Influence of the vineyard’s surrounding vegetation on the phenolic potential of Vitis vinifera L. cv Tempranillo grapes

Abstract

Wine industry has to develop new strategies to reduce the negative impact of global climate change in wine quality while trying to mitigate its own contribution to this climate change. The term “ecosystem services”, whose use has been recently increasing, refers to the benefits that human beings can obtain from the interactions between the different living beings that coexist in an environment or system. The management of biodiversity in the vineyard has a positive impact on this crop. It has recently been reported that practices such as plant cover can reduce the occurrence of pests, increase pollination of the vine, improve plant performance1 and affect the phenolic content of grapes.2 The phenolic potential of the grape is directly related to wine organoleptic properties, among which color and astringency outstand. It also conditions the winemaking process and the ability of a wine to undergo ageing. More recently, the role that the vegetation around the vineyard can play in supplying ecosystem services beneficial to grape production and quality is beginning to be considered. Given the absence of previous studies, this present work aims at studying the influence that this vineyard’s surrounding vegetation can exert on the phenolic potential of red Vitis vinifera L. cv Tempranillo grapes, grown in two vineyards surrounded by uncultivated and naturalized lands belonging to two different “Denominaciones de Origen” (DO Toro and DO Ribera de Duero). In both vineyards, grapes were harvested at the same date from different sampling points selected according to the distance to vegetation. Differences in the grape maturity status that might be due to their location in the vineyard were assessed by the determination of harvest parameters (pH of the must, titrable acidity and sugar content-°Brix). Furthermore, differences in the phenolic potential that might be influenced by the distance from the vegetation around the vineyard were studied. To be precise, total polyphenol index (TPI), color intensity (CI) and hue were evaluated by UV-vis spectrometry and the detailed flavonol, flavanol and anthocyanin compositions of grape skins and the flavanol composition of grape seeds were analyzed by means of HPLC-DAD-MSn.3
Regarding harvest parameters, a clear relationship between distance to the surrounding vegetation and technological maturity could be observed for DO Toro grapes, whereas it was less remarkable for DO Ribera de Duero grapes. TPI did not seem to be affected by the location of the grapevine, whereas CI were greater in the samples collected in the vines nearer to the surrounding vegetation. Regarding flavonoid compositions, different behaviors were observed for the different types of compounds. The results of this study highlight that the vegetation around the vineyard can influence the phenolic composition of grapes, so this factor should not be neglected when choosing a vineyard to produce quality grapes and wines.

References

[1] Abad, J. et al. (2021). OENO One 2021, 1, 295-312.
[2] Escribano-Bailón, M.T. et al. (2005). Advances in oenological sciences and techniques. Libro de resúmenes de la octava Conferencia de los grupos de investigación en enología, GIENOL’05, p 25-27.
[3] Alcalde-Eon, C. et al. (2019). Food Research International, 126, 108650.