Flor yeast diversity and dynamics in biologically aged wines

In this work, an innovative analytical method has been proposed for fast and reliable in-line analysis of tannins in wines; the method is fast, does not require sample preparation and is based on the selective reactivity of tannins in a mixture containing proteinaceous matter (i.e. gelatin), under pH 3.5, resulting in the formation of white cloudiness.

Commercial grapevine propagation relies on the ability of dormant wood material to develop adventitious roots.

Elemental sulfur is a fungicide used by grape growers to control the development of powdery mildew, caused by the fungus Erysiphe necator. This compound is effective, cheap and has a low toxicity with no withholding period recommended. However, high levels of S0 residues in the harvested grapes can lead to the formation of reductive sulfur compounds that can impart taints and faults to the wine. Hydrogen sulphide (H2S) is a very volatile and unpleasant sulfur compound which formation is connected to high residues of S0 in juice (10 – 100 mg/L).

Astringency is a crucial sensory attribute typically described as the drying and/or puckering sensation occurring after the consumption of tannin-rich foods and beverages. In this study, thirty-seven red wines from different varieties, origins and styles were evaluated, analyzing both chemical and sensory features. Principal Component Analysis was used for dimensionality-reduction and for correlating selected chemical parameters against astringency. The results showed that tannin content was the most important chemical parameter influencing overall astringency but more clearly the dryness sub-quality, followed by pH, titratable acidity and alcohol content.

Interest and willing-ness to buy alcohol-free wines by customers is increasing for several years [1]. Due to the rising relevance of dealcoholised wines it is the objective of this study to contribute to a better understanding of the flavor variation among dealcoholised wines and to explore enological measures, how to improve final quality.
First a range of commercial, alcoholfree white wines were analysed by the holistic sensory method projective mapping, including a question for hedonic acceptance. Based on the combination of a non-target-HS-SPME-GC/MS analysis with sensory analysis we obtained a clustering of the wines into three groups.