Phenolic content and antioxidant potential of macerated white wines

Influence of maceration on phenolic content and antiradical activity was analyzed in fourteen white wines from Italian region Friuli–Venezia Giulia and Croatian region Istria. Total phenols were determined by Folin–Ciocalteu reagent, twelve individual polyphenols were determined by high-performance liquid chromatography and antiradical activity was determined using 2,2-diphenyl-1-picrylhydrazyl free radical (DPPH^·). The experiments showed that the maceration process increases significantly the amount of total phenols and inhibition of DPPH^·. Furthermore, a high synergistic activity of individual phenols was observed. The strongest inhibition of DPPH^· and the highest amount of total phenols were obtained for 800 Bianco, a blending macerated wine made from 3 white wine varieties. Our study shows that the antioxidant potential of white grape phenols can be preserved during wine processing. The maceration step allows the extraction of phenolic compounds from grape skins, seeds and stalks, resulting in phenol-rich white wine with strong antioxidant properties.     

Antioxidant and antimicrobial potentials of Serbian red wines produced from international Vitis vinifera grape varieties

BACKGROUND: Antioxidant and antimicrobial potentials of Serbian red wines produced from different international Vitis vinifera grape varieties and their correlation with contents of phenolic compounds were studied by spectrophotometric and chromatographic methods. The antioxidant activity of red wines was estimated through their ability to scavenge 2,2′‐diphenyl‐1‐picrylhydrazyl free radical (DPPH^?). The red wines, gallic acid, (+)‐catechin and quercetin were screened in vitro for antimicrobial activity against Gram‐positive and Gram‐negative strains using microdilution and disc diffusion techniques. RESULTS: Excellent correlations between the contents of quercetin‐3‐glucoside (R² = 0.9463) and quercetin (R² = 0.9337) and DPPH^?‐scavenging ability of the red wines were found. Serbian red wines exhibited significant activity against Staphylococcus aureus, Listeria inocua, Micrococcus flavus, Sarcina lutea, Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa, Salmonella enteritidis and Shigella sonnei strains, which was in correlation with their phenolic composition and antioxidant activity. The compounds gallic acid, quercetin and (+)‐catechin showed high activity against B. subtilis, S. aureus, S. lutea and M. flavus Gram‐positive and S. enteritidis and P. aeruginosa Gram‐negative strains. CONCLUSION: The results show that quercetin‐3‐glucoside and quercetin concentrations can be used as markers for the determination of antioxidant and antimicrobial potentials of red wines. Copyright © 2012 Society of Chemical Industry     

Free radical scavenging capacity of selected red,rosé and white wines

The free radical scavenging capacity of selected red, rosé and white Spanish wines from different grape varieties was determined by the 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH^·) method using a new methodology developed at our laboratory. The amount of sample necessary to decrease by 50% the initial DPPH^· concentration (EC₅₀), the time needed to reach the steady state at EC₅₀ concentration (T_EC50) and the antiradical efficiency (AE = 1/EC₅₀T_EC50) were determined in the wine samples. Some differences between rosé wines made with Garnacha and Tempranillo grape varieties were observed in the UV‐vis spectra and in the free radical scavenging parameters, those from Garnacha variety having the highest antioxidant activity. The antiradical efficiency of the wines followed a decreasing order: red wines (22.44 × 10⁻⁶) > rosé wines (4.90 × 10⁻⁶) > white wines (1.88 × 10⁻⁶). There was a correlation between antiradical efficiency and total polyphenol (TP): AE = −3.33135 + 0.0180535TP; the correlation coefficient was r = 0.951454. © 1999 Society of Chemical Industry     

Indian Grape Wines: A Potential Source of Phenols,Polyphenols, and Antioxidants

Indian grape wines are analyzed for total phenolic content and antioxidant activity along with other parameters, such as pH, alcohol content, and reducing sugars. Concentration of polyphenols, like tannic acid, catechol, vanillin, caeffic acid, ferullic acid, and resveratrol, was quantified using reverse phase-high performance liquid chromatography and ultra high performance liquid chromatography. The red wines showed the highest concentration of phenolic content (6.5 ± 0.1 mg/ml) and antioxidant activity (84.60 ± 1%) as compared to white and port wines, while red wine R2 showed the highest radical scavenging activity among red wines and R4 showed the lowest total phenolic content. The white wine W3 showed less total phenolic content and antioxidant activity. Further, a positive correlation between phenolic content and antioxidant activity was observed.     

