

Ramsden (1995) defined the saponification value of a lipid as the

number of milligrams of potassium hydroxide needed to neutralize the

fatty acids formed by the complete hydrolysis of one gram of the lipid

Jacob and Krishnamurthy (1990) found that the saponifiction value of

groundnut oil varied from 188 to 196. Codex Alimentarius Commission

(1993) mentioned that the saponifcation value as mg/KOH/g oil should

range between 187 and 196.

2.10.3 Free fatty acids

Jacob (1990) reported that the free fatty acids ,as oleic acid, of

groundnut oil should be less than 3%. In Codex Alimentarias

Commission (1993) it was reported that acid value for groundnut oil

should not be more than 4.0mg /KOH/g oil. Branseome and Young

(1972) claimed that the free fatly acids ,as oleic acid ,of peanut oil should

have a maximum value of 0.05%.

2.10.4 Peroxide value:

Balla (2001) reported that, the peroxide value for crude groundnut

oil ranged from 0.7 to 1.2 mille. equiv. O2/Kg, and 2.9 – 4.1 mille. equiv.

O2/Kg for the refined oil. The legal limit for peroxide in edible oil was

10mmol kg-1. Applewhite (1982) pointed out that the effects of

atmospheric oxidation apply to all fats and oils, regardless of their stage

of processing.

CHAPTER THREE

Materials and Methods

3.1 Materials:-

Moringa seeds, investigation, were obtained from used in the

present the Blue Nile state (Damazin town). Seed pods were harvested

from trees after they turn brown. Samples were packed in polyethylene

bags and kept at room temperature (30-35C) till sample preparation.

Photos of moringa tree, moringa pods and moringa seeds were presented

in figs 3.1, 3.2, 3.3 respectively.

3.2 Chemicals:

All chemicals and reagents, used in this study, were of analytical grade.

3.3 Methods:

3.3.1 Sample preparation:-

Samples of moringa seeds were cleaned by removing foreign

particles. Then about 100 grams samples were weighed, ground until

standard homogenous powder of the sample was obtained. The prepared

samples were kept in polyethylene bags for further analysis away from

light at room temperature. The homogenous powder of moringa seeds

shown in fig 3.4.

3.3.2 100 – Seed weight:

Hundred seed weight was determined according to AOAC (1984)

in which 100 seeds of moringa were taken and weighed. The

determination was repeated three times and the average was calculated.

3.3.3 Proximate composition of moringa seeds:

Proximate analysis was done according to AOAC (1984) and

AOAC (1990).The parameters determined were, moisture, ash, crude

protein, crude fiber, fats and carbohydrates. The percent carbohydrate

was calculated by difference.

Figure (3.1): Moringa Tree

Figure (3.2): Moringa pods

Figure (3.3): Moringa seeds

Figure (3.4): moringa seeds powder

3.3.4 Extraction of moringa oil:

3.3.4.1 Mechanical pressing:

The extraction of the oil from moringa seeds was done according to

Baileys (1996) in the manner described by Balla (2001) with minor

modification. About one kilogram seeds was weighed after removal of

impurities, using mortar the size of the seeds was reduced to increase the

surface area for oil extraction. The sample was transferred to cloth bag, then

the oil was extracted from the seeds using a hand-operated screw press.

3.3.4.2 Solvent extraction:

Solvent extraction of the oil was done using the cold method

described by Eltinay (1988). The powder obtained after grinding of moringa

seeds was put in glass container and n-hexane (b-p. 69C) was added. Ratio

of solvent to sample was 10:1 (v/w). the mixture was mechanically stirred

for 16.0 hours at room temperature, the mixture was then filtered twice

using standard filter paper. The clean filtrate was concentrate using rotating

evaporator to remove the solvent from the oil. The distilled oil was allowed

to stand in open air at room temperature to ensure removal of all solvent

from the oil. Enough quantity of oil was eventually extracted. The oil was

then stored in a bottle in refrigerator for further analysis (fig. 3.5).

