Chemical characteristics of wine made by disease tolerant varieties

Vitis vinifera L. is the most widely cultivated Vitis species around the world which includes a great number of cultivars. Owing to the superior quality of their grapes, these cultivars were long considered the only suitable for the production of high quality wines. However, the lack of resistance genes to the major grapevine pathogens (Plasmopara viticola and Erysiphe necator) makes it necessary the application of huge amounts of chemical products in vineyard. Thus, the search for alternative and more sustainable methods to control the grapevine diseases have increased the interest in new resistant interspecific hybrids. These varieties show high resistance to fungal diseases since they are the result of crosses between resistant wild Vitis species, with resistance traits and V. vinifera varieties. Characterization of the chemical composition of these hybrid varieties is an important prerequisite to evaluate and promote their use on the global wine market. The aim of this project was to produce a comprehensive study of the most promising varieties recently introduced to the cultivation by identifying the peculiar aspects of their composition, and measuring their positive and negative quality traits. A multi-targeted approach using different analytical techniques (GC-MS, UPLC-MS, NMR and FTIR analysis) was adopted to investigate the main classes of volatile and non-volatile compounds which play a key role in the organoleptic and sensory properties of wine. The findings of this study provide a clear picture of the chemical profile of the wines made from different PIWI varieties. Knowledge gained would serve to evaluate the use of interspecific hybrids for quality wine production as well as to suggest the most appropriate winemaking style, allowing the improvement of the wine quality and valorization of the characteristics of each grapevine variety. Considering that grape quality is crucial for wine quality, the chemical composition of the grapes from interspecific hybrid varieties was also investigated. Additionally, bearing in mind the link existing between interspecific hybrids and wild Vitis genotypes the metabolomic profile of red grapes from two hybrids and five American genotypes was determined. By evaluating these wild genotypes, it is possible to assess the value of this grape germplasm and provide wider choices to the breeders.To the best of our knowledge this survey is the most extended metabolomics profiling study on non-V. vinifera genotypes.