The Total Antioxidant Capacity of Foods: A Reappraisal. Application To Commercial Orange Juices - The Total Antioxidant Capacity of Foods: A Reappraisal. Application To Commercial Orange Juices - Open Access Pub

Since a few years, more and more attention has been specifically given to dietary antioxidants as agents promoting health and preventing the incidence of diseases. As part of these efforts, analytical methods and assays have been developed to measure the antioxidant content in food substances. In this paper, the antioxidant capacity of 17 orange juices is determined by various assays (DPPH, ORAC, heamolysis, xanthine/xanthine oxidase) as the content in ascorbic acid and total phenolics. The results evidence all the complexity to evaluate the in vitro antioxidant capacity of foods. In very general terms, in spite of the wide utilization in these tests (FRAP, TAC, ORAC TRAP and others), their significance remains obscure. The discrepancy of the results and the absence of good correlation between the assays clearly highlight all the importance of understanding the strengths and weakness of assays evaluating antioxidant potential of a food at the risk of giving erroneous information to the consumer. It is clear that the use of "total antioxidant capacity" assays for the in vitro assessment of antioxidant quality of food does not be employed by food industrials as a marketing argument or for the assessment of the "wholesomeness" of a food. DOI10.14302/issn.2471-2140.jaa-15-715 Since a few years, more and more attention has been specifically given to dietary antioxidants as agents promoting health and preventing the incidence of pathologies1. As part of these efforts, analytical methods and assays have been developed to measure the antioxidant content in food substances. The methods generally used to determine the total antioxidant capacity in foods are: the Trolox Equivalent Antioxidant Capacity (TEAC) assay, the Ferric Reducing Ability of Plasma (FRAP) assay, the copper reduction (CUPRAC) assay, the 2,2-diphenyl-1-picrylhydrazyl radical scavenging capacity (DPPH) assay, based on single electron transfer reaction, the crocin bleaching assay, the Total peroxyl Radical-trapping Antioxidant Parameter (TRAP) assay and the Oxygen Radical Absorbance Capacity (ORAC) assay, based on hydrogen atom transfer reaction. Additional methods have also been developed like scavenging of superoxide anion generated by the xanthine/xanthine oxidase system2, red blood cell resistance to oxidative stress (haemolysis)3 or cellular antioxidant activity (CAA)4. Among all these tests, the most publicized assay was the ORAC assay (Oxygen Radical Antioxidant Assay) initially developed two decades ago by scientists belonging to the National Institutes of Health and the U.S. Department of