Electrochemical behavior and determination of major phenolic antioxidants in selected coffee samples.

The redox behavior of commercial roasted coffee products were evaluated by electroanalysis, whereas high performance liquid chromatography (HPLC) was used for determination of cinnamic acid markers, the total phenolic content (TPC) was achieved by Folin-Ciocalteu assay, and the traditional DPPH (1-diphenyl-2-picrylhydrazyl) method for antioxidant power determination. In turn, an optimized electrochemical index was proposed to estimate the antioxidant power of different samples and it was found a great correlation between all methods. The voltammetric profile of all coffee samples was quite similar, presenting the same number of peaks at the same potential values. Minor differences on current levels were in agreement with the total phenolic and major markers content, as well as, to the antioxidant power. Therefore, the electrochemical methods showed to be practical, low cost and very useful to evaluate the antioxidant properties of coffee samples, which is a relevant quality parameter of this widely consumed beverage.