Phenolic profile and free radical‐scavenging activity of Cabernet Sauvignon wines of different geographical origins from the Balkan region

BACKGROUND: The phenolic profile, determined by the relative proportions of different phenolic compounds, is characteristic for each grape variety and its corresponding wine. The aim of this study was to determine the phenolic and hydroxycinnamate acid, flavan‐3‐ol and flavonol contents and free radical‐scavenging activity of single‐cultivar (Cabernet Sauvignon) wines from selected Balkan vineyard regions by spectrophotometric methods and high‐performance liquid chromatography with photodiode array and fluorescence detection. RESULTS: The contents of phenolic compounds varied depending on the agroclimatic factors and oenological practices of the vineyard region. The antioxidant activity of wine samples was estimated by their ability to scavenge the stable 2,2′‐diphenyl‐1‐picrylhydrazyl free radical (DPPH). All wines showed high DPPH‐scavenging activity (70.03–83.53%, mean 73.76%). Significant correlations between catechin (R² = 0.8504) and quercetin (R² = 0.8488) concentrations and DPPH‐scavenging ability of the wines were found. CONCLUSION: The concentrations of the main components catechin and quercetin can be used as biochemical markers for the authentication of red grape cultivars and their corresponding single‐cultivar wines. Copyright © 2010 Society of Chemical Industry     

Optimisation of the Amido Black assay for determination of the protein content of grape juices and wines

While the heat/chill stability of white wines cannot be predicted from the total protein concentration, this information is useful in assessing the effectiveness of fining treatments. We have adapted the Amido Black assay for use in grape juice and wine. The response of bovine serum albumin (BSA) was similar in water, model wine and model juice. The linear range of the assay (<100 mg l^?1) extends beyond protein concentrations typically found in grape juices and wines. The limit of quantification was 11.1 mg l^?1 for BSA in model wine and 7.6 mg l^?1 in model juice, while the limit of detection was found to be less than 3 mg l^?1 in either solution. In contrast to other methods of protein determination, this assay is not affected by common wine phenolic and pectic compounds or by glutathione. The mean response of BSA was similar in model juice and red and white grape juices. The mean response of BSA in red wine was lower than in white wine and model wine (p < 0.001), and there was considerable variation in response among wines. Protein concentrations determined using this method were reproducible (CV < 10%). This optimised assay can be used to monitor protein levels in grape juices and wines. © 2001 Society of Chemical Industry     

外源脱落酸处理对葡萄果实及葡萄酒中抗氧化成分的影响

以天津蓟州区栽培的"美乐"和"赤霞珠"葡萄为试验品种,分别在其始熟期的初、中和末期3个阶段利用外源脱落酸(200 mg/L)处理果实,采用分光光度法测定葡萄和葡萄酒中酚类总含量和抗氧化活性,利用液质联用技术分析花色苷的含量和组成.研究结果表明:始熟期的外源脱落酸处理对成熟果实的质量、可溶性固形物、可滴定酸和pH值,以及葡萄籽的酚类含量和抗氧化活性没有显著影响,但对葡萄皮和葡萄酒的酚类物质含量和活性具有显著影响.在始熟期中期(30％ ～50％果实转色)以前,对果实喷施外源脱落酸可以显著提高葡萄皮和葡萄酒的酚类总含量、花色苷总含量和抗氧化活性.始熟期外源脱落酸处理使"美乐"和"赤霞珠"果实的酚类总含量分别提高了14％ ～39％和73％ ～172％,花色苷总含量和抗氧化活性分别提高了18％ ～143％和88％ ～178％;外源脱落酸处理使葡萄酒的3个指标(酚类总含量、花色苷总含量和抗氧化活性)分别提高了17％ ～69％、18％ ～36％和21％ ～46％,而这些影响可以有效改善葡萄酒的感官品质和营养价值.外源脱落酸处理时期的精准控制可以提高酿酒葡萄及葡萄酒中酚类物质含量及抗氧化作用,进而提高葡萄酒品质和营养价值.     

