Evaluation of the antiradical and reducing properties of selected Greek white wines: correlation with polyphenolic composition

Abstract

The total hydroxycinnamate (THC) and total¯avanol (TF) contents were determined in 26 selected Greek white wines of`Appellation of Origin of High Quality' using well-established spectrophotometric methodology. Furthermore, two parameters related to the antioxidant capacity of wines, the antiradical activity (A AR ) and the reducing power (P R ), were also determined using the stable DPPH . radical and a ferric reducing power assay respectively. THC content varied from 64.4 to 197.1 mg l À1 chlorogenic acid equivalents (CGAE), whereas TF content exhibited larger variation, ranging from 3.3 to 205.3 mg l À1 catechin equivalents (CTE). A AR and P R were found to range from 0.47 to 0.60 mM Trolox equivalents (TRE) and from 0.32 to 2.05 mM quercetin equivalents (QE) respectively. Regression analysis at 95% signi®cance level indicated that reducing effects are likely to be exerted by the¯avanol fraction (SF < 0.05), as opposed to antiradical ef®ciency which is primarily affected by the sum of THC and TF contents (SF < 0.05), suggesting that synergistic phenomena account for the overall antioxidant status of white wines.

Effect of Extraction Conditions on Measured Total Polyphenol Contents and Antioxidant and Antibacterial Activities of Black Tea

“…With the DPPH method, antioxidant activity and total phenolics of black tea extracts correlated significantly at 2, 8 and 18 h of extraction (R 2 =0.89, 0.85 and 0.84, respectively). Contrary to the results of Psarra et al [28] on wines, this study showed that correlation of RP with total polyphenols is stronger than that of radical scavenging activity, which can be attributed to different reactivity of polyphenols in black tea in different antioxidant assays.…”

“…Satoh et al [27] also observed that there was a strong correlation between the RP and total phenolic content of different tea extracts including black tea. However, Psarra, et al [28] found a poor correlation (R 2 =0.60) between RP and total polyphenol of wines and also a high correlation (R 2 =0.81) for radical scavenging activity. The differences may be due to the different polyphenol composition of materials investigated.…”

An Investigation on the Recovery of Antioxidant Phenolics from Onion Solid Wastes Employing Water/Ethanol-Based Solvent Systems

“…A previously established method described by Psarra et al (2002) was employed with modifications. An aliquot of 0.05 mL of extract was mixed with 0.05 mL FeCl 3 (3 mM in 5 mM HCl).…”

Relationship between antioxidant capacity and total phenolic content of red, rosé and white wines

“…Hence the beneficial properties of wines have been mainly interpreted on the basis of the antioxidant properties on the flavonoid fraction, which are related to both free radical scavenging and transition metal chelating . However, because of the different types of grapes used and the different production processes implemented, there are fundamental and crucial differences in white and red wine composition in terms of both the nature and quantity of polyphenols (Psarra, Makris, Kallithraka, & Kefalas, 2002).…”