On sample preparation methods for fermentative beverage VOCs profiling by GCxGC-TOFMS

Hanseniaspora vineae (Hv) is a fermenting non-Saccharomyces yeast that compared to Saccharomyces cerevisiae (Sc) present some peculiar features on its metabolism that make it attractive for its use in wine production. Among them, it has been reported a faster yeast lysis and release of polysaccharides, as well as increased ß-glucosidase activity. Hv also produces distinctive aroma compounds, including elevated levels of fermentative compounds such as ß-phenylethyl acetate and norisoprenoids like safranal. However, it is known for its high nutritional requirements, resulting in prolonged and sluggish fermentations, even when complemented with Sc strain and nutrients.

Infection of the grapes with Botrytis cinerea has a tremendous impact on the resulting crop yield and quality. Well-known problems that are associated with B. cinerea are specific off-flavors, poor filterability, and brownish color in white wines. The development of a B. cinerea infection strongly depends on weather conditions and is highly variable through different vintages. Typical control measures include defoliation and the use of fungicides, which involves high personnel and material costs. They also involve a great risk, especially since the effectiveness and time point of these treatments are difficult to predict.

Wine grapes exposed to wildfire smoke have resulted in wines with burnt and ashy sensory characteristics¹, that are undesirable qualities in wine. In extreme wildfire events, this can lead to total loss of grape crop. Currently there are no effective solutions in the market to prevent the uptake of smoke compounds into grapes. In this study, previously developed innovative film coatings were tested to analyze their effectiveness in reducing smoke phenol absorption². Four different cellulose nanofiber-based film types were investigated.

The selection, characterization, and recruitment of autochthonous yeast strains to drive the alcoholic fermentation process is a highly researched practice because it allows the differentiation of the organoleptic properties of wines, assuring process standardization, reducing fermentation times and improving the quality and safety of the final products [1, 2]. Sparkling wines are “special wines” obtained by secondary fermentation of the base wine. ​In the traditional method (Champenoise method), the re-fermentation takes place in the bottle after the addition to the base wine of the so-called tirage solution. This step, also known as prise de mousse, is followed by an aging period characterized by the release of compounds from the yeast cells that affect the organoleptic properties of the final product. The use of autochthonous yeasts as starter cultures for secondary fermentation is one of the recent innovations proposed to enhance and differentiate these wines’ sensory quality [3,4]. Apulia is the second Italian wine-producing region, and its productive chain is now going through a qualitative evolution by implementing the employment of innovative approaches to exalt the peculiar properties of regional wines.

The yeast Metschnikowia pulcherrima is a microorganism of great biotechnological interest, both for improving winemaking processes and for other applications outside the wine supply chain.