Phenolic acid characterization in new varieties descended from Monastrell.

The assessment of wine authenticity is of great importance for consumers, producers and regulatory agencies to guarantee the geographical origin of wines and grape variety as well. Since mid-infrared (MIR) spectroscopy with chemometrics represent a suitable tool to ascertain the wine composition, including features associated with the polyphenolic compounds, the aim of this study was to generate MIR spectra of red wines to be exploited for classification of red wines based on the relationship between grape variety and wine composition. Several multivariate data analyses were used, including Principal Component Analysis (PCA), Discriminant Analysis (DA), Support Vector Machine (SVM), and Soft Intelligent Modelling of Class Analogy (SIMCA).

Tannins are chemically diverse polyphenols contributing to important sensory attributes of food and beverages. In wine, their structure and quantity depend on several factors, such as the grape variety, climate, soil, viticultural and enological practices and the wine-aging process.

Wine industry has to develop new strategies to reduce the negative impact of global climate change in wine quality while trying to mitigate its own contribution to this climate change. The term “ecosystem services”, whose use has been recently increasing, refers to the benefits that human beings can obtain from the interactions between the different living beings that coexist in an environment or system. The management of biodiversity in the vineyard has a positive impact on this crop. It has recently been reported that practices such as plant cover can reduce the occurrence of pests, increase pollination of the vine, improve plant performance1 and affect the phenolic content of grapes.2

After Champagne popping, the first consumer’s observation is the shape of the cork stopper. Consumers expect a “mushroom shape”. Nevertheless, we sometimes observe a “barrel” shape due to inappropriate cork’s elastic properties. The aim of this study was to follow the loss of cork stopper resiliency during 26 months according to the density (d) of the cork in contact with the wine. 1680 disks were weighed + measured and divided in 6 density classes: High (H1 d= 0,19 g/cm3 – H2 d= 0,21 g/cm3), Medium (M, not studied) and Low (L1 d= 0,13 g/cm3 – L2 d= 0,14 g/cm3). Then, 138 technical cork stoppers were produced for each of the 4 studied groups. These corks consisted of an agglomerated natural cork granule body to which two natural cork disks were glued. A total of 552 bottles of sparkling wine were closed with these corks and open after 13, 19 and 26 months to follow cork resiliencies. Wine bottles were stored horizontally; thus, the external natural cork disks were in contact to the wine. During the 26 months of the study, highly significant differences (ANOVA) were observed between the resiliencies of H-corks and those of L-corks, whatever the time studied. The diameters of the L-corks were statistically higher than those of the H-corks. No significant differences were observed between L1 and L2 corks. At the opposite, differences were noted between H1 and H2 at 19 and 26 months. This could be explained by the heterogeneity of the resiliency that was higher for H-corks than for L-corks. Finally, the corks were visually (12 judges) divided in 3 classes corresponding to high (expected mushroom shape, i.e high resiliency), medium (irregular shape of the disk in contact with the wine and/or low premature deterioration of the expected resiliency) and low qualities (barrel shape = premature deterioration of the resiliency). The corks were also divided in 3 categories corresponding to 0-33%, 34-66% and 67-100% resiliency. A strong correlation was noted between the visual and the instrumental categorizations. This study strongly evidenced 1) the importance of the cork density on the cork stopper behaviour when opening the bottle and 2) the interest of an instrumental approach reflecting the consumer’s perception.

Understanding the physiological and molecular bases of grapevine responses to mild to moderate water deficits is fundamental to optimize vineyard irrigation management and identify the most suitable varieties. In Mediterranean regions, the higher frequency of heat waves and droughts highlights the importance of precision irrigation to meet vine water demands and demonstrates the necessity for a deeper understanding of the different physiological responses among varieties under water stress. In this context, previous reports show an interplay between stomatal regulation of transpiration and changes in leaf hydraulic conductivity, also with the involvement of aquaporins (AQPs), particularly under water stress. However, how those signaling mechanisms are regulated in different grapevine varieties along phenological phases is unclear.