Varietal aromatic potential and volatile fingerprinting from several Portuguese grape varieties: impact of variety and year

Studies on volatile composition consistently show that native and minority grape varieties often exhibit unique volatile profiles, supporting their use for wine differentiation, market diversification, and the valorisation of typicity. To advance knowledge of Portugal’s native grapevines, this study provides a comprehensive assessment of the volatile composition of three white (Encruzado, Malvasia Fina, and Terrantez) and red (Coração de Galo, Jaen, and Touriga Nacional) grape varieties over two consecutive years. This work helps us understand the aromatic potential of the varieties studied and the potential influence of annual climatic conditions on volatile composition. Results for the white varieties showed that the varietal aroma potential index (IPAv) was significantly modulated by year, depending on the variety, indicating differential accumulation of glycosylated aroma precursors. In contrast, for the red varieties studied, IPAv was unaffected by year, variety, or their interaction, suggesting a more stable precursor pool. Regarding individual volatile compounds, obtained by GC×GC-TOFMS, white varieties were mainly driven by varietal identity, particularly for terpenes and C13norisoprenoids, while year effects were stronger for C6 compounds and especially benzenoids. For the red varieties studied, volatile composition reflected combined genetic and year effects, with strong year × variety interactions for terpenes and C13 norisoprenoids, while C6 compounds were largely influenced by variety. Finally, benzenoids were mainly influenced by year. Overall, both variety and year influenced the volatile compounds and aromatic potential of the traditional Portuguese grape varieties studied. This work allowed for a first approach to the study of the aromatic potential of some traditional Portuguese grape varieties grown in northern Portugal, also contributing to a first approach to how the year, and particularly climatic conditions, may influence the main groups of volatile compounds.