General phenolic characterisation, individual ... - Wiley Online Library

Research Article Received: 2 October 2012

Revised: 11 December 2012

Accepted article published: 24 January 2013

Published online in Wiley Online Library: 4 March 2013

(wileyonlinelibrary.com) DOI 10.1002/jsfa.6064

General phenolic characterisation, individual anthocyanin and antioxidant capacity of matured red wines from two Portuguese Appellations of Origins ´ ˜ a,∗ Rosa Cristino,a Elisa Costa,a Fernanda Cosmeb and Antonio M Jordao Abstract BACKGROUND: The main aim of this work was to evaluate the general phenolic composition, individual anthocyanin content and total antioxidant capacity from 20 commercial matured red wine samples (vintage from 2005 to 2008) produced in two Appellations of Origin from the north of Portugal: Douro and Dão. RESULTS: The results showed that the levels of general phenolic compounds, individual anthocyanins and antioxidant capacity in the 20 matured red wine samples analysed differed significantly. In addition, matured red wine samples aged in oak wood had a lower total individual anthocyanin content (from 13.85 to 56.79 mg L−1 , averaging 46.13 mg L−1 ) than wines aged in bottle (from 25.93 to 252.82 mg L−1 , averaging 94.17 mg L−1 ). The total antioxidant capacity values of the analysed wines showed quantitative differences among the values obtained from each antioxidant method applied as well as differences in the range of variation, especially for the values obtained by the DPPH method. CONCLUSION: The wines used in this study constitute quite a heterogeneous group, made from different Portuguese red grape varieties, with diverse ages and two ageing processes (bottle and oak wood barrels); and accordingly, they showed important differences, especially in their phenolic composition. Finally, the oak wood ageing process before bottling had a negative effect in individual anthocyanins content in contrast to matured red wines submitted only to a bottle ageing process. c 2013 Society of Chemical Industry Keywords: antioxidant capacity; colour; individual anthocyanins; wine ageing; red wine

INTRODUCTION

2486

The antioxidant potential of red wines is due to the presence of phenolic compounds, which may inhibit platelet aggregation, prevent oxidation of the human low-density lipoproteins and decrease inflammatory and carcinogenic processes.1 – 3 Phenolic compounds can be classified into two groups: flavonoids and non-flavonoids. The major C6 –C3 –C6 flavonoids in wine include conjugates of the flavonols, quercetin and myricetin; the flavan-3-ols (+)-catechin and (+)-epicatechin, and malvidin-3glucoside and other anthocyanins. The non-flavonoids incorporate the C6 –C1 hydroxy-benzoic acids, gallic and ellagic acids; the C6 –C3 hydroxycinnmates caffeic, caftaric, and p-coumaric acids, and the C6 –C2 –C6 stilbenes trans-resveratrol, cis-resveratrol, and trans-resveratrol glucoside. Wine anthocyanins are the 3-O-monoglucosides of delphinidin, cyanidin, petunidin, peonidin and malvidin. Glucosylated derivatives of these anthocyanins esterified in the C6 of the glucose with acetyl or cumaroyl groups have also been detected, yet generally in low concentrations. Malvidin is the predominant anthocyanin in grapes and wines and the reddest of all anthocyanins, providing the characteristic colour of young red wines. The content and composition of polyphenols as well as the antioxidative or antiradical capacity of wines could be affected by J Sci Food Agric 2013; 93: 2486–2493

many extrinsic and intrinsic factors, such as grape variety, wine growing region and climatic conditions, viticultural practices, and not least, technological procedures during winemaking, including clarification, stabilisation, storage and ageing techniques and conditions.4 – 10 According to several studies, flavan-3-ols, flavonols and anthocyanins are the most important compounds that contribute to the antioxidant proprieties of red wines.11,12 According to ´ Rivero-Perez et al.13 free anthocyanins are mainly responsible for the total antioxidant capacity and scavenger activity in red wines. However, other authors have reported that there is no correlation between antioxidant activity and spectral anthocyanin content

∗

Correspondence to: António M Jordão, Polytechnic Institute of Viseu (Centre for the Study of Education, Technologies and Health), Agrarian Higher School, Department of Food Industries, Estrada de Nelas, Quinta da Alagoa, Ranhados, 3500–606 Viseu, Portugal. E-mail: [email protected]

a Polytechnic Institute of Viseu (Centre for the Study of Education, Technologies and Health), Agrarian Higher School, Department of Food Industries, Estrada de Nelas, Quinta da Alagoa, Ranhados, 3500-606 Viseu, Portugal b Institute for Biotechnology and Bioengineering – Centre of Genomics and Biotechnology, University of Trás-os-Montes and Alto Douro, School of Life Science and Environment, 5001-801 Vila Real, Portugal

www.soci.org

c 2013 Society of Chemical Industry

Characterisation of Portuguese red wines

www.soci.org

in grapes and finished wines.14 – 16 Considering some individual anthocyanins (cyanidin-3-glucoside, peonidin-3-glucoside and malvidin-3-glucoside) from Italian wines, Di Majo et al.17 reported low correlations between these individual compounds and their antioxidant capacity (ranging from 0.29 to 0.54). Thus, there has been conflicting evidence in the relationship between anthocyanins and the antioxidant capacity of wines. In recent years several authors have reported the phenolic composition and the antioxidant capacities of wines from different countries, namely from Austria,18 Croatia,19 Czech Republic,20 Italy,17 the United States of America,21 China,22 South Africa,23 Greece,15 Spain,13,24 France25 and Brazil.26 With respect to Portuguese wines, Jordão et al.27 recently reported the relationship between phenolic composition and the antioxidant capacity of sparkling wines from a specific Portuguese wine region. However, there is a considerable lack of information regarding the antioxidant capacity and individual anthocyanin content of Portuguese red wines with different ageing times and made from native red grape varieties. Thus the main object of this study was to analyse the general phenolic composition (especially the different individual anthocyanins) and total antioxidant capacity of several representative commercial matured red wines produced in two Portuguese Appellations of Origin – Douro and Dão – located in the north of Portugal. In addition, this paper will contribute to a better understanding of the general phenolic composition, individual anthocyanin content and the total antioxidant capacity in red wines with different ageing times and process (bottle or oak wood barrel).

