MI EILUNGEN KLOSTERNEUBURG 69 2019: 174183 LAMPÍŘ and PAVLOUŠEK

ANTIOXIDANT PROPERTIES AND TOTAL PHENOLIC CONTENTS IN WINES OF DIFFERENT G PE VARIETIES FROM ORGANIC PRODUCTION

L L1 and P P2

1 Department of Horticulture, Faculty of Agrobiology, Food and Natural Resources Czech University of Life Sciences Prague CZ-165 21 Prague 6 – Suchdol 2 Department of Viticulture and Enology, Faculty of Horticulture Mendel University Brno CZ-69144 Lednice, Valtická 337 E-Mail: [email protected]

Among wine consumers interest in wines from resistant varieties and organic grape production is increasing. e health bene ts associated with grapes and wine are related to phenolic compound content and antioxidant proper- ties of the wines. In this study we evaluated the wines made from three grapevine varieties from two localities with organic grape production. For each wine total content of phenolic compounds, total avanols, antioxidant properties and content of gallic acid, catechin, epicatechin and trans-resveratrol were evaluated. e variety 'Malverina' is cha- racterized by the highest total content of total phenols, the highest antioxidant activity and high content of trans-res- veratrol. Furthermore signi cant correlations were also found between total phenolic content and antiradical activity (r = 0.7430) and total avanols and antiradical activity (r = 0.7001). Keywords: grapevine, wine, grape variety, organic production, authenticity

Antioxidative Eigenscha en und Gesamtphenolgehalt von Weinen verschiedener Rebsorten aus biologischem Anbau. Unter Weinkonsumenten steigt das Interesse an Weinen aus resistenten Sorten und biologischer Trauben- produktion. Der mit Trauben und Wein verbundene gesundheitliche Nutzen hängt mit dem Gehalt an Phenolver- bindungen und den antioxidativen Eigenscha en der Weine zusammen. In dieser Studie haben wir die Weine aus drei Rebsorten aus zwei Herkün en mit ökologischem Anbau untersucht. Für jeden Wein wurden der Gesamtge- halt an Phenolverbindungen, die Gesamt avanole, die antioxidativen Eigenscha en und der Gehalt an Gallussäure, Catechin, Epicatechin und trans-Resveratrol bewertet. Die Sorte 'Malverina' zeichnet sich durch den höchsten Ge- samtgehalt an Gesamtphenolen, die höchste antioxidative Aktivität und einen hohen Gehalt an trans-Resveratrol aus. Darüber hinaus wurden auch signi kante Korrelationen sowohl zwischen dem Gesamtphenolgehalt und der Aktivität gegen Freie Radikale (r = 0,7430) als auch den Gesamt avanolen und der Aktivität gegen Freie Radikale (r = 0,7001) gefunden. Schlagwörter: Rebe, Wein, Rebsorte, biologische-Produktion, Authentizität

