Tehran University of Medical Sciences Journal of Food Safety and Hygiene 2476-3241 11 4 2026 06 06 352 364 Fatemeh Zamani Mazdeh Food and Drug Administration, Tehran University of Medical Sciences, Tehran, Iran Shaghayegh Keikhosravy Drug and Food Control Department, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran Mohsen Amini Medical Chemistry Department, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran Anita Chalipour Drug and Food Control Department, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran Akram Rostami Drug and Food Control Department, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran Naficeh Sadeghi Drug and Food Control Department, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran Mannan Hajimahmoodi Drug and Food Control Department, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran 2025 07 30 2026 06 06 Food fraud, defined as the deliberate alteration or misrepresentation of food products for economic gain, has long posed significant challenges for consumers and the food industry. Fruit juices are among the ten commodities most vulnerable to fraudulent practices, as identified by the European Committee on the Environment, Public Health and Food Safety. Therefore, the development of robust, sensitive, and economically viable analytical techniques is essential to ensure the authenticity, quality, and safety of fruit juice products. The main objective of the present study was to develop and apply an analytical method for the quality control of commercial juice products. For this purpose, 73 Iranian commercial juices from 11 brands were analyzed. Based on their labels, the samples were classified into two categories: still fruit drinks and nectars, including orange, pineapple, peach, and sour cherry flavors. Physicochemical parameters, including pH and Brix, as well as total polyphenol content and flavonoid profiles, were determined. Total polyphenol content was measured using a spectrophotometric method, while catechin, eriocitrin, naringin, hesperidin, and quercetin were quantified by reverse-phase high-performance liquid chromatography with UV detection at 280 nm. The chromatographic separation was performed on a C8 column using gradient elution with water, acetic acid, and acetonitrile, and was completed within 30 min. The method showed acceptable analytical performance, with the highest limit of detection being 1.39 ppm for eriocitrin and spike recovery values of at least 82.81% for naringin. Statistical analysis revealed significant differences in total polyphenol and flavonoid contents among different types of fruit juices. Overall, the results indicated that flavonoid profiling is a valuable tool for the quality control  and authenticity assessment of commercial fruit juices, whereas physicochemical parameters such as pH, Brix, and total polyphenol content alone are not sufficient for this purpose. https://jfsh.tums.ac.ir/index.php/jfsh/article/view/570 https://jfsh.tums.ac.ir/index.php/jfsh/article/download/570/308