Table 4: Common used methods for NEAC measurements.

MethodReaction and quantificationLimitations and confoundings

HAT
ORAC
AAPH—induced:
R-phycoerytherin (red) or fluorescein (green) fluorescence decay
Competitive reaction kinetic, AUC
Lipophilic antioxidants not included
Proteins
HAT
TRAP
AAPH—induced:
R-phycoerytherin fluorescence decay (red)
DCFH ➔ DCF fluorescence increase (green)
Competitive reaction kinetic, lag phase
Lipophilic antioxidants not included
Not all the antioxidants give a lag phase
Self-propagation of DCF radicals
HAT
Crocin bleaching
AAPH- or AMVN-induced absorbance decay (450 nm)
Competitive reaction kinetic, Stern-Volmer-like relation
Bilirubin and carotenoids that absorb at the wavelength of determination
HAT
TAP
MeO-AMVN induced
C11-BODIPY fluorescence increase (green)
Competitive reaction kinetic, AUC
TASFenton reaction-induced dianisidyl radical absorbance increase (444 nm)
Competitive, endpoint, TEAC
SET (Randox)Fenton reaction-induced ABTS radical formation (734 nm)
Competitive reaction, endpoint, TEAC
SET
ABTS•+
Absorbance decay (734 nm)
Noncompetitive, endpoint, TEAC
SET
DPPH
Absorbance decay (515 nm)
Noncompetitive, endpoint, EC50
Carotenoids that absorb at the wavelength of determination
SET
FRAP
Absorbance increase (593 nm)
Noncompetitive, endpoint
SH not included
Biliverdin absorb at the wavelength of determination
SET
CUPRAC
Neocuproine absorbance increase (450 nm).
Noncompetitive, endpoint
Bilirubin and carotenoids that absorb at the wavelength of determination

AAPH: 2,2′-azobis(2-methylpropionamidine) dihydrochloride; ABTS: 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid); AMVN: 2,2′-azobis 2,4-dimethylnaleronitrile; AUC: area under the curve; CUPRAC: copper-reducing assay; DCFH: 2′,7′-dichlorodihydrofluorescein; DPPH: 2,2-diphenyl-1-picrylhydrazyl; EC50: efficient concentration (EC), the amount of antioxidant necessary to decrease by 50%; FRAP: ferric reducing antioxidant power; HA: T hydrogen atom transfer; MeO-AMVN: 2,2′-azobis(4-methoxy-2,4-dimethylvaleronitrile); NEAC: nonenzymatic antioxidant capacity; ORAC: oxygen radical antioxidant capacity; SET: single electron transfer; SH: thiols; TAC: total antioxidant capacity; TAP: total antioxidant performance; TAS: total antioxidant status; TEAC: Trolox equivalent antioxidant capacity; TRAP: total radical-trapping antioxidant parameter.