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

Valpolicella is a famous Italian wine-producing region. One of its main characteristic is the intensive use of grapes that are submitted to post-harvest withering. This is rather unique in the context of red wine, especially for the production of a dry red wine such as Amarone. Amarone wines produced in Valpolicella different geographic origin are anecdotally believed to be aromatically different, although there is no systematic study addressing the chemical bases of such diversity. Aroma is the product of a biochemical and technological series of steps, resulting from the contribution of different volatile molecules deriving from grapes, fermentations, and reactions linked to aging, as well as one of the most important features in the expression of the geographic identity and sensory uniqueness of a wine.

A lot of work has been done on the impact of Botrytis on the foam of sparkling wines. This work often concerns wines produced in cool regions, where Botrytis is the dominant fungal pathogen. However, in southern countries such as Spain, in particularly hot years such as 2022, the majority fungal pathogen is sometimes Rhizopus. Like Botrytis, Rhizopus is a fungus that produces an aspartic protease.

Monitoring vine water status is a major challenge for vineyard management because it influences both yield and harvest quality. It is also a challenge at the territorial scale for identifying periods of high water restriction or zones regularly impacted by water stress. This information is of major importance for defining collective strategies, anticipating harvest logistic or applying for irrigation authorisation. At this spatial scale, existing tools and methods for monitoring vine water status are few and often require strong assumptions (e.g. water balance model). This paper proposes to consider a collaborative collection of observations by winegrowers and wine industry stakeholders (crowdsourcing) as an interesting alternative. Indeed, it allows the collection of a large number of field observations while pooling the collection effort. However, the feasibility of such a project and its interest in monitoring vine water status at regional scale has never been tested.

The objective of this article is to explore the possibility of making a regional map of vine water status based on crowdsourcing observations. It is based on the study of the free mobile application ApeX-Vigne, which allows the collection of observations about vine shoot growth. This information is easy to collect and can be considered, under certain conditions, as a proxy for vine water status. This article presents the first results obtained from the nearly 18,000 observations collected by winegrowers and wine industry stakeholders during 2019, 2020 and 2021 seasons. It presents the vine shoot growth maps obtained at regional scale and their evolution over the three vintages studied. It also proposes an analysis of the factors that favoured the number of observations collected and those that favoured their quality. These results open up new perspectives for monitoring vine water status at a regional scale but above they provide references for other crowdsourcing projects in viticulture.

Aims: Wine perceived quality lies on a number of different factors. Among these, sensory features, which are in turn dependent on chemical composition, play a primary role. There is traditionally a great emphasis on producing wines that have specific sensory profiles, particularly aroma, that reflect identity features connected to the place and the variety of origin. In the case of high quality

With climate change, it is progressively more often to obtain grapes with an acceptable content in sugars or acids but with immature tannins described as green, aggressive or hard (noted as GAH onwards). During winemaking, the oenologist has to make decisions related to the elaboration of such grapes based mainly on empirical experience, given the lack of objective criteria to this concern. An increase in the chemical and sensory knowledge of immature tannins would allow managing this GAH character of grapes with the maximum possible efficiency during winemaking processes. The present work aims at isolating and identifying the group of compounds responsible for the GAH character present in wines.