Free radical scavenging capacity in the aging of selected red Spanish wines

Free radical scavenging capacity by the DPPH(*) method and main physicochemical properties, polyphenols content by HPLC, color by a tristimulus colorimeter, and UV-vis spectra in the aging of selected red Spanish wines, were studied. As the wines age, they become darker (lower lightness, L) and increase their hue angle (lower red color) as well as the ratio of absorbance at 420 nm to that at 520 nm. Main polyphenolics identified in the samples were tannic acid, oenin, and gallic acid. The antiradical efficiency of the samples increased during aging, which could be related to an increase in the tannic acid concentration shown by the following correlationship: EC(50) = 1/(0.18 + 0.0011[tannic acid](mg/L)) with a correlation coefficient of 0.744.     

Effect of addition of commercial grape seed tannins on phenolic composition, chromatic characteristics, and antioxidant activity of red wine

The effect of addition of grape seed tannins on the phenolic composition, chromatic characteristics, and antioxidant activity of red wine was studied. Two highly pure commercial grape seed tannins (GSE100 and GSE300) were selected, and their phenolic compositions were determined. Two types of red wines were made with Castela?o/Tinta Miu?da (3/2, w/w) grapevine varieties by fermentation on skin using two different maceration times, which correspond to the wines rich and poor in polyphenols, respectively. Each of these wines was used for experimentation with the addition of GSE100 and GSE300 before and immediately after alcoholic fermentation. Phenolic composition, chromatic characteristics, and antioxidant activity of the finished red wines were analyzed by HPLC-DAD, CIElab 76 convention, and DPPH radical test, respectively. The results showed that the addition of grape seed tannins had obvious effects of increasing color intensity and antioxidant activity only in the wines poor in polyphenols. Although GSE300 contained much higher amounts of di- and trimer procyanidins and a lower amount of polymeric proanthocyanidins, it provided effects of increasing the color intensity and antioxidant activity of the wines poor in polyphenols similar to those of GSE100. Furthermore, GSE100 released more gallic acid to wines than GSE300, although no gallic acid was detected in GSE100. Tannins added after alcoholic fermentation had a better effect on phenolic composition of red wine than tannins added before alcoholic fermentation.     

Rapid method for the discrimination of red wine cultivars based on mid-infrared spectroscopy of phenolic wine extracts

Mid-infrared spectroscopy and UV-vis spectroscopy combined with multivariate data analysis have been applied for the discrimination of Austrian red wines, including the cultivars Cabernet Sauvignon, Merlot, Pinot Noir, Blaufr?nkisch (Lemberger), St. Laurent, and Zweigelt. Both authentic wines and their phenolic extracts were investigated by attenuated total reflectance (ATR)-mid-infrared spectroscopy. Phenolic extracts were also investigated by UV-vis spectroscopy. The wine extracts were obtained by solid-phase extraction with C-18 columns and elution by methanol containing 0.01% hydrochloric acid. Hierarchical cluster analysis was performed with mid-infrared spectra of both wines and extracts, as well as with UV-vis spectra of the phenolic extracts. Data processing involved vector normalization and derivation of the spectra. Due to varying concentrations of main components including sugar and organic acids, satisfactory classification of untreated wines was not achieved. However, when using mid-infrared spectra of the phenolic extracts, almost complete discrimination of all cultivars investigated was achieved. The use of UV-vis spectroscopy for cultivar discrimination was found to be limited to the authentication of the Burgundy species Pinot Noir. In addition, soft independent modeling of class analogy was applied to the mid-infrared spectra of the extracts. It was possible to establish class models for five different wine cultivars and to classify test samples correctly.     

