Market survey of wholesome citric acid level in soft drinks by first derivative potentiometric titration

Abstract

Various soft drink products available in markets in Benin City were screened for their citric acid concentration as an index of wholesomeness in soft drinks. Eleven (11) samples were obtained and subjected to potentiometric titration and the values obtained were compared with the permissible values in literature. These values were calculated based on the equivalent volume obtained from each first derivative potentiometric plot. The permissible value in literature for citric acid concentration in soft drinks is 1.76g/L to 1.90g/L (0.131% to 0.640%). However, the values obtained for the concentration of citric acid in various soft drink samples range from 0.148% to 4.379%. The results obtained revealed that seven (07) samples have values that range within the standard (0.148% to 0.444%) while four (4) samples have values exceeding the standard (2.254% to 4.579%). These values were calculated based on the equivalent volume obtained from each first derivative potentiometric plot. The optimum activity of citric acid for the samples in the soft drinks range from pKa 2.600 to pKa 6.300. Findings revealed a high level of acid in some soft drink which might be as a result of increase in other acids other than citric acid. Similarly, unwholesome practices of industries could be another reason. It is recommended that
public health awareness should be used as a guideline for formulating health policies.