EVALUATION OF SOME CHEMICAL CONSTITUENTS OF SELECTED ENERGY DRINKS
Abstract
This research work examined and compares the physicochemical properties and some chemical constituents of selected energy drinks. Fourteen (14) brands of energy drinks samples consisting eleven (11) liquid and three (3) powdered forms were randomly purchased. All samples were analyzed for their physicochemical properties (pH, turbidity, conductivity and total dissolved solids), trace and heavy metals, aspartame, sugar and caffeine contents. Results showed that the physicochemical properties (i.e. pH, turbidity, conductivity and total dissolved solids) ranged from 4.47 ± 0.012 – 5.96 ± 0.012, 8 ± 0.577 – 592 ± 1.155 NTU, 2.21 ± 0.006 – 1975 ± 1.732 µs/cm, and 243 ± 0.577 – 1064 ± 0.577 mg/L respectively. Energy drinks analyzed all fell within the FDA recommended range for the physicochemical properties analyzed. Iron, calcium, zinc and potassium were found in all the energy drinks and their concentration ranged from 1.961 ± 0.0003 – 0.294 ± 0.0005 mg/L, 2.763 ± 0.0009 – 19.310 ± 0.0015 mg/L, 0.045 ± 0.0001 – 13.887 ± 0.0037 mg/L, and 2.0 to 2500 mg/L respectively. The copper, lead and manganese concentration of energy drinks ranged from 0.002 ± 0.0002 – 0.102 ± 0.0003 mg/L, 0.028 ± 0.0006 – 0.209 ± 0.0009 mg/L and 0.003 ± 0.0001 – 0.024 ± 0.0002 mg/L respectively. The concentration of copper and manganese were below the MCL of 1.0 mg/L and 0.05 mg/L respectively while lead had a concentration above the MCL of 0.01 mg/L. Cadmium was not detected in all energy drinks except for sample EJ which had a concentration of 0.102 ± 0.0003 mg/L and exceeded the MCL of 0.005 mg/L. The caffeine, aspartame and sugar concentrations ranged from 1.11 mg/L – 2487.13 mg/L, 6.51 mg/L – 1491.19 mg/L, and 16.98 – 1686.73 mg/L respectively. Caffeine and aspartame concentrations in all the energy drink samples were below the FDA set standard of 400 mg/L and 3000 mg/L respectively except for sample AL which had a concentration above the set standard for caffeine. Though the analyzed parameters were mostly below the set standards, especially caffeine, aspartame and sugar, it is important that the pattern of consumption of these drinks must be monitored to minimize ingestion of excess doses of harmful substances to prevent the reported adverse effects.
TABLE OF CONTENTS
Title page
Abstract
Table of Contents
List of Abbreviations
CHAPTER ONE
1.0Â Â Â Â Â Â INTRODUCTION
1.1Â Â Â Â Â Â Energy Drinks
1.2Â Â Â Â Â Â Contents of Energy Drinks
1.2.1Â Â Â Caffeine
1.2.2Â Â Â Taurine
1.2.3Â Â Â Guarana
1.2.4Â Â Â Glucuronolactone
1.2.5Â Â Â Ginseng
1.2.6Â Â Â Vitamins
1.2.7Â Â Â Sugar
1.3Â Â Â Â Â Â Justification
1.4Â Â Â Â Â Â Aim and Objectives
CHAPTER TWO
2.0Â Â Â Â Â Â LITERATURE REVIEW
2.1Â Â Â Â Â Â Review Work on Energy Drinks
2.2Â Â Â Â Â Â Caffeine
2.2.1Â Â Â Metabolism of caffeine
2.2.2Â Â Â Caffeine and health
2.2.3Â Â Â Research works on caffeine
2.3Â Â Â Â Â Â Aspartame
2.3.1Â Â Â Chemistry of aspartame
2.3.2Â Â Â Biochemical data
2.4Â Â Â Â Â Â Heavy Metal
2.4.1Â Â Â Lead
2.4.2Â Â Â Cadmium
2.4.3Â Â Â Copper
2.4.4Â Â Â Zinc
2.4.5Â Â Â Manganese
2.4.6Â Â Â Iron
2.4.7Â Â Â Calcium
2.4.8Â Â Potassium
2.5Â Â Â Â Â Â Carbohydrates
2.5.1Â Â Â Sugar
2.5.2Â Â Â Added sugars
2.5.3Â Â Â Sugar-sweetened beverage
2.5.4Â Â Â Sugar-sweetened beverages and health risks
2.6Â Â Â Â Â Â Research Work on Beverages
CHAPTER THREE
3.0Â Â Â Â Â Â MATERIALS AND METHODS
3.1Â Â Â Â Â Â Materials
3.1.1Â Â Â Chemicals and reagents
3.1.2Â Â Â Preparation of stock solution
3.1.2.1 Preparation of standard solution for AAS
3.1.2.2 Preparation of standard solution for HPLC
3.1.2.3 Preparation of standard solution for UV
3.1.3Â Â Â Apparatus and equipments
3.1.4Â Â Â Sample collection
3.1.5Â Â Â Sample preparation
3.1.5.1 Sample preparation for AAS
3.1.5.2 Sample preparation for HPLC
