Genetic study of wild grapevines in La Rioja region

Controlling the development of the bacterial population during the winemaking process is essential for obtaining correct wines[1]. Carbonic Maceration (CM) wines are recognised as high-quality young wines. However, due to its particularities, CM winemaking implies a higher risk of bacterial growth: lower SO2 levels, enrichment of the must in nutrients, oxygen trapped between the clusters… Therefore, wines produced by CM have slightly higher volatile acidity values than those produced by the destemming/crushing method[2].

The use of grapevine genetic diversity is a way to mitigate the negative impacts of climate change on viticulture systems. Leaf epidermal flavonoids (including flavonols and anthocyanins) are involved in plant defense mechanisms against environmental stresses, like high temperatures or excessive solar radiation [1,2]. Among other factors, they modulate light absorption, which reduces photoinhibition processes in photosynthetic tissues [1]. Therefore, the identification of grapevine cultivars with an increased content on leaf epidermal flavonoids arises as a potential avenue to improve grapevine tolerance to some detrimental environmental stresses.

Cover cropping in vineyard is a sustainable and alternative soil management system to conventional tillage that is gaining more and more importance among winegrowers and is being promoted, among other organizations, by the European Union through the eco-schemes of the Common Agricultural Policy.
However, the use of cover crops in Mediterranean viticultural environments is conditioned, to a large extent, by the availability of irrigation water which, in a context of global warming like the one we are experiencing, must be adjusted to savings strategies, supplying to the vine only what it needs in each moment.

This essay was aimed to describe the clonal diversity of Oenococcus oeni in the malolactic fermentation of the carbonic maceration (CM) winemaking. The free and the pressed liquids from CM were sampled and compared to the wine from a standard winemaking with previous destemming and crushing (DC) of grapes [1]. O. oeni strain typification was performed by PFGE as González-Arenzana et al. described (2014) [2]. Results showed that 13 genotypes, referred as to letters, were distinguished from the 49 isolated strains, meaning the genotype “a” the 27%, the “b” the 14%, the “c” the 12%, the “d and e” the 10 % each other, and the remaining ones less than the 8% each one.

Tropical fruit aromas in wines are thought to be important to wine consumers, although there is little research to confirm this statement. With so many wine styles available, it has become important to understand the qualities that are desirable to consumers and how to achieve those qualities. Thiols and esters are compounds that have been found to cause tropical fruit aromas in chardonnay (ref). Fermentation temperature gradients and skin contact were found to increase these compounds using micro scale fermentations. This work aimed to scale up these fermentations/operations to determine if the desired tropical fruit aromas could still be achieved and if there is a perceivable difference in tropical fruit aromas, liking, and emotional response in the wines at the consumer level.