ORAC: The Method of Choice for Determining Antioxidant Capacity of Food Products?

The Oxygen Radical Absorbance Capacity (ORAC) assay is one of the most popular assays of antioxidant activity/capacity. It has several advantages over other common assays, including the use of an oxidant (peroxyl radicals) relevant in physiology and food storage and processing, as well as reactions in the physiological pH range and temperature. These advantages make ORAC the method of choice for the determination of antioxidant activity/capacity. This review presents the methodology and application of ORAC to the analysis of food products, various versions of the assay, including the lipophilic ORAC-related assays like the Hydroxyl Radical Absorbance Capacity (HORAC), Peroxynitrite Absorbance Capacity (NORAC), Superoxide Anion Absorbance Capacity (SORAC), and Singlet Oxygen Absorbance Capacity (SOAC); discusses the pros and cons, nd technical details affecting the reproducibility of ORAC. Examples of applications of the assay are given, including ORAC values [mol Trolox equivalent/mol, and mmol Trolox equivalents/kg or per L, respectively] for over 90 antioxidants and over 900 food products and medicinal plants.