Reducing Antioxidant Capacity Evaluated by Means of Controlled Potential Electrolysis

Oliveira, Raquel; Marques, Juliana Filipa Gouveia; Bento, M. Fátima; Geraldo, M. Dulce; Bettencourt, Ana Paula

doi:10.1002/elan.201000485

Cited by 9 publications

(16 citation statements)

References 46 publications

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“…Also the peak current ( i p ) values showed the same trend as seen for E p . As the current value is related to the number of electron transferred ( n ) 15, when equimolar concentrations of antioxidants are compared, the i p value provides information on the number of electrons available. The resulting peak current values, for 0.10 mM concentrations, follow the trend, ethoxyquin (4.9 µA/µM), dl ‐tocopherol (3.7 µA/µM), retinyl acetate (3.5 µA/µM) and BHT (2.4 µA/µM).…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Concerted Determination of the Hydrogen Atom and Electron Transfer Capacity of Lipid Soluble Reducing Agents

Lemma

Scampicchio

Bulbarello³

et al. 2014

Electroanalysis

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This paper describes a method based on square wave voltammetry to evaluate either the electron transfer or the hydrogen atom transfer of lipid soluble antioxidants such as dl‐mix‐tocopherol, BHT, ethoxyquin and retynil acetate. The electron transfer (ET) capacity was evaluated by the peak current, peak potential and the area under the anodic wave, whereas the hydrogen atom transfer (HAT) capacity by the kinetic rate of the reaction between antioxidants and 2,2‐Azobis(2‐methylpropionamidine) dihydrochloride (AAPH). The results indicate that ethoxyquin and tocopherol have the highest ET and HAT capacity. However, HAT capacity of tocopherol, BHT and retinyl acetate depend on the concentration. The approach has the advantage to assess HAT and ET capacity of lipid soluble antioxidant in a single concerted protocol.

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Section: Resultsmentioning

confidence: 99%

“…The comparison between these protocols has been reviewed 13,14. In addition, electrochemical based assays have been also proposed 15–20 and the main approaches reviewed 21,22. Among other, electrochemical based assays generally measure the reducing capacity of an antioxidant as a function of the potential applied to an inert electrode.…”

Section: Introductionmentioning

confidence: 99%

Concerted Determination of the Hydrogen Atom and Electron Transfer Capacity of Lipid Soluble Reducing Agents

Lemma

Scampicchio

Bulbarello³

et al. 2014

Electroanalysis

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“…The reactions that take place in wine when it is exposed to oxygen have been deeply studied (Singleton, 1987 ; Atanasova et al, 2002a ; Waterhouse and Laurie, 2006 ; Danilewicz, 2007 ; Danilewicz et al, 2008 ; Dimkou et al, 2011 ; Oliveira et al, 2011b ; Laurie et al, 2012 ; Ugliano, 2013 ). The accepted mechanism (Figure 1 ) supports that once oxygen is dissolved in wine, its activation is carried out by metal ions, particularly iron and copper in lower oxidation states (Fe 2+ and Cu + ), supposedly forming the yet undetected hydroperoxy radical (

) (Danilewicz and Wallbridge, 2010 ; Danilewicz, 2011 ; Waterhouse et al, 2016 ) and Fe 3+ .…”

Section: Introductionmentioning

confidence: 99%

Formation and Accumulation of Acetaldehyde and Strecker Aldehydes during Red Wine Oxidation

et al. 2018

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The main aim of the present work is to study the accumulation of acetaldehyde and Strecker aldehydes (isobutyraldehyde, 2-methylbutanal, isovaleraldehyde, methional, phenylacetaldehyde) during the oxidation of red wines, and to relate the patterns of accumulation to the wine chemical composition. For that, eight different wines, extensively chemically characterized, were subjected at 25°C to three different controlled O2 exposure conditions: low (10 mg L−1) and medium or high (the stoichiometrically required amount to oxidize all wine total SO2 plus 18 or 32 mg L−1, respectively). Levels of volatile aldehydes and carbonyls were then determined and processed by different statistical techniques. Results showed that young wines (<2 years-old bottled wines) hardly accumulate any acetaldehyde regardless of the O2 consumed. In contrast, aged wines (>3 years-old bottled wines) accumulated acetaldehyde while their content in SO2 was not null, and the aged wine containing lowest polyphenols accumulated it throughout the whole process. Models suggest that the ability of a wine to accumulate acetaldehyde is positively related to its content in combined SO2, in epigallocatechin and to the mean degree of polymerization, and negatively to its content in Aldehyde Reactive Polyphenols (ARPs) which, attending to our models, are anthocyanins and small tannins. The accumulation of Strecker aldehydes is directly proportional to the wine content in the amino acid precursor, being the proportionality factor much higher for aged wines, except for phenylacetaldehyde, for which the opposite pattern was observed. Models suggest that non-aromatic Strecker aldehydes share with acetaldehyde a strong affinity toward ARPs and that the specific pattern of phenylacetaldehyde is likely due to a much reduced reactivity toward ARPs, to the possibility that diacetyl induces Strecker degradation of phenyl alanine and to the potential higher reactivity of this amino acid to some quinones derived from catechin. All this makes that this aldehyde accumulates with intensity, particularly in young wines, shortly after wine SO2 is depleted.

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“…Cyclic voltammetry (CV) or linear sweep voltammetry (LSV) [12][13][14], differential pulse voltammetry [15,16], square wave voltammetry [17,18], the combination with HPLC detection [19,20] and flow systems such as flow injection analysis (FIA) [9] have been used over a broad range of biological fluids. More recently, other assays such as the reducing antioxidant capacity evaluated by electrolysis (RACE) [21], the rapid electrochemical screening of antioxidant capacity (RESAC) [22] or microfluidic devices [23] were proposed. In addition, a new pseudo-titration voltammetry (PTV) concept where AOs that are rapidly oxidized at low oxidation potentials are mathematically separated from slow reacting and less relevant compounds has also been described [24].…”

Section: Introductionmentioning

confidence: 99%

Large scale inkjet-printing of carbon nanotubes electrodes for antioxidant assays in blood bags

Lesch

Cortés‐Salazar

Prudent

et al. 2014

Journal of Electroanalytical Chemistry

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a b s t r a c tHerein, we present the large scale fabrication of carbon nanotubes (CNT) electrodes supported on flexible polymeric sheets by subsequent multilayer inkjet printing of a silver layer for electrical connection, CNT layers as active electrode material and an insulation layer to define a stand-alone CNT active electrode area with high accuracy. Optical and electrochemical characterization using several redox mediators demonstrates the reproducibility of the electrode surfaces and their functionality even with a single inkjet printed CNT layer. These electrodes are targeted to the clinical sector for the determination of the antioxidant power (AOP) of biologically relevant fluids by pseudo-titration voltammetry. As a proof-ofconcept, the AOP of ascorbic acid solutions and biological samples such as erythrocyte concentrates (ECs) from different blood donors were determined demonstrating the potential use of the presented CNT sensors on ECs for blood transfusion purposes and the clinical sector.

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Reducing Antioxidant Capacity Evaluated by Means of Controlled Potential Electrolysis

Cited by 9 publications

References 46 publications

Concerted Determination of the Hydrogen Atom and Electron Transfer Capacity of Lipid Soluble Reducing Agents

Concerted Determination of the Hydrogen Atom and Electron Transfer Capacity of Lipid Soluble Reducing Agents

Formation and Accumulation of Acetaldehyde and Strecker Aldehydes during Red Wine Oxidation

Large scale inkjet-printing of carbon nanotubes electrodes for antioxidant assays in blood bags

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