MATERIAL AND METHODS Wine samples A total of 20 representative commercial Portuguese matured red wines from Douro and Dão Appellations of Origin produced

between 2005 and 2008 were analysed in 2011. All the wines were from the most characteristic Vitis vinifera L. native red grape varieties cultivated in each region and made by classic winemaking technology. General characteristics such as origin, vintage year, grape cultivar and ageing process from the different commercial red wines tested in this study are listed in Table 1. General chemical and phenolic analysis The red wine samples tested in our study were analysed for pH, titratable acidity, alcohol content, total tannins, colour density (A420 + A520 + A620 ) and hue (A420 /A520 ) using the analytical methods recommended by the OIV.28 The total polyphenol index was determined by measuring absorbance at 280 nm.29 Total anthocyanins were determined by the SO2 bleaching procedure using the method described by Ribéreau-Gayon and Stronestreet.30 All laboratory measurements were performed in triplicate (n = 3). Chromatographic analysis of individual anthocyanins For analysis of individual anthocyanins from the commercial matured red wines the apparatus used was a high-performance liquid chromatography (HPLC) Dionex Ultimate 3000 Chromatographic System (Sunnyvale, CA, USA) equipped with a quaternary pump Model LPG-3400 A, an auto sampler Model ACC-3000, a thermostatted column compartment (adjusted to 25◦ C) and a multiple Wavelength Detector MWD-300. The column (250 × 4.6 mm, particle size 5 µm) was a C18 Acclaim 120 (Dionex) protected by a guard column of the same material. The solvents were (A) 40% (v/v) formic acid, (B) pure acetonitrile and (C) bi-distilled water. The individual anthocyanins were analysed by HPLC using the method described by Dallas and Laureano.31 Thus, initial conditions were 25% A, 10% B, and 65% C, followed by a linear gradient from 10 to 30% B, and 65 to 45% C for 40 min, with a flow rate of 0.7 mL min−1 . The injection volume was

Table 1. Origin, vintage year, varietal composition and ageing process of commercial matured red wines from Douro and Dão Appellation of Origins Wine sample code Da05PDRe Da05MS Da05VMRe Do05CaRe Da06MARe Do06CP Da07APRe Da07VMRe Do07Ca Do07Fr Do07Ch Do07CC Da08ES Da08GV Da08Gr Da08EP Do08FiRe Do08Fi Do08Le Do08VT

Dão Dão Dão Douro Dão Douro Dão Dão Douro Douro Douro Douro Dão Dão Dão Dão Douro Douro Douro Douro

Vintage year 2005 2005 2005 2005 2006 2006 2007 2007 2007 2007 2007 2007 2008 2008 2008 2008 2008 2008 2008 2008

Grape cultivars

Ageing process

Touriga Nacional, Tinta Roriz and Alfrocheiro Preto Touriga Nacional Touriga Nacional, Tinta Roriz and Alfrocheiro Preto Touriga Nacional, Touriga Franca and Tinta Roriz Touriga Nacional, Tinta Roriz and Jaen Touriga Nacional, Tinta Barroca and Touriga Franca Touriga Nacional, Tinta Roriz and Jaen Touriga Nacional Touriga Nacional, Touriga Franca and Tinta Roriz Touriga Nacional, Touriga Franca and Tinta Roriz WIa Touriga Nacional, Touriga Franca, Tinta Roriz and Tinta Barroca Touriga Franca, Tinta Roriz, Tinta Amarela and Tinta Barroca Touriga Nacional, Tinta Roriz and Jaen WIa Touriga Nacional, Aragonês and Jaen Tinta Barroca, Tinta Roriz, Touriga Franca and Touriga Nacional WIa Touriga Nacional, Touriga Franca, Tinta Roriz and Tinta Barroca WIa

Oak wood barrels Oak wood barrels Oak wood barrels Bottle Oak wood barrels Bottle Oak wood barrels Oak wood barrels Bottle Oak wood barrels Bottle Bottle Bottle Bottle Bottle Bottle Oak wood barrels Bottle Bottle Bottle

Without information from the wine company.

J Sci Food Agric 2013; 93: 2486–2493

2487

a

Appellation of Origin


wileyonlinelibrary.com/jsfa

www.soci.org 40 µL. Detection was made at 520 nm and a Chromeleon software program version 6.8 (Dionex, Sunnyvale, CA, USA) was used. Individual anthocyanins were quantified by using a calibration curve obtained with diverse standard solutions containing different concentrations of malvidin-3-glucoside. The chromatographic peaks of anthocyanins were identified according to reference data previously described by Dallas and Laureano.31 All analyses were done in triplicate (n = 3). Total antioxidant capacity For antioxidant capacity analysis from the red wines two analytical methods were used for antioxidant capacity analysis: 2,2 azinobis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) and DPPH 2,2-diphenyl-1-picrylhydrazyl (DPPH). The ABTS method is based on discoloration which occurs when the radical cation ABTS•+ is reduced to ABTS.32 The radical was generated by reaction of a 7 mmol L−1 solution of ABTS in water with 2.45 mmol L−1 potassium persulfate (1:1). The assay was made up with 980 µL of ABTS•+ solutions and 20 µL of the diluted sample (1:50 in water). The reaction took place in darkness at room temperature. Absorbance measurements at 734 nm were made after 15 min of reaction time. The procedure used to determine antioxidant capacity using DPPH method is described by Brand-Williams et al.33 This spectrophotometric technique employs the 2.2-diphenyl1-picrylhydrazyl free radical (DPPH• ), which shows a characteristic UV–visible spectrum with a maximum absorbance close to 515 nm in methanol. Briefly, 0.1 mL of different sample concentrations was added to 3.9 mL of a DPPH methanolic solution (25 mg L−1 ). The DPPH solution was prepared daily and protected from light. Absorbance at 515 nm was measured after 30 min of reaction at 20◦ C. The reaction was carried out under shaking in closed Eppendorf tubes at 20◦ C. Methanol was used as a blank reference. The antioxidant capacity results were expressed as Trolox equivalents (TEAC mmol L−1 ) by a calibration curve obtained with standard Trolox. All laboratory measurements were performed in triplicate (n = 3). Statistical analysis All data are expressed as the mean ± standard deviation from three replicates (n = 3). In order to determine whether there was a statistically significant difference between the results obtained for the different analytical parameters studied from the red wine samples analysed, an analysis of variance and comparison of treatment means (ANOVA, one-way) were carried out using Statistica software program version 6.0 (StatSoft, Tulsa, OK, USA). Differences between means were tested using Scheffler’s test (P < 0.05).

RESULTS AND DISCUSSION

2488

General chemical and phenolic composition The pH, titratable acidity and alcohol content of all commercial matured red wine samples are summarised in Table 2. The alcohol content ranged from 12.5 to 14.5% (v/v) and the average value was 13.1% (v/v). For titratable acidity the values quantified varied from 4.75 to 7.50 g L−1 in equivalents of tartaric acid and the average value was 5.96 g L−1 in equivalents of tartaric acid. The medium values of alcohol content and total acidity obtained are typical of the red wines produced in the two Portuguese wine regions considered. In general, these values are a consequence of


R Cristino et al.

