EVALUATION OF ANTIOXIDANT POTENTIAL OF MONODORA MYRISTICA (AFRICAN NUTMEG)

ABSTRACT

This work evaluates the antioxidant potential of Monodora myristica African nutmeg. Monodora myristica extract was obtained by solvent extraction using nhexane and used as treatment on freshly prepared crude palm kernel oil and palm oil. Equal volume of oil samples were subjected to different concentration of extract treatment 0.2ml,0.4ml, 0.6ml, 0.8ml, 1.0ml using syringe. These oil samples were equally divided into two groups SS and SR. Group SS was stored under the sun and group SR was stored in the room for three weeks. These treated oil samples were analyzed on weekly basis at two different parameters: Acid value AV of free fatty acid and thiobarbituric acid TBA value, using standard methods. The main effect of extract was determined using ANOVA. For the two varieties of oil, the acid value of free fatty acid increased significantly Plt;0.05 as the period extends for group SS without extract while those for group SR showed no significant increase. But AV of oil samples treated with higher extract concentration decreased significantly Plt;0.05 for both groups SS and SR. TBA value also showed the same trend of AV. Hence, monodora myristica extract yielded reducing effect in the oxidative level of the oil varieties.

TABLE OF CONTENTS

Title page i

Approval page ii

Dedication iii

Acknowledgement iv

Abstract v

Table of content viviii

List of tables xi

List of figure x

Abbreviation xi

CHAPTER ONE

1.0 Introduction 1

1.1 Significance of study 6

CHAPTER TWO

2.0 Literature Review 7

2.1 African nutmeg Monodora myristica 7

2.1.1 Scientific classification 7

2.1.2 Habitat/ ecology of Mondora myristica 8

2.1.3 Characteristics/morphology of monodora myristica 8

2.2 Oil Palm 9

2.2.1 Scientific classification 10

2.2.2 Origin and description of palm oil 10

2.2.3 The Chemical composition of palm oil 11

2.2.4 Physical characteristics of palm oil products 14

2.3 Palm kernel oil 14

2.3.1 The chemical composition of palm kernel oil 15

2.4 Modern uses of palm oil and palm kernel oil 16

2.5 Lipid oxidation 16

2.5.1 Lipid oxidation pathway 21

2.5.2 Mechanism of oxidation 22

2.6 General antioxidant action 24

2.6.1 Mechanism of antioxidant action 24

2.6.2 Antioxidant molecules 26

2.7 General review of photochemistry of monodra myristica 27

2.7.1 Alkaloids 27

2.7.2 Flavonoids 27

2.7.3 Glycosids 28

2.7.4 Saponins 28

2.7.5 Tannins 29

2.8 Application of vegetable oils 29

2.8.1 Factors that cause oxidative rancidity in vegetable oil 30

2.9 Nutritional signification 33

CHAPTER THREE

3.0 Materials and methods 34

3.1 Equipment/apparatus 35

3.2 procedurement of raw materials 35

3.3 Study design 37

3.4 Sample preparation 37

3.5 Chemical analysis 38

3.5.1 Determination of acid value Av 38

3.5.2 Determination of thiobarbituric acid number. 38

3.6 Statistical analysis 39

CHAPTER FOUR

4.0 Result and Discussion 40

4.1 Changes in Acid value of Palm Kernel and palm oil 46

4.2 Changes thiobarbituric acid value of palm kernel and palm oil 46

4.3 Effect of monodora myristica extract on the

chemical indices of oil on storage 47

CHAPTER FIVE

5.0 Summary and conclusion 48

5.1 limitations 51

5.3 Future recommendation 51

References 53

Appendix I 62

Appendix II 63

Appenedix III 65