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 %.