Table 2. General chemical composition of commercial matured red wines from Douro and Dão Appellation of Origins Wine sample code Da05PDRe Da05MS Da05VMRe Do05CaRe Da06MARe Do06CP Da07APRe Da07VMRe Do07Ca Do07Fr Do07Ch Do07CC Da08ES Da08GV Da08Gr Da08EP Do08FiRe Do08Fi Do08Le Do08VT

pH 3.96 ± 0.02 3.69 ± 0.02 3.65 ± 0.01 3.70 ± 0.02 3.53 ± 0.01 3.77 ± 0.01 3.55 ± 0.02 3.59 ± 0.01 3.80 ± 0.01 3.78 ± 0.03 3.67 ± 0.00 3.99 ± 0.02 3.66 ± 0.01 3.85 ± 0.02 3.71 ± 0.02 3.67 ± 0.01 3.57 ± 0.01 3.57 ± 0.03 3.54 ± 0.01 3.63 ± 0.01

Titratable acidity (g L−1 tartaric acid) 5.00 ± 0.22 6.00 ± 0.08 5.00 ± 0.43 6.00 ± 1.30 6.25 ± 0.11 5.75 ± 0.43 6.25 ± 0.22 6.00 ± 0.75 5.00 ± 0.43 7.50 ± 0.75 6.75 ± 0.75 6.50 ± 1.15 5.78 ± 0.20 6.25 ± 0.43 4.75 ± 0.87 6.00 ± 1.30 6.75 ± 0.00 5.75 ± 1.15 5.75 ± 1.15 6.25 ± 0.53

Alcohol content (%, v/v) 13.5 ± 0.1 13.5 ± 0.2 13.0 ± 0.1 14.0 ± 0.2 13.0 ± 0.1 13.0 ± 0.2 13.0 ± 0.1 13.5 ± 0.1 13.5 ± 0.2 14.0 ± 0.1 13.0 ± 0.2 14.5 ± 0.1 12.5 ± 0.1 13.0 ± 0.1 13.0 ± 0.1 12.5 ± 0.2 12.5 ± 0.1 12.5 ± 0.1 13.0 ± 0.2 12.5 ± 0.2

Values are given as the mean ± SD of the three replicates.

several factors, such as the natural acidity and potential alcohol content of the varieties used, the climatic conditions (namely the high temperatures that occur during grape maturation in these two wine regions) and the technological procedures during winemaking (including the alcoholic and malolatic fermentation). Total polyphenol index, total anthocyanins and tannins, and colour density and hue of the commercial matured red wines tested are presented in Table 3. The results show that the levels of all general phenolic parameters in the 20 matured red wines analysed differed significantly especially for total polyphenol index, total anthocyanin, and colour intensity. In contrast, total tannin content did not differ significantly. Thus, total polyphenol index values ranged from 20.1 to 65.7 (average value of 51.7) while total anthocyanins ranged from 113.5 to 356.4 mg L−1 (average value of 238.7 mg L−1 ). Total tannins ranged from 1.1 to 2.4 g L−1 (average value of 1.6 g L−1 ) and the coefficient of variation was lower (16.9%) than the coefficient of variation values calculated for total polyphenol index (28.6%) and for total anthocyanins (35.4%). Anthocyanins are responsible for the basic chromatic characteristics of red wine. Under different pH values, the structure of anthocyanins undergoes reversible changes. At pH equal to 1.0, anthocyanins exist in the form of the flavylium cation, resulting in bright red colours; when the pH is 4.5, they are nearly colourless. Table 3 also shows the colour density and hue evaluated in the matured red wines studied. Generally speaking, for all matured red wines studied, the values of each colour component can be seen to have decreased in the following order: red (A520 ) > brown and yellow (A420 ) > violet (A620 ). These results are in accordance with those available in the literature for red wines.34 The values for red varied from 0.437 to 0.687 abs. units (average value of 0.545 abs. units) while for brown and yellow the values varied from 0.300 to 0.514 abs. units (average value of 0.424 abs. units). For violet colour values, a variation from 0.087 to 0.192 abs.


J Sci Food Agric 2013; 93: 2486–2493



214.0 ± 7.6bcdef 113.5 ± 17.1a 179.4 ± 0.8abc 284.7 ± 4.4defgh 184.0 ± 1.3abc 308.3 ± 5.1fgh 240.0 ± 12.6cdefg 187.8 ± 20.2abcd 356.4 ± 19.9hi 163.3 ± 11.4abc 204.8 ± 10.9abcde 442.5 ± 24.8i 130.4 ± 13.8ab 311.5 ± 6.1fgh 222.0 ± 10.0bcdef 324.9 ± 13.4gh 129.5 ± 66.0ab 218.5 ± 15.4bcdef 257.3 ± 28.0cdefg 303.0 ± 12.9efgh 238.7 35.4 113.5–356.4

54.6 ± 2.9cdef 16.6 ± 7.3b 55.5 ± 0.2cdefgh 64.5 ± 0.1fgh 20.1 ± 1.3a 57.1 ± 0.4cdefgh 21.4 ± 4.5b 55.1 ± 0.3cdefg 65.7 ± 0.1h 63.6 ± 0.1fgh 55.2 ± 0.2cdefg 62.2 ± 0.6efgh 58.7 ± 0.5defgh 56.2 ± 0.9cdefgh 46.9 ± 0.1c 65.2 ± 0.1gh 58.7 ± 0.1defgh 48.7 ± 0.2cd 53.2 ± 0.1cde 55.9 ± 1.9cdefgh 51.7 28.6 20.1–65.7

Da05PDRe Da05MS Da05VMRe Do05CaRe Da06MARe Do06CP Da07APRe Da07VMRe Do07Ca Do07Fr Do07Ch Do07CC Da08ES Da08GV Da08Gr Da08EP Do08FiRe Do08Fi Do08Le Do08VT Average values CV (%) Range

2489

J Sci Food Agric 2013; 93: 2486–2493 1.7 ± 0.2a 1.8 ± 0.0a 1.7 ± 0.1a 1.9 ± 0.0a 1.8 ± 0.1a 1.2 ± 0.1a 1.7 ± 0.1a 1.7 ± 0.4a 2.4 ± 1.0a 1.9 ± 0.0a 1.4 ± 0.2a 1.7 ± 0.2a 1.6 ± 0.1a 1.8 ± 0.1a 1.9 ± 0.1a 1.5 ± 0.1a 1.6 ± 0.2a 1.5 ± 0.6a 1.1 ± 0.2a 1.4 ± 0.1a 1.6 16.9 1.1–2.4

Total tannins (g L−1 ) 0.460 ± 0.008efg 0.525 ± 0.005i 0.352 ± 0.007b 0.477 ± 0.002gh 0.500 ± 0.009hi 0.383 ± 0.005bc 0.514 ± 0.022i 0.451 ± 0.010efg 0.457 ± 0.00fgh 0.467 ± 0.001efg 0.354 ± 0.007b 0.430 ± 0.002de 0.436 ± 0.003ef 0.380 ± 0.001bc 0.300 ± 0.007a 0.316 ± 0.002a 0.461 ± 0.004efg 0.400 ± 0.001cd 0.373 ± 0.006bc 0.444 ± 0.001efg 0.424 15.08 0.300–0.514

A420 (abs. units)‡ 0.485 ± 0.008ab 0.497 ± 0.016abc 0.439 ± 0.012a 0.642 ± 0.010de 0.546 ± 0.005abcde 0.447 ± 0.003a 0.641 ± 0.014cde 0.687 ± 0.127e 0.651 ± 0.005de 0.547 ± 0.003abcde 0.482 ± 0.007ab 0.579 ± 0.006abcde 0.531 ± 0.006abcd 0.437 ± 0.001a 0.445 ± 0.018a 0.644 ± 0.017de 0.607 ± 0.003 bcde 0.546 ± 0.002abcde 0.487 ± 0.005ab 0.573 ± 0.004abcde 0.545 14.66 0.437–0.687