Contribution of proanthocyanidins to the peroxy radical scavenging capacity of some Italian red wines

Highly reactive radicals, ROO(*), were generated from 2, 2'-azobis[2-(2-imidazolin-2-yl)propane] and linoleic acid. The ROO(*) scavenging capacity of some Italian red wines was evaluated following the changes in oxygen consumption. Under the experimental conditions the time course of oxygen consumption shows two typical behaviors: trolox-like (class I) and gallic acid-like (class II). Usually the time course of wine was similar to that of gallic acid. The rate of oxygen consumption was found to decrease exponentially with the amount of wine or gallic acid added to the test solution. On this basis the capacity of red wines to scavenge peroxy radicals was expressed as content of gallic acid (S(GA)). The S(GA) values were found to be correlated to the amount of total proanthocyanidins and total polyphenols of some Italian red wines (p < 0.01). The proanthocyanidins extracted from seeds were shown to make a major contribution to the peroxy radical scavenging capacity of red wines, whereas, interestingly, the chemical class of the low molecular weight tannins reactive to vanillin did not correlate with the S(GA) values.     

Multivariate analysis of antioxidant power and polyphenolic composition in red wines

It has been demonstrated that the dietary intake of compounds having antioxidant activity is very important, and various chemical, biological, and electrochemical methods have been proposed to evaluate the antioxidant power of compounds such as polyphenols. Wine, although nonessential, has a high polyphenol content up to 2-3 g/L in red wines obtained by traditional maceration. The polyphenol content of wines is usually evaluated by the Folin reagent, which provides an appropriate response to the requirements of wine manufacturers. Because the presence of individual polyphenols may be evaluated by HPLC, more or less selective methods toward the various chemical classes of polyphenols have been developed. An HPLC method set up recently was applied to evaluate how individual polyphenols contributed to the overall antioxidant power (AOP) of 60 Italian red wines, trying to identify the effect that individual compounds may have on the total AOP. Application of the multivariate analysis allowed us to detect some determining compounds such as gallic acid and some flavonols. On the basis of the correlation between two traditional chemical methods, namely the total polyphenol determination by the Folin reagent and the flavanol determination by the condensation reaction with p-(dimethylamino)-cinnamaldehyde, it was shown that the use of these two merely chemical methods is well correlated (r = 0.83 and 0.87) to an AOP evaluation of red wines.     

Detection of lipid peroxidation catalyzed by chelated iron and measurement of antioxidant activity in wine by a chemiluminescence analyzer.

We measured directly the reactive oxygen generated from a peroxide-free reaction system when a ferrous complex with nitrilotriacetic acid was oxidized to the ferric complex. Further, it was observed by a measurement of chemiluminescence that peroxidation of a lipid substrate added in the system is initiated by the Fe(3+)-type of reactive oxygen generated. Antioxidant activity can be estimated by contrasting the reaction rates of lipid peroxidation between the systems with and without a putative antioxidant sample. By this method, the antioxidant activity, expressed as catechin equivalent, of red wines for linoleic acid peroxidation was shown to be higher than those of rosé and white wines (189-311, 84, and 37 microM for red, rosé, and white wines, respectively) because of a higher concentration of polyphenols such as flavanol and anthocyanin in red wines. The chemiluminescence measurement would be a promising method for evaluating the antioxidant potential because of its highly specific and sensitive detection of the hydroperoxide and for monitoring in situ peroxidation reaction.     

White wine with red wine-like properties: increased extraction of grape skin polyphenols improves the antioxidant capacity of the derived white wine.

Lower antioxidant activity in white wines in comparison to red wines lies in the low grape-skin-derived polyphenol content. This paper reports the analysis of the antioxidant capacities of white wine samples obtained along two different processing procedures directed to enrich the wine with polyphenols. White wine samples derived from whole squeezed grapes stored for increasing periods of time (up to 18 h) contained increasing concentrations of polyphenols (from 0.35 to 0.55 mmol/L) and, in parallel, exhibited increased capacity to scavenge free radicals and to inhibit copper ion-induced low-density lipoprotein (LDL) oxidation. However, addition of increasing concentrations of alcohol (up to 18%) to the whole squeezed grapes remarkably augmented the extraction of grape skin polyphenols into the wine up to 1.25 mmol/L, resulting in an increased capacity of the wine to scavenge free radicals and to inhibit LDL oxidation, to an extent similar to that of red wine. The extent of LDL oxidation inhibition was directly related to the wine polyphenolic content (r = 0.986). It is concluded that processing white wine by imposing a short period of grape skin contact in the presence of alcohol leads to extraction of grape skin polyphenols and produces polyphenol-rich white wine with antioxidant characteristics similar to those of red wine.     

