Symbiotic microorganisms application in vineyards: impacts on grapevine performance and microbiome

Wine perception is a multisensory experience that makes use of the sight, smell, and taste senses. When wine is sensorially assessed, the stimulus received generates multiple signals that tasters convert into organoleptic descriptors. Colour is commonly the first attribute evaluated during wine tasting. Moreover, the colour properties provide the taster with a priori information of the wine’s aroma. This preconceived perception is later confirmed or denied during the aroma evaluation.

Condensed grape tannins play a major role in the organoleptic properties and quality of red wine. Recently, a new sub-family of macrocyclic condensed tannins has been identified in red wine and named “crown tannins”. Indeed, the first compound of the family identified and characterised by NMR was the crown procyanidin tetramer which is composed of a macrocyclic structure composed of four (-)-epicatechins link together by B-type interflavanoid linkage in the following an alternative sequences of C4-C8 and C4-C6 linkage. The 3D structure of this unusual crown procyanidin family reveals a central cavity in the molecule [1].

The odors of wines are diverse, complex and dynamic and much research has been devoted to the understanding of their chemical bases. However, while the “basic” chemical part of the problem, namely the identity of the chemicals responsible for the different odor nuances, was satisfactorily solved years ago, there are some relevant questions precluding a clear understanding. These questions are related to the physicochemical interactions determining the effective volatilities of the odorants and, particularly, to the perceptual interactions between different odor molecules affecting in different ways to the final sensory outputs.

The Mediterranean basin is one of the most vulnerable regions to Climate Change effects. According to unanimous forecasts, the vineyards of Castilla-La Mancha will be among the most adversely affected by rising temperatures and water scarcity during the vine’s vegetative period. One potential strategy to mitigate the negative impacts of these changes involves the identification of grapevine varieties with superior water use efficiency, while ensuring satisfactory yields and grape quality.

Wine flavour is the integration of distinct physiologically defined sensory systems that combine taste, aroma and trigeminal sensations, and it is a key determinant factor for the acceptance of wine by consumers. Volatile compounds, are important contributors to wine flavour, specially to aroma. These small and low-boiling point compounds are easily released into the air allowing to enter and move within the nasal or oral cavities where they can bind the olfactory receptors. Additionally, wine also contains aroma precursors, which are non-volatile compounds, but that can be broken down releasing volatile odorants. During wine tasting, all these chemicals (volatiles and non-volatiles) can be submitted to the action of salivary enzymes.