The Study of Phenolic Compounds as Natural Antioxidants in Wine

Plant phenolics present in fruit and vegetables, and that are particularly rich in red wine, have received considerable attention because of their potential antioxidant activity. Human consumption of antioxidants has many alleged health benefits, including protection against cardiovascular diseases, and, most recently, cancer. Red wines contain a variety of polyphenolic antioxidants. Five samples of commercial red wines from Spain and four phenolic compounds of red wine: gallic acid, trans-resveratrol, quercetin and rutin, have been studied. The total phenolics content and the total antioxidant activity (TAA) of wines was determined. The total phenolic content, determined according to the Folin-Ciocalteu method, varied from 1800 to 2300?mg/L, expressed as gallic acid equivalents (GAE). The antioxidative effects of wine phenolics were determined using a system based on the inhibition by antioxidants of the absorbance of the radical cation. The relationship between antioxidant activity of phenolic compounds, as hydrogen donating free radical scavengers, and their chemical structures was studied. Furthermore, the total antioxidant activity of the wines investigated was well correlated with phenol content. Thus, the results confirm that red wine polyphenols are, in vitro, significant antioxidants.     

Free radical scavenging and antibacterial activities of southern Serbian red wines

Free radical scavenging and antibacterial activities were determined for several red wines from different grape varieties from the southern Serbia wine region. The amount of polyphenols and anthocyanins in selected wines was investigated and the potential antibacterial activity of the wines against pathogenic strains of Staphylococcus aureus and Escherichia coli was also determined. The free radical scavenging and antibacterial activity of the wines was correlated with polyphenolic and anthocyanin content. The significant differences in the antioxidant and antibacterial activities between the wines from grape cultivars (Cabernet Sauvingon and Pinot Noir) and the indigenous varieties (Vranac and Prokupac) were not confirmed. The hypothesis of a protective effect of red wine is supported by our results that show that the red wines with higher amounts of polyphenols and anthocyanins had higher antioxidant and antibacterial properties.     

Colour and phenolic compounds in sweet red wines from Merlot and Tempranillo grapes chamber-dried under controlled conditions

Chamber drying under controlled temperature and humidity conditions of the red grape varieties Merlot and Tempranillo grown in Andalusia (Spain), and the fortification and maceration of the musts in the presence of skin from both types of grapes, to obtain sweet red wines, has been studied. Changes in colour and in monomeric and polymeric phenols during the vinification process were examined. Chamber drying increased the sugar content to about 31.4 °Brix within 48 h in Merlot grapes and 72 h in Tempranillo grapes. This drying process also causes skin rupture, facilitating the access of phenolic compounds to the pulp. The resulting musts exhibited slight browning and increased red hues, due to a high concentration of anthocyanins; maceration in the presence of grape skins for 24 h provided the best results. The end-product contained highly acceptable tannin, colour and phenolic compounds for marketing as a high quality sweet red wine, in comparison with other commercial sweet red wines.     

干红树葡萄酒与干红葡萄酒功能成分及其抗氧化活性对比

分别测定干红树葡萄酒与2种干红葡萄酒(法国干红葡萄酒、国产干红葡萄酒)中的总多酚、总黄酮、白藜芦醇、单宁、酚酸、维生素、花青素及矿物质等功能性成分,采用DPPH法、ABTS法、邻二氮菲法和FRAP法分析3种酒的抗氧化能力,并对其差异进行分析比较。结果表明:干红树葡萄酒与2种干红葡萄酒功能成分种类及含量各有特点和优势。干红树葡萄酒中没食子酸、VA、VC、Mn与Zn含量均极显著高于国产干红葡萄酒和法国干红葡萄酒;法国干红葡萄酒中总多酚、总黄酮、白藜芦醇、儿茶素、咖啡酸、香豆酸、阿魏酸、矢车菊色素及Fe含量均极显著高于国产干红葡萄酒和干红树葡萄酒;国产干红葡萄酒中单宁、VD、飞燕草色素、矮牵牛色素、天竺葵色素、芍药色素、锦葵色素、Ca和Mg含量均极显著高于法国干红葡萄酒和干红树葡萄酒。3种酒抗氧化活性亦各具特色,树葡萄红酒对DPPH·的清除能力最强,法国干红葡萄酒对·OH的清除能力最强,国产干红葡萄酒对ABTS~+的清除能力及对铁离子的还原能力最强。     