Antioxidant profile of red wines evaluated by total antioxidant capacity, scavenger activity, and biomarkers of oxidative stress methodologies

The study of the antioxidant capacity of foodstuffs requires the use of diverse determination methods to gain a wider picture of their multiple effects. The aim of this work was to evaluate the "antioxidant profile" of red wines applying TAC (total antioxidant capacity) methods: 2,2'-azinobis(3-ethyl-benzthiazoline-6-sulfonic acid) (ABTS), 2,2-diphenyl-1-picrylhydrazyl, N,N-dimethyl-p-phenylenediamine dihydrochloride, oxygen radical absorbance capacity, ferric reducing/antioxidant power, hydroxyl and superoxide radical scavenger activities, and biomarkers of oxidative stress methods such as lipid peroxidation inhibition and inhibition of damage to DNA. Furthermore, levels of total polyphenols (TPP) of wines were also evaluated. Three bottles of 107 different Spanish red wines (total samples 321), made from different grape varieties, aging processes, and vintages, were analyzed. The validation of TAC methods, the first step in this work, provided a good linearity, proportionality, and low detection limits. Among these methods, the ABTS was the most satisfactory for its rapidity, cost, and precision. All wines showed an important capacity to scavenge hydroxyl radicals and were capable of blocking superoxide radicals but with 10 times lower intensity. Wines also showed important protective action on biomarkers of oxidative stress; they were much more active to inhibit lipid peroxidation than DNA oxidation. Few statistically significant correlations among levels of TPP and antioxidant properties of wines were detected. Furthermore, values of these correlations were very low.     

Vitisin A content in Chilean wines from Vitis vinifera Cv. Cabernet Sauvignon and contribution to the color of aged red wines

Vitisin A was prepared from malvidin 3-glucoside and pyruvic acid in model wine medium, isolated by countercurrent chromatography, and purified by preparative high-performance liquid chromatography (HPLC). The synthesized compound was used as a reference standard to quantify vitisin A in Chilean wines from Vitis vinifera cv. Cabernet Sauvignon, including a vertical row of wines from the same vineyard over 16 years. Maximum vitisin A content was reached within the first year of storage. Importantly, up to half of the initial amount of vitisin A in young wines was still present in 15 year old wines. Although vitisin A was found to be much more stable as compared to other monomeric C-4 underivatized anthocyanins, it also slowly degrades after reaching its peak concentration. The "color activity concept" was applied to vitisin A, malvidin 3-glucoside, malvidin 3-(6' '-acetylglucoside), and polymeric pigments isolated by countercurrent chromatography in order to estimate their contribution toward the overall color expression of wines. It was found that vitisin A is only a minor contributor to the visually perceived color of aged red wines (color contribution approximately 5%). The major contributor is the polymeric fraction (color contribution approximately 70-90%).     

Effect of principal polyphenolic components in relation to antioxidant characteristics of aged red wines.

Aged red wines possess significantly different polyphenolic composition compared with young ones, mainly due not only to formation of polymeric compounds but also because of oxidation, hydrolysis, and other transformations that may occur in native grape phenolics during aging. Representative Greek, single-variety, aged red wines were examined for total phenol, total flavanol, and total anthocyanin content using spectrophotometry, and attempts were made to establish correlations with the antiradical, reducing, and hydroxyl free radical scavenging activity. In addition, HPLC analyses were carried out, to ascertain whether individual polyphenols are actually responsible for the antioxidant effects of aged red wines. It was found that total flavanols are the class of polyphenols that account for hydroxyl free radical scavenging efficacy and to a lesser extent for antiradical and reducing ability, whereas there was a less significant link between the antioxidant properties and the total phenolics and only a weak relationship to total anthocyanin content. The correlation of the antioxidant properties with the principal polyphenols showed that individual compounds are weakly associated with all the antioxidant parameters, suggesting that the expression of antioxidant activity in aged red wines is rather a consequence of synergism between various phenolics, and it is not simply attributed to specific constituents.     

