PhD: Anthocyanin profile of the Macedonian red wines

Maja Dimitrovska
Department of Food Technology and Biotechnology, Faculty of Technology and Metallurgy, Ss. Cyril and Methodius University, Skopje, Macedonia
May, 2013
 

Abstract

The anthocyanin composition of red grape varieties Vranec, Cabernet Sauvignon, Merlot and Pinot Noir grown in R. Macedonia was determined analyzing the skin extracts of the grape berries. The relative content of the identified anthocyanins was calculated and the obtained anthocyanin profiles were compared in terms of acylation and anthocyanidin distribution. The predominant anthocyanin in all varieties was malvidin-3-glucoside. Vranec variety was characterized by high proportions of coumaroyl derivatives and peonidins. The most pronounced difference among the studied grape cultivars was the relative amount of acetate derivatives. Different relationships among the anthocyanin groups of compounds were considered as parameters for differentiation of the cultivars. The relationship between coumarates and acetates in Vranec was significantly higher compared to Merlot and Cabernet. Moreover, the greatest difference of ratio between delphinidins and peonidins allows clear discrimination between the studied grape cultivars.

Evolution of the individual monomeric anthocyanins during vinification of grapes into wines was investigated using different oenological treatments for each of the studied grape varieties. The dynamics of the extraction was observed daily during the maceration, analysing the anthocyanins in the must using HPLC. Additionally, the effect of the applied vinification protocols on the anthocyanin composition of the obtained wine at the end of maceration and wine aged 6 months was investigated and compared with the anthocyanin patterns of the original grape. The results confirmed that anthocyanin composition of the grapes changed during fermentation. Different vinification protocols applied to a same raw material resulted in wines with similar anthocyanin patterns. However, the similarity decreased with the aging of the wines.

Wines of Vranec, Cabernet Sauvignon and Merlot varieties, from 1 to 3 years old, produced in different wineries in R. Macedonia were examined for their anthocyanin and chromatic profiles, total phenols, antioxidant potential and macro and micro elements. The established data were submitted to analysis of variance and principle component analysis in order to evaluate their potential for differentiation of wines according to variety and vintage. Vranec wines have shown distinctive characteristics, with the highest content of anthocyanins and values of colour intensity, % red and % dA, compared to the other two studied varieties. The content of petunidin-3-glucoside, peonindin-3-glucoside and anthocyanin acetates were established as possible markers for differentiation of Vranec wines from Cabernet Sauvignon and Merlot wines. However, none of the assayed parameters could be used for differentiation of Cabernet Sauvignon from Merlot wines. It was observed that successful classification of the wines by variety according to anthocyanins is limited by the wine age. The chromatic parameters allowed distinguishing of young from old Vranec wines. Additionally, it was found that elemental composition distinguished domestic wines from wines produced in other regions of the world.