Conventional methods and new trends for antioxidant analyses
Anielle de Oliveira, Grazielle Silva De Oliveira, Valéria Maria Costa Teixeira, Rosana Aparecida da Silva-Buzanello, Evandro Bona
Abstract
ABSTRACT Antioxidants are compounds capable of neutralizing reactive oxygen and nitrogen species (ROS/RNS), preventing damage to the body’s cells and tissues. These compounds can be found in plant-based foods, especially fruits, vegetables, and grains. Consumption of these compounds is essential, as they aid in preventing chronic diseases, such as cancer, cardiovascular, and neurodegenerative diseases. Therefore, the determination of antioxidant capacity has become crucial for the characterization of several products. Given the above, this work aims to comprehensively review the primary methods used to determine the antioxidant capacity in different matrices, focusing on conventional approaches and emerging analytical trends. Classic methods covered include hydrogen transfer (HAT)-based assays, such as ORAC, HORAC, TRAP, and TOSC, as well as electron transfer (ET)-based methods, such as CUPRAC, Folin-Ciocalteu, mixed methods (such as DPPH and ABTS), and enzyme assays are also discussed, which are essential to evaluate antioxidant activity under physiological conditions. The work also highlights the advancement of instrumental techniques such as voltammetry, mass spectrometry, chromatography, chemiluminescent methods, and the use of sensors and biosensors, which increase the sensitivity, selectivity, and applicability of antioxidant analyses. Finally, the challenges that still exist are discussed, such as the lack of methodological standardization and the need for quality control and analytical validation to ensure reliable and reproducible results.