engleski

The level of citric acid in fruit juices available on Croatian market

The aim of this study was to check the level of citric acid in fruit juices (lemon, orange, apple and fruit-mix) available on Croatian market. The level of citric acid was determined by use of high performance liquid chromatography (HPLC). UV/Vis detector was set at 214 nm, mobile phase (50 mM phosphate buffer, pH= 2.8) flow rate at 0.5 mL/min and separation was performed on RP-18 column (125.0 x 4.6 mm, 5 µm ; LiChrospher, Merck, Darmstadt, Germany). Calibration curve obtained from citric acid working standards (0.125 to 1.0 g/L) was linear (R2=0.9998), repeatability (expressed as relative standard deviation, RSD) was less than 5%, the limit of detection was 0.02 g/L and the limit of quantification was 0.06 g/L, indicating that developed method is sensitive and reliable for determination of citric acid. The level of citric acid in fruit juice samples (n = 5) ranged from 1.6 g/L to 3.98 g/L. The manufacturer did not declare the level of citric acid, however in two orange juice samples the level of citric acid was higher than recommended by Commission regulation EU No. 1129/2011 (3.0 g/L), implying to the importance of monitoring the level of citric acid in products intended for human consumption.

citric acid, fruit juices, high performance liquid chromatography, monitoring

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