Assessment of pH, titratable acidity, and caffeine content of some brands of energy drinks

Abstract

Purpose: Caffeinated beverages that contain high levels of stimulant ingredients, usually caffeine, as well as sugar and often supplements, such as B vitamins or carnitine, and that are promoted as a product capable of enhancing mental alertness and physical performance are referred to as energy drinks. Energy drinks are generally consumed by adolescents and athletes. This study aims to evaluate the endogenous pH, titratable acidity, and caffeine content in selected brands of energy drinks commonly consumed by athletes and adolescents in Benin City. Methods: Eight (8) commonly consumed energy drinks were evaluated. A digital pH meter was used to measure the pH of the selected energy drinks and the titratable acidity was evaluated by titrating 0.1N sodium hydroxide solution against 30 ml of each energy drink till the end-point was reached. The caffeine content was determined by titrating the caffeine-iodine complex formed against standard sodium thiosulphate using iodometric back titration. Results: All the energy drinks were acidic with a pH ranging from 2.61 to 3.48 which is less than the critical pH (5.5). The titratable acidity of the energy drink samples ranged from 5.1 to 15.6 g/100 ml and the caffeine content varied from 0.029 to 0.165 mg/ml. Conclusion: The outcome of this study confirms that energy drinks had low pH values and high titratable acidity except for ED G and ED H with low titratable acidity and low caffeine content. Keywords: Caffeine, endogenous, energy drinks, pH, titratable acidity