Formation of hydroxyphenyl-pyranoanthocyanins in Grenache wines: precursor levels and evolution during aging

Grenache red wines were produced following three different winemaking techniques, that is, small-scale standard experimental wines and industrial-scale wines by both double-mash fermentation and fermentation in Ganimede vats. Wines were analyzed for their color properties, as well as the anthocyanin, flavonol, hydroxycinnamic acid, and pyranoanthocyanin profiles following alcoholic and malolactic fermentation. The evolution of pyranoanthocyanins and their corresponding precursors in the experimental wines was monitored at 6 and 10 months of aging. Wines produced by double-mash fermentation exhibited superior color properties compared to Ganimede wines and the experimental red wines, due to better extraction of flavonols and anthocyanins as well as a lower degree of polymerization. Pyranoanthocyanin formation varied within the different classes of pigments. Vitisins A and B were formed only during alcoholic fermentation. Pinotin A (i.e., the reaction product from malvidin 3-glucoside and caffeic acid) formation took place only during the aging process, whereas formation of hydroxyphenyl-pyranoanthocyanins derived from p-coumaric and ferulic acid followed two different pathways, that is, an enzymatically assisted production during fermentation and a pure chemical formation during aging.     

Pulsed electric field-assisted vinification of aglianico and piedirosso grapes

Pulsed electric field (PEF) treatments were applied to increase the polyphenolic content of fresh red wines made from Aglianico and Piedirosso grapes. Prior to the fermentation/maceration step, the grape skins were treated at different PEF intensities (field strengths from 0.5 to 1.5 kV/cm and energy inputs from 1 to 50 kJ/kg), with their permeabilization being characterized by electrical impedance measurements. Furthermore, the release kinetics of the total polyphenols and anthocyanins were characterized during the maceration stage by spectroscopic and Folin-Ciocalteu colorimetric methods, respectively. Finally, the fresh wine, obtained after pressing, was characterized for total acidity, pH, reducing sugar, color intensity, total polyphenols, anthocyanins content, antioxidant activity, and volatile compound composition. PEF treatment on Aglianico grapes induced a significantly higher release of polyphenols (+20%) and anthocyanins (+75%), thus improving the color intensity (+20%) and the antioxidant activity of the wine (+20%) while preserving the other organoleptic characteristics. In contrast, there was only a minor impact on the polyphenolic release kinetics of Piedirosso grapes, despite the significant degree of cell membrane permeabilization.     

Champagne wine polyphenols protect primary cortical neurons against peroxynitrite-induced injury

White wines are generally low in polyphenol content as compared to red wines. However, Champagne wines have been shown to contain relatively high amounts of phenolic acids that may exert protective cellular actions in vivo. In this study, we have investigated the potential neuroprotective effects of Champagne wine extracts, and individual phenolics present in these extracts, against peroxynitrite-induced injury. Organic and aqueous Champagne wine extracts exhibited potent neuroprotective activity against peroxynitrite-induced injury at low concentrations (0.1 microg/mL). This protection appeared to be in part due to the cellular actions of individual components found in the organic extracts, notably tyrosol, caffeic acid, and gallic acid. These phenolics were observed to exert potent neuroprotection at concentrations between 0.1 and 10 microM. Together, these data suggest that polyphenols present in Champagne wine may induce a neuroprotective effect against oxidative neuronal injury.     

Effect of flash release treatment on phenolic extraction and wine composition

The flash release (FR) process, consisting of rapidly heating the grapes and then applying strong vacuum, has been proposed to increase the polyphenol content of red wines. Its impact on polyphenol extraction kinetics and on the polyphenol composition of red juice and wines was studied over two seasons on different grape varieties (Grenache, Mourvedre, Carignan). The FR process allows fast extraction of all phenolic compounds (hydroxycinnamic acids, flavonols, anthocyanins, catechins, proanthocyanidins) and can be used to produce polyphenol-enriched grape juices. However, the concentration of all polyphenols dramatically decreased throughout fermentation when pressing was achieved immediately after FR. The FR wines made with pomace maceration were also enriched in polyphenols compared to the corresponding control wines. Increasing the duration of high-temperature exposure in the FR treatment further increased extraction of phenolic compounds but also accelerated their conversion to derived species. The tannin-to-anthocyanin ratio was particularly low in the wine fermented in the liquid phase, higher after FR than in the control, and even higher after longer heating. FR resulted in an increased tannin-to-anthocyanin ratio and an increased conversion of anthocyanins to tannin-anthocyanin adducts showing the same color properties as anthocyanins. The tannin-to-anthocyanin ratio was particularly low in the wine fermented in the liquid phase that also contained larger amounts of orange sulfite bleaching-resistant pigments.     

