EXTRACTION AND CHARACTERIZATION OF OIL FROM Moringa

Oleifera SEEDS USING SOXHLET EXTRACTION

by

KHADIJAH BINTI MD NOH

Thesis submitted in fulfilment of the

requirements for the degree of

Master of Science

April 2018

ii

ACKNOWLEDGEMENT

In the name of Allah, the Most Gracious and Most Merciful. My greatest

thank to Allah the Almighty for the blessing and guidance, with His willing, I was

able to complete my master thesis. All praise belongs to Him.

I would like to express my genuine gratitude to both my dedicated

supervisors Professor Dr. Abdul Latif Ahmad and Dr. Derek Chan Juinn Chieh for

their support and encouragement during the period of my studies. Your practical

view and guidance on my research work was of the utmost important. Thank you

very much for the unending help throughout the course of my research.

To my dearest husband, Mr Ihsan bin Ahmad Zubir, my beloved children,

Hannan and Muhammad Bilal, thank you for your everlasting love, endless moral

support, care, patient, prays and always being there for me when I need you most.

Special dedication to my beloved parents, Mr. Md Noh bin Ma’ruf (passed

away on 4th of June 2016) and Mrs. Fatimah binti Emran, my parents in law, my

brothers and sisters, thanks for your everlasting prays and support.

My best regards to Ministry of Higher Education for granting me the Mybrain

(MyMaster) scholarship to assist financially for my study.

Last but not least, I would like to address my gratitude to all the staffs and

assistant engineers of School of Chemical Engineering of USM, especially the staffs

of (MTDC) lab, Unit Operational, Chemical and Analytical laboratory, for their

cooperation and assistance. And also to all people that contributed their helps directly

and directly, thank you so much and all your contribution will not be forgotten.

