Determination of Sodium Benzoate and Potassium Sorbate Contents in Selected Processed Packed Fruit Juices by Uv-Vis Spectrometry

Abstract

Benzoic and sorbic acid, and their salts are most commonly used food preservatives and they are permitted food additives by international laws in processing in restrictive amounts, but their content must be declared and must not exceed the established limits by legislation. The purpose of this study is to determine the amount of sodium benzoate and potassium sorbate in selected packed fruit juices available on markets of Jimma City. The content of these preservatives in six commercially available different brands of packed fruit juices were analysed using UV-Vis spectrophotometer. The concentrations of sodium benzoate and potassium sorbate in all samples were calculated by employing external standard method with a calibration of correlation coefficient of 0.998 and 0.997 from the standards calibration curves. The ranges of concentration of sodium benzoate and potassium sorbate were 19.49 ± 0.87 mg/L to 43.0.3 ± 1.92 mg/L and 23.15 ± 1.36 mg/L to 43.68 ± 0.62 mg/L, respectively. The highest level of sodium benzoate was observed in Alang juice (43.03 mg/L) and the lowest value was in Yoyo mango juice (19.49 mg/L). Similarly, the content of potassium sorbate was the highest in Raubi juice (43.68 mg/L) and the lowest was observed in Yoyo (23.15 mg/L).The level of both preservatives in the analyzed fruit juices were within the Food Drug Administration standard range. The limit of detection and quantification for sodium benzoate analysis was 2.38 mg/L and 7.94 mg/L, respectively and that for potassium sorbate was 1.96 mg/L and 6.54 mg/L, respectively. The UV Vis Spectrophotometer method was linear in the concentration range of 10 mg/L to 50 mg/L for both sodium benzoate and potassium sorbate and the mean recoveries for the samples ranged from 87-104 %.