Comparing the Drama location effect in red wines: international varieties vs. native Greek

Introduction: Terroir is considered an essential factor in producing wines with unique quality. This region can give distinct terroir expressions of the same grape variety, which, in turn, can produce wines differing in quality parameters, phenolic compounds, and antioxidant activity. The present work evaluated the effect of diverse locations in the PGI region of Drama on the main quality parameters of red wines and their phenolic and antioxidant activity.

Methods: Two international and one native grape variety, grown during the 2022 cultivation season, were obtained from diverse locations of the PGI Drama. The wines were made using the same procedure to avoid variation. The berries of properly mature intact grapes (25 kg batch-scale) were crushed to obtain the juice, inoculated (25 g/hL) with the same Saccharomyces cerevisiae strain, and allowed to ferment. Fermentation was performed in duplicate in 30L vessels under controlled temperature conditions. Besides wine quality parameters such as pH, titratable acidity (TA), sugars, alcohol (%vol), and colour, total phenolic and flavonoid contents (TPC, TFC) were determined, as well as antioxidant activity, by three different analytical assays (DPPH, ABTS, FRAP).

Results: The wines produced differ not only in their quality attributes but also in the amount of phenolics and flavonoids and their antioxidant capacity, suggesting that terroir plays a primary role in this variation. On the other hand, altitude correlated positively with the red colour proportion (0.484, p<0.5) and alcohol content (0.590, p<0.01) and negatively with the blue colour proportion (-0.597, p<0.01) and pH (-0.457, p<0.5) of the wines.

Conclusions: Apart from the wine quality parameters, the TPC and TFC are revealed as distinct terroir expressions of the three wine varieties examined in the present work. The native grape variety showed stability among the locations regarding the phenolic content and the antioxidant capacity of the produced wine.