A520 (abs. units)‡ 0.117 ± 0.002abcd 0.087 ± 0.002a 0.136 ± 0.003abcd 0.181 ± 0.004bcd 0.089 ± 0.015a 0.141 ± 0.003abcd 0.100 ± 0.001ab 0.187 ± 0.007bc 0.191 ± 0.002d 0.143 ± 0.002abcd 0.112 ± 0.001abcd 0.159 ± 0.001abcd 0.120 ± 0.001abcd 0.133 ± 0.002abcd 0.126 ± 0.003abcd 0.192 ± 0.073d 0.148 ± 0.001abcd 0.131 ± 0.001abcd 0.108 ± 0.001abc 0.140 ± 0.001abcd 0.137 23.40 0.087–0.192

A620 (abs. units)‡ 10.620 ± 0.045bcde 11.090 ± 0.170def 9.273 ± 0.141ab 13.013 ± 0.145gh 11.357 ± 0.124ef 9.717 ± 0.083abcd 12.557 ± 0.189fgh 13.250 ± 1.271h 12.993 ± 0.066gh 11.577 ± 0.020efg 9.487 ± 0.144abc 11.693 ± 0.043efg 10.877 ± 0.081cde 9.507 ± 0.023abc 8.710 ± 0.125a 11.540 ± 0.572efg 12.170 ± 0.026efgh 10.777 ± 0.011bcde 9.687 ± 0.035abcd 11.573 ± 0.035efgh 11.073 12.20 8.710–13.250

Colour intensity (abs. units)‡

Values are given as the mean ± SD of the three replicates. Different superscript letters in a column for each parameter indicate statistically significant differences between the red wines tested according to Scheffler’s test (P < 0.05). † Values expressed in malvidin-3-glucoside equivalents. ‡ 1 mm path length cell used. CV (%), coefficient of variation.

Total anthocyanins (mg L−1 )†

Total polyphenol index

Wine sample code

Table 3. General phenolic composition of commercial matured red wines from Douro and Dão Appellation of Origins

0.94 ± 0.03cd 1.059 ± 0.03e 0.803 ± 0.01bcd 0.743 ± 0.00bc 0.917 ± 0.01cde 0.857 ± 0.01bcde 0.803 ± 0.04bcd 0.803 ± 0.01bcd 0.701 ± 0.00b 0.852 ± 0.00bcd 0.736 ± 0.00bc 0.742 ± 0.01bc 0.820 ± 0.00bcd 0.870 ± 0.00bcde 0.670 ± 0.04ab 0.490 ± 0.01a 0.750 ± 0.00bcd 0.733 ± 0.00bc 0.760 ± 0.02bcd 0.770 ± 0.00bcd 0.790 14.59 0.490–1.059

Colour hue (abs. units)

Characterisation of Portuguese red wines www.soci.org

www.soci.org units (average value of 0.137 abs. units) was obtained. As a result of the individual colour values, low colour intensity was generally quantified in all of the matured red wines studied varying from 8.710 to 13.250 abs. units (average value of 11.073 abs. units) while a higher colour hue was obtained (varying from 0.490 to 1.059 abs. units, averaging 0.790 abs. units). It is important to note that, in general for the matured red wines studied, the relative red colour values quantified were lower compared to brown and yellow colour values, which were higher than usually expected for red wines. This result indicates that the wines were aged (between 4 and 6 years) and consequently the colour properties changed (especially the red colour) during the ageing time. According to several authors35,36 wine colour changed during wine ageing through the conversion of monomeric anthocyanins to the polymerised form. Previously, several authors37,38 reported a decrease in total anthocyanin content during wine bottle ageing which is consistent with the participation of monomeric anthocyanins in numerous condensation reactions, as well as in hydrolytic and other degradation reactions, to a minor extent. In addition, there is a partial parallelism between total anthocyanins and colour density evolution during red wine ageing which was evidence that the anthocyanins decrease was not only due to their degradation but also to their gradual polymerisation with other phenolics (flavan3-ol, monomers and polymers, flavones and phenolic acids). These new compounds, which contribute to an orange–red hue, are more stable with regards to pH changes and promote colour stability.

2490

Individual anthocyanin content Individual anthocyanins quantified in all commercial matured red wines studied are shown in Table 4. Although only low levels of some of them were present, 12 individual anthocyanins were detected, as shown on the chromatogram of a commercial matured red wine (Fig. 1). As expected, malvidin-3-glucoside was the individual anthocyanin with the highest values in all matured red wines analysed (varying from 13.50 to 178.95 mg L−1 , averaging 66.55 mg L−1 ), followed by petunidin-3glucoside (varying from 0.13 to 15.53 mg L−1 , averaging 5.50 mg L−1 ) and malvidin-3-p-coumaroyl glucoside (varying from 0.03 to 15.18 mg L−1 , averaging 4.11 mg L−1 ). Petunidin-3-p-coumaroyl glucoside (varying from 0.03 to 1.90 mg L−1 , averaging 0.39 mg L−1 ), cyanidin-3-glucoside (varying from 0.01 to 5.95 mg L−1 , averaging 0.51 mg L−1 ) and petunidin-3-acetylglucoside (varying from 0.04 to 2.28 mg L−1 , averaging 0.55 mg L−1 ) were the individual anthocyanins quantified in the lowest concentrations. The pattern of the anthocyanin chemical groups showed that the simple glucoside group was the main group in all matured red wines studied (varying from 9.05 to 203.63 mg L−1 , averaging 77.88 mg L−1 ) followed by acetyl glucosides (varying from 0.74 to 30.08 mg L−1 , averaging 10.43 mg L−1 ) and the coumaroyl glucoside group (varying from 0.28 to 19.10 mg L−1 , averaging 19.10 mg L−1 ). The high variation of the individual anthocyanin values quantified allows the distinction of certain grape varieties to be made concerning their anthocyanin pattern, but the differences could not be simply attributed to varietal composition. According to several authors39 – 41 the levels of polyphenols (namely anthocyanins) in red wine depended on the maceration time during the winemaking process and the evolution profile of major polyphenol groups. For Burns et al.4 the high levels of anthocyanin


R Cristino et al.

