The following standards
were applied (the m/z ratios used for quantification are shown in parentheses): cis/trans-linalool oxide (59), linalool (71), hotrienol (71), cis/trans-rose oxide (139), cis-limonene oxide (67), trans-limonene oxide (94), α-terpineol (93), β-terpineol (71) γ-terpineol (121), nerol (69), β-citronellol (69), geraniol (69), nerol oxide (68) and lavandulol (69). Rose oxide was obtained from Moellhausen (Vimercate, Italy), hotrienol from Dabrafenib Treatt (Lakeland, Florida), nerol oxide from Roth (Karlsruhe, Germany). All other standards were obtained from Fluka (Sigma–Aldrich, Vienna, Austria). The limit of quantification (LOQ) was determined as 0.3 μg/L, the relative standard deviation between repeated samples (repeatability) was below 6%. The wines were evaluated in triplicate by a panel of seven trained tasters. The participants are officially approved tasters for the quality assessment of Austrian wines. The tasters are trained according to the Austrian wine law and their performance is evaluated annually. Assessment took place in a standard sensory analysis chamber (EN ISO 8589) equipped with separate booths under yellow light forcing the
tasters to focus only on the aroma and taste of the wines. The tasters were presented with the wines in groups of five wine glasses each. The wines were presented in randomised order in coded standard tasting glasses (ISO 3591). In each group, the tasters were first asked to rank the wines on their aroma intensity using an unstructured MS-275 cost scale ranging from 1 to 5 with 1 the highest and 5 the lowest aroma intensity. The
wines where then sorted according to the perceived aroma intensity, following the method of Cartier et al. (2006). Second, the tasters had to assess each wine based on their olfactory and taste sensations on an unstructured scale from 0 to 10, with 10 reflecting the highest intensity of each attribute. The attributes involved were typical Riesling descriptors (stone fruit, citric, pomaceous fruit), attributes usually associated with white wines but not with Riesling (freshness, spice, tropical, candy). Further attributes were “floral” (corresponding to terpenoid aroma compounds) and “typicality” Abiraterone concentration (Riesling). The data from terpene analysis (Section 2.4) were statistically analysed with the software package SPSS 18. One-way analysis of variance (ANOVA) was applied to test for significant differences between the individual treatments. The results were analysed by Student’s t-test (Student–Newman–Keuls) at a significance level of 95% (α = 0.05). The results from the sensory evaluation (Section 2.5) were analysed for significant differences (α = 0.05) by ANOVA (Statgraphics). The first enzyme assays were performed under optimal enzyme conditions (pH 5.5, ethanol removed) using an extract from a white wine (Traminer, Austria). According to Mateo and Jiménez (2000), Traminer is classified as a non-Muscat, but aromatic variety, that depends on monoterpenes as major flavour components.