Identification of key odourants of sauvignon blanc and regional differences between wines from New Zealand and overseas

Abstract

In this thesis the chemical composition of Sauvignon Blanc wine aroma and its sensory descrition was explored. 83 wines from two consecutive vintages were analyzed for quantities of a range of aroma compounds. For these wines data from quantitative sensory analyses from another PhD student were available for comparison. From the quantitative data Odour Activity Values (OAV) were calculated to obtain information about the impact of quantitative differences on the aroma. Another approach to evaluate the impact of aroma compounds on the overall aroma of wine bouquet was undertaken using Aroma Extract Dilution Analysis (AEDA). The final confirmation of results obtained by OAV and AEDA was then achieved by reconstitution and omission tests with deodorized Sauvignon Blanc wine using quantitative descriptive analysis by a trained sensory panel. The main findings of this thesis were that thiols are present on average in higher concentrations in Sauvignon Blanc wines from New Zealand, especially from Marlborough, compared to wines from other countries. This was also the case for several esters and C₆-alcohols. Thiols and esters had the highest impact on the overall aroma of Sauvignon Blanc according to OAV. AEDA revealed β-damascenone as most important compound, followed by thiols, higher alcohols and esters. Linalool scored surprisingly high in AEDA as well. Reconstitution and omission tests showed that esters and terpenes had a higher impact compared to thiols, β-damascenone showed an enhancing effect on the impact of thiols in the model wine. Overall no major impact for methoxypyrazines was seen in the various experiments.