3.3.5 Analytical procedures of moringa oil:

3.3.5.1 Physical characteristics:

3.3.5.1.1 Refractive index:

Refractive index was determined by Abbe refract meter as described

by AOAC (1990). A double prism was used and few drops of sample were

placed on the prism. The instrument was left to stand for few minutes before

reading in order to equilibrate the sample temperature with that of the

instrument. The refractive indices of all samples were determined at 40Co.

Figure (3.5): moringa oil

3.3.5.1.2 Viscosity:

The viscosity of the oil was determined at 30co according to AOAC

(1984) in the manner described by Ahmed (2001). The sample was shacked

vigorously to remove carbon dioxide .The suspended materials were

removed by dry filtration. Appropriate amount of water was added to

viscometer, left in a water bath at 30co, until it's content reached 30co, then

by using suction the distilled water level was allowed to fall.

The initial time was taken with a stopwatch and as the meniscus

passed the upper mark, time was stopped. When meniscus passed lower

mark and the viscometer was dried and the flow time of sample free of

carbon dioxide was processed in the same manner as above for distilled

water. The viscosity was calculated as follows:

Viscosity (centistokes) = (T1/T0)1.003

Where:

T1 = flow time of sample at 30co

T0 = flow time of distilled water at 30co

1.0038 = Viscosity of water in centistokes at 30co

3.3.5.1.3 Specific gravity:-

The specific gravity was determined according to AOAC (1990)

methods, using psycho-meter. The psycho-meter was filled with water and

kept at constant temperature of 25co in a water bath for 30min.At the end of

time Stoppard psycho-meter was adjusted to proper level, dried with a cloth

and weighed. An empty Stoppard psychomtor was weighed the weight of

water at 25co was determined by subtracting weight of empty psychomotor

from its weight filled with water. In the same manner, the weight of the oil

at 25co was determined. Specific gravity was calculated as follows:-

Specific gravity at 25co = w/w1

Where :

W = Weight of oil at 25co

W1 = Weight of water at 25co

3.3.5.1.4 Color:

The color intensity was recorded using lovibond tintometer.Units

of red, yellow and blue were determined according to AOAC (1990) in

the manner described by Balla (2001). Samples were filtered through a

filter paper immediately before testing. Appropriate 5.25 inches cell was

filled with oil and placed in the tintometer slides which were adjusted

until color matching was obtained.

Then the readings of the filters, used to make the match (red,

yellow and blue) were registered.

3.3.5.2 Oil chemical characteristics:

3.3.5.2.1 Iodine Value:

The iodine value was determined according to AOAC Hanus

iodine solution method (1990), in the manner described by Balla (2002).

a) Preparation of Hanus iodine solution:

Iodine (13.65g) was dissolved in 0.825mls glacial acetic acid with

aid of heating. After cooling, 2.5mls of the solution were titrated against

0.1N standardized sodium thio-sulphate solution. Acetic acid (200mls)

was mixed with 3mls of bromine solution, then 5mls of this solution plus

10mls of 15% iodine solution were taken and titrated against standardized

0.1N sodium thio-sulphate solution, using starch as indicator. The

bromine solution required to make a double halogen of remaining 80mls

iodine solution was calculated as:

C

BX =

Where:

X = number of mls of bromine solution required to double halogen

B = 800mls × mls of 0.1N Na2S2O3 equiv. of one mls iodine solution

C = mls of 0.1N Na2S2O3 equiv. of one mls bromine solution

(b) Determination:

About 0.1- 0.25g oil was weighed into 250mls round bottomed

flask, 10mls chloroform was added. Using pipette 25mls of Hanus iodine

solution were added, then the mixture was left in the dark for 30 minutes,

with periodical shacking. Then 10mls of 15% potassium iodide were

added which followed by 100mls of freshly boiled, cooled distilled water.

The librated iodine was titrated against standardized 0.1N Na2S2O3 with

constant shaking, until yellow solution turns almost colorless. Few drops

of starch indicator were added and titration was continued until blue color

disappeared. Two blank test were conducted similarly.

