Under-vine cover crop: effect over glycosidic aroma precursors of Vitis vinifera L. Cv Syrah

Abstract

AIM: Volatile compounds joint to aromatic precursors form the aroma of grape must that will provide a characteristic aroma to the wine. A high proportion of aromatic compounds are present in the berry in their precursor form linked to sugars. The amount of the glycosidic fraction may be influenced by many factors such as soil, climatic conditions, viticultural practises, etc. [1]. The use of cover crops is a practice that is expanding in vine culture and to study indeep the effect of this practice on the aroma of grape is required. To this end, the effects of the employment of “Zulla” as cover crop on glycosidic aromatic precursors of Shyraz grapes has been studied.

METHODS: Grape samples from vines with three different amount of cover crop (one line, two lines and four lines) and without cover crop were recolected during two harvests (2019 and 2020). Glycosidic aroma precursors fraction was extracted and hydrolized following the method proposed by Loscos et al., [2] and the aglycons were analyzsed by SPME-GC-MS following the method appliyed by Talaverano et al. [3] with modifications.

RESULTS: A total of 40 aromatic precursors were determined in the Syrah must samples analyzed. Among them, 12 terpenes, 11 norisoprenoids, 7 alcohols, 5 aldehydes and 3 acids. Significant differences were found among the precursors volatile compounds found in the different under-vine cover crop strategies tested. The employment of “Zulla” showed a positive effect in the amount of aroma precursors in the must.

CONCLUSION

The employement of “Zulla” as under-vine cover crop influences the composition in aromatic precursor present in the grape and potentially the volatile profile of the resulting wines.