extraction are attributable to the high proportion of solid parts of the grapes as compared to pulp. In addition it is interesting to note that, in general, the matured red wines submitted to an oak wood ageing process before bottling (ageing process type shown in Table 1) had a lower content of individual anthocyanins than matured red wines submitted only to a bottle ageing process. Thus, for the total individual anthocyanin values quantified by HPLC in matured red wines submitted to an oak wood ageing process the values varied from 13.85 to 56.79 mg L−1 and the average value was 46.13 mg L−1 while for matured red wines submitted only to a bottle ageing process the values varied from 25.93 to 252.82 mg L−1 and the average value was 94.17 mg L−1 . A similar tendency was also found for total anthocyanins quantified by the spectrophotometric method (average value for 176.43 mg L−1 for matured red wines submitted to an oak wood ageing process and an average value of 280.35 mg L−1 for matured red wines submitted only to a bottle ageing process). These results are in accordance with data obtained by several authors using model wine solutions.42 – 44 According to these authors, some oak wood components, such as ellagitannins, extracted from oak wood barrels affect wine proanthocyanidin condensation rates and induce a reduction in anthocyanin content during wine oak wood ageing. In addition, other authors45 reported a less pronounced decrease in anthocyanin in wines without oak wood contact than in wine ageing in contact with staves, chips or aged in oak barrels as a consequence of the lower level of condensation with tannins in the wines aged without oak wood contact. Finally, it is noteworthy that the individual anthocyanin concentrations obtained by HPLC were lower than the concentrations obtained by the spectrophotometric method (Table 3 and Table 4). Total individual anthocyanin values quantified by HPLC varied from 13.85 to 252.82 mg L−1 and the average value was 93.65 mg L−1 , while the total anthocyanin values quantified by the spectrophotometric method varied from 113.5 to 356.4 mg L−1 and the average value was 238.7 mg L−1 . This difference, previously documented by other authors,46 is attributed to the individual anthocyanins, detected by HPLC, in comparison with the total anthocyanins detected by spectrophotometry. In addition, these differences have also been demonstrated by Bakker et al.,47 who observed that spectral determination of total anthocyanins always gave much higher values than the HPLC method in aged red Port wines.

Total antioxidant capacity Total antioxidant capacities in the commercial matured red wines were measured using two different methods: ABTS and DPPH. Several methods are available for measuring the antioxidant capacity of substances. However, one single method cannot demonstrate the antioxidant capacity of substances comprehensively. First, organisms have more than one antioxidant system; currently, according to Meng et al.48 at least four such systems have been confirmed, including the antioxidant enzyme system, proteins and other macromolecules, polyphenols, vitamins, ascorbic acid, and other macromolecules such as hormones. Second, different free radicals have different antioxidant clearance mechanisms. The two methods currently employed (ABTS and DPPH) to measure total antioxidant capacity are mainly in vitro determinations and thus cannot simulate the physiological environment.


J Sci Food Agric 2013; 93: 2486–2493



0.17 ± 0.04ab

ND

0.29 ± 0.12ab

0.22 ± 0.24a

4.08 ± 0.32ef

3.15

83.55

0.02–9.55

Do08Le

Do08VT

Average values

CV (%)

