Low-interferences Determination of the Antioxidant Capacity in Fruits Juices Based on Xanthine Oxidase and Mediated Amperometric Measurements in the Reduction Mode

• Published in: Analytical Sciences Vol. 32; no. 2; pp. 135 - 140
• Main Authors: BUCUR, Madalina-Petruta, RADULESCU, Maria-Cristina, BUCUR, Bogdan, RADU, Gabriel Lucian
• Format: Journal Article
• Language: English
• Published: Singapore The Japan Society for Analytical Chemistry 2016; Springer Nature Singapore; Japan Science and Technology Agency
• Subjects: Analytical Chemistry; Antioxidant capacity evaluation; Antioxidants; Antioxidants - analysis; Antioxidants - chemistry; ascorbic acid; Ascorbic Acid - chemistry; Calibration; Chemistry; Electrochemistry - methods; Electrodes; Ferrocyanides - chemistry; Food Analysis - methods; Free Radicals - chemistry; Fruit and Vegetable Juices - analysis; Hydrogen peroxide; Hydrogen Peroxide - chemistry; Juices; Linear Models; Oxidation-Reduction; Prussian blue; Radicals; Reduction; Sensors; Superoxides - chemistry; Xanthine oxidase; Xanthine Oxidase - chemistry; Antioxidant capacity evaluation; ascorbic acid; Prussian blue; xanthine oxidase
• ISSN: 0910-6340; 1348-2246
• DOI: 10.2116/analsci.32.135

A low-interferences enzymatic sensor for evaluating the antioxidant capacity was developed. Xanthine oxidase was used to produce superoxide radicals that spontaneously dismutate to hydrogen peroxide. Low xanthine concentrations were used to minimize the rapid dismutation of the superoxide radical before its fast reaction with antioxidants. The sensor operates in the reduction mode, and evaluations with low interferences of the antioxidant capacity are based on the detection of remaining hydrogen peroxide using Prussian blue electrodes at low potentials. The linear calibration graph is between 2 – 10 μM ascorbic acid. No interferences were observed from easily oxidisable substances including uric acid, which is produced in the enzymatic reaction or other substances usually found in foods. The method was used to evaluate the antioxidant capacity in different real juice samples.