scholarly journals Determination of antioxidant capacity in some foods by oxygen radical absorbance capacity (ORAC)

Author(s):  
Thuy Le Thi ◽  
Thuong Nguyen Nhu ◽  
Bang Nguyen Thi ◽  
Truc Quynh Do ◽  
Trang Vu Thi ◽  
...  

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.

1995 ◽  
Vol 41 (12) ◽  
pp. 1738-1744 ◽  
Author(s):  
G Cao ◽  
C P Verdon ◽  
A H Wu ◽  
H Wang ◽  
R L Prior

Abstract Reactive oxygen species are of interest in biology and medicine because of evidence relating them to aging and disease processes. A relatively simple but sensitive and reliable method for quantifying the oxygen radical absorbance capacity (ORAC) of antioxidants in biological tissues has been automated for use with the COBAS FARA II centrifugal analyzer with a fluorescence-measuring attachment. In this assay, beta-phycoerythrin (beta-PE) is used as an indicator protein, 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH) as a peroxyl radical generator, and 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (Trolox) as a calibrator for antioxidant activity. This assay is unique because the reaction goes to completion so that both inhibition time and inhibition degree are considered in quantifying ORAC (micromoles of Trolox equivalent per liter or per gram of tissue). This method can be used not only for serum but also other tissue and food samples and is suitable for application to a range of nutritional and clinical conditions.


2004 ◽  
Vol 50 (5) ◽  
pp. 952-954 ◽  
Author(s):  
Chi Chiu Wang ◽  
Ching Yan Chu ◽  
Kai On Chu ◽  
Kwong Wai Choy ◽  
Kim Sun Khaw ◽  
...  

2013 ◽  
Vol 96 (6) ◽  
pp. 1372-1376 ◽  
Author(s):  
Boxin Ou ◽  
Tony Chang ◽  
Dejian Huang ◽  
Ronald L Prior

Abstract An improved method for the measurement of oxygen radical absorbance capacity (ORAC) was developed and validated using fluorescein (3′,6′-dihydroxyspiro[isobenzofuran-1[3H], 9′[9H]-xanthen]-3-one) as a new fluorescence probe (ORACFL). Randomly methylated β-cyclodextrin (RMCD) was introduced as the water-solubility enhancer for lipophilic antioxidants. 7% RMCD (w/v) in 50% acetone–H2O mixture sufficiently solubilized vitamin E compounds and other lipophilic phenolic antioxidants in 75 mM phosphate buffer (pH 7.4). Results indicated that fluorescein shows excellent photostability under the plate reader conditions. This ORACFL was validated through linearity, precision, accuracy, and ruggedness. The validation results demonstrated that the ORACFL assay is reliable and robust. The mean of intraday and interday CVs were <15%; for hydrophilic ORAC, LOD and LOQ are 5 and 6.25 μM, respectively; for lipophilic ORAC, LOD and LOQ are 6.25 and 12.5 μM, respectively. It is concluded that unlike other popular methods, the ORACFL assay provides a direct measure of total antioxidant capacity against the peroxyl radicals.


2016 ◽  
Vol 22 (2) ◽  
pp. 301-305
Author(s):  
Manabu Wakagi ◽  
Yuuki Taguchi ◽  
Jun Watanabe ◽  
Tasuku Ogita ◽  
Masao Goto ◽  
...  

2002 ◽  
Vol 50 (18) ◽  
pp. 5053-5057 ◽  
Author(s):  
Anne C. Kurilich ◽  
Elizabeth H. Jeffery ◽  
John A. Juvik ◽  
Matthew A. Wallig ◽  
Barbara P. Klein

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