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Organic viticulture and winemaking has experienced a × 'Pinot gris'). In the Czech Republic, this grape varie- huge development in recent years in the Czech Republic. ty has been grown by small winemakers from the 1990s One aim of organic viticulture is the production of wine onwards. e 'Hibernal' variety originates from the Gei- free of chemical residues (Z et al., 2003). One senheim University’s cross ('Riesling Gm239' × 'Seibel way of achieving this goal is growing grapevine varieties 7053')F2. 'Hibernal' is the most cultivated resistant va- that have increased resistance to fungal pathogens. Addi- riety in the Czech Republic (275 ha). 'Malverina' is a tionally, secondary metabolites, such as phenolic com- variety introduced by M M at Vinselekt pounds, may be present in higher doses in organically Rakvice in the Czech Republic. It was the rst resistant grown grapevines (V et al., 2011). variety registered in the Czech Republic. It is used for Diff erent grapes and wines contain speci c levels of phe- the production of wines and musts. nolic compounds, especially avonoids, and a higher e current work is focused on the research on varieties content of phenolic compounds present in wine may suitable for organic wine production. e aim of this produce antioxidant properties (K et al., 1994). work is to determine their antioxidant potential and the Antioxidant activity is related to the content of total phe- principal representation of phenolic compounds in va- nolics. Very effi cient compounds among them in this re- rieties suitable for cultivation under organic condition. gard, contributing to the antioxidant properties of wine Based on the results, it is then possible to recommend are monomeric avanols (catechin and epicatechin), di- suitable varieties for making wines with be er antioxi- meric, trimeric and polymeric proanthocyanidins, con- dant properties. densed tannins, phenolic acids (gallic acid and ellagic acid) and resveratrol (L and Š, 2009). MATERIALS AND METHODS e concentration of these phenolic compounds is very important for understanding the antioxidant activity G PEVINE VARIETIES AND LOCALITIES of wines (R et al., 2012). Phenolic com- pounds in wine can be divided into a group of avonoids Wines from resistant grapevine varieties were evalua- and non- avonoids. Among the non- avonoids hydroxy- ted: 'Hibernal', 'Malverina', and 'Merzling'. Wines origi- cinnamic acid, hydroxybenzoic acid and stilbenes can be nated from two localities, i. e. from Perná (the wine-gro- included. e avonoids and avonols include avan-3- wing subregion Mikulov) and Sádek (the wine-growing ols as well as anthocyanins of red wines (L et al., 2009). subregion Znojmo). e activity of phenolic compounds as peroxyl radical Characteristics of locality Perná: seasonal average tem- scavengers and in the formation of complexes with me- perature (9 °C), seasonal precipitation rate (552 mm), tals has been clearly shown by in vitro studies. e ability sum of active temperature (2900 °C), geological be- of polyphenols to cross the intestinal wall of mammals drock is limestone. e soil is sandy-loam with a higher confers to biological and antioxidant properties of these content of lime. compounds (B et al., 2012). Characteristics of locality Sádek: seasonal average tem- e content of phenolic compounds and antioxidant perature (8 °C), seasonal precipitation rate (480 mm), properties in organic wines have been analysed in stu- sum of active temperature (2700 °C); geological be- dies by Z et al. (2003), M et al. (2009) drock is granite and orthorul. Soil is loam-sandy. Table and V et al. (2011). e content of phenolic com- 1 shows detailed meteorological parameters from both pounds and antioxidant and antiradical properties in localities. wines can be aff ected by many factors, such as vineyard In this study wines from vintages 2005 and 2006 were location (F et al., 2004), degree of grape ripeness evaluated. Vineyards were treated according to the (P-M et al., 2006) and wine technology principles of organic production. In the vineyards no (M et al., 2006; L et al., 2007). synthetic pesticides or mineral fertilizers were used. e varieties 'Merzling', 'Hibernal' and 'Malverina' were Only preparations based on copper and sulphur were evaluated within this study. e 'Merzling' variety’s ori- used against fungal pathogens. gin lies in the State Viticultural Institute Freiburg, as a e vineyard in Perná was planted in 1997 with vine result of the cross of 'Seyve-Villard 5276' × ('Riesling' spacing 2.2 m between rows and 1.0 m in-row on SO4