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TABLE OF CONTENTS

Page

ACKNOWLEDGEMENT ii

TABLE OF CONTENTS iii

LIST OF TABLES vii

LIST OF FIGURES ix

LIST OF ABBREVIATIONS x

LIST OF SYMBOLS xi

ABSTRAK xii

ABSTRACT xiv

CHAPTER ONE: INTRODUCTION

1.1 Introduction 1

1.2 Problem Statement 4

1.3 Research Objectives 6

1.4 Scope of Study 6

1.5 Organization of Thesis 7

CHAPTER TWO: LITERATURE REVIEW

2.1 General Description of M. oleifera 8

2.2 The Uses of M. oleifera 10

2.2.1 Medicinal Application 10

2.2.2 Waste and Wastewater Treatment 13

2.2.3 Industrial Application 14

2.3 The Composition and Characteristic of M. oleifera Oil 15

iv

2.4 Method for Oil Extraction 17

2.4.1 Cold Press Method 17

2.4.2 Soxhlet Extraction Method 18

2.4.3 Supercritical Fluid Extraction 21

2.4.4 Aqueous Enzymatic Extraction 23

2.4.5 Microwave Assisted Extraction (MAE) 24

2.4.6 Comparison of Different Methods of Oil Extraction 25

2.5 Kinetics of Extraction 26

2.5.1 First-order Extraction Kinetic Model 27

2.5.2 Second-order Extraction Kinetic Model 28

2.6 Activation Energy 29

CHAPTER THREE: MATERIALS AND METHODS

3.1 Materials and Equipment 33

3.2 Sample Preparation 34

3.3 Analysis of Moisture Content 35

3.4 Soxhlet Extraction 35

3.4.1 Yield Determination 35

3.4.2 Temperature 36

3.4.3 Extraction Time 36

3.4.4 Particle Size of Seeds 36

3.4.5 Solvent to Solid Ratio 37

3.5 Characterization of M. oleifera Seeds Before and After Oil Extraction 37

3.5.1 Scanning Electron Microscope (SEM) 37

3.5.2 Fourier Transform Infrared (FTIR) spectroscopy 38

v

3.5.3 Elemental Analyzer 38

3.6 Physico-chemical Characterization of Extracted Oil 39

3.6.1 Determination of Specific Gravity and Density 39

3.6.2 Determination of Refractive Index 39

3.6.3 Determination of Viscosity 39

3.6.4 Determination of Saponification Value 40

3.6.5 Determination of Free Fatty Acid 41

3.7 Phytochemical Screening 42

3.7.1 Tannins 42

3.7.2 Saponins 42

3.7.3 Flavonoids 43

3.7.4 Phenols 43

3.7.5 Terpenoids 43

3.7.6 Steroids 43

3.8 Extraction Kinetic Studies 44

3.9 Calculation of Thermodynamics Activation Energy 44

CHAPTER FOUR: RESULTS AND DISCUSSION

4.1 Determination of Moisture Content 45

4.2 Effect of Parameters in the Yield of M. oleifera Oil 45

4.2.1 Temperature 46

4.2.2 Time of Extraction 48

4.2.3 Particle Size of M. Oleifera Seeds 51

4.2.4 Solvent to Solid Ratio 53

4.2.5 Total Oil Yield 55

vi

4.3 Characterization of M. oleifera Before and After Oil Extraction 55

4.3.1 Surface Morphology 56

4.3.2 Fourier Transform Infrared (FTIR) Analysis 58

4.3.3 Elemental Analyzer Analysis 60

4.4 Characterization of Extracted M. oleifera Oil 61

4.4.1 Physical Properties 61

4.4.2 Chemical Properties 64

4.5 Phytochemical Screening 67

4.6 Extraction Kinetic studies 68

4.6.1 First-order Extraction Kinetic Study 68

4.6.2 Second-order Extraction Kinetic Study 70

4.6.3 Analysis of First and Second-order Extraction Kinetic Models 72

4.7 Calculation of Activation Energy 73

4.8 Thermodynamics of M.oleifera Oil Extraction 74

CHAPTER FIVE: CONCLUSION AND RECOMMENDATIONS

5.1 Conclusions 78

5.2 Recommendations 79

REFERENCES 80

vii

LIST OF TABLES

Page Table 2.1: Nutritional compositions and medicinal uses of different

parts of M. oleifera (Gopalakrishnan et al., 2016)

12

Table 2.2: Physico-chemical properties of M. oleifera oil (Adegbe et al. 2016)

16

Table 2.3: Comparison of physical and chemical properties of M. oleiferea seed oil using solvent and aqueous enzymatic extraction methods (Abdulkarim et al. 2005)

20

Table 2.4: Comparison the advantages and disadvantages of different method of M. oleifera oil of extraction

25

Table 2.5:

Oil yields of different different method of M. oleifera oil of extraction

26

Table 3.1: List of chemicals

33

Table 3.2: List of equipment

33

Table 3.3:

Sieves number used for analysis with respective diameter of particles

34

Table 4.1: Oil yield (%) with respective particle size of seeds

52

Table 4.2: Volume of heptane used respective to the solvent to solid ratio

53

Table 4.3: Comparison in percentage of elements in M. oleifera seeds before and after extraction

61

Table 4.4: Comparison of physical properties between M. Oleifera and olive oil

62

Table 4.5: Data for viscosity test of Rheometer DV III viscosity meter

63

Table 4.6: Saponification value of M. Oleifera and olive oil

64

Table 4.7: Results of phytochemical screening

67

Table 4.8: Oil yield % at different time and temperature

68

Table 4.9: Value of k and R2 at different temperature for first-order model

9

viii

Table 4.10:

Oil concentration at different time and temperature

70

Table 4.11:

Value of Cs, h, k and R2 at different temperature for second-order model

71

Table 4.12: Comparison of first order second order extraction of M. oleifera oil kinetic constants

72

Table 4.13:

Thermodynamic parameters of M. oleifera oil extraction using heptane

76

 

 

ix

LIST OF FIGURES

Page Figure 2.1:

Part of M. oleifera (a) tree, (b) leaves (c) flowers (d) fruits/pods (e) kernels and (f) seeds (Parrotta, 2009; Price, 2007)

9

Figure 2.2: The uses different parts of M. oleifera

11

Figure 2.3: Set-up of Soxhlet extractor (Azwanida, 2015)

19

Figure 3.1: Flowchart of the overall experimental study for extraction of oil from M. Oleifera seed kernels.

