Vitamins in grape must: let’s lift a corner of the veil

The presence of acetic acid bacteria in wine can lead to the appearance of acetic acid at concentrations above the perception threshold, causing the wine rejection by the consumer. During the winemaking process, avoiding the presence of acetic acid bacteria is very difficult, as there is always a residual population accompanying the wine[1], and the problem arises with the significant development of these microorganisms that metabolizes large amounts of acetic acid.
The concern of wineries to control the presence of acetic acid bacteria in wines during their conservation is due to the absence of simple and effective analyses that allow the detection of these microorganisms in the initial stages.

In the last decades, climate change required already adaptation of vineyard management. Increase in temperature and unexpected weather events cause changes in all phenological stages requiring new management tools. For example, defoliation can be a useful tool to reduce the sugar content in the berries creating differences in the wine profiles. In a ten-year field experiment using Riesling (Vitis vinifera L, planted 1986, Geisenheim, Germany), various mechanical defoliation strategies and different intensities were trialed until 2016 before the vineyard was uprooted. Wood was sampled from the plant compartments root, trunk, cordon and shoot for analyses of physicochemical properties (e.g. lignin and element content, pH, diameter), nonstructural carbohydrates and the microbial communities. The aim of the study was to investigate the influence of reduced canopy leaf area on the sink-source allocation into different compartments and potential changes of the fungal and prokaryotic wood-inhabiting community using a metabarcoding approach. Severe summer pruning (SSP) of the canopy and mechanical defoliation (MDC) above the bunch zone decreased the leaf area by 50% compared to control (C). SSP reduced the photosynthetic capacity, which resulted in an altered source-sink allocation and carbohydrate storage. With lower leaf area, less carbohydrates are allocated. This for example resulted in a decreased trunk diameter. Further, it affected the composition of the grapevine wood microbiota. SSP and MDC management changed significantly the prokaryotic community composition in wood of the root samples, but had no effect in other compartments. In general, this study found strong compartment and less management effects of the microbial community composition and associated physicochemical properties. The highest microbial diversities were identified in the wood of the trunk, and several species were recorded the first time in grapevine.

Soil plays an important role in wine quality, especially its water holding capacity because it affects the balance between vigour and grape yield. The aim of this work was to study the influence of different soil types on the must quality in a vineyard at DO Ca Rioja

The maintenance and valorization of genetic diversity is an undoubtable resource for the viticulture of the future, since the climate crisis is forcing us to think of new, more resilient varieties. For this reason, the grapevine germplasm of the Fondazione Edmund Mach has been continuously expanded in the last decade to a total of 3,120 accessions, whose trueness-to-type has been verified by means of the universal set of nine microsatellites. About two thirds are V. vinifera subsp. vinifera accessions, while the rest consists of naturalized and selected hybrids, V. vinifera subsp. sylvestris, and pure species. The genetic material has also been characterized over three consecutive years for ampelographic, vine development, and biotic stress response traits to be exploited for experimental purposes.

La presente relazione mira ad individuare il ruolo del paesaggio nella determinazione delle preferenze della domanda, in modo da far emergere i fattori immateriali che definiscono il valore territoriale dei vini tipici su cui far leva per le strategie di marketing. L’analisi ha riguardato vini tipici del Veneto e coinvolto soggetti non provenienti da questa Regione. Ne è emerso l’effetto amplificativo dell’immagine del paesaggio sulla qualità percepita.