Pre-bottling use of dehydrated waste grape skins to improve colour,phenolic and aroma composition of red wines

Different dehydrated waste grape skins from the juice industry were added into aged and young red wines as an innovative way of compensating for colour loss before bottling. After addition of grape skins, colour intensity of wines increased a mean 11% and a maximum of 31% with predominance of the red component. Total polyphenols mean increase was 10% with a maximum value of 20%. Analysis of low molecular weight phenolic compounds by HPLC–DAD showed a significant (p < 0.05) content increase of the bioactive compounds gallic acid, (+)-catechin, (−)-epicatechin, and (E)-resveratrol. Anthocyanins content also increased at an average of 50 mg/l. The volatile profile of wines analysed by SBSE–GC–MS was only moderately influenced by the treatments. Mixtures of dehydrated waste grape skins were useful to improve the colour and polyphenol profile of red wines, considering them a useful tool for correcting colour loss before bottling.     

Effect of high pressure treatments on the physicochemical properties of a sulphur dioxide-free red wine

The application of high hydrostatic pressure (HHP) in winemaking for substitution of the use of sulphur dioxide is still at a very early stage of development, since knowledge about the effect on physicochemical and sensorial characteristics of the wine during storage is very scarce. In this work, the evolution of colour, antioxidant activity and total phenolic compounds of SO₂-free red wines treated by HHP and aged in bottles was followed for 12 months. The pressurised wines were compared with wine samples prepared with addition of 40 ppm of SO₂ and without any of these two treatments. After 12 months, the pressurised wines presented higher values of CIELab parameters (a^∗, b^∗, and L^∗) and a lower monomeric anthocyanin content (45–61%) when compared to the unpressurised ones. The pressurised wines showed also a better global sensorial assessment, with the pressure treatments imparting aged-like characteristics to the wines. The wine deposits of pressurised wines had higher total phenolic content, namely proanthocyanidins (3- to 10-fold). The results demonstrate that HHP can influence long term red wine physicochemical and sensorial characteristics, hypothesised to be due to an increase of condensation reactions of phenolic compounds, forming compounds with higher degree of polymerisation that became insoluble in wine along storage.     

Antioxidant activity and phenolic content of wine vinegars produced by two different techniques

BACKGROUND: The presence of phenolics in fruit, red wine and vinegar has positive health effects due to their significant antioxidant activity. The aim of the study was to determine the effects of two different vinegar production methods on antioxidant activity and phenolic level of vinegars derived from Ulugbey Karasi grapes. Traditional surface and industrial submerge methods were used to make vinegar. Samples were taken from fresh red grape juice, maceration, wine, traditional vinegar and industrial vinegar. RESULTS: Total phenolic content of traditional and industrial vinegar samples were 2690 mg L^?1 and 2461 mg L^?1 GAE, respectively. ORAC values of traditional and industrial vinegar samples were 10.50 µmol mL^?1and 8.84 µmol mL^?1 TE, respectively. Antioxidant activity values of traditional and industrial vinegars were 13.50 mmol L^?1 and 10.37 mmol L^?1 TEAC, respectively. Gallic acid, catechin, epicatechin, chlorogenic acid, caffeic acid, syringic acid, p‐coumaric acid and ferulic acid were detected in grape juice, wine and vinegar samples. The content of catechin in industrial vinegar (27.50 mg L^?1) was significantly higher than that of in traditional vinegar (13.76 mg L^?1) (P < 0.05). Traditional vinegar had higher amounts of chlorogenic and syringic acids than the industrial vinegar (P > 0.05). CONCLUSION: Results of this study showed that different production methods affected the functional constituents of wine vinegars. Copyright © 2010 Society of Chemical Industry     