32

Figure 4.1:

Graph of yield of M. oleifera oil vs temperature using 0.5-1.0 mm seeds, 3 hour, 150 ml heptane

47

Figure 4.2:

Graph of yield of M. oleifera oil vs time using 0.5-1.0 mm seeds, 100 ºC, 150 ml heptane

49

Figure 4.3: Graph of oil yield vs solvent to solid ratio at 4 hour, 150 ml heptane and using 0.50 mm-1.00 mm seeds

54

Figure 4.4: SEM image of M. oleifera seeds before extraction

56

Figure 4.5: SEM image of M. oleifera seeds after extraction (3 hour)

57

Figure 4.6:

SEM image of M. oleifera seeds after extraction (4 hour) 58

Figure 4.7: FTIR spectra of M. oleifera seeds before and after extraction

59

Figure 4.8: Fatty acid profile from GC/MS of M. oleifera oil

66

Figure 4.9: Fatty acid profile from GC/MS of olive oil

66

Figure 4.10: Plot of first order extraction kinetics of M. oleifera oil

69

Figure 4.11: Plot of second order extraction kinetics of M. oleifera oil

71

Figure 4.12: Plot of linearized Arrhenius Equation

74

Figure 4.13: Plot of ln k against 1/T

76

x

LIST OF ABBREVIATIONS

AOCS American Oil Chemist Society

AOAC Association of Analytical Communities

CO2 Carbon dioxide

FAME Fatty acid methyl ester

FTIR Fourier Transform Infrared

GC Gas Chromatography

HCl Hydrochloric Acid

HPLC High Performance Liquid Chromatography

IUPAC International Union of Pure and Applied Chemistry

N Neutrality

Na2SO4 Sodium sulphate

SAP Saponification value

SEM Scanning Electron Microscopy

TAG Triacyglycerol

xi

LIST OF SYMBOLS

- Single bond in organic compound

= Double bond in organic compound

≥ Greater than or equal to

≤ Less than or equal to

% Percentage

ρ Density

μ Viscosity

α Alpha ( value of 1 in Greek numerals)

γ Gamma (value of 3 in Greek numerals)

® Registered trademark symbol

wt.% Weight percentage

xii

PENGEKSTRAKAN DAN PENCIRIAN MINYAK DARIPADA BIJI Moringa

Oleifera MENGGUNAKAN PENGEKSTRAKAN SOXHLET

ABSTRAK

Moringa oleifera diklasifikasikan sebagai salah satu tumbuhan sangat berharga

kerana kebanyakan bahagian tumbuhan ini; akar, kulit, getah, daun, dan biji

mempunyai kegunaan tersendiri. Minyak yang diekstrak daripada biji M. oleifera

telah digunakan secara meluas dalam masakan, ubat-ubatan dan kosmetik. Kaedah

pengekstrakan Soxhlet dengan menggunakan heksana sebagai pelarut pengekstrakan

telah digunakan secara meluas untuk mengeluarkan minyak M. oleifera daripada

bijinya. Walaubagaimanapun, kesan buruk penggunaan heksana terhadap alam

sekitar dan kesihatan mungkin mengehadkan penggunaan heksana. Dalam kajian ini,

heptana digunakan sebagai pelarut pengekstrakan kerana pelarut ini serupa dengan

heksana tetapi ia tidak mempunyai masalah terhadap alam sekitar dan kesihatan yang

berkaitan dengan heksana. Kesan suhu pengekstrakan, masa pengekstrakan, saiz

zarah biji, dan nisbah pelarut kepada pepejal telah dikaji dalam penyelidikan ini.

