Influence of Wine-making Technologies on Phenolic Content and Antioxidant

8/4/2019 Influence of Wine-making Technologies on Phenolic Content and Antioxidant

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Influence of wine-making technologies on phenolic content and antioxidant

power ofPrimitivo musts and wines*

Baiano A., Gambacorta G., Terracone C., la Gatta B., Pati S., La Notte E.

Dipartimento di Scienze degli Alimenti, Facolt di Agraria, Universit degli Studi di Foggia

Via Napoli, 25 71100 Foggia ITALYTel. +39 881 589117, Fax +39 881 589308, e-mail: [email protected]

Keywords: antioxidant power, polyphenols, Primitivo, wine, wine-making technologies*Project financed by Camera di Commercio di Taranto -Italy

Abstract

Wines are un important source of phenolic compounds. In particular, red wines had a

polyhenol content (especially tannins but also resveratrol, caffeic acid and catechins)considerably higher than white wines. The purpose of this work was to evaluate the influence

of nine wine-making technologies on the phenolic content and the antioxidant activity ofPrimitivo musts and wines. The addition of tannins allowed to increase the phenolic content.

The results of the antioxidant activity determination were different as a function of theanalytical method applied.

Introduction

The importance of phenolic compounds is related to their antioxidant activity.Epidemiological studies have demonstrated that the consumption of phenolrich foods and

beverages contributes to the reduction of coronary heart disease mortality (Cul et al., 2002),the inhibition of chronic inflammation and thrombosis (Kinsella et al., 1993) and the

prevention of certain types of cancer and that the benefits are greater with a diet rich in aparticular class of phenols named flavonoids (Bell et al., 2000).

Phenolic compounds contribute to wine colour, taste, structure and make the product suitable

for ageing. Red wines are rich in simple and complex phenolic compounds mainlyrepresented by phenolic acids, flavonols, monomeric catechins, and tannins (Katalinic et al.,2004).

The grape phenol composition and content are affected by several factors such as variety,ripening time, climate, soil, place of growing. In addition, winemaking technologies together

with oenological practices and ageing modify both the phenolic composition and amount andthe antioxidant activity.

Several analytical methods are available for assessing the antioxidant activity of foods andbeverages but, in absence of a standardised method, their results depend on the experimental

conditions applied.Primitivo is a typical Italian vine cultivated in Apulia region that, when processed into a

varietal wine, allows to obtain a high alcoholic and tannic wine, endowed with a ruby-purplecolour and a spicy and red-fruit flavour. Primitivo is genetically similar to the Californian

Zinfandeland the CroatianPlavac mali vines.In spite of the importance and spreading ofPrimitivo wine, literature on its phenolic content

and antioxidant properties is rather insufficient.The aim of the present work was to assess the influence of nine wine-making technologies on

the phenolic content and the antioxidant activity ofPrimitivo musts and wines.


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Materials and Methods

Samples - Grapes ofcv. Primitivo were picked at the right ripening time and submitted to ninewine-making technologies (each of them performed two times), including traditional

vinification, delestage, "saigne", delayed "punching-down", addition of tannins from grape-seeds, addition of ellagic tannins and tannins from skins and seeds, thermo-vinification, cryo-

maceration and extended maceration. Samples of musts were withdrawn and analysed at 0and 6 days of maceration whereas the wines were analysed immediately after pressing and

after a 1-year aging.Total phenolic content - The total phenolic content was spectrophotometrically (at 765nm)

measured according to the Folin-Ciocalteu method as reported by Singleton and Rossi (1965)and the results were expressed as gallic acid equivalents (mgl -1).

The phenolic content was also expressed as Total Phenolic Index at 280nm (TPI, anadimensional number) according to the O.I.V. method n. ENO/SCMAV/04/298 (2006).

Determination of the antioxidant activity - In absence of a standard accepted method forwines, the evaluation of the antioxidant activity of musts and wines was made through the

following tests:- 1,1-diphenyl-2-picrylhydrazyl (DPPH) method, according to O.I.V. method n.

ENO/SCMAV/03/269 (2006). Results were expressed as ED50 (Dilution effective to reduceof 50% the initial DPPH concentration) and as % of steady DPPH;

- carotene bleaching method, according to the methods of Katalinic et al. (2004) and von

Gadow et al. (1997) appropriately modified;

- 2,2-azinobis-(3-ethylbenzothiazoline)-6-sulfonic acid (ABTS+)-metamyoglobin method,according to Miller et al. (1993).

Results and Discussion

The addition of tannins from seeds and from a mixture of skins and seeds positively affectedthe phenolic content in the first steps of maceration. The respective wines, considered

immediately after production and at 1-year aging (Fig. 1 and 2) showed phenolic contents justhigher than those obtained through the other technologies. Concerning, the antioxidant

activity (Fig. 3, 4, 5, and 6), the application of different methods gave different results. Themost important result was the not always good correlation (correlation coefficient

0.426


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- Cul J., Juhasz B., Tosaki A. 2002. Cardioprotection with grapes. Journal ofCardiovascular Pharmacology, 40, 762-769.

- Katalinic V., Milos M., Modun D., Music I., Boban M. 2004. Antioxidanteffectiveness of selected wines in comparison with (+)-catechin. Food Chemistry, 86,593-600.

-

Kinsella J. E., Frankel E. N., German J. B., Kanner J. 1993. Possible mechanisms forthe protective role of antioxidants in wine and plant foods. Food Technology, 47, 467-

469.- Miller N. J., Rice-Evans C., Davies M. J., Gopinathan V., Miller A. 1993. A novel

method for measuring antioxidant capacity and its application to monitoring theantioxidant status in premature neonates. Clinical Sciences, 84, 407-412.

- O.I.V. 2006. Progetti di Risoluzioni Tappa 5 Metodo n. ENO/SCMAV/03/269,Metodo rapido di valutazione del potere antiradicalico dei vini e delle acqueviti

mediante luso di DPPH; Metodo n. ENO/SCMAV/04/298, Stima e quantificazionedei composti fenolici dei vini.

- Singleton V. L., Rossi J. A. 1965. Colorimetry of total phenolics with phosphomolybdic phosphotungstic acid reagents. American Journal of Enology and

Viticulture, 16, 144-158.- von Gadow A., Joubert E., Hansmann C. F. 1997. Comparison of the antioxidant

activity of aspalathin with that of other plant phenols of Rooibos Tea (Aspalathuslinearis), -tocopherol, BHT, and BHA. Journal of Agricultural and Food Chemistry,

45, 632-638.


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Fig. 1 Phenolic content of musts and wines obtained through the different wine-making

procedures.

Fig. 2 Total phenolic index of musts and wines obtained through the different wine-making

procedures.


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Fig. 3 Antioxidant activity (expressed as ED50) of musts and wines obtained through thedifferent wine-making procedures.

Fig. 4 Antioxidant activity (% of steady DPPH) of musts and wines obtained through the

different wine-making procedures.


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Fig. 5 Antioxidant activity, measured according to the carotene bleaching method, of

musts and wines obtained through the different wine-making procedures.

Fig. 6 Antioxidant activity,measured according to the ABTS+-metamyoglobin method, ofmusts and wines obtained through the different wine-making procedures.

Influence of Wine-making Technologies on Phenolic Content and Antioxidant

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