A Device for the Semiautomatic Determination of Oxygen-Radical Absorbance Capacity

2000 ◽  
Vol 287 (2) ◽  
pp. 226-233 ◽  
Author(s):  
Charles R. Caldwell
2016 ◽  
Vol 22 (2) ◽  
pp. 301-305
Author(s):  
Manabu Wakagi ◽  
Yuuki Taguchi ◽  
Jun Watanabe ◽  
Tasuku Ogita ◽  
Masao Goto ◽  
...  

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.


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.


Author(s):  
Greeshma Murukan ◽  
Murugan K.

Objective: The present study evaluates purification, characterization of anthocyanin from in vitro culture of teak and its antioxidant potential.Methods: Anthocyanin was extracted from in vitro culture, purified by using amber lite XAD column and fractionated by Liquid chromatography mass spectrometry (LC-MS/MS). Various antioxidant assays were carried such as 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH), 2,2'-azino-bis-3-ethyl-benzothiazoline-6-sulphonic acid (ABTS), Oxygen radical absorbance capacity (ORAC), Nitric oxide (NO) and Hydrogen peroxide (H2O2).Results: Liquid chromatography mass spectrometry (LC-MS/MS) revealed the major fraction as cyanidin 3-(2-xylosyl-rutinoside) with unknown peaks. The amount of anthocyanin was 15.23 mg/g monomeric anthocyanin. Further, the potential antioxidant capacity of the teak anthocyanin was comparable to common vegetables and fruits. Similarly, high correlations of anthocyanin with antioxidant activity, such as oxygen radical absorbance capacity (ORAC), 2,2'-azino-bis-3-ethyl-benzothiazoline-6-sulphonic acid (ABTS), and 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) (r = 0.95, 0.93, and 0.80) were found.Conclusion: The high anthocyanins content and potential antioxidant activity suggests that teak anthocyanin may be applied in the food industry as a good source of natural pigments


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