Hasil minyak bergantung kepada dengan perubahan pembolehubah yang dikaji. Suhu

antara 85 ᴼC hingga 105 ᴼC, masa pengekstrakan antara 2 jam hingga 4.5 jam, nisbah

pelarut kepada nisbah pepejal antara 7.5: 1 hingga 15: 1 dan saiz biji antara 0.5 mm

hingga 2.0 mm telah digunakan semasa kajian. Keadaan optimum yang

menghasilkan hasil minyak tertinggi adalah suhu pada 100 °C, masa pengekstrakan 4

jam, saiz zarah kurang daripada 0.50 mm dan nisbah pelarut kepada pepejal 15: 1.

Hasil minyak maksimum ialah 40.10%. Biji M. oleifera dicirikan sebelum dan

selepas proses pengekstrakan dengan menggunakan Pengimbasan Elektron

Microskopik (SEM), Fourier Transform Infrared (FTIR) dan ujian penganalisis

xiii

unsur. Pengelasan fizikal dan kimia minyak yang diekstrak telah dianalisa. Asid

oleik, asid palmitik dan asid oksalat dikesan dengan asid oleik mendominasi kira-kira

65.90%. Minyak M. oleifera yang diekstrak berwarna kuning dan mempunyai

ketumpatan 0.905 g/mL. Nilai indeks biasnya adalah 1.46705 dan 65cP kelikatan.

Nilai pengekstrakan ditentukan ialah minyak 198.63 mg KOH/g. Daripada kajian

kinetik, model pengekodan urutan kinetik kedua berpadanan dengan data eksperimen

dengan pekali korelasi (R2) hampir 1.00. Kewujudan fitokimia dalam minyak M.

oleifera yang diekstrak telah diuji dan hasilnya menunjukkan bahawa flavonoid,

saponin, fenol, tanin dan terpenoid wujud di dalam minyak. Daripada penyelidikan,

didapati bahawa heptana adalah pelarut yang berkesan untuk proses pengekstrakan

minyak M. oleifera menggunakan kaedah pengekstrakan Soxhlet.

xiv

EXTRACTION AND CHARACTERIZATION OF OIL FROM Moringa

Oleifera SEEDS USING SOXHLET EXTRACTION

ABSTRACT

Moringa oleifera is classified as one of the most valuable plants as most parts of this

plant; root, bark, gum, leaf, and seed have their special usages. The oil extracted

from M. oleifera seeds has been widely used in culinary, medicine and cosmetics.

Soxhlet extraction method by using hexane as the extraction solvent has been widely

used to extract the M. oleifera oil from its seed. However, the environmental and

health concerns about hexane may limit its usage. In this research, heptane is used as

the extraction solvent as this solvent is similar to hexane but it does not have the

environmental and health concerns associated with hexane. Effects of extraction

temperature, extraction time, particles size of the seeds, and solvent to solid ratio

towards the extraction yield were investigated. The oil yield varied with the changing

of the parameters. Temperature between 85 ᴼC to 105 ᴼC, extraction time between 2

hours to 4.5 hours, solvent to solid ratio between 7.5:1 to 15:1 and seeds size

between 0.5 mm to 2.0 mm were used during the investigation. The optimum

parameters that give highest oil yield of 40.10 % were temperature at 100°C, 4 hour

extraction time, particle sizes less than 0.50 mm and solvent to solid ratio of 15:1.

The M. oleifera seeds were characterized before and after the extraction process by

using Scanning Electron Microscopic (SEM), Fourier Transform Infrared (FTIR) and

elemental analyzer tests. Physical and chemical characterizations of the extracted oil

were analyzed. Oleic acid, palmitic acid and oxalic acid were detected with oleic acid

having the dominant percentage of about 65.90%. M. oleifera oil extracted was

yellow in color and has density of 0.905 g/mL. The refractive index and viscosity

xv

values were 1.46705 and 65cP, respectively. Saponification value determined was

198.63 mg KOH/g oil. From the kinetics study, the kinetics second-order extraction

model fitted well with the experimental data with correlation coefficient (R2) almost

1.00. The existence of phytochemicals in the extracted M. oleifera oil was tested and

the results showed that the flavonoids, saponins, phenol, tannins and terpenoids exist

in the oil. From the investigation, it was found that heptane is an effective solvent for

the extraction of M. oleifera oil using Soxhlet extraction method.

