Physico-Chemical Analysis of Some Soft Drinks Available in Pakistan

Abstract

Soft drinks are widely consumed worldwide; therefore, it is necessary to study their qualitative and quantitative analysis. For this purpose, we studied 18 brands of soft drinks purchased from the local market of Bahawalpur, Pakistan. Carbon dioxide, glucose, sucrose, ascorbic acid, phosphates, caffeine, and alcohol were analyzed qualitatively, while pH, conductivity, density, potassium, sodium, and total soluble solids were estimated quantitatively. This physico-chemical analysis was determined by the Association of Official Analytical Chemists (AOAC) methods. The obtained results demonstrated that these soft drinks were highly acidic, ranging from 2.3±0.01 to 3.68±0.01 due to carbon dioxide and phosphates. Most soft drinks contain traces of caffeine and alcohol, while very few contain ascorbic acid. The conductivity of all the soft drinks was high due to soluble ions. Similarly, density was higher than water due to a large amount of sugar. The concentration of total soluble solids, mainly known as sucrose, was also high, ranges 64±0.01 g/L (2.56±0.01 Brix°) to 126.5±0.02 g/L (21.57±0.02 Brix°). Most cold drinks contain some amount of sodium (0.3±0.01 to 3.0±0.01 mg/L), potassium (0±0.00 to 12.8±0.01 mg/L), and a small amount of calcium (0.1±0.01 to 0.53±0.01 mg/L), the potassium concentration was higher than the sodium. In contrast, calcium concentration is very small. The strength of acid was estimated quantitatively using a titrimetric method, the maximum concertation of acid is 20.92±0.01. Similarly, using redox titration, alcohol concentration was measured, ranges 0.46±0.01 to 0±0.00, but this concentration was less than WHO’s concentration, therefore considered safe to use.

Keywords

• soft drink
• alcohol
• caffeine
• ascorbic acid
• flame photometer