Polyphenolic and aroma profile of Vranec wines fermented with isolated yeasts from Tikveš wine area

Project summary

Project title: Polyphenolic and aroma profile of Vranec wines fermented with isolated yeasts from Tikveš wine area 

Duration: March 2013 – March 2015

Wine contains a number of polyphenolic constituents classified as flavonoids and non-flavonoids that play a major role in enology. They contribute to wine sensory characteristics, especially colour, flavor and astringency and therefore, to the differences between red and white wines. On the other hand, wine aroma is a one of its most important characteristics produced by a complex balance of different groups of volatile compounds, belonging to alcohols, esters, aldehydes, lactones, terpenes, norisoprenoids and phenols. In this study, Vranec wines, the most important red variety in Republic of Macedonia, will be subject of investigation. Fermentation yeasts will be, for the first time, isolated from local grapes and identified, followed by application to the grape mush for fermentation. This project will be focused on determination of the effects of isolated yeast strains on the content of total phenolics, anthocyanins, colour, volatile compounds and antioxidant activity. For this purpose three different techniques will be applied: spectrophotometry, GC-QQQ-MS and electrochemical voltammetric methods. Spectrophotometry will be used for analysis of total phenolics, anthocyanins and colour The aroma composition of the wines will be characterized by means of gas chromatography-triple quadrupole mass spectrometer (GC-QQQ MS). Liquid-liquid extraction with dichlorometane will be used for extraction and concentration of volatile compounds from the wine. Higher alcohols, esters, and fatty acids are expected to be identified and quantified. In addition, electrochemical methods will be applied to characterize the polyphenols in wine using square-wave and cyclic voltammetry and to determine the antioxidant activity. Statistical treatments, including means, standard deviations, one-way ANOVA, Student–Newman Keuls test, Factor Analysis and Cluster Analysis will be performed in order to ascertain possible significant differences between the studied wines.

Keywords: wine, aroma, polyphenolics, spectrophotometry, GC-QQQ-MS, yeasts, Vranec

Concept and objectives

Polyphenols are large and complex group of compounds responsible for the characteristics, quality and colour of the grape and wine, especially for the red ones. Wine containс a number of polyphenolic constituents classified as flavonoids and non-flavonoids which contribute to wine sensory characteristics, especially to colour, flavour and astringency and therefore, to the differences between the red and white wines. The family of wine flavonoids includes anthocyanins, flavan-3-ols, flavonols and dihydroflavonols, whereas the non-flavonoids include phenolic acids (hydroxybenzoic and hydroxycinnamic acids and their derivatives) and stilbenes (resveratrol). Various assay methods for polyphenolic compounds have been developed and among them spectrophotometry as very fast and simple method, as well as liquid chromatography (HPLC-DAD-MS). The aroma compounds are another class of very important wine components affecting its aromatic attributes, wine character, the complexity of wine bouquet and hence its quality. Different groups of volatile compounds have been identified in grapes and wines, including alcohols, esters, aldehydes, lactones, terpenes and phenols. Estimation of aroma compounds is usually performed by gas chromatography as highly efficient separation technique for volatiles analysis and for characterization of the wine bouquet. GC-MS. “Vranec” is the most widely cultivated and the most important red variety in Republic of Macedonia for production of high quality wines. Therefore, the purpose of this study is to provide data for the phenolic and aroma profile of Vranec wines produced with different yeast strains, in order to study their influence on wine quality.  

Considering the importance of the phenolic and aromatic profile of wines and their influence on the wine quality, Vranec wines produced with different yeast strains, are the subject of investigation of this project. Therefore, the main objectives of this project are: 

1. Wine-making, including production of Vranec wines with different yeast strains.

2. Determination of total phenolics, antohocyanins and colour, applying spectrophotometric and HPLC methods.

3. Aroma characterization of wine, by gas chromatography coupled with triple-quadrupole mass spectrometer (GC-QQQ MS)

4. Electrochemical characterization of polyphenols in wine.

5. Dissemination of the results

Research team

The coordinator of the project is Dr. Violeta Ivanova Petropulos, Assistant Professor of Oenology and Chemistry

Senior Researchers: Prof. Dr. Sasha Mitrev; Prof, Dr. Ilija Karov; and Prof. Dr. Violeta Dimovska

Junior Researchers: Fidanka Ilieva, PhD; Biljana Balabanova, MSc; and Biljana Kovacevic, MSc

Contacts

Contact address
Coordinator: Dr. Violeta Ivanova-Petropulos
Assistant Professor of Oenology and Chemistry
Faculty of Agriculture

Published papers in other journals

1. Ivanova Petropulos V., Mitrev S. (2014). Determination of SO2 and total sugars in Macedonian wines. Yearbook of the Faculty of Agriculture at Goce Delcev University – Štip, in press.
2. Ilieva F., Ivanova Petropulos V., Dimovska V., Mitrev S., Karov I., Spasov H. (2013).Influence of autochthonous yeasts on the quality of wines from Vranec and Cabernet Sauvignon varieties, Proceedings at the 24th International Scientific-Expert Conference of Agriculture and Food Industry, 25-28 Sept 2013, Sarajevo, Izmir, pp. 220-225.

Participations at conferences

- Violeta Ivanova Petropulos and Biljana Balabanova participated at the XXIII Congress of Chemists and Technologists of Macedonia, 8-11 Oct 2014, Ohrid, Macedonia. The following papers were presented:

1. Balabanova B., Ivanova-Petropulos V., Nedelkovski D., Mitrev S. (2014). Component analysis for the influence of yeasts on multi-element composition of Vranec wines. XXIII Congress of Chemists and Technologists of Macedonia, 8-11 Oct 2014, Ohrid, Macedonia, poster.
2. Ivanova-Petropulos V., Ricci A., Nedelkovski D., Dimovska V., Parpinello G.P., Versari A. (2014). Influence of yeast strains on phenolic composition and antioxidant activity of Vranec wines. XXIII Congress of Chemists and Technologists of Macedonia, 8-11 Oct 2014, Ohrid, Macedonia, poster.

- Violeta Ivanova Petropulos and Violeta Dimovska participated at the 24th Internatiional Scientific-Expert Conference of Agriculture and Food Industry, September 25-28, in Saraevo, Bosnia and Hercegovina. The following papers were presented:

1. Ilieva F., Ivanova Petropulos V., Dimovska V., Mitrev S., Karov I., Spasov H. Influence of authochtonous yeasts on the quality of wines from Vranec and Cabernet Sauvignon, 24th International Scientific-Expert Conference of Agriculture and Food Industry, September 25-28, Saraevo, Bosnia and Hercegovina, 2013, oral lecture.
2. Dimovska V., Ivanova Petropulos V., Durakova S., Neceva Z., Ilieva F., Characteristics of Sangiovese grape variety (Vitis vinifera L.) grown in Tikveš vineyards, 24th International Scientific-Expert Conference of Agriculture and Food Industry, September 25-28, Saraevo, Bosnia and Hercegovina, 2013, poster.
3. Tašev, K., Ivanova – Petropulos,  V., Stefova M. Determination of main organic acid in Macedonian wine by RP-HPLC, 24thInternational Scientific-Expert Conference of Agriculture and Food Industry, September 25-28, Saraevo, Bosnia and Hercegovina, 2013, oral lecture.

Visit to Plovdiv

- Fidanka Ilieva stayed at the University of Food Technology, Plovdiv, Bulgaria for three weeks (Nov. 2013)