Calculation:

( ) wNSBvalueiodine /69.12××−=

where:

B = volume of 0.1N sodium thio-sulphate required by blank

S = volume of 0.1N sodium thio-sulphate required by sample

W = weight of sample

N = normality of sodium thio-sulphate solution

3.3.5.2.2 Saponification value:

Saponification value was calculated according to AOAC (1990)

method. Five grams filtered sample were weighed into 25mls round

bottomed flask, 50mls alcoholic potassium hydroxide (prepared by 40g of

ground potassium hydroxide and 54g powdered calcium oxide in 100mls

alcohol); were added. The volume was completed to one liter, the mixture

was shacked several times, Next day solution was filtered into clean, dry

glass bottle. The flask was connected to an air condenser, saponified, then

cooled and titrated against standardized 0.5N hydrochloric acid using

phenolphthalein solution as indicator, blank was determined along with

the sample.

Calculation:

( )( )W

S-BN56.1mgKOH/g tion valueSaponifica

××=

where:

B = mls of hydrochloric acid used in blank test

S = mls of hydrochloric acid used in sample test


N = exact normality of the hydrochloric acid solution used

3.3.5.2.3 Free fatty acids:

Free fatty acids were determined according to FAO (1986) method.

Oil sample of 5-10g of oil was weighed into 250mls conical flask. The oil

was dissolved in 50mls of a mixture (1:1) of ethanol and diethyl ether

pre-neutralized using phenol-phathalin as indicator. The contents of the

flask were titrated against standardized solution of 0.1N ethanolic sodium

hydroxide, with shacking until the color of the indicator changed pink.

Calculation:

( )W

NV28.5acid) oleic(asFFA %

××=

V = number of mls of the ethanolic sodium hydroxide solution

N = exact normality of the ethanolic sodium hydroxide solution

W = sample weight

3.3.5.2.4 Peroxide value:

Peroxide value was determined according to IUPAC (1959)

titration method.

About 4.5g sample was weighed in 250mls round bottomed flask.

A 250mls mixture of acetic acid and chloroform (3:2) and 0.5mls

saturated potassium iodide were added. The flask contents were Stoppard,

Shacked for one minute, and then left in the dark for 5 minutes. Distilled

water (75mls) was added and the mixture was then titrated slowly with

occasional shaking against standardized. 0.002N sodium thio-sulphate

solution with vigorous shaking until the yellow color almost disappeared.

About 0.5mls of 1% starch solution was added and titration was

continued with vigorous shaking until blue color just disappeared.

Calculation:

( ) ( )W

NSkgOeqmilliasvaluePeroxide

1000/. 2

××=

where:

S = volume of sodium thio-sulphate required by sample

N = normality of sodium thio-sulphate


CHAPTER FOUR

Results and Discussion

4.1 100 Seed - weight:

The hundred seed weight of moringa was found to be 206 grams.

This value is higher compared to values reported for some groundnut

cultivars (Elahmadi etal,1993;Balla, 2001) and peanut cultivars (Eckey,

1954). Balla (2001) attributed the variation in groundnut weight to

differences in cultivar types.

4.2 Proximate chemical composition of moringa seeds:

Table one shows the proximate chemical composition of moringa

seeds. The results showed a relatively high content of oil (39.1%) and

protein (47.2) and lower percentages were observed for moisture, ash,

crude fiber and carbohydrates (5.5%, 3.6%, 1.2%, 3.4 %) respectively.

The results of the proximate chemical composition of moringa seeds were

also shown in fig (4.1).

4.2.1 Moisture content:

The moisture content of moringa seeds was found to be 5.5%

(table 1). The percentage moisture content of moringa is slightly higher

than the range of 4.8 to 5.1 reported by Balla (2001) for the moisture

content of three cultivars of groundnut seeds. The values obtained are

higher than the values reported by Ahmed (2001) for sunflower seeds

(3%). The moisture content of moringa lies within the range 3.9% to

13.2% reported by Cobb and Johnson (1973) for the moisture content of

the whole kernel of peanut.