Range

0.30 ± 0.13ab

0.13–15.53

89.02

5.50

1.52 ± 0.46abc

3.47 ± 0.48cde

4.88 ± 1.28de

3.93 ± 0.45cde

12.55 ± 0.24f

5.29 ± 0.12i

12.83 ± 0.76b

178.95 ± 2.61j

44.41 ± 1.62f

25.93 ± 0.61cd

170.67 ± 1.99j

30.95 ± 0.53d

36.75 ± 0.72e

139.84 ± 1.94i

31.22 ± 0.35d

98.05 ± 2.03h

43.40 ± 0.68f 125.24 ± 2.00i

5.29–0.29

76.30

2.17

4.00 ± 0.08fg

3.51 ± 0.03de

4.45 ± 0.25gh

13.50–178.95

76.94

66.55

64.83 ± 1.05g

71.95 ± 0.24g

49.93 ± 1.41f

1.76 ± 0.24bcd 23.50 ± 0.81c

3.40 ± 0.55ef

0.06 ± 0.01a

0.18 ± 0.03a

0.20 ± 0.12ab

0.04 ± 0.04a

ND

0.06 ± 0.04a

Peon

1.15 ± 0.02i

ND

0.04 ± 0.04ab

1.07 ± 0.15hi

0.08 ± 0.08bc

acet-gluc

Malv

2.28 ± 0.06d

0.35 ± 0.07cde

0.52 ± 0.17def

0.32 ± 0.15cde

0.02–4.52

67.89

2.31

0.30 ± 0.40a

4.08 ± 0.17ef

4.40 ± 0.39f

0.24 ± 0.22a

1.82 ± 0.20j

0.73 ± 0.07efg

0.54 ± 0.07def

0.04–2.28

122.79

0.55

0.04–1.82

77.97

0.63

0.35 ± 0.08ab 0.95 ± 0.04ghi

0.35 ± 0.21ab 0.07 ± 0.09bc

1.06 ± 0.15c

0.26 ± 0.19ab 1.14 ± 0.32i

4.03 ± 0.82def 1.73 ± 0.02d

3.20 ± 0.16cde 0.15 ± 0.08a

3.60 ± 0.03cde 0.77 ± 0.00bc 0.60 ± 0.04def

2.47 ± 0.93bcd 0.34 ± 0.17ab 0.90 ± 0.05ghi

4.08 ± 0.23ef

0.13 ± 0.10a

2.56 ± 0.45bcd 0.04 ± 0.02a 4.52 ± 0.62f

0.27 ± 0.04cde

0.55 ± 0.10bc 0.83 ± 0.14ghi

0.34 ± 0.42ab 1.14 ± 0.14i

3.89 ± 0.19def 1.95 ± 0.00d

2.18 ± 0.52bc

3.85 ± 0.35def

Petun

4.61 ± 0.15def

12.87 ± 0.86g

1.11–23.39

96.36

6.94

1.34 ± 0.38ab

6.51 ± 0.17f

4.30 ± 0.70def

2.17 ± 0.20bc

16.49 ± 0.97h

5.99 ± 0.39ef

1.48 ± 0.07ab

2.44 ± 0.09bc

23.39 ± 0.50i

4.55 ± 0.38def

4.50 ± 0.39def

19.35 ± 1.22i

3.69 ± 0.12cde

4.12 ± 0.00def

Peon coum-gluc

0.09 ± 0.01a

0.03–1.90

125.90

0.39

0.13 ± 0.06bc

0.50 ± 0.19cd

0.75 ± 0.03de

0.23 ± 0.10bc

1.01 ± 0.02ef

0.30 ± 0.16bc

1.20 ± 0.03f

0.03 ± 0.01a

1.90 ± 0.23g

ND

0.14 ± 0.05bc

0.36 ± 0.22bc

ND

0.31 ± 0.05bc

0.05 ± 0.00a

0.12 ± 0.02bc

0.04 ± 0.01a

Malv

1.59 ± 1.63cd

0.03 ± 0.02a

13.85 ± 1.34hi

2.78 ± 0.11cde

3.77 ± 0.07cde

10.95 ± 0.73gh

3.40 ± 0.17cde

4.20 ± 0.75de

3.00 ± 0.15cde

0.93 ± 0.07bc

0.36 ± 0.05ab

coum-gluc

0.13–2.98

96.28

0.84

0.67 ± 0.02a

0.38 ± 0.18a

1.12 ± 0.11ab

0.18 ± 0.03a

1.38 ± 0.30ab

0.32 ± 0.16a

0.81 ± 0.00a

1.40 ± 0.12ab

0.03–15.18

109.06

4.11

74.51

93.65

81.17

91.55

74.06

39.13

183.39

76.44

123.46

25.93

252.82

61.76

39.79

236.49

54.37

56.79

190.78

45.91

123.10

45.60

13.85

56.52

Total

13.85–252.82

2.71 ± 0.22cde

1.50 ± 0.47cd

2.23 ± 0.42cd

2.40 ± 0.39cde

8.18 ± 0.38fg

5.62 ± 0.07ef

1.45 ± 0.04cd

0.82 ± 0.04bc

2.02 ± 2.30ab 15.18 ± 2.54j

0.14 ± 0.09a

0.13 ± 0.06a

2.98 ± 0.43b

0.61 ± 0.04ab

0.13 ± 0.03a

2.26 ± 0.18a

0.15 ± 0.06a

0.31 ± 0.12a

0.88 ± 0.03ab

1.18 ± 0.04ab

0.39 ± 0.03bc 0.50 ± 0.17a

coum-gluc

3.65 ± 0.11cde 0.19 ± 0.01bc

1.47 ± 0.05ab

1.11 ± 0.21a

acet-gluc

3.02 ± 0.11cde 0.28 ± 0.17ab 0.19 ± 0.04bcd 15.27 ± 1.54h

1.14 ± 0.03ab

0.51 ± 0.17a

34.37 ± 0.09de 1.07 ± 0.03ab

1.10 ± 0.04abc 90.56 ± 0.10h

0.94 ± 0.09ab

3.36 ± 0.61ef

2.07 ± 0.10cd

1.03 ± 0.08ab

3.58 ± 0.15fg

3.58 ± 0.15fg

0.34 ± 0.18a

0.29 ± 0.40a

0.51 ± 0.12a

0.35 ± 0.40a

4.01 ± 0.20fg

7.09 ± 0.12a

Petun acet-gluc

Values are given as the mean ± SD of the three replicates. Different superscript letters in a column for each individual anthocyanin indicate statistically significant differences according to Scheffler’s test (P < 0.05). Individual anthocyanins are expressed in malvidin-3-glucoside equivalents (mg L−1 ). Delp gluc, delphinidin-3-glucoside; Cyan gluc, cyanidin-3-glucoside; Petun gluc, petunidin-3-glucoside; Peon gluc, peonidin-3-glucoside; Malv gluc, malvidin-3-glucoside; Cyan acet-gluc, cyanidin-3-acetylglucoside; Petun acet-gluc, petunidin-3-acetylglucoside; Peon acet-gluc, peonidin-3-acetylglucoside; Malv acet-gluc, malvidin-3-acetylglucoside; Peon coum-gluc, peonidin-3-p-coumaroyl glucoside; Malv coum-gluc, malvidin-3-p-coumaroyl glucoside. ND, not detected; CV (%), coefficient of variation.

0.01–5.95

254.27

0.51

0.24 ± 0.15ab

3.09 ± 0.35de

0.24 ± 0.33a

Do08Fi

ND

Do08FiRe

5.95 ± 0.51d

5.21 ± 0.07fg

0.51 ± 0.04abc

9.55 ± 0.04i

Da08GV

7.57 ± 0.36h

1.25 ± 0.03abc 0.13 ± 0.06ab

Da08ES

Da08EP

ND

5.79 ± 0.56g

Do07CC

Da08Gr

2.38 ± 0.15abcde 11.83 ± 0.12f

0.01 ± 0.00a 15.53 ± 1.55g

3.14 ± 0.20bcde 4.50 ± 0.09de

1.94 ± 0.16bcd 0.09 ± 0.02ab

12.63 ± 1.20f

2.29 ± 0.81cd

1.02 ± 0.19c

5.95 ± 0.31g

Do07Ca

4.84 ± 0.09de

2.87 ± 0.38abcde

Do07Ch

0.59 ± 0.08bc

14.08 ± 0.52fg

2.10 ± 0.31abcd

5.16 ± 1.85e

0.13 ± 0.03a

Do07Fr

0.06 ± 0.07ab

3.27 ± 0.42de

0.29 ± 0.10ab

4.37 ± 0.54ef

Do06CP

3.76 ± 0.00e

0.27 ± 0.13ab

1.08 ± 0.16abc

Da06MARe

Da07VMRe

0.03 ± 0.02ab

1.37 ± 0.26abc

Do05CaRe

Da07APRe

0.48 ± 0.11abc

1.19 ± 0.30abc

Da05VMRe

0.82 ± 0.05ab

0.02 ± 0.02a

Da05MS

2491

J Sci Food Agric 2013; 93: 2486–2493 1.08 ± 0.06abc

50.48 ± 1.29f

0.04 ± 0.06ab

0.02 ± 0.02a

0.18 ± 0.03a

0.09 ± 0.09ab

0.80 ± 0.22ab

Da05PDRe

2.99 ± 0.16abcde

Cyan Malv gluc

acet-gluc

Peon gluc

code

Petun gluc

Cyan gluc

Delp gluc

sample

Wine

Table 4. Individual anthocyanins of commercial matured red wines from Douro and Dão Appellation of Origins

Characterisation of Portuguese red wines www.soci.org

www.soci.org

ANTHOCYANINS wine sample

300

WVL:520 nm

Absorbance [mAU]

5

200

100 3 1

4 2

6

9

7

8

12 10 11

-50 0

13

25

38

50

63

75

88

110

Retention Time [min]

Figure 1. Chromatogram of a commercial matured red wine sample tested directly injected at 520 nm. The peaks correspond to: 1, delphinidin-3glucoside; 2, cyanidin-3-glucoside; 3, petunidin-3-glucoside; 4, peonidin3-glucoside; 5, malvidin-3-glucoside; 6, cyanidin-3-acetylglucoside; 7, petunidin-3-acetylglucoside; 8, peonidin-3-acetylglucoside; 9, malvidin3-acetylglucoside; 10, petunidin-3-p-coumaroyl glucoside; 11, peonidin-3p-coumaroyl glucoside; 12, malvidin-3-p-coumaroyl glucoside.

The data in Table 5 show the total antioxidant capacity results quantified in the commercial matured red wines tested. As shown in Table 5, through the ABTS method, the results obtained varied

R Cristino et al.

from 11.64 to 18.88 TEAC mmol L−1 , averaging 16.13 TEAC mmol L−1 , while as a result of using the DPPH method, the values obtained varied from 8.02 to 23.32 TEAC mmol L−1 , averaging 17.84 TEAC mmol L−1 . These results are similar to values reported by Rivero-Pérez et al.24 in 80 red Spanish wines from different native Vitis vinifera varieties, different regions, different vintages (2000–2004) and from different ageing processes (bottle and barrel aged). The total antioxidant capacity values of the analysed wines showed quantitative differences among the values obtained from each antioxidant method applied as well as differences in the range of variation, especially for the values obtained as a result of applying the DPPH method. Consequently, a higher coefficient of variation was shown for DPPH values (20.42%), which indicated that this method was more sensitive to the intrinsic variability of the matured red wine samples studied than the ABTS method ˜ et al.49 (coefficient of variation of 11.91%). According to Villano the different values between the two antioxidant methods used in our study is due to the different reactivity of the polyphenols with each method applied. For Wang et al.50 ABTS and DPPH radicals have a different stereochemical structure and another method of genesis, and so after the reaction with the antioxidants, they lend a qualitatively different response to the inactivation of their radical.

