Analytical methodologies for antioxidant capacity assessment: An updated review

Antioxidants are crucial molecules protecting biological systems from harmful oxidation reactions and free radicals. This class of compounds attracted remarkable attention for their potential in functional foods and dietary supplements. The imbalance between oxidants and antioxidants leads to oxidative stress, associated with various chronic diseases. Accurate measurement of antioxidant activity is therefore essential for evaluating potential health-enhancing agents in food science, medicine, and biotechnology. This review provides a comprehensive overview of contemporary analytical methodologies for assessing antioxidant capacity across food, cosmetic, pharmaceutical, and biomedical applications, exploring four major categories of techniques: spectrophotometric methods, including UV–Vis, electron paramagnetic resonance (EPR), and near infrared (NIR) spectroscopy, highlighting their principles and applications in radical scavenging assays and antioxidant characterization. Electrochemical techniques are rapid, sensitive, and cost-effective alternatives, focusing on voltammetry, amperometry, and biosensor development for direct measurement of electron transfer processes. The role of biosensors, employing bioreceptors like enzymes and DNA, for selective and sensitive antioxidant detection is also examined. Chromatographic methods, such as high-performance liquid chromatography (HPLC) and gas chromatography (GC), paired with selective detectors, are used to separate, identify, and quantify antioxidant compounds in complex matrices. This review highlights the principles, advancements, advantages, and limitations of these diverse methodologies in the accurate evaluation of antioxidant potential.