A Flavoromics Approach To The Characterisation Of Pinot Noir Wine Sensory Properties PDF Download

The importance of Pinot noir for the New Zealand wine industry has grown and stands second only to Sauvignon blanc in production volume. This thesis investigates the chemical composition of the aroma of Central Otago Pinot noir and its sensory description with the aim of characterising it in a way that an association is made with the typicality of the region. The first stage included a general exploration of the composition of Pinot noir where the chemical aroma, phenolic, tannin composition and colour properties of 105 Pinot noir wines from New Zealand, Australia, France and USA were determined using five different analytical methods across two vintages. The main finding was that the chemical constituents of Pinot Noir wines can vary both between and within different growing regions. There were several compound families where perception thresholds were exceeded for most of the wine samples, including C13 norisoprenoids, higher alcohols, esters of isoacids and fatty acids and cinnamic esters; these can be considered of importance to the overall varietal aromas of Pinot Noir wines. The second aim was to focus on Pinot noir wines from Central Otago where both chemical composition and sensory attributes were explored using reconstitution studies. Aroma Extract Dilution Analysis (AEDA) was applied to two distinct Central Otago Pinot noir wine styles, a blended estate and a single vineyard premium, over two consecutive vintages. The aroma compounds and/or compound families of importance varied across the wines, while a number of compounds were in common. A total of 42 odorants were identified in the AEDA study with flavour dilution (FD) factors ranging from 3 to 19683, with over 20 having FD > 81. The compounds with the highest FDs for the Estate wines were fruity esters and phenylethyl alcohol, while for the Premium wines the norisoprenoids and volatile phenols originating from oak had the highest FDs. The aroma reconstitution experiments, which considered both chemical and sensorial properties, revealed no overwhelming differences when compound families were omitted. Overall, these results suggest that Central Otago Pinot noir wines do not depend on a few key odorants for their aromatic complexity, but instead on the interactions of many aromatic compounds. An additional aim of the study was to measure the effects on wine quality and volatile composition of two cluster thinning regimes on Vitis vinifera cv. Pinot noir in vineyards located in Central Otago across three seasons. The main finding here was that cluster thinning may have an effect on ripening times and the non-volatile and volatile chemical composition of the subsequent wines. These effects may also lead to detectable sensory differences in the final product. It would seem that crop thinning, while a costly practice due to increased labour and yield reduction, is effective in influencing wine quality. However, a particularly intense level of thinning was not necessary to achieve differences in the wines, as a moderate level of thinning also provided a marked enhancement to several attributes.