Correlation between sensory data and chemical data: case studies

B. P. Machado¹, D. Alves¹, and A. C. Silva Ferreira¹*
* Escola Superior de Biotecnologia, Universidade Católica Portuguesa
Rua Dr. António Bernardino de Almeida 4200-072 Porto, Portugal
E-mail address:  acferreira@aesbuc.pt

The sensory effect of “terroir” and wine production technique on the varietal aroma of TN wines was evaluated by comparing twenty four wines from four regions (Estremadura, Douro, Alentejo e Dão) of Portugal, plus ten Port wines (Fortified wines) both 100% Touriga Nacional (TN).

The aroma of TN varietal wines was profiled using descriptive analysis (QDA).
Eleven trained judges evaluated sixteen aroma attributes (Bergamot, Violet, Critic, Balsamic, Veggie, Herbaceous, Caramel, Butter, Spicy, Dried Fruit, Berry Fruit, Tree Fruit Tropical Fruit, Oak, Nutty and Alcohol). All the fourteen aromas differed significantly among wines.

The principal component analysis, where the first two PCs accounted for 73.20% of the variance, indicated that Port wines were higher in alcohol, balsamic, caramel and dried fruit aromas and lowest bergamot, berry-fruit, tropical-fruit and tree-fruit compared the others table wines. Table wines from the Douro and Alentejo regions were higher scored in Bergamot, citrus and violet for TN.

By gas chromatography-olfactometry analysis three odorant zones (OZ) could be related to TN wines, described as: “Bergamot”; “Citric”; “Tropical-fruits”. By AEDA their importance was confirmed and it was observed that it discriminates from other varietals. The “Bergamot-Like”; “Citric”; were related to the presence of Linalol (in agreement with the aroma of both isomers of these terpenol) and with linalyl acetate.  A similarity test was performed with a non TN wine supplemented with linalool alone or in combinations. The highest similarity value was observed on supplemented samples with linalool (SV=5.9). Analysis of several red wines from different varieties show that terpenols are present in higher amounts in TN wines which prove that these compounds are the clue of the varietal aroma of TN wines.

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