Antioxidant activity refers to the rate of reaction between a specific antioxidant and a specific oxidant. On the other hand, antioxidant capacity is a measure of the quantity of a free radical in a concentration, neutralized by antioxidant molecules under examination. All common methods such as: Ferric Reducing Antioxidant Power (FRAP), Total Peroxyl Radical Antioxidant Parameter (TRAP), Oxygen Radical Absorption Capacity (ORAC), Crocin Bleaching Assay (CBA), 2,2-diphenyl-1-picrylhydrazyl (DPPH), and others have some technical limitations. All methods, before any analytical test, require a sample preparation, which is separated into hydrophilic and lipophilic fractions. However, this already represents an artifact, because some of the properties of the biological matrix are lost. The new OXEFIN unit defined as the ratio between the electrical power of the sample and the control allows us to compare the antioxidant capacities of single substances or a mixture of them, without the use of a target molecule and equipment such as a spectrophotometer or other optical detection instruments. Moreover, we are able to detect the total antioxidant capacity in an opaque solution without sample preparation (such as food). The milks range from 2.73 +/- 0.02 to 0.20 +/- 0.003 at 4 ml and 4.33 +/- 0.04 to 0.26 +/- 0.003 at 8 ml. The berries and fruit juices range from 5350 +/- 38 to 673 +/- 5.8 at 4 ml and from 5220 +/- 40 to 915 +/- 5 at 8 ml. The method proposed in this paper represents a new approach to the antioxidant capacity measurements reducing the cost, analysis time, the amount of reagents and avoid the possible chemical interferences during the radical chain reaction.
