Composition and extractability of grape anthocyanin glucosides under different environmental conditions: terroir and vintage effects

Abstract

Two terroirs of the Eger Wine District (a steep-sloped and a flat vineyard) were examined in two years in order to describe the changes in the concentration and composition of berry skin/wine anthocyanins of the Kékfrankos variety at different harvest dates and to examine a possible relationship between the extractability of anthocyanin glucosides and terroir/vintage characteristics. The two growing sites and the vintages were characterized by climatic data. Temperature and precipitation parameters were recorded by automatic weather station at both sites. Experimental wines were made at three harvest dates from both terroirs. Anthocyanin glucosides composition and concentration of the wines and skin extractions were measured by HPLC. There were remarkable differences in grape ripening characteristics, skin anthocyanin concentration and composition between the vineyards as well as the vintages. Interestingly, comparing the terroirs the higher skin anthocyanin concentration was not accompanied with higher anthocyanin concentration in the experimental wines. In both vineyards, similar berry skin/flesh weight ratios were detected; therefore, the difference in wine anthocyanin glycoside concentration was probably due to the difference in extractability. Anthocyanin glycoside composition of the skin and wines showed only a little shift during the ripening within a year. However, the changes in the ratio of the different anthocyanin glucosides between the years were more pronounced compared to harvest dates and terroir. Extractability is an important factor of the so called “terroir effect”. However, vintage characteristics were found to have a greater effect on wine and berry skin anthocyanin composition then the location of the vineyard.