Abstract:

Currently, in vitro evaluation of antioxidant activity is widely used in the fields of food, medicine and cosmetics, but none of the methods can truly and accurately reflect the “total antioxidant capacity” of antioxidants, and each assay has certain shortcomings and limitations. The DPPH and ABTS methods are widely accepted and used because they are rapid, simple, low-cost, and can detect a large number of samples. However, different antioxidant solvents, structures, concentrations and spatial polarizability, absorption signals, and reaction times have an impact on the accuracy of the results. In this study, based on the analysis of different factors affecting the accuracy of the DPPH and ABTS methods, it is found that DPPH method is more suitable for evaluating antioxidants with organic solvents as reaction solvents, nonpolar/lower polarity, and slower reaction, and the method is easily affected by the color of the antioxidants, such as pigments, light, metal ions, and fluctuations in pH. The ABTS method is more suitable for evaluating antioxidants with water as the reaction solvent, high polarity and rapid reaction. Therefore, in order to accurately determine the antioxidant activity, suitable methods should be selected according to the characteristics of the samples, and it is also recommended to use at least two or more methods to fully reflect the antioxidant activity.

Key words: antioxidant activity, free radicals, influence factors