Chemical and sensory influences of the UV-C light of 254 nm in combination with the antioxidant substances in wine

The elaboration of sparkling wine is a demanding process requiring technical as well as scientific skills. Uncovering the role of the terroir to the final product quality is of great importance for the wine market. Although the impact of the yeast strains and their metabolites on the final product quality is well documented, the action of bacteria still remains unknown. The malolactic fermentation (MLF) is carried out by the lactic acid bacteria after the alcoholic fermentation in order to ensure the microbial stability during the second fermentation that takes place in the bottle or in tanks. Oenococcus oeni is the only selected species to drive MLF that has been commercialized for sparkling wine elaboration and it is naturally present on grapes, in the cellar and also in the final product. However, whether the bacterial strain contributes to the sensory characteristics of sparkling wine is still questioned.

Non-saccharomyces yeasts play a crucial role in fermentation, producing a variety of secondary metabolites and enzymes that contribute to aromatic and sensory complexity compared to saccharomyces yeasts. It is crucial to understand and control the dynamics of non-saccharomyces yeasts to produce distinctive and high-quality fermented beverages.

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.

In a situation of uncertainty towards the overall effect of climate change and the reduction of pestice utilization on quality, the wine sector needs to maintain the profitability of producers, which inexorably depends on ensuring the quality of grapes and wines. Among the various alternatives that can be adopted, hybrid varieties carrying resistance genes are currently gaining the attention of researchers and producers. Some of them are already a reality and are included in the national catalogue of some countries, selected by research institutes all over Europe.

The aim of this study was to determine how artificial shading influenced berry development and anthocyanin accumulation in ‘Cabernet sauvignon’. Opaque polypropylene boxes were applied to grape bunches over three different developmental stages.