用多酚类指标表征干红葡萄酒味感质量的模型构建

采用葡萄酒多酚系列指标,构建味感质量预测模型,实现干红葡萄酒涩感和余味的客观量化。试验以宁夏和新疆的50款赤霞珠干红葡萄酒为原料,利用常规方法检测样品总酸、挥发酸和pH值,采用自由基清除法测定抗氧化活性,通过紫外-可见分光光度计法分析总酚、花色苷、黄烷醇、黄酮醇、酒石酸酯含量,并以感官品评法量化干红葡萄酒的涩感和余味。相关性分析结果显示,总酚、花色苷、黄烷醇、黄酮醇等对涩感和余味的影响有显著差异（P<0.05）,酒石酸酯对余味的影响较小,而总酸和pH值对供试干红葡萄酒的涩感没有显著影响（P>0.05）。感官品评量化结果显示,宁夏和新疆产区酒样的涩感得分为6.18和5.70,余味得分为5.37和4.85,供试酒样的涩感与余味质量良好,且存在相似的变化趋势。以多酚系列指标表征的涩感质量偏最小二乘回归（partial least squares regression,PLSR）模型的决定系数（r-square,R²）为0.83,余味模型的R²为0.78,结果表明,总酚、黄烷醇、挥发酸、DPPH等指标对葡萄酒的涩感和余味贡献较大,黄酮醇和酒石酸酯主要影响葡萄酒的涩感,而花色苷、总酸和pH值则主要影响葡萄酒余味。研究得出,基于紫外-可见分光光度计法设计的多酚系列指标可以较好地解析干红葡萄酒的味感质量,降低检测成本,具备表征和预测干红葡萄酒味感质量的能力。     

Antioxidant activity of South African red and white cultivar wines: free radical scavenging

The free radical scavenging activity of South African red (n = 46) and white (n = 40) cultivar wines was determined using 2,2'-azinobis(3-ethylbenzothialozinesulfonic acid) radical cations (ABTS(.+)) and 2,2-diphenyl-1-picrylhydrazyl radicals (DPPH.). The total antioxidant activities (TAA) of red and white wines using ABTS(.+) were 14.916 and 0.939 mM Trolox, respectively, at corresponding total phenol (TP) contents of 2339.0 and 273.8 mg of gallic acid equiv/L. Ruby Cabernet wines had the lowest TAA(ABTS) (13.177 mM Trolox) of the red wines, whereas the TAA(ABTS) values of Chardonnay and Chenin blanc wines were the highest (1.060 mM Trolox) and lowest (0.800 mM Trolox) of the white wines. The TAA(DPPH) values were of the same magnitude as the TAA(ABTS) values, and similar trends were observed. TAA correlated (P < 0.001) with total phenol content of red (r = 0.935) and white (r = 0.907) wines, as well as flavanol content of red wines (r = 0.866) and tartaric acid ester content of white wines (r = 0.767). Canonical discriminant analysis using phenolic composition and antioxidant activity was applied to differentiate between red and white cultivar wines.     

Content of the flavonols myricetin, quercetin, and kaempferol in finnish berry wines