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rootstocks. e vineyard has western exposure. DETERMINATION OF TOTAL PHENOLS e vineyard in Sádek was also planted in 1997 with 2.2 m between rows and 1.0 m in-row vine spacing on SO4 e Folin-Ciocalteu method, based on the reduction of a rootstocks. is vineyard has southern exposure. e phosphotungsten-phosphomolybdate complex by phe- experimental varieties were planted in 200 meter rows nols to blue reaction products, was used for determinati- oriented down the slope. e rows were divided into 4 on of phenolic compounds. e sample (0.5 ml) was pi- parts, and these represented experimental repetitions. pe ed into cuve e and diluted with ACS water (1.5 ml). e grapes were harvested at the same time. In 2005, the Subsequently, Folin-Ciocalteu reagent (50 µl) was ad- harvest was on October, 10th, and in 2006 a er October, ded and the solution was incubated at 22 °C for 30 min. 12th, at both sites. e experiment was performed in 4 e absorbance was measured using a HELIOS Gama replicates. spectrometer ( ermoFischerScienti c, Brno, Czech Republic) at a wavelength λ = 670 nm against blank (all VINIFICATION TECHNOLOGY chemicals without a sample or gallic acid).Concentrati- on of total phenols was calculated from the calibration All white wines were made with an identical vini cati- curve using gallic acid as standard (25 to 1000 mg/l). on technology. Fermentation and ageing of wine took e results are expressed in the form mg/l equivalents place in glass carboys with a capacity of 50 l. Harvested of gallic acid (Gallic Acid Equivalents; GAE). Gallic acid grapes were destemmed, macerated for a short period was obtained from SigmaAldrich (St. Louis, USA). e (2 hours at 15 °C) and pressed to the must yield of 60 evaluation was performed in 4 replicates. %. Identical yeast strain was used for the inoculation of all wine samples. A er the end of fermentation, the DETERMINATION OF TOTAL FLAVANOLS young wine was racked and treated with sulphur dioxi- Total flavanols concentration was determined using a de to the content of 30 mg/l free SO2. erea er, the young wine was bo led (without any further clari cati- method based on reaction with p-dimethylaminocinna- on and/or ltration) for analyses.

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maldehyde (DMACA) (L et al., 1996). In this method, DETERMINATION OF PHENOLIC unlike the widely used reaction with vanillin, no inter- COMPOUNDS ference with the anthocyanins exists. Concentration of total flavanols was calculated from the calibration curve Concentrations of the individual phenolic compounds using catechin as standard (10 to 200 mg/l). e results were determined by a method published in K are expressed in the form of mg/l catechin equivalents. et al. (2012)). e samples of wine were centrifuged Catechin was obtained from SigmaAldrich (St. Louis, at 3,000 g for 6 min, diluted at ratio 1:1 by 100 mM USA). e evaluation was performed in 4 replicates. HClO4 and directly injected into a HPLC system. e chromatographic system LC-10A (Shimadzu, Kyoto, DETERMINATION OF ANTI DICAL ACTIVI Japan) consisted of 2 pumps LC-10ADvp (Shimadzu), TY ANTI DICAL ACTIVITY; AAR a column thermostat with manual injection valve, a di- ode array detector (DAD) (SPD-M10Avp; Shimadzu) e method is based on the deactivation of the com- and a personal computer running the chromatographic mercially available 2.2-diphenyl-β-picrylhydrazyl radi- so ware LC solution (Shimadzu). e chromatographic cal (DPPH), manifested by the decrease of absorbance separations were performed on a column Alltima C18 - at 515 nm (A et al., 2001). To 980 μl solution 3 µm, 3 × 150 mm (Alltech, Deer eld, USA) equipped of DPPH in methanol (150 μM) 20 μl of sample were with a guard column (3 × 7.5 mm i.d.) lled with the added, shaken for 30 minutes and the measured absor- same sorbent. e temperature of separations was 60 °C bance at 515 nm compared with demineralized water. To and volume of an injector loop was 20 µl. e mobile determine the antiradical activity the optical density dif- phases were the following: A=15 mM HClO4 and B=15 ference between the blank (dilution buff er) and sample mM HClO4, 10 % MeOH, and 50 % ACN. e gradient was used. Antiradical activity was calculated from the ca- program is described in Table 2. With a ow rate of 0.6 libration curve, using gallic acid as standard (10 to 100 ml/min the total length of the analysis was 43 min and mg/l). e results are expressed in the form mg/l antira- the regeneration time was 4 min. Data were recorded in dical equivalents of gallic acid. Gallic acid was obtained the wavelength range of 200 to 520 nm. e detection from SigmaAldrich (St. Louis, USA). e evaluation wavelength was 200 nm for (+)-catechin and (-)-epica- was performed in 4 replicates. techin, 275 nm for gallic acid and 310 nm for trans-res- veratrol. DETERMINATION OF REDUCING POWER In all wine samples the following phenolic compounds REDUCING POWER, PR were analysed: hydroxybenzoic acids (gallic acid), stil- benes (trans-resveratrol) and avan-3-ols (catechin, To determine the reducing ability of wine a method ba- epicatechin). Gallic acid, trans-resveratrol, catechin, epi- sed on the reduction of iron ions (Ferric Reducing / an- catechin were obtained from SigmaAldrich (St. Louis, tioxidant power, F P) (P et al., 2000) has been USA). e evaluation was performed in 4 replicates. modi ed. In 1.5 ml Eppendorf tube 50 μl of solution of iron ions (3 mM FeCl3 in 6 mM citric acid) were mixed STATISTICAL DATA TREATMENT with 20 μl of the sample and the mixture was incubated for 30 minutes at 37 °C. en 930 μl of solution TPTZ e obtained data were processed according to localities (2,4,6-tripyridyl-s-triazine) were added in 50 mM HCl, and grapevine varietes and expressed by mean values. and shaken for 12 minutes, absorbance was measured at Based on the observed homogeneity of the variances, 620 nm against a blank prepared in the same manner in non-parametric method of testing, the Kruskal-Wallis which the sample was replaced by dilution buff er. Redu- test, was used. e in uences of the variety, the locality cing power was calculated from calibration curves using and the year on the analytical parameters were deter- gallic acid as standard (0.1 to 2 mM). e results are ex- mined by a non-parametric method of testing, the Krus- pressed in the form mM gallic equivalents. Gallic acid kal-Wallis test. was obtained from SigmaAldrich (St. Louis, USA). e All statistical analyses were performed with the use of a evaluation was performed in 4 replicates. statistical program UNISTAT (Unistat, Brno, Czech Re- public).