3.1.5.3 Sample preparation for UV
3.2Â Â Â Â Â Â Analysis of Physicochemical Properties
3.2.1Â Â Â Determination of pH
3.2.2Â Â Â Determination of conductivity
3.2.3Â Â Â Determination of turbidity
3.2.4Â Â Â Total dissolved solid
3.3Â Â Â Â Â Â Elemental Analysis
3.4Â Â Â Â Â Â Determination of Carbohydrates (Sugar)
3.5Â Â Â Â Â Â Determination of Caffeine and Aspartame
3.5.1Â Â Â Preparation of pH 4.0 and pH 7.0 buffer solution
3.5.2Â Â Â Buffer preparation
3.5.3Â Â Â Mobile phase preparation
3.6Â Â Â Â Â Â Statistical Analysis
CHAPTER FOUR
4.0Â Â Â Â Â Â RESULTS
4.1Â Â Â Â Â Â Physicochemical Parameters of Samples
4.2Â Â Â Â Â Â Metal Concentrations
4.2.1Â Â Â Concentration of heavy metals
4.2.2Â Â Â Concentrations of essential metals
4.3Â Â Â Â Â Â Concentrations of Caffeine, Aspartame and Sugar
CHAPTER FIVE
5.0Â Â Â Â Â Â DISCUSSION
5.1Â Â Â Â Â Â Physicochemical Parameters of the Samples
5.1.1Â Â Â pH
5.1.2Â Â Â Turbidity
5.1.3Â Â Â Total dissolved solids
5.1.4Â Â Â Conductivity
5.2Â Â Â Â Â Â Metal Concentrations
5.2.1Â Â Â Heavy metals
5.2.1.1 Cadmium
5.2.1.2 Lead
5.2.1.3 Copper
5.2.1.4 Manganese
5.2.1.5 Zinc
5.2.2Â Â Â Essential Metals
5.2.2.1 Iron
5.2.2.2 Calcium
5.2.2.3 Potassium
5.3Â Â Â Â Â Â Caffeine, Aspartame and Sugar Concentrations in Energy Drinks
5.3.1Â Â Â Caffeine
5.3.2Â Â Â Aspartame
5.3.3Â Â Â Sugar
CHAPTER SIX
6.0Â Â Â Â Â Â Conclusion
6.1Â Â Â Â Â Â Recommendations
Reference
Appendices
List of Abbreviations
AAS Atomic Absorption Spectroscopy
ATP Adenosine Triphosphate
CYP1A2 Cytochrome P450 1A2
CYP2A6 Cytochrome P450 2A6
DKP 5-benzyl-3, 6-dioxo-2-piperazine acetic acid
DNA Deoxyribonucleic Acid
EU European Union
FAO Food and Agriculture Organization
FDA Food and Drinks Administration
GC–MS Gas Chromatography–Mass Spectrometry
HDL High Density Lipoprotein Cholesterol
HPLC High Performance Liquid Chromatographic
NAT2 N-acetyltransferase 2
NAG N-acetyl-beta-glucosaminidase
NNS National Nutrition Survey
RDA Recommended Daily Allowance
RNA Ribonucleic Acid
SCF Scientific Committee for Food
SSB Sugar Sweetened Beverages
USA United States of America
UV Ultraviolet Visible Spectroscopy
WHO World Health Organization
XO
CHAPTER ONE
INTRODUCTION
Energy drinks refer to beverages that contain large doses of caffeine and other legal stimulants such as taurine, carbohydrates, glucuronolactone, inositol, niacin, panthenol, and β-complex vitamins which are considered as source of energy (Attila and Çakir, 2009). The consumption of readily available energy drinks has increased significantly with young adults forming the largest part of the consumers. History of energy drink dates back to 1987 when Red Bull was introduced in Austria. It became more popular in the 1990s following its introduction to the United States. Since then the sale of this drink has increased exponentially. In 2006, the energy drink market grew by 80% (Foran et al., 2011). This is because manufactures claim the drinks can boost energy levels as well as physical endurance, improve concentration and reaction speed (Van den Eynde et al., 2008).
In recent years, a number of different energy drinks have been introduced in the Nigerian market to provide an energy boost or as dietary supplements. These drinks are marketed specifically to children and young adults. These products have been used for various reasons. A survey conducted among college students shows that 67% of students admitted using energy drinks to cope with insufficient sleep, 65% mentioned increasing energy and 54% use it for fun at parties; 50% for studying or completing a major course project, 45% used it while driving a car for a long period of time and 17% for treating hangover (Malinauskas et al., 2007). These products have also been used to reduce the depressor effect of alcohol or even to gain social status (Ferreira et al., 2004; Kaminer, 2010).