4.2.2 Oil content:

The oil content of moringa seeds was found to represent 39.1% of

the proximate chemical composition of the plant (table 1). The percent oil

content of moringa seeds was lower than the oil content of groundnut

reported by Balla (2001) who found a range of 49.7% and 52.5% for

three cultivars of groundnut seeds. It is also lower than the value of 51%

reported by Nigam, et al., (1994) for groundnut seed oil. Mortreail

(1993) showed that the oil content of fastigiated varieties range between

50% and 51%. Khalil and Chughtai (1983) observed differences between

groundnut cultivars in their oil content which varied between 45% to

49.5%. Sanders, et al., (1982) found the percentage for peanut seed oil to

range from 36% to 56% . Gupta, et al., (1982) reported that the variation

in oil content is mainly due to the genetical characteristics of cultivars.

The percent oil content in this study is also lower compared to the value

reported by Ahmed (2001) for the sunflower was 44.3% oil content.

Misra etal ,(1992) found oil content between 42.5% and54.5% in

groundnut. The result showed that moringa seeds contain substantial

amount of oil (39.1%). This finding encouraged the removal of the oil for

moringa seeds and therefore, the subsequent investigations on its quality.

4.2.3 Protein content:

Table 1 shows the mean value of protein content of moringa seeds

which is 47.2%. This value is higher than the values reported for protein

content from other sources. Balla (2001) reported 20.1% to 26.1% for

groundnut seeds, Eckey (1954) reported 30.8% for Spanish peanut

kernels and 29.81% for Virginia groundnut kernels, where as Khalil and

Chughtai (1983) reported different protein content ranged between 24.5%

and 28.3% for five peanut cultivars grown in Pakistan. The finding of this

study indicated that the residues from the processing of moringa seeds oil

extraction ,are generally high in protein content and therefore the residue

obtained is suitable as animal feed stuff.

4.2.4 Crude fiber:

Table 1 shows the mean value of 1.2% crude fiber content of

moringa seeds, This value was in line with the findings of Balla (2001)

who reported 1.3-1.5% for groundnut. The value obtained in this study is

lower than the value of 17% reported by Ahmed (2001) for sunflower

seeds.

4.2.5 Ash content:

The average value of moringa seed ash content was found to be

3.6% (table 1). This value is slightly higher than the value (3%) reported

by Ahmed (2001) for sunflower seeds. Moringa seed ash content is higher

than groundnut ash content reported by Balla (2001) who found the range

of 2.2% to 2.5% for three cultivars of groundnut seeds.

4.3 Solvent extraction versus mechanical extraction for moringa oil:

Oil and fats are obtained from oil-bearing seeds by either of two

methods: mechanical pressing or extraction by solvent, the treatment by

either methods is to separate the oil more or less completely from the

solid matter naturally associated with it. In the present investigation the

average oil content obtained by solvent extraction is higher than the

average obtained by mechanical pressing. Solvent extraction separated

39.1% oil while mechanical pressing gave 26% oil. Sanders, et al.,

(1982), reported that the oil content in peanut seed obtained by

mechanical pressing ranged from 30- 36% compared to 48- 56% obtained

by solvent extraction. The residue of moringa seed contains

approximately from 10-14% of oil by using mechanical method and 4-6%

by solvent extraction. Williams (1966), reported that the residue of peanut

contains from 4-8% of oil by mechanical pressing and 1-3% when the

materials is extracted by solvent, and therefore the separation of the oil

from the original materials is much more nearly perfect by solvent

extraction than by mechanical pressing .Thou the difference varies greatly

with different material.