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RESULTS AND DISCUSSION Similar results as for the total phenols were also demons- trated in the contents of total avanols. e content of e contents of total phenols, total avanols and anti- total avanols was the lowest in 'Malverina' from Perná oxidant properties observed in this study are shown in (17.30 mg/l), the highest in 'Merzling' from Sádek Table 3. e average content of total phenols in white (32.25 mg/l). e lowest average content of avanols has wines ranges from 260.0 mg/l in 'Merzling' from Sádek been detected in 'Malverina' and the highest in 'Merz- to 313.50 mg/l in 'Malverina' from Sádek. Similar levels ling'. Similar levels of total avanols were also found in of total phenols in wines from the variety 'Riesling' were Chinese white wine from Vitis vinifera varieties (L et al., also found by F et al. (2004) (223 to 532 mg/l 2009). e content of total avanols was not aff ected by in the wines from the Czech wine region and 175 to 465 variety or location. However, the vintage year was found mg/l in wines from South Moravia). e value of total to be impactful. In Polish wines of the 'Hibernal' variety, phenols found in this study corresponds with contents a lower content of total phenols, but signi cantly higher in Chinese white wines (L et al., 2009), white wines content of avanols (66.13 mg/l) was found (K from South Africa (R et al., 2005) and Croatian et al., 2018). white wines (K et al., 2004). When wines from e antioxidant power of food products is a manifesta- diff erent varieties are compared, the highest content of tion of their ability to defend the human body against total phenols is in the variety 'Malverina' and the lowest free radicals and prevent degenerative damage caused by in the variety 'Merzling'. sustained oxidative stress (D M et al., 2008). Antio- In the current study the highest content of total phe- xidant activity in this study is presented using antiradical nols was detected in 'Malverina', 'Merzling' showed the activity determined by the DPPH and reducing power lowest value. Diff erences between varieties, localities method. Results are shown in Table 3. DPPH antiradical and years were not statistically signi cant. In contrast, activity was not aff ected by varieties or locality, however, signi cant diff erences were observed by L et the in uence of the vintage year was shown. e highest al. (2009), who reported signi cant diff erences between value of antiradical activity was found in 'Malverina' Czech and Moravian wines. from Sádek (59.95). Similarly, reducing power was the