1

CHAPTER ONE

INTRODUCTION

1.1 Introduction

Moringa oleifera (M. oleifera ) belongs to the Moringaceae and Moringa

genus has been used for such a wide variety of purposes that it has been described as

a ‘miracle tree’. It is grown in many parts of the world as a ‘vegetable tree’, with the

roots, leaves, flowers and fruit all being used for food. Since M. oleifera leaves

contain more calcium than milk, more iron than spinach, more Vitamin C than

oranges and more potassium than banana, this tree’s portion has been taken to

overcome malnutrition issue especially among infants and nursing mother (Zhao and

Zhang, 2013c). The leaves are probably the most widely used part, being compared

to spinach in appearance and nutritional quality (Papillo 2007). M. oleifera seeds

kernel (Figure 1.1) is contain of oil which is called “Ben oil”. The seed kernels

contain approximately 35-40% of oil according to Ruttarattanamongkol et al. (2014),

33-41% by Zhao and Zhang (2013a) or 39% of oil by da Silva et al. (2010). This oil

composed of approximately 13-18% saturated and 82-87% unsaturated fatty acid

make it resistance to oxidative rancidity (Anwar et al., 2007). Moreover, it has

linoleic acid, behenic acid and high degree of saturation (Tsaknis and Lalas, 2002).

2

Figure 1.1 Seeds and kernels of M. oleifera

Besides sunflower, corn, palm or olive oil, M. oleifera oil has been proposed

as alternative source to be used in making biodiesel. It can react with alcohol to

produce biodiesel which later can be used as energy sources in transportation.

Another uses of this oil is it acts as the lubricant in watch making and precision

equipment (Mani et al., 2007). M. oleifera oil was widely used for medical purpose

too. It is reported contain large quantity of tocopherols, an organic chemical

compound which has vitamin E activity, rich in vitamin A and C plus it is a good

antioxidant. For treatment of rheumatism and gout, this oil could be effective in

advance. Furthermore, it enhances cardiovascular system as it helps in the

purification of blood. According to Foidl et al. (2001), the oil externally applied for

curing skin diseases due to the antimicrobial, antiseptic and anti-inflammatory

properties content in it (Ruttarattanamongkol et al., 2014).

In cosmetic industries, M. oleifera oil is useful in producing hair care

products, soap, perfumes and cosmetic preparation. Since the oil consists high

amount of oleic acid (more than 70%) as reported by Mani et al. (2007), hence, it is

edible and can be used for food consumption. In Haiti, it is commercially used as

ingredient in culinary and salad oil. It is a good choice for frying purpose as it is very

3

stable with the presence high oleic acid. Other than that, from the oil extraction

process, the press cake obtained as residue has positively charged protein molecules.

These molecules have coagulant properties which can be utilized in purification and

wastewater treatments.

Production of vegetable oil either from its fruits, leaves or seeds is usually

through the solvent extraction due to high oil yield obtained which is approximately

more than 99 wt.% (Zhao and Zhang, 2013b). Examples of commonly used solvents

are hexane (Kostić et al., 2014; Lohani et al., 2015; Silva et al., 2016), petroleum

ether (Sayyar et al., 2009; Tian et al., 2013; Fakayode and Ajav, 2016), acetone

(Mani et al., 2007; De Oliveira et al., 2013; Palafox et al., 2012) and alcohol like

ethanol (Toda et al., 2016; Santos et al., 2015; Dagostin et al., 2015) and methanol

(Mani et al., 2007). Hexane is widely used due to its efficiency and easy to recover