Table (1)

Proximate chemical composition of moringa seeds

Constituent

Percentage

Moisture

5.5%

Oil

39.1%

Crude protein

47.2%

Crude fiber

1.2%

Ash

3.6%

*Carbohydrates

3.4%

*Calculated by difference

• each value is a mean of three determinations

Fig. (4.1): Proximate chemical composition of moringa seeds

0

5

10

15

20

25

30

35

40

45

50

1

Parameters

Pe

rce

nta

ge

moisture

oil

protein

fiber

ash

carbohydrates

4.4 Oil physical characteristics:

4.4.1 Refractive index:

Table 2 shows the physical characteristics of moringa oil and the

standard groundnut oil . The results showed that the refractive index of

moringa oil is 1.464 compared to 1.466 for groundnut oil at 40Cْ. It is

clear that the refractive index of moringa oil was slightly lower than the

refractive of groundnut oil at 40Cْ (figure 4.2). Balla (2001) reported that

the refractive index for crude and refined groundnut oil varied from 1.463

to 1.466, a result which also slightly lower than the value obtained in this

study for moringa oil. The refractive index of moringa oil lies within the

range of 1.460 and 1.464 reported by Allen, et al., (1962) for groundnut

oil. In Codex Alimentarius Commission (1993), the refractive index of

groundnut oil was mentioned as 1.460 and 1.465 at 40Cْ. Once again the

refractive index of moringa oil lies within the Codex Alimentarus

Commission (1993) range. High refractive index ranges of 1.469 and

1.479 were reported by Salunkhe, et al., (1992). The refractive indices for

oils for some plants was reported by SSMO (2003). The values were

1.465-1.469; 1.460-1.465; 1.458-1.466 and 1.461-1.464 for, sesame,

groundnut, cotton and sunflower oils respectively. The results, obtained

in this study, showed that the refractive index value of moringa oil lies

within the range recommended by SSMO (2003) . Harry (1951) reported

that the refractive index varied with the specific gravity, highest value

were also obtained with larger molecular weight. Eckey and Lawrence

(1954) found that increase in saturation caused an increase in refractive

index value and Erkilla, et al., (1978) reported that the refractive index

value increases during the linearly autoxidation stage.

4.4.2. Viscosity:

Table 2 shows the viscosity of moringa oil and groundnut oil which

were 45.82 and 62.28 centistokes at 30Cْ respectively. Its obvious that

moringa oil viscosity value is lower than that of groundnut oil . It is also

lower than the values reported by other investigators. Balla (2001)

reported 40.0 to 52.43 for oils of three groundnut cultivars. Ahmed

(2001) reported 54.1 as initial viscosity of fresh oil extracted from newly

harvested sunflower seeds. Higher values were reported by many

investigators, Good and low (1982) reported that the viscosity of

groundnut oil at 21.1Cْ was 70.0 cost and Koman and Kotuc (1976)

showed that viscosity of groundnut at ranged between 71.07 to 86.15

centipoises. Salunkhe, et al., (1992) found that heating increases the

viscosity, foaming properties, free fatty acids content refractive index and

decrease the iodine value. Also Wakeham (1954) claimed that

hydrogenation of oil increased its viscosity as it decrease with it is un

saturation.

4.4.3 Specific gravity:

Table 2 shows the specific gravity of moringa oil which was found

to be 0.9469 compared to 0.9525 of groundnut oil at 30Cْ. This value is

higher compared to the range of 0.911 – 0.918 reported by Balla (2002)

at 25Cْ. Mohammed (1996) showed that the specific gravity of groundnut

at 21Cْ to be 0.915. In Codex Alimentarius Commission (1993) it was

reported that the relative density of groundnut oil vary from 0.914 to

0.917 at 20Cْ. SSMO (2003) reported 0.915-0.924; 0.925-0.912; 0.918-

0.926 and 0.918-0.923 specific gravity of sesame, groundnut, cotton and

sunflower oils respectively.

It is clear from the result obtained in this study that the specific

gravity of moringa oil lies within the range reported by SSMO (2003) for

some plants oil.