The amounts of myricetin, quercetin, and kaempferol were analyzed in 16 red and 2 white berry and grape wines after acid hydrolysis using an RP-HPLC method with diode array detection. The red berry wines analyzed were made mainly from black currant, crowberry, and bog whortleberry, i.e., berries rich in flavonols. The red grape wines were made mainly from Cabernet Sauvignon or Merlot grapes in several countries. The white wines studied were gooseberry and white currant wines and Chardonnay and Riesling wines. The amount of myricetin ranged from 3.8 to 22.6 mg L(-1) in red berry wines and from 0 to 14.6 mg L(-1) in red grape wines. The amount of quercetin was from 2.2 to 24.3 mg L(-1) red berry wines and from <1.2 to 19.4 mg L(-1) in red grape wines. Low levels of kaempferol were found in all red berry wines and in 9 red grape wines. The total concentration of these flavonols was from 6 to 46 mg L(-1) (mean 20 mg L(-1)) in red berry wines and from 4 to 31 mg L(-1) (mean 15 mg L(-1)) in red grape wines. Small amounts of quercetin were found in white currant and gooseberry wines, whereas no flavonols were detected in white grape wines. These results demonstrate that the contents of flavonols in red     

Characterization of wines by nuclear magnetic resonance: a work study on wines from the Basilicata region in Italy

We explored the possibility of differentiating Italian wines produced in different regions by means of nuclear magnetic resonance (NMR) techniques. Ten commercial red Aglianico wines were selected from different areas of the Basilicata region in the south of Italy. Some important components of these wines were identified by the assignments of their (1)H and (13)C resonances using one- and two-dimensional homonuclear and heteronuclear NMR experiments. These data were compared with those obtained from 10 Aglianico wines produced in Campania, another southern Italian region. Differences were found among the wines according to their geographical origin and vintage. A fine discrimination of Aglianico wines from Basilicata and Campania was obtained, suggesting that the selected NMR parameters may be a valuable tool for wine authenticity control.     

Antioxidant activity of selected Spanish wines in corn oil emulsions

Wines contain phenolic compounds that may be useful for preventing lipid oxidation as dietary antioxidants. This study was aimed at evaluating the antioxidant activity in corn oil emulsions of seventeen selected Spanish wines and two California wines. The inhibition of hydroperoxide formation at 10 microM gallic acid equivalents (GAE) varied from 8.4% to 40.2% with the red wines, from 20.9% to 45.8% with the rosé wines, and from 6.5% to 47.0% with the white wines. The inhibition of hydroperoxide formation at 20 microM GAE varied from 11.9% to 34.1% with the red wines, from 0.1% to 34. 5% with the rosé wines, and from 3.3% to 37.2% with the white wines. The inhibition of hexanal formation at 10 microM GAE varied from 23. 6% to 64.4% with the red wines, from 42.7% to 68.5% with the rosé wines, and from 28.4% to 68.8% with the white wines. The inhibition of hexanal formation at 20 microM GAE varied from 33.0% to 46.3% with the red wines, from 11.3% to 66.5% with the rosé wines, and from -16.7% to +21.0% with the white wines. The antioxidant effect decreased with increasing concentration. This antioxidant activity was related to the five main groups of phenolic compounds identified in wines by HPLC. The relative antioxidant activity correlated positively with the total phenol content of wines (by the Folin-Ciocalteu method and by HPLC), benzoic acids, anthocyanins, flavan-3-ols, and flavonols, for the inhibition of hydroperoxides and hexanal at 10 and 20 microM GAE.     

Polyphenol content and total antioxidant activity of vini novelli (young red wines)

Eight commercial Italian vini novelli (red wines prepared by carbonic maceration and supposed to be consumed within three months from their wine-making) were evaluated for their total antioxidant activity. The wines had an average total phenol content (1605.4 +/- 337.4 mg/L gallic acid equivalents) lower than that of wines prepared by traditional maceration and consumable after aging (2057. 3 +/- 524.0 mg/L gallic acid equivalents). The average flavanol content (424.7 +/- 121.3 mg/L catechin equivalents) and the total antioxidant activity (16.8 +/- 3.8 mmol/L Trolox equivalents) of vini novelli were higher than the corresponding values (382.7 +/- 174.5 mg/L catechin equivalents and 12.3 +/- 3.3 mmol/L Trolox equivalents) found for aged wines. Three couples of experimental wines were prepared from the same grapes by traditional or carbonic maceration. These wines showed a different phenolic pattern, anthocyanins being more abundant in vini novelli. However, the average total antioxidant activities of the wines were similar, suggesting that aging (and not the wine-making technique) is the main factor influencing the antioxidant activity of red wines.