Oxygen radical absorbance capacity (ORAC) assay has been applied to determine the Hydrophilic – ORAC index in food. The method measures antioxidant scavenging activity against peroxyl radical induced by 2,2′-azobis(2-amidino-propane) dihydrochloride (AAPH) at 37ºC, used fluororescein as the fluorescent probe. The antioxidant capacity is measured by assemssing the fluorescence decay curve (AUC) of the sample as compared to that of the blank in which no antioxidant is present. Results expressed in ORAC units, equivalent to micromole Trolox per 100 grams sample (Trolox equivalent). The method was shown with high selectivity, a wide linear range, from 5 to 50µM Trolox with linear coefficient R2 = 0.9987. The recovery from 93.2% to 104.4% and repeatability (RSD) was less than 6.60%. The limits of detection and quantitation were 5 and 10µM Trolox, respectively. The method has been applied to determine of H-ORAC index in 65 samples including vegetables, fruits, vegetable products and health supplements with content ranging from 720 µM TE/100g to 310878 µM TE/100g.
ORAC, antioxidant capacity, food.
. A. Phaniendra, D. B. Jestadi, and L. Periyasamy, "Free radicals: properties, sources, targets, and their implication in various diseases," Indian Journal of Clinical Biochemistry, vol. 30, pp. 11-26, 2015.
. I. Gülcin, "Antioxidant activity of food constituents: an overview," Archives of toxicology, vol. 86, pp. 345-391, 2012.
. A. Karadag, B. Ozcelik, and S. Saner, "Review of methods to determine antioxidant capacities," Food Analytical Methods, vol. 2, pp. 41-60, 2009.
. V. T. Trang, L. T. H. Hao, N. D. Hao, N. H. Thu, L. H. Duc, và N. X.Trung, "Xác định tính chống oxy hóa của một số anthocyanin và anthocyanidin bằng phương pháp đo quang sử dụng phản ứng với 2,2’-diphenyl-1-picrylhydrazyl (DPPH)," Tạp chí phân tích Hóa, Lý và Sinh học, tập 23, số 5, tr. 33-38, 2018.
. B. S. Haytowitz DB, "USDA Database for the Oxygen Radical Absorbance (ORAC) of selected foods, Release 2, May 2010.
. G. Cao, E. Sofic, and R. L. Prior, "Antioxidant capacity of tea and common vegetables," Journal of Agricultural and Food Chemistry, vol. 44, pp. 3426-3431, 1996.
. AOAC Official Method 2012.23, "Total Antioxidant Activity Oxygen Radical Absorbance Capacity (ORAC) Using Fluorescein as the Fluorescence Probe First Action 2012".
. B. Ou, M. Hampsch-Woodill, and R. L. Prior, "Development and validation of an improved oxygen radical absorbance capacity assay using fluorescein as the fluorescent probe," Journal of Agricultural and Food Chemistry, vol. 49, pp. 4619-4626, 2001.
. F. Shahidi and Y. Zhong, "Measurement of antioxidant activity," Journal of Functional Foods, vol. 18, pp. 757-781, 2015.