4.4.4 Color:

The evaluation of moringa oil color was shown in table 3 as 6.3,

1.5 and 0.0 for yellow, red and blue colors respectively. The evaluation of

groundnut oil was 2.0, 1.1 and 0.4 for yellow, red and blue colors

respectively. Figure (4.3) show the color evaluation of moringa oil which

has no blue color which is responsible for the formation of dark colors in

oils, therefore no extra processing operation will be required. Cobb and

Johnson (1973) reported that the color of groundnut oil using lovibond

as maximum yellow 16-26 and 2.0 for red. Patte, et al., (1982) concluded

that the high yellow color of peanut oil was due to β -carotenes. Also

Allen,etal (1975) reported that the yellow color appeared in the crude oil

of peanut is due to presence of β -carotenes and other pigments. In Codex

Alimentarius Commission (1993) the color of groundnut oil was

mentioned to depend on the characteristics of the designated product.

Table (2)

Physical Characteristics of Moringa and Groundnut Oils

(Refractive index, specific gravity and viscosity)

Parameters

Moringa oil

Groundnut oil

Refractive index

1.464

1.466

Specific gravity

0.9469

0.9525

Viscosity

45.82

62.28


Table (3)

Physical Characteristics of Moringa and Groundnut Oils

(Color)

Color Moringa oil Groundnut

Yellow 6.3 2.0

Red 1.5 1.1

Blue 0 0.4

Refractive index and specific gravity

Viscosity

Fig (4.2): Physical characteristics of moringa and Groundnut oils

and Groundnut oils

0

0.5

1

1.5

2

Moringa oil Groundnut

oil

Va

lue

s

Refractive indexe

Spesific gravity

0

20

40

60

80

Va

lue

s Moringa oil

Groundnut oil

Fig. (4.3): Physical characteristics of moringa and groundnut oils - color scale

4.5 Oil Chemical characteristics:

The chemical characteristic investigated in the present study

include , iodine value, saponification value, peroxide value and free fatty

acids. The results were presented in table 4 and figure (4.4).

4.5.1 Iodine value:

The iodine value of moringa oil, as Iodine/100g oil, was found to

be 88 while that of the groundnut oil, was estimated as 86. The iodine

value of moringa oil was located within the range of 85-95 reported by

Jacob and Krishnamurthy (1990) for groundnut oil and the range of 79-

107 reported by Norden, et al., (1987) for Florida bearing lines.

The results obtained in the present study were fairly compatible

with the range of 89-96 reported by Balla (2001), for the crude and

refined oil obtained from five types of groundnut, iodine values from 82-

107 were reported by Cobb and Johnson (1973) for peanut oil and from

80-106 by Codex Alimentarius Commission (1993) for groundnut oil.

SSMO (2003) recommended iodine values of 104-120; 86-107; 99-

119 and 110-193 for sesame, groundnut, cotton and sunflower oil

respectively. The iodine value of moringa oil, obtained in this study, is

therefore lies within the range reported by many investigators and the

range recommended by SSMO (2003). I

4.5.2 Saponification value:

The saponification value of both moringa and groundnut oil as mg /

KOH /g oil was determined.

The results are shown in table 4 and figure (4.4). Values obtained

were 182 for moringa and 191 for the groundnut oil. The saponification

value of moringa oil is therefore observed to be lower if compared to that

of groundnut .It is also lower than the value for groundnut oil reported by

other investigators. Among them are Sreemvasan (1968), Jacob and

Krishnaurthy (1990) and Balla (2001) who reported values of 194.1;

188-196 and 187-198 respectively compare with the values recommended

by SSMO (2003) reported saponification values, as mg KOH /g oil, as

186-195; 186-196; 189-199 and 188-199 for sesame, groundnut, cotton

and sunflower oils respectively. Higher saponification values indicated

shorter chain of fatty acids.

4.5.3 Free fatty acids:

The percentage of moringa and groundnut oil free fatty acids

(FFA) as oleic acids were calculated. The results were shown in table 4

and figure (4.4) free fatty acids of 1.128 and 1.972 were found in the

present study for moringa and groundnut oils respectively . Acid value for

fresh oil extracted from stored sunflower seeds was reported to be 2.112

(Ahmed, 2001). Acid value for virgin groundnut oil should not be more

than 4mg/KOH/g oil while that for non-virgin oil should not be more than

0.6mg KOH/g oil as recommended by Codex Alimentarius Commission

(1993). On the other hand Jacob (1990) claimed that the value of free

fatty acids as oleic acid of groundnut oil should be less than 3%. Acid

value of 3.0-2.5 (sesame) 3.0-2.0; (groundnut) and 3.0-2.6 (cotton and

sunflower) oils were recommended by SSMO (2003).

