Phenolic Composition and Total Antioxidant Capacity by Electrochemical, Spectrophotometric and HPLC‐EC Evaluation in Portuguese Red and White Wines

Abstract

Phenolic composition and in vitro total antioxidant capacity have been evaluated, in red and white Portuguese wines, by electrochemical methods, spectrophotometric methods, and reverse‐phase high performance liquid chromatography with electrochemical detection (HPLC‐EC). The different phenolic compounds present in seventeen red and white wines, with different grape varieties, and from different geographical locations, were successfully identified and detected. The wines in vitro total antioxidant capacity, using the method of capture of diphenilpicrilhydrazil (DPPH.) free radical “efficient concentration” (EC50), and the electrochemical quantitative index (EI), was determined. The wine with the highest total antioxidant capacity exhibited the lowest antioxidant power, and the EI and EC50 assays had a very good correlation.

Electrochemical Methods to Evaluate the Antioxidant Activity and Capacity of Foods: A Review

“…Generally, the peak current is used to estimate the antioxidant capacity or the concentration of antioxidants, whereas the peak potential can be used to identify the type of antioxidants. Applications of this technique for the measurement of antioxidants has been reported for tea [101][102][103][104], fruits, peels and pulps [78,[105][106][107][108][109], wines [67,[110][111][112][113][114][115], spices [116], herbal, plants or roots [79 ,87, 117, 118], dry fruits [119,120], honey [121] and propolis [75,122,123], meats [124], ginger [90], medicinal plant's leave and husk [125,126], beverage [127], coffees [128] and green coffee beans [62], fish oils [129], hops and malt [130] and algae [131].…”

Development of a dispersive liquid–liquid microextraction method for the determination of plastic additives in seawater

“…18,21,34 The hydrophobicity of the seven additives is too large so a gradient elution will be necessary. The most employed acids for adjusting the pH of the mobile phase for the determination of these additives are acetic acid, 19,21 formic acid 18,23 and phosphoric acid. 13,35 In this work phosphoric acid was selected since organic acids exhibit absorbance at 200 nm, and consequently they cannot be used in gradient elution.…”

“…High-performance liquid chromatography (HPLC) with ultraviolet (UV) detection or diode array detection (DAD) is the most commonly employed technique in the analysis of these additives. [9][10][11][12][13][14][15][16][17][18][19] The reversed-phase mode using octadecyl columns [10][11][12][13][14][20][21][22][23] and mixtures of acetonitrile/water or methanol/water as mobile phase 11,12,14,16,17,22 is by far the most commonly used chromatographic conditions currently for the analysis of these additives.…”

Palladium/Rhodium/Iridium Trimetallic Octahedral Nanozymes Exhibiting Enhanced Peroxidase-like Activity for Detecting Total Antioxidant Capacity in Food

“…Current instrument-based methods, including high-performance liquid chromatography (HPLC) and Fourier transform infrared (FT-IR), are used for detecting the total antioxidant capacity. Colorimetric methods based on radical scavenging assays, including 2,2′-azinobis­(3-ethylbenzothiazoline-6-sulfonate) (ABTS) and 1,1-diphenyl-2-picryl-hydrazyl radical (DPPH), are used for detecting the total antioxidant capacity (TAC). − However, the drawbacks of these methods typically limit their wide applications. HPLC and FT-IR can accurately detect the content of reducing reagents.…”