CONCLUSIONS Table 5. Total antioxidant capacity (ABTS and DPPH methods) values of commercial matured red wines from Douro and Dão Appellation of Origins Wine sample code Da05PDRe Da05MS Da05VMRe Do05CaRe Da06MARe Do06CP Da07APRe Da07VMRe Do07Ca Do07Fr Do07Ch Do07CC Da08ES Da08GV Da08Gr Da08EP Do08FiRe Do08Fi Do08Le Do08VT Average values CV (%) Range

ABTS (TEAC mmol L−1 )† 12.05 ± 0.77a 11.64 ± 0.00ab 16.48 ± 0.45defg 17.32 ± 0.93defg 15.14 ± 0.06bcd 17.98 ± 0.06efg 13.45 ± 0.09ab 16.31 ± 0.27cdef 18.80 ± 0.09fg 18.88 ± 0.13g 16.51 ± 0.19defg 16.65 ± 0.51defg 16.86 ± 0.14defg 16.67 ± 0.06defg 16.29 ± 0.60cdef 16.60 ± 0.39defg 15.87 ± 0.35cde 14.79 ± 0.13abc 17.18 ± 0.13defg 17.18 ± 0.70defg 16.13 11.91 11.64–18.88

DPPH (TEAC mmol L−1 )† 19.36 ± 0.89abcd 9.36 ± 0.51abcd 16.37 ± 0.93ab 20.44 ± 0.99bcd 18.97 ± 0.26abc 21.70 ± 1.30cd 8.02 ± 1.66e 17.59 ± 0.06abc 23.32 ± 0.49d 20.10 ± 0.57bcd 17.72 ± 0.89abc 17.22 ± 0.06abc 18.06 ± 0.06abc 19.04 ± 0.45abcd 18.95 ± 0.12abcd 19.47 ± 0.25abcd 20.73 ± 0.32bcd 15.16 ± 0.57a 17.85 ± 0.57abc 17.45 ± 0.38abc 17.84 20.42 8.02–23.32

2492

Values are given as the mean ± SD of the three replicates. Different letters in a column for each antioxidant method indicate statistically significant differences according to Scheffler’s test (P < 0.05). † Trolox equivalent. CV (%), coefficient of variation.


The wines used in this study constitute quite a heterogeneous group, made from different grape varieties, with diverse ages and two ageing processes; and, accordingly, they showed important differences, especially in their phenolic composition. So, the high coefficients of variation for the parameters analysed (especially for individual anthocyanins) were in agreement with the heterogeneity of the samples as cited. Finally, it is important to consider that a study of the antioxidant capacity and the phenolic composition of wines, should always take into account the structure–activity of antioxidant components, the contribution of specific polyphenolic fractions and the influence of the ageing conditions used.

REFERENCES 1 Gryglewski RJ, Korbut R, Robak J and Swies J, On the mechanism of antithrombotic action of flavonoids. Biochem Pharmacol 36:317–322 (1987). 2 Frankel EN, Kanner J, German JB, Parks E and Kinsella JE, Inhibition of oxidation of human low-density lipoprotein by phenolic substances in red wine. Lancet 341:454–457 (1993). 3 Tapiero H, Tew KD, Nguyen BAG and Mathé G, Polyphenols: Do they play a role in prevention of human pathologies? Biomed Pharmacother 56:200–207 (2002). 4 Burns J, Gardner PT, Matthews D, Duthie GG, Lean MEJ and Crozier A, Extraction of phenolics and changes in antioxidant activity of red wines during vinification. J Agric Food Chem 48:220–230 (2001). 5 De Coninck G, Jordão AM, Ricardo-da-Silva JM and Laureano O, Evolution of phenolic composition and sensory properties in red wine aged in contact with Portuguese and French oak wood ships. J Int Sci Vigne Vin 40:25–34 (2006). ´ ˜ S and González-SanJose´ ML, Polyphenols and colour 6 Perez-Magari no variability of red wines made from grapes harvested at different ripeness grade. Food Chem 96:197–208 (2006). 7 Cosme F, Ricardo-da-Silva JM and Laureano O, Protein fining agents: characterization and red wine fining assay. Ital J Food Sci 19:39–56 (2007). 8 Gonçalves FJ and Jordão AM, Changes in antioxidant activity and proanthocyanidin fraction of red wine aged in contact with Portuguese (Quercus pyrenaica Willd.) and American (Quercus alba L.) oak wood chips. Ital J Food Sci 21:51–64 (2009).


