Evaluation of antioxidant activities of some small fruits containing anthocyanins using electrochemical and chemical methods

Abstract

The objective of this work was to estimate the antioxidant capacity of some fruits extracts containing anthocyanins (strawberry, raspberry, elderberry, mulberry, blackberry, bilberry, black and red currant) using an electrochemical technique and three classical chemical methods based on reaction between antioxidants and a chromogen compound. evaluation of antioxidant activities of extracts was performed by using FRAP (ferric reducing/antioxidant capacity), ABTS (2, 2′-azinobis[3-ethylbenzothiazoline-6-sulphonate]) and DPPH (2, 2-diphenyl-1-picrylhydrazyl) assays. Antioxidant activities of the extracts were correlated with their content of monomeric anthocyanins and total phenolics. Good correlations were obtained especially between antioxidant activities and total phenolics content. Cyclic voltammetry was used for the evaluation of overall reducing capacity of the extracts using a glassy carbon electrode. Reducing capacity of selected fruits extracts was assessed based on the half-peak potential (E1/2) of the first oxidation peak. The oxidation potentials characterized by E1/2 value were not correlated with the antioxidant activities evaluated by the classical methods.