ABSTRACT
The consumption of the popular beverage coffee, increases day by day. However, upcoming brands of coffee with health benefits made by claims of the product ignites curiosity in the components of the coffee. The current study deals with the phytochemical analysis, antioxidant capacity and proximate analysis of Liven Alkaline Coffee, Nescafe Caffeinated and Nescafe Decaffeinated coffee performed using standard procedures. The phytochemical analysis revealed higher contents of carbohydrates and alkaloids of 1.033mg/g and 3.098% respectively in Liven Alkaline coffee compared to Nescafe Caffeinated (0.415mg/g and 1.47%) and Nescafe Decaffeinated (0.342mg/g and 2.55%). Antioxidant capacity of samples was performed using three methods. Nescafe Caffeinated coffee showed the highest ferric-reducing antioxidant power (FRAP) value of 2.262 mg/g tannic acid equivalent, Nescafe Decaffeinated coffee (2.245mg/g TAE) and Liven Alkaline coffee (1.021 mg/g TAE). The lowest IC50 value which is correspondent to high antioxidant power of 249μg/ml for DPPH was found in Nescafe Caffeinated coffee compared to Liven Alkaline coffee (299.6 µg/ml) and Nescafe Decaffeinated coffee (328.1 µg/ml). TBARS assay showed the same trend with DPPH. Moisture, ash and reducing sugar contents were performed having values of 3.3% ash content for Liven Alkaline coffee, Nescafe Caffeinated (3.1%) and Nescafe Decaffeinated (2.8%). Nescafe Decaffeinated coffee had the lowest moisture content of 4.8% and the highest shelf life compared to Nescafe Caffeinated coffee (5.1%) and Liven Alkaline coffee (4.9%).
Key Words: Coffee, Liven Alkaline, Caffeinated, Decaffeinated, Phytochemicals, Antioxidants.
TABLE OF CONTENTS
Title Page
Dedication ii
Certification iii
Acknowledgement iv
Table of Content v
List of Figures ix
List of Tables x
Abstract xi
CHAPTER ONE
1.0 Introduction 1
1.1 The Background to the Study 1
1.2 The Statement of the Problem 1
1.3 The Objective of the Study 2
1.4 The Justification of the Study 2
1.5 The Significance of the Study 3
CHAPTER TWO
2.0 Literature Review 4
2.1 Liven Alkaline Coffee 4
2.2 Nescafe Caffeinated and Decaffeinated Coffee 5
2.3 Coffea Beans 6
2.3.1 The Process of Coffee Production 8
2.4 Overview of Phytochemicals 10
2.4.1 Phenols 11
2.4.2 Alkaloids 12
2.4.3 Terpenoids 12
2.4.4 Saponins 13
2.4.5 Tannins 13
2.4.6 Flavonoids 13
2.5 Free Radicals 14
2.6 Antioxidants 15
2.7 Significance of Moisture Content 16
2.8 Significance of Ash Content 17
2.9 Significance of Reducing Sugar Content 17
CHAPTER THREE
3.0 Materials and Methods 18
3.1 Sample Material Collection 18
3.2 Materials and Equipment 18
3.3 Reagents and Chemicals 18
3.4 Sample Preparation 19
3.5 Qualitative Phytochemical Analysis 19
3.5.1 Presence of Tannins 19
3.5.2 Presence of Saponins 19
3.5.3 Presence of Flavonoids 20
3.5.4 Presence of Phenols 20
3.5.5 Presence of Terpenoids 20
3.6 Quantitative Phytochemical Analysis 21
3.6.1 Determination of Saponin content 21
3.6.2 Determination of Alkaloid content 22
3.6.3 Determination of Flavonoid content 23
3.6.4 Determination of Tannin content 23
3.6.5 Determination of Polyphenol content 24
3.6.6 Determination of Carbohydrate content 25
3.7 In vitro Antioxidant assays 26
3.7.1 Ferric reducing-antioxidant capacity 26
3.7.2 DPPH (1, 1-diphenyl-2-picryl hydrazyl) Scavenging activity assay 27
3.7.3 Thiobarbituric Acid Reactive Species (TBARS) Assay 28
3.8 Proximate Analysis 29
3.9 Statistical Analysis 29
CHAPTER FOUR
4.0 Results 30
4.1 Qualitative Phytochemical Screening 30
4.2 Quantitative Phytochemical Screening 32
4.3 In vitro Antioxidant assay 34
4.3.1 Ferric-reducing Antioxidant power 34
4.3.2 DPPH Radical Scavenging Activity 34
4.3.3 Thiobarbituric Acid Reactive Species Assay 36
4.4 Proximate Analysis and Reducing Sugar 38
CHAPTER FIVE
5.0 Discussion, Conclusion and Recommendation 39
5.1 Discussion 39
5.2 Conclusion 41
5.3 Recommendation 41
REFERENCES 42
APPENDIX 50