(Akaranta and Anusiem, 1996). Petroleum ether with boiling point in the ranging

from 30-70°C has saturation paraffin such as pentane and hexane that make it

suitable for extracting oil (Mani et al., 2007). Plus, they are chemically inert, high

selective dissolving power and very volatilite. However, sulfur and nitrogenous

compounds must be removed from petroleum ether (Mani et al., 2007). The

disadvantage of using solvent extraction method is the solvent residues may remain

in the oil that can be dangerous to human health and environment. Therefore,

selection of a suitable extraction technique is very important for the standardization

of products as it is utilized in the removal of desirable soluble constituents, leaving

out those not required with the aid of the solvents. Furthermore, the optimization of

various parameters is also a critical factor to improve the quality and efficiency the

yield of product.

4

1.2 Problem Statement

Since almost every part of M. oleifera tree such as seeds, leaves and roots

have benefits, there are quite a number of research were done in order to study the

characteristics, properties, yield and uses of the products obtained. The current

research focuses more on the extraction of oil from the M. oleifera seeds. From

previous research done, the authors concerned about the method used for the

extraction process in order to achieve high yield of the oil. Commonly, there are two

favourable extraction methods used which is Soxhlet extraction and supercritical

fluid extraction.

Currently, the demand of vegetable oil in the world was quite high. The

common oil in the market was coming from various kind of plant such as palm

kernel, sunflower seeds, sesame seeds and corn. Therefore, M. oleifera seeds were

proposed as another source for oil extraction. Based on the results from recent

studies, it can be seen that, most of the researchers used Soxhlet extraction method

with similar solvent which is hexane but, the percentage of Ben’s oil extracted is

different. In addition, the use of hexane as solvent was detriemental to the

environment and human health. Other type of solvents such as petroleum ether,

chloroform, methanol and acetone was also commonly used in oil extraction.

However, they are not preferable since low yield of about less than 34 % of oil was

produced (Mani et al., 2007). Hence, use of heptane as the solvent in extraction of oil

had been proposed in this study. Heptane may be a good choice to replace hexane as

the extraction solvent as it does not have the environmental and health issue

associated with hexane (Conkerton et al., 1995). Moreover, literature review on using

heptane as the extraction solvent has never been reported.

5

Therefore, this research focuses on the characterization of oil before and after

extraction. In addition, further study is done on the extraction process chosen which

could verify the possible parameters that can affect the yield of the M. oleifera oil.

Soxhlet extraction method is straightforward and inexpensive (Luque-Garcıa and De

Castro, 2004). Since hexane is typically used in the Soxhlet extraction, heptane is

used as the solvent instead, and the yield of the oil is determined in this experiment.

Besides, in order to maximize the extraction of M. oleifers oil, this study is purposely

done to determine either by varying the variables such as extraction time,

temperature, ratio solvent in solid and particle size could give effects to the yield of

oil.

Once the oil is extracted, the characterization of extracted oil is done to

identify the physical and chemical properties of the oil. The oil extracted from the M.

oleifera seeds is compared with the olive oil for its properties, compositions and

edibility to be used as food consumption. Olive oil is chosen to be compared with the

extracted M. oleifera oil as it is well known as one of the most beneficial and widely

used edible oil nowadays. Finally, the kinetics and thermodynamis studies for the

extraction process are done.

6

1.3 Research Objectives

The objectives of the research are:

1. To study the extraction of M. oleifera oil using heptane as solvent in Soxhlet

extraction process.

2. To characterize the M. oleifera seeds used in the extraction study and

determine the physical and chemical characteristics of the oil extracted from

M. oleifera seed kernels.

3. To study the extraction of oil kinetics and thermodynamics from M. oleifera

seeds.

1.4 Scope of Study

Basically, this study can be divided into three phases which are:

A study on the M. olifeira oil extraction process by using Soxhlet extraction

method and heptane as the extraction solvent

Characterization of the M. oleifera seeds before and after oil extraction and

characterization of the extracted oil

Kinetic and thermodynamic studies of M. oleifera oil extraction

7

1.5 Organization of Thesis

This thesis covers five chapters and each chapter describes the in sequence of this

research.