J Sci Food Agric 2013; 93: 2486–2493

Characterisation of Portuguese red wines

www.soci.org

9 Gonçalves FJ and Jordão AM, Influence of different commercial fining agents on proanthocyanidin fraction and antioxidant activity of a red wine from baga grapes. J Int Sci Vigne Vin 43:111–120 (2009). 10 Cosme F, Ricardo-da-Silva JM and Laureano O, Behavior of various proteins on wine fining: effect on different molecular weight proanthocyanidin fractions of red wine. Am J Enol Vitic 112:197–204 (2009). 11 Ghiselli A, Nardini M, Baldi A and Scaccini C, Antioxidant activity of different phenolic fractions separated from Italian red wine. J Agric Food Chem 46:361–367 (1998). 12 Beecher GR, Overview of dietary flavonoids: Nomenclature, occurrence and intake. J Nutr 133:3248–3254 (2003). ´ ˜ P and González-SanJose´ ML, Antioxidant pro13 Rivero-Perez MD, Muniz file of red wines evaluated by total antioxidant capacity, scavenger activity, and biomarkers of oxidative stress methodologies. J Agric Food Chem 55:5476–5483 (2007). 14 Burns J, Gardner PT, O’Neil J, Crawford S, Morecroft I, Mcphail DB, et al, Relationship among antioxidant actitivty, vasodilation capacity, and phenolic content of red wines. J Agric Food Chem 48:220–230 (2000). 15 Arnous A, Markis DP and Kefalas P, Correlation of pigment and flavanol content with antioxidant properties in selected aged regional wines from Greece. J Food Compos Anal 15:655–665 (2002). 16 Kallithraka S, Mohdaly AA, Makris DP and Kefalas P, Determination of major anthocyanin pigments in Hellenic native grape varieties (Vitis vinifera sp.): Association with antiradical activity. J Food Compos Anal 18:375–386 (2005). 17 Di Majo D, La Guardia M, Giammancos S, La Neve L and Giammanco M, The antioxidant capacity of red wine in relationship with its polyphenolic constituents. Food Chem 111:45–49 (2008). ˇ ak M and Gescheidt G, A 18 Staˇsko A, Brezová V, Mazur ´ M, Eertik M, Kalin´ comparative study on the antioxidant properties of Slovakian and Austrian wines. Food Sci Technol 41:2126–2135 (2008). 19 Piljac-Zegarac J, Martinez S, Valek L, Stipcevic T and KovacevicGanic K, Correlation between the phenolic content and DPPH radical scavenging activity of selected Croatian wines. Acta Aliment 36:185–193 (2007). 20 Lachman J, Sˇ ulc M and Schilla M, Comparison of the total antioxidant status of Bohemian wines during the wine-making process. Food Chem 103:802–807 (2007). 21 Lee J and Rennaker C, Antioxidant capacity and stilbene contents of wines produced in the Snake River Valley of Idaho. Food Chem 105:195–203 (2007). 22 Li H, Wang X, Li Y and Wang H, Polyphenolic compounds and antioxidant properties of selected China wines. Food Chem 112:454–460 (2009). 23 Beer D, Joubert E, Marais J and Manley M, Maceration before and during fermentation: Effect on Pinotage wine phenolic composition, total antioxidant capacity and objective colour parameters. S Afr J Enol Vitic 27:137–150 (2006). ´ ˜ P and González-SanJose´ ML, Contribution of 24 Rivero-Perez MD, Muniz anthocyanin fraction to the antioxidant properties of wine. Food Chem Toxicol 46:2815–2822 (2008). 25 Landrault N, Poucheret P, Ravel P, Gasc F, Cros G and Teissedre PL, Antioxidant capacities and phenolics levels of French wines from different varieties and vintages. J Agric Food Chem 49:3341–3348 (2001). 26 Ishimoto EY, Ferrari CKB, Bastos DHM and Torres EAFS, In vitro antioxidant activity of Brazilian wines and grape juices. J Wine Res 17:107–115 (2006). 27 Jordão AM, Gonçalves FJ, Correia AC, Cantão J, Rivero-Pérez MD and González-SanJose´ ML, Proanthocyanidin content, antioxidant capacity and scavenger activity of Portuguese sparkling wines (Bairrada Appellation of Origin). J Sci Food Agric 90:2144–2152 (2010). 28 Organisation International de la Vigne et du Vin (OIV), Recueil des méthodes internationales d’analyse des vins et moûts, edition officielle. OIV, Paris (2006). ´ 29 Ribereau-Gayon P, Peynaud E and Sudraud P, Science et techniques du vin, tome 4. Dunod, Paris (1982). ´ 30 Ribereau-Gayon P and Stronestreet E, Le dosage des anthocyanes dans le vin rouge. Bull Soc Chimie 9:2649–2652 (1965).

31 Dallas C and Laureano O, Effects of pH, sulphur dioxide, alcohol content, temperature and storage time on colour composition of a young Portuguese red table wine. J Sci Food Agric 65:477–485 (1994). 32 Re R, Pellegrini N, Proteggente A, Pannala A, Yang M and Rice-Evans C, Antioxidant activity applying an improved ABTS radical cation decolorization assay. Free Radic Biol Med 26:1231–1237 (1999). 33 Brand-Williams W, Cuvelier ME and Berset C, Use of a free radical method to evaluate antioxidant activity. Food Sci Technol 28:25–30 (1995). ´ 34 Ribereau-Gayon P, Glories Y, Maujean A and Dubourdieu D, Handbook of Enology – The Chemistry of Wine Stabilization and Treatments, vol. II, 2nd edition. John Wiley & Sons, Ltd, Chichester, UK (2006). ´ MS, Garrido J, Mart´ınez-Carballo E, 35 Castillo-Sánchez JX, Garc´ıa-Falcon Martins-Dias LR and Mejuto XC, Phenolic compounds and colour stability of Vinhão wines: Influence of wine-making protocol and fining agents. Food Chem 106:18–26 (2008). 36 Johnson MH and Gonzalez de Mejia E, Comparison of chemical composition and antioxidant capacity of commercially available blueberry and blackberry wines in Illinois. J Food Sci 71:141–148 (2012). 37 Santos-Buelga C, Francia-Aricha EM, De Pascual-Teresa S and RivasGonzalo JC, Contribution to the identification of the pigments responsible for the browning of anthocyanin–flavanol solutions. Eur Food Res Technol 209:411–415 (1999). ´ ´ C and Bartolome´ B, Evolution of the 38 Monagas M, Gomez-Cordov es phenolic contente of red wines from Vitis vinifera L. during ageing in bottle. Food Chem 9:405–412 (2006). ´ 39 Ribereau-Gayon P, The anthocyanins of grapes and wines, in Anthocyanins as Food Color, ed. by Markakis P. Academic Press, New York, pp. 209–244 (1982). 40 Yokotsuka K, Sato M, Ueno N and Singleton V, Colour and sensory characteristics of Merlot red wines caused by prolonged pomace contact. J Wine Res 11:7–18 (2000). ˜ S, Correia AC and Gonçalves FJ, Antioxidant activity 41 Jordão AM, Simoes evolution during Portuguese red wine vinification and their relation with the proanthocyanidin and anthocyanin composition. J Food Process Preserv 36:298–309 (2012). 42 Vivas N and Glories Y, Role of oak wood ellagitannins in the oxidation process of red wines during aging. Am J Enol Vitic 47:103–107 (1996). 43 Jordão AM, Ricardo-da-Silva JM and Laureano O, Role of oak wood extract, ellagic acid and oxygen on malvidin-3-glucoside, (+)catechin and colour parameters evolution in model wine solutions. Am J Enol Vitic 57:377–381 (2006). 44 Jordão AM, Ricardo-da-Silva JM, Laureano O, Mullen W and Alan C, Effect of ellagitannins, ellagic acid and some volatile compounds from oak wood on the (+)-catechin, procyanidin B1 and malvidin3-glucoside content of model wine solutions. Aust J Grape Wine Res 14:260–270 (2008). 45 Sanza MA, Dom´ınguez IN and Merino SG, Influence of different aging systems and oak woods on aged wine color and anthocyanin composition. Eur Food Res Technol 219:124–132 (2004). 46 Rivas-Gonzalo JC, Gutierrez Y, Hebrero E and Santos-Buelga C, Comparison of methods for the determination of anthocyanins in red wines. Am J Enol Vitic 43:210–214 (1992). 47 Bakker J, Preston NW and Timberlake CF, The determination of anthocyanins in aging red wines: Comparison of HPLC and spectral methods. Am J Enol Vitic 37:121–126 (1986). 48 Meng J, Fang Y, Gao J, Qiao L, Zhang A, Guo Z, et al, Phenolics composition and antioxidant activity of wine produced from Spine grape (Vitis davidii Foex) and Cherokee Rose (Rosa laevigata Michx.) fruits from South China. J Food Sci 71:8–14 (2012). ˜ D, Fernández-Pachon ´ MS, Troncoso AM and Garc´ıa-Parrilla 49 Villano MC, Influence of enological practices on the antioxidant activity of wines. Food Chem 95:394–404 (2006). 50 Wang CC, Chu CY, Chu KO, Choy KW, Khaw KS, Rogers MS, et al, Trolox-equivalent antioxidant capacity assay versus oxygen radical absorbance capacity assay in plasma. Clin Chem 50:952–954 (2004).

2493

J Sci Food Agric 2013; 93: 2486–2493

