Targeted UHPLC-QqQ-MS/MS metabolomics for phenol identification in grapevine and wine: study of a Tempranillo clone with a dark-blue berry colour

Abstract

Grapevine vegetative multiplication allows the accumulation of spontaneous mutations and increase intra-cultivar genetic diversity that can be exploited to maintain grape wine quality, tipicity and adaptation to different climate conditions. Non-volatile phenolic compounds are intrinsic components of grape fruits and derived products, particularly wine. They constitute a heterogeneous family of compounds and play an important role on the sensorial attributes of wine because they are responsible for some of important organoleptic properties as colour, flavour, bitterness and astringency. In the present study, we used a targeted metabolomics approach based on ultra-high performance liquid chromatography with tandem mass spectrometry (UHPLC-QqQ-MS/MS) to study the anthocyanin and non-coloured phenol profiles of a singular Tempranillo clone (Tempranillo negro or VN21), characterized by a dark-blue color in grape berry skin, as compared to RJ43, one of the most cultivated clones in D.O.Ca. Rioja (Spain). In addition, we investigated differences between VN21 and RJ43 clones, in the phenolic transference from grape to wine at different phases of the winemaking process. The results showed that anthocyanin and non-colored phenol content was higher in VN21 grape skin and seeds than in RJ43. With respect to anthocyanins, the singular color of grape skin in VN21 could be explained by higher concentrations of peonidin and cyanidin derivatives. Regarding non-colored phenols, the main differences were observed for proanthocyanidins and stilbenes concentration in grape skin and more importantly in seeds. Those content differences observed in berries were enhanced in the VN21 wines, displaying significantly higher concentrations of anthocyanins, as well as significantly increased contents of mainly proanthocyanidins and stilbenes. The results manifest the importance of intra-cultivar genetic diversity to obtain red wines with a high phenolic content, responsible of key quality aspects of the wine such as organoleptic properties, stability, complexity and health benefits. Moreover, this study exemplifies how spontaneous somatic variation can be used through grapevine clonal selection combining metabolomic analyses.

FUNDING SOURCES

This work was partially supported by project BIO2017-86375-R from the Spanish Ministry of Economy and Competitiveness (co-funded by the European Social Fund, European Union); YF was supported by a grant from Government of La Rioja; M.J. Motilva thanks to CSIC for partial funding through the “Ayudas incorporación a escalas científicas CSIC, 2018” (Reference 201870I129).