Chapter 1 explains about the introduction of the M. oleifera and the benefits

of that valuable plant. This chapter also presents the problem statement, objective of

the studies, and finally the organization of the thesis.

Chapter 2 refers to literature review that covers the literature of M. oleifera

oil, various methods of oil extraction and kinetics and mechanisms of solid liquid

extraction. This chapter also elaborates on the kinetics and mechanisms of the

extraction process, and also the physical and chemical characteristics of M. oleifera

seeds oil.

Chapter 3 covers the materials and methods used throughout the research.

The chapter describes the experimental procedures in details for characterization of

M. oleifera seeds, Soxhlet extraction process, and followed by characterization of

extracted M. oleifera oil and kinetics and thermodynamics studies of the extraction

process.

Chapter 4 covers results and discussion and presents all the acquired results

and explained all the findings followed by discussion about results.

Chapter 5 refers to conclusions and recommendations for future research.

The findings reported in Chapter 4 are used as the as the reference to write the

conclusions. Recommendations for prospect studies are presented due to their

significance with current research.

8

CHAPTER TWO

LITERATURE REVIEW

2.1 General Description of M. oleifera

Moringa oleifera (M. oleifera ) belongs to the Moringaceae and Moringa genus,

the best known and most widely distributed species. There are a few known varieties

namely Jaffna, Chauakacheri Murunga, Chem, Kadu, Palmurungai and Periyakulam 1

(Tsaknis et al., 1999). M. oleifera is the scientific name for the Moringa tree which is

believed originated in Northern India. This species is from the Moringaceae family and

grows in Asia, Africa, South America, the Caribbean and Oceania. In Malaysia, M.

oleifera, commonly known as kacang merunggai (Endut et al., 2016). Some other

common names of Moringa are drumstick tree, (Horse) radish tree, Morango and

Benzolive (Abdulkarim et al., 2005). The tree of M. oleifera (Figure 2.1(a)) carries

some physical characteristics such as it is filled with long and delicate-looking

branches, which are covered with small and oval-shaped dark green leaves (Ghazali and

Yasin, 2016). The height of the tree can reach a maximum of 7-12 m and a diameter of

20-40 cm at chest height (Foidl et al., 2001). The leaves are 20-70 cm long, grayish-

downy when young, long petiole with 8-10 pairs of pinnae each bearing two pairs of

opposite, elliptic or obovate leaflets and one at the apex, all 1-2 cm long; with glands at

the bases of the petioles and pinnae (Figure 2.1 (b)). The flowers (Figure 2.1 (c)), which

are pleasantly fragrant, and 2.5 cm wide are white or cream colored and yellow-dotted

at the base. M. oleifera fruits (pod-like capsules) borne singly or in pairs, air light-green,

slim tender, firm and thinly woody (Padayachee and Baijnath, 2012). The seed pods can

reach well 20-60 cm in length and when they are dry they open into 3 parts. Each pod

contains between 12 and 35 seeds (Figure 2.1 (d)) (Abdulkarim et al., 2005). M. oleifera

9

seeds (Figure 2.1 (e)) are circular-shaped, 7 to 8 mm in diameter, with 4 papery wings

and are yellow-grey (Padayachee and Baijnath, 2012). Each tree can produce between

15,000 and 25,000 seeds/year. The average of seed weight of approximately 0.3 g and

about 70-75% of the weight are composed from the kernel(Mani et al., 2007). M.

oleifera seed kernel is white in color (Figure 2.1 (f)) and contains a significant amount

of oil which is commonly known as “Ben Oil” (Daba, 2016; Yadav, 2013).

Figure 2.1: Part of M. oleifera (a) tree, (b) leaves (c) flowers (d) fruits/pods (e) kernels and (f) seeds (Parrotta, 2009; Price, 2007).

(c)

(a) (b)

(d)

(e) (f)