C 13 -Norisoprenoids in Grape and Wine Affected by Different Canopy Management. In: Ebeler SB, Sacks G, Vidal S, Winterhalter P, editors. Advances in Wine Research. Washington: American Chemical Society; 2015. pp. 147-60. [DOI: 10.1021/bk-2015-1203.ch010]

Aroma precursors of Grignolino grapes (Vitis vinifera L.) and their modulation by vintage in a climate change scenario

Current climatic conditions may cause significant changes in grapevine phenology and maturity dynamics linked often with changes to ecoclimatic indicators. The influence exerted by different meteorological conditions during four consecutive years on the aromatic potential of Grignolino grapes was investigated for the first time. The samples were collected from three vineyards characterized by different microclimatic conditions mainly related to the vineyard exposure and by a different age of the plants. Important differences as far as temperature and rainfall patterns are concerned during ripening were observed among the 4 years. Grape responses to abiotic stress, with particular emphasis on aromatic precursors, were evaluated using gas chromatography coupled to mass spectrometry. The results highlighted significant differences among the vintages for each vineyard in terms of the berry weight and the aromatic precursor concentration. For the grapes of the younger-vine vineyard, the content of aroma compounds showed a different variability among the vintages if compared to the old-vine vineyards. Optimal conditions in terms of temperature and rainfall during the green phase followed by a warm and dry post-veraison period until harvest favored all classes of compounds especially terpenoids mainly in the grapes of the old vines. High-temperature (>30°C) and low-rainfall pattern before veraison led to high benzenoid contents and increased differences among vineyards such as berry weight, whereas cooler conditions favored the terpenoid levels in grapes from southeast-oriented vineyards. In a hilly environment, lack of rainfall and high temperature that lately characterize the second part of berry development seem to favor the grape quality of Grignolino, a cultivar of medium-late ripening, by limiting the differences on bunch ripening, allowing a greater accumulation of secondary metabolites but maintaining at the same time an optimum balance sugar/acidity.

Resurgence of minority and autochthonous grapevine varieties in South America: a review of their oenological potential

In contrast with the general trend of producing wine from the most famous grapevine varieties, associated with the French paradigm, such as Cabernet-Sauvignon, Merlot, Pinot Noir, Syrah, Sauvignon Blanc, and Chardonnay, there is a tendency to revalorize and preserve minority or autochthonous grapevine varieties worldwide. The South American wine region, where most of the varieties derived from varieties brought after European colonization, is not exempt from this. This has allowed new wines to be provided with distinctive identities that are markedly different from the current homogeneous wine production. Moreover, varietal homogenization increases vineyard genetic vulnerability in relation to the emergence of grapevine diseases, to which the commonly cultivated varieties are not resistant. This review summarizes the oenological potential of minority or autochthonous grapevine varieties cultivated within the South American wine region, focusing on Argentina, Chile, and Bolivia. © 2019 Society of Chemical Industry.

Effect of seasonal climate fluctuations on the evolution of glycoconjugates during the ripening period of grapevine cv. Muscat à petits grains blancs berries

BACKGROUND

Temperature changes and rainfall fluctuations affect the winemaking industry by altering vine phenology, crop yield, must composition and wine quality. Here, the evolution of the varietal aroma potential during ripening over three consecutive seasons has been analyzed considering climate conditions. The effect of season, ripening date and climatic conditions on aroma precursor accumulation in grapes was studied by multivariate analysis and discussed in regard to the potential aromatic quality of the wine.

RESULTS

In contrast to musts obtained from grapes harvested in warm and dry seasons (2014 and 2015), musts obtained from grapes harvested in the coolest and most humid year (2013) showed a lower pH, higher total acidity, higher varietal aroma potential index (IPAv), and higher aromatic potential of linalool, geraniol and nerol (typical of the Muscat flavor).

CONCLUSION

Considering the three seasons, grapes synthesized and accumulated more precursors when milder temperatures and late rains throughout veraison were recorded. However, we observed a high fluctuation of aroma precursors during the ripening period, so choosing the correct harvesting date (according to grape aroma potential) may overcome some of the negative effects linked to climate conditions. © 2017 Society of Chemical Industry.