This study showed that the free fatty acid of moringa oil is lower

than that of the groundnut oil and the earlier findings reported for oils

extracted from groundnut and sunflower. Once again, the value is lower

than the values recommended by SSMO (2003) for oils of sesame,

groundnut, cotton and sunflower oils.

4.5.4. Peroxide value:

peroxide value of moringa and groundnut oils were given in

table (4). Histograms of these values were shown in fig. (4.4). The

peroxide value of moringa oil was found to be 9 compared to 13.5 for

groundnut oil. The peroxide value of moringa oil was higher than the

earlier findings of Ahmed (2001) who reported 7.98 for sunflower oil.

The peroxide value reported, in the present study, for moringa oil is lower

than the value obtained for groundnut oil (standard). It is also lower than

the values recommended by SSMO (2003) for oils of sesame (15.0),

groundnut (15.0), cotton (13.0) and sunflower (15.0). The peroxide value

may be taken as an indicator of the extent of primary oxidation products

in the oil (Prasad; Dutt ,(1989) and Codex Alimentrius Commission

(1993)).

Table (4)

Chemical Characteristics of Moringa and Groundnut Oils

Parameters

Moringa oil

Groundnut oil

Iodine value

88

86

Saponification

value

182

191

Free fatty acids

1.128

1.972

Peroxide value

9.0

13.5


Iodine and saponifications values

Free fatty acids and peroxide values

Fig (4.4):Chemical characteristics of moringa and groundnut oils

0

50

100

150

200

250

iodine saponification

Va

lue

s Moringa oil

Groundnut oil

0

2

4

6

8

10

12

14

16

free faty acids peroxide

Valu

es Moringa oil

Groundnut oil

Conclusions and Recommendations

Conclusions:

The following conclusions could be drown from the findings of the

present investigation:

1- The chemical composition of morigna indicated clearly that, like

other oil-bearing seeds, the seeds of the plant contain appreciable

amount of oil (39.1%). In addition appreciable amount of protein

(47.2%), was also found, and therefore residue resulting after the

separating of the oil from the solid matter normally associated with

it could be used for agricultural purposes either for stock feeding or

as fertilizer. The seed cake can be used for water purification.

2- The 100-seed weight of morigna is higher than the values reported

from earlier findings for oil-bearing seeds of other plants such as

groundnut. Sesame and sunflower which were used as commercial

sources for extracting edible oils.

3- Solvents extraction was proved to be a better procedures for the

extraction of oil from morigna and therefore from other oil-bearing

seeds.

4- The oil extracted from morigna has good physicochemical

properties in such away that no additional processing operation

methods will be needed for the oil.

5- The physical and chemical characterization of the extracted oil

indicated clearly that morigna seed can be considered as a potential

source for the extraction of high-grade oil.

6- Hence moringa, which grow wildly, could be used as a substitute

for other oil-bearing seeds sources such as soybean, sunflower and

groundnut… etc.

Recommendations:

The following recommendations were drawn from the present

investigation:

1- Solvent method is recommended for the extraction of the oil from

moringa seeds.

2- Moringa is recommended for commercial production of oil, as it

gave high oil content and good physical and chemical

characteristics. i.e. high-grade oil.

3- Further research is required to strengthen the finding of the present

investigation, such as establishment of the fatty acids profile, effect

of storage, frying quality and stability of the oil and packaging.

4- Moringa tree could be considered as a promising plant naturally

found in Sudan. Besides its high oil content, moringa contained

substantial amount of protein 47.2% compared to other oil bearing-

seeds and as mentioned before, moringa is recommended to be

used for many agricultural purposes.

5- In spite of the many uses reported for moringa, tests on safety and

anti nutritional factor should be carried out.

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