Aromatypicity of Austrian Pinot Blanc Wines

Pinot blanc is a grape variety found in all wine-growing regions of Austria. However, there are only few scientific studies which deal with the aroma of wines of this variety. In the course of this project, the relationship between aroma profile and the typicity of Austrian Pinot blanc wines was studied. The aim was to describe the typicity and to find significant differences in aroma profiles and aroma descriptors of typical and atypical Pinot blanc wines. Since the typicity of a jointly anchored prototype is embedded in the memory, typical attributes for Austrian Pinot blanc wines were first identified by consumers and experts or producers. According to this, 131 flawless commercial Austrian wines of the variety Pinot blanc of the vintages 2015 to 2017 were analysed for more than 100 volatile substances. The wines of the vintages 2015 to 2017 were judged by a panel of producers and experts for their typicity; furthermore, the wines of the vintage 2017 were also evaluated by a consumer panel and a trained descriptive panel. Subsequently, typical and atypical wines were described by the trained descriptive panel. It was found that Pinot blanc wines typical of Austria showed significantly higher concentrations of the ester compounds ethyl hexanoate, ethyl butanoate, ethyl octanoate, ethyl decanoate, methyl hexanoate, hexyl acetate and isoamyl acetate, while atypical wines had higher concentrations of free monoterpenes such as linalool, trans-linalool oxide, nerol oxide, nerol and alpha-terpineol. The sensory description of typical Pinot blanc wines was significantly more pronounced for the attribute “yellow pome fruit”, and tended to be more pronounced for the attributes “green pome fruit”, “pear”, “walnut”, “pineapple”, “banana” and “vanilla”, while the atypical Pinot blanc wines were described more by the attribute “citrus”. These findings could help to ensure that, through targeted measures, Austrian Pinot blanc wines become even more typical and distinguish themselves from other origins such as Germany or South Tyrol through a clear concept of typicity.

Austrian Pinot blanc wines: Typicity, wine styles and the influence of different oenological decisions on the volatile profile of wines

Pinot blanc is found in all wine regions of Austria. However, it plays an economically subordinate role compared to the most important white grape variety, Grüner Veltliner. The concept of wine typicity and terroir is that the geographical origin and oenological practices, along with the grape variety, make an important contribution to the final expression of the finished wine. The purpose of this study was to discuss different styles of Austrian Pinot blanc wines and to discuss the various wine production decisions in terms of wine stylistics and aromatic profile. 131 commercial Austrian wine samples of the Pinot blanc variety of the 2015 to 2017 vintages were collected and the manufacturer's practices were determined by means of a questionnaire related to the wine styles. Using various GC-SIM-MS methods, more than 100 essential volatile substances were quantified. A trained panel, an expert panel and consumers evaluated the wines based on typicity and quality. 15 typical wines were then assessed on a sensory basis by means of predetermined aroma and wine styles. The four Austrian Pinot blanc wine styles previously discussed and presented by the same authors (citrus (1st style), green apple and green pear (2nd style), ripe yellow apple, quince, cooked pear, bread and honey notes (3rd style), as well as intensive oak notes (4th style)) were able to be partially reproduced by the trained panel. The following three wine styles could be better understood by the consumers: fresh fruity (style A), complex aroma with or without moderate wood (style B) and lots of wood aroma (style C). These styles (A–C) were able to withstand a sensory examination and a discriminant analysis by substance. An oenological guideline could help the producers to achieve the respective style. Austria's wine-growing area is probably too small and the importance of the Pinot blanc variety for the individual areas still too low to support the terroir concept for this grape variety.

Determination of Glutathione in Austrian Wine Samples: The Effects of Freezing, the Choice of Yeast and Storage

Glutathione (GSH, γ-L-Glutamyl-L-Cysteinyl Glycine) is a tripeptide of L-glutamate, L-cysteine and glycine. GSH in wine is derived from either grapes or yeast, during alcoholic fermentation. The GSH concentration in wine is very variable and depends on the environmental conditions as well as viticultural practices. During winemaking GSH has a significant role in oxidation prevention due to its unique redox and nucleophilic properties. Since GSH is very reactive it is highly important to prepare samples immediately and under inert conditions just prior to the determination of the GSH concentration. Therefore the aim of this research was to implement a method for the quantitative determination of GSH levels in grape juices (musts) made from different Austrian grape varieties and to investigate the influence of yeast on the GSH content in wine after aging. The results of this research have shown that monitoring with nitrogen gas, sulphur dioxide and freezing process at −25 ºC led to a good protective effect on the free glutathione amount in wine and grape samples. The GSH concentration in the samples was variable. Levels were ranging from non-detectable to up to 23.10 mg/l, and it showed that grape variety has no impact on GSH concentration in the must. Furthermore the results suggest that the choice of yeast has an impact on GSH content in wine even after 6 and 18 months of aging.