Characterization of 25 white grape varieties from the variety collection of ICVV (D.O.Ca.Rioja, Spain)

Abstract

AIM: The effects of climate change produce an increase in sugar concentration and a decrease in acidity, without reaching the optimum grape phenolic maturity [1]. The aim of this work was to characterize 25 white grape varieties to find new strategies to fight against climate change.

METHODS: The Variety Collecction that belongs to Instituto de Ciencias de la Vid y del Vino (ICVV), it’s made of 511 national and international grape varieties. This Collection was chosen due to the great diversity of grape varieties that contains. