Article

Effect of winemaking treatment and wine aging on phenolic content in Vranec wines.

Institute of Chemistry, Faculty of Natural Sciences and Mathematics, Sts Cyril and Methodius University, Arhimedova 5, 1000 Skopje, Republic of Macedonia ; Department for Enology, Institute of Agriculture, Sts Cyril and Methodius University, Aleksandar Makedonski bb, Skopje, Republic of Macedonia.
Journal of Food Science and Technology -Mysore- (Impact Factor: 2.02). 04/2012; 49(2):161-72. DOI: 10.1007/s13197-011-0279-2
Source: PubMed

ABSTRACT Phenolic compounds and colour stability of red wines produced from Vranec Vitis vinifera L. grape variety were investigated by means of different maceration times (3, 6 and 10 days), two doses of SO2 (30 and 70 mg/L SO2), two yeasts for fermentation (Vinalco and Levuline), temperature of storage and time of aging (3, 6 and 16 months). In general, maceration time influenced the phenolics extraction from the grapes into the wine. Highest concentrations of phenolic components were observed in the wines produced with 6 days of maceration, except for the flavan-3-ols which were present in highest amounts in the wines macerated for 10 days. Higher doses of SO2 increased the extraction of polyphenols, preventing the wines from oxidation, while the effect of yeast on phenolics extraction was not significant. Wine aging affected the phenolic content of wines produced with 3 days of maceration and caused intensive decrease of anthocyanins during the storage period. Wines aged at higher temperature showed lower anthocyanin levels and less intense coloration. Principal component analysis revealed that separation of the wines was performed according to the hue value in correlation with the maceration time and time of wine aging.

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    ABSTRACT: This study evaluates the effect of using of pectolytic enzyme preparations on the phenolic content and chromatic characteristics of young red wines produced from Vranec (Vitis vinifera L.), the important grape variety in Macedonia. Phenolic compounds and chromatic characteristics of young red wines were investigated by means of enzyme treatments with diverse enzyme preparations (Vinozym Vintage FCE, Rohapect), with four doses and time of aging (6 months). Enzyme treatments and maceration time influenced the phenolics extraction from grapes into wine. In the wines produced with 6 days of enzyme maceration, highest concentrations of phenolic components were observed, and aging for 6 months lead to increasing the phenolic content to 32 %, total anthocyanins to 66 %. The color intensity rose with aging in enzyme treated grapes. Results from the analysis showed that all enzyme preparations increased the extraction of polyphenols and elicited an improvement in the visual aspect of the wine. Keywords - enzyme preparations; red wine; phenolic compounds; color; spectrophotometry
    (IJIRSE) International Journal of Innovative Research in Science & Engineering ISSN (Online) 2347-3207. 12/2014; 2(12):817-824.
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    ABSTRACT: The purpose of this work is to study the effect of grape pomace enrichment in solid phase (stems and seeds) on phenolic compounds and colour stability of obtained red wines, before and after use of different fining agents. Results have shown increase in total phenols and flavan-3-ols content after grape solid phase addition. On the other hand, decrease in anthocyanins content has generally been recorded in all wine samples except in wines obtained with addition of 40 g/l of seeds during maceration. Stems addition caused decrease in colour intensity while addition of seeds has increased this colour parameter. The use of four fining agents (albumin, gelatine, bentonite and PVPP) has been investigated and compared, especially in terms of their influence on potential stabilization effect of grape solid phase on wine colour. Fined wines tended to have considerably lower anthocyanin and flavan-3-ol levels, especially in the case of gelatine and PVPP treatment (decrease up to 60 and 70%, respectively). In the case of chromatic parameters, the used fining agents caused colour intensity decrease but it is important to emphasize that their values, after fining, were still as high as expected from red wine. This can be explained by the stabilization effect of increased flavan-3-ols content. Keywords: red wine; stems; seeds; fining agents; phenolic compounds; colour. Grapes contain a great amount of different phenolic compounds, which are located in different parts of grape cluster (seeds, pulp, skin and cluster stems), and their types and amount are affected by several factors [1–6]. These compounds, especially anthocyanins and proanthocyanidols, are extracted in the maceration process and they are responsible for the characteristic colour, flavour and astringency of red wine. Seeds, stems and skin are the main source of these compounds in wine [7–9]. Seeds contain about 60% of total phenolic compounds of grapes, wherein most of these compounds are flavan-3-ol monomers and poly-mers (proanthocyanidols) [10]. Significant concentra-tions of tannins are found in cluster stems, of which 40−50% is polymerized [11]. Flavan-3-ols and tannin ex-traction from seeds is more intensive with the increase of ethanol content in pomace during vinification, ac-cording to their lower solubility in water [5,12]. Cate-chins, as the most widespread in the plant world, are the most important flavan-3-ol derivative. These com-pounds are found in free form, but can also be este-rified, most commonly with gallic acid. In grapes and wine (+)-catechin, (–)-epicatechin, epicatechin-3-O-gal-late and their dimers, trimers and oligomers are found Correspondence: U.
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: This study evaluates the effect of using of pectolytic enzyme preparations on the phenolic content and chromatic characteristics of young red wines produced from Vranec (Vitis vinifera L.), the important grape variety in Macedonia. Phenolic compounds and chromatic characteristics of young red wines were investigated by means of enzyme treatments with diverse enzyme preparations (Vinozym Vintage FCE, Rohapect), with four doses and time of aging (6 months). Enzyme treatments and maceration time influenced the phenolics extraction from grapes into wine. In the wines produced with 6 days of enzyme maceration, highest concentrations of phenolic components were observed, and aging for 6 months lead to increasing the phenolic content to 32 %, total anthocyanins to 66 %. The color intensity rose with aging in enzyme treated grapes. Results from the analysis showed that all enzyme preparations increased the extraction of polyphenols and elicited an improvement in the visual aspect of the wine. Keywords - enzyme preparations; red wine; phenolic compounds; color; spectrophotometry
    (IJIRSE) International Journal of Innovative Research in Science & Engineering ISSN (Online) 2347-3207. 12/2014; 2(12):817-824.

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