Phenolic composition profile of cv. Tempranillo wines obtained from severe shoot pruning vines under semiarid conditions

Abstract

One of the limitations of vineyards in warm areas is the loss of wine quality due to higher temperatures during the grape ripening period. In order to adapt the vineyards to these new climatic conditions, a possible solution is to delay the ripening process of the grapes towards periods with milder temperatures, by means of management practices and thus improve the quality of the fruit and the wine produced. The technique of severe shoot pruning (SSP) has proven useful in achieving this objective. This technique consists of trimming the developed primary shoots at the end of flowering, above the node number seven. The aim of this work was to evaluate the effect of SSP under drought conditions and high temperatures on the ‘Tempranillo’ wine phenolic composition compared with non-trimming vines (NT) grown under conventional practices (just winter pruning) during the 2022 season. None of the treatments were irrigated. The wines were elaborated according to traditional red wine-making method and their general and chromatic parameters were analysed. Respect to NT, the SSP treatment showed slightly lower ethanol content and significantly reduced the dry extract, pH, malic acid and potassium, total phenolic content and color intensity values. When the polyphenolic profile of wine was analysed by HPLC techniques, respect to NT wines, the SSP ones showed an increase in coumarilated anthocyanins, and a decrease in the concentration of monoglucoside anthocyanins, flavonols, phenolics acids and total anthocyanins content. In conclusion, under these study conditions (including non-irrigation, extremes temperatures and dry weather), severe pruning of the vine shoots was not effective in improving the phenolic profile of the wine. It would therefore be necessary to analyse this technique accompanied by supportive irrigation during the ripening cycle of the grapes.

Acknowledgements: This research was supported by funds from Project IB20082, the ERDF, Junta de Extremadura, AGA001 (GR21196) and Investigo Program, financed by The Recovery and Resilience Facility. The authors would like to thank Bodegas Viñas De Alange S.A. for their collaboration.