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highest also in 'Malverina' from Sádek (1.32). Although calculation of Spearman correlation coeffi cients (Tab- the study fails to demonstrate signi cant diff erences le 5). A signi cant correlation was found between the between varieties, 'Malverina' shows good antioxidant values of antiradical activity and epicatechin content (r properties. Antioxidant properties of the variety 'Mal- = 0.6874) . Similarly, a signi cant association was also verina' were also studied by K and M found in Brazilian white wines (M et al., 2003). (2009), who, however, found lower antioxidant activity Signi cant correlation dependences were also found than in this study. e antiradical activity for 'Malverina' between total phenolic content and antiradical activity was shown to be up to 25 in the standard wine produc- (r = 0.7430) and total avanols and antiradical activity tion technology. (r = 0.7001). Signi cant correlation between total phe- e concentration of phenolic compounds is very im- nolics and antioxidant properties was also determined in portant for understanding the antioxidant activity of French white wines ( L et al., 2001) and Serbi- wines (R et al., 2012). e Pearson's cor- an white wines (M et al., 2010). Similarly signi cant relation shows the relations between antioxidant and correlation was found between the content of total phe- phenolic compounds. nols and reducing power of AA in this study. Very potent antioxidant compounds are epicatechin Based on the obtained results, it is therefore possible to (V-B et al., 2002), catechin (L and conclude that the wines that have a high content of total Š, 2009), resveratrol (F et al., 2004), gal- phenols, also have high antioxidant activity. In contrast, lic acid (S et al., 2011), total phenols (L whereas gallic acid is also regarded as a compound with et al., 2009; J et al., 2012; L and Š, a close relationship to the antioxidant properties of wine 2009) and total avanols (L et al., 2009; J et (L and Š, 2009), this study focused on or- al., 2012). e contents of these phenolic compounds ganic wines found no signi cant correlation between the in studied wines from organic production are shown in antioxidant properties and the content of gallic acid. Table 4. Statistically signi cant eff ect of the variety was Canonical discriminant analysis (CDA) was used for de- shown only for the content of trans-resveratrol. Wines termination of chemical markers which are also the most made from the variety 'Malverina' had a signi cantly hig- important for the wine diff erentiation on the variety ba- her content of these compounds than those made from sis. CV1 and CV2 represented approximately 99.8 % and 'Hibernal' and 'Merzling'. On the other hand, K 0.20 % of the variation, respectively (CV = canonical va- et al. (2018) found higher levels of catechin and epi- riable, 100 % represents total variation). e diff erences catechin in Polish wines of the 'Hibernal' variety. ey between the regions were signi cant (Wilks' lambda = also showed that catechins and epicatechins were clearly 0.0001 at the value of p = 0.00). e Wilks' lambda value the dominant compounds in white wines made from re- near zero indicates a good discrimination function of the sistant varieties with their ratio being 2:1. individual CV. In the present study the variety 'Hibernal' had a lower It can be seen from the achieved results that the CV1 content of trans-resveratrol than that stated in a previous most considerably correlates with antiradical activity study by M et al. (2001). In the variety 'Malveri- and epicatechin in a positive way and with total avanols na' from Perná in contrast, our study revealed a high level and total phenols in a negative way. e CV2 is positi- of trans-resveratrol with an average of 1.61 mg/l. is va- vely connected with epicatechin, and negatively with riety was found to contain high levels of trans-resveratrol catechin. Figure 1 presents the distribution of the grape also in previous studies, for example by K and varieties based on results of the canonical discriminant M (2009) a higher value of 4.09 mg/l was analysis. e 'Merzling' variety can be characterized by reported. total avanols, total phenols and catechin, 'Hibernal' e statistical relationship between the antiradical ac- variety by antiradical activity and epicatechin, and 'Mal- tivity and the phenolic compounds was evaluated by verina' by antiradical activity, epicatechin and catechin.

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Fig. 1: Results of canonical variate analysis for rst (CV1) and second (CV2) variate analysis of wines from diff erent varieties (a = 'Merzling', b = 'Hibernal', c = 'Malverina')

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CONCLUSION

Wines from 'Malverina' are characterized by the highest of total avanols. Signi cant, but not statistically signi- content of total phenols and antioxidant activity. Wines cant correlations con rm, that the total phenols, total from 'Merzling' are characterized by the highest content avanols and epicatechin may be considered important antioxidants. REFERENCES

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Received January, 7th, 2019

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