Effects of exogenous abscisic acid on phenolic characteristics of red <Emphasis Type="Italic">Vitis vinifera</Emphasis> grapes and wines

The effects of exogenous abscisic acid (ABA) on phenolic characteristics of grapes and wines were investigated in Vitis vinifera cvs. Merlot and Cabernet Sauvignon. Exogenous ABA treatment at veraison significantly improved phenolic contents, mainly anthocyanins and flavonols, and antioxidant properties of the grape skins, but had no effects on total phenolics and antioxidant activities in the seeds or on basic fruit qualities. The wines made from ABA-treated grapes were also consequently enhanced in total phenolics, anthocyanins, flavonols and antioxidant activities. The proportions of methylated anthocyanins in the skins and acylated anthocyanins and derived pigments in the wines were decreased to some degree by exogenous ABA treatment. No distinct relationships were observed between ABA concentrations and phenolic characteristics, and the effects were observed even with 200 mg/L ABA. The results revealed that exogenous ABA applied at veraison offered opportunities to improve phenolic contents and nutritional values of grape skins and wines.     

Phenolic Content and Antioxidant Activity of Primitivo Wine: Comparison among Winemaking Technologies

ABSTRACT: The aim of this study was to assess the influence of 9 winemaking technologies (traditional, delestage, saignée, delayed punching‐down, addition of grape seed tannins, addition of ellagic‐skin‐seed tannins, heating of must‐wine, cryo‐maceration, and prolonged maceration) on the phenolic content and antioxidant activity of Primitivo musts and wines. Three methods for the determination of the antioxidant activity were compared: DPPH, β‐carotene bleaching assay, and ABTS. Oenological parameters and composition of the phenolic fraction of 1‐y‐aged wines was also determined. The addition of tannins allowed the increase of the phenolic content of musts and wines in a greater amount than the other technologies. The results concerning the antioxidant activity depended on the method applied. Concerning musts, the DPPH assay did not highlight great differences among technologies, whereas the addition of tannins allowed the obtainment of the highest antioxidant activity according to β‐carotene and ABTS assays. The wine aging determined an increase of the antioxidant activity, independently on the method applied. Wine obtained through traditional technology, saignée, and addition of tannins showed the highest antioxidant activities according to DPPH and β‐carotene. The highest correlation coefficients (0.961 and 0.932) were calculated between phenolic content and ABTS values of musts whereas the lowest values (0.413 and 0.517) were calculated between phenolic content and ABTS values of wines. Wines produced through traditional technology were the richest in anthocyanins. The addition of tannins allowed to obtain high content in monomeric anthocyanins, flavonoids, flavans reactive to vanillin, and coumaroylated malvidin and a low content in acetylated malvidin. Practical Applications: It is well known that a moderate consumption (equivalent to 2 glasses per day) of red wine is actually recommended since it appears associated with a decreased incidence of cardiovascular diseases. The mechanisms involved in this protective effect are not completely understood although they appear related to the presence of phenolic compounds. To increase the intake of these compounds without increase of the wine consumption, it is necessary to improve their extraction during maceration. This study could represent a helpful tool for wineries aimed to know the way to increase the antioxidant content of their wines, thus changing them in functional beverages and prolonging their shelf life.     

Assessment of grey mould (Botrytis cinerea) impact on phenolic and sensory quality of Bordeaux grapes,musts and wines for two consecutive vintages

Background and Aims: The impact of grey mould (Botrytis cinerea (B. cinerea)) was quantified on chemical, phenolic and sensory qualities of grapes, derived musts and wines. Methods and Results: Analyses were carried out by using naturally or artificially infected grape berries at ripeness or overripeness. In grape seeds, chemical analyses revealed no major differences between healthy and rotten grapes. In grape skins of Botrytis‐affected berries, concentrations of all the phenolic compounds (anthocyanins and proanthocyanidin monomers, dimers and trimer) decreased drastically. Mean degree of polymerization of the proanthocyanidin polymeric fraction was also affected in skins. Chemical analyses of musts and wines made with different percentages of rotten berries showed a moderate impact of the pathogen on their phenolic composition. Nevertheless, sensory analyses underlined a loss of wine sensory quality perceptible from a threshold as low as 5% of Botrytis‐affected grapes onwards. Conclusion: Phenolic variations and the associated negative impact in grapes, derived musts and wines may be related to oxidation phenomena from B. cinerea. The main effects of severity/age of grey mould and the level of berry maturity are also discussed. Significance of the Study: B. cinerea drastically affects the phenolic and organoleptic properties of grape skins and derived wines. Therefore, prophylactic actions early in the vineyard, evaluation of the sanitary status of the harvested grapes and berry sorting are primordial even under low disease pressure.     

Effect of in vitro gastrointestinal digestion on the bioavailability of phenolic components and the antioxidant potentials of some Turkish fruit wines

This study was designed to evaluate the effects of in vitro gastrointestinal simulation method on the antioxidant potentials and phenolic profile of some Turkish fruit wines and to compare the results with a Turkish red wine prepared from native grape varieties (Papazkarası). For this purpose, blueberry, black mulberry and cherry wines were studied since they are widely consumed in Turkey. Papazkarası wine was chosen due to the lack of studies regarding this type of wine. Antioxidant potentials of samples were measured with four different methods: DPPH radical-scavenging activity, H₂O₂-scavenging activity, cupric reducing capacity and total antioxidant capacity assays. The phenolic profiles of samples were evaluated by the determination of total phenolic content and HPLC-DAD analysis of seven different molecules. The results of this study provided information not only the effect of gastrointestinal digestion on parameters mentioned above, but also the bioaccessibility about the phenolic compounds found in these four different wine samples.     

Antioxidant properties and bioactive components of Norton (Vitis aestivalis) and Cabernet Franc (Vitis vinifera) wine grapes

Three wine grapes, Norton (Vitis aestivalis), Cabernet Franc clone1, and Cabernet Franc clone313 (Vitis vinifera), collected from a Virginia vineyard were evaluated and compared for their antioxidant properties and phenolic profile. All grape extracts exerted remarkable antioxidant activities. Their oxygen radical absorbance capacity (ORAC) values were not significantly different from one another, ranging from 22.9 to 26.7 μmol TE/g of fresh weight. The Cabernet Franc clone1 had the strongest 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals scavenging activity (8.8 μmol TE/g) compared to the Norton or Cabernet Franc clone313 grape extracts (7.9 μmol TE/g and 5.4 μmol TE/g, respectively). The Norton grape contained significantly higher total phenolic, anthocyanin, and flavonoid content than the Cabernet Franc grapes (p < 0.05). The hydroxybenzoic acids, in particular gallic acid, were the major phenolic acids in all the grape extracts. The Norton grape variety was found to be rich in malvidin-diglucoside and malvidin-glucoside, while the malvidin-diglucoside was negligible in the Cabernet Franc grapes. The results suggest a remarkable impact of grape genotype on its antioxidant properties and phenolic composition in Virginia-grown wine grapes.     

Anthocyanin pattern of several red grape cultivars and wines made from them

A high-performance liquid chromatography (HPLC) method with in-line photodiode array detection was applied to separate anthocyanins from red grape skin extracts of several Spanish cultivars, before and after winemaking, and from finished red wines. Data show that, for every cultivar studied, the anthocyanin pattern of the three materials considered (fresh grape skins, crushed grape skins after winemaking, and finished red wines) is quite different. These results may be explained by taking into account the different chemical structures of each anthocyanin and the degradation reactions that should take place during winemaking. On the other hand, the HPLC fingerprint of every material (fresh grape skins, crushed grape skins after fermentation, and wines) is related to cultivar characteristics. Thus, HPLC determination of the anthocyanin pattern of wines may be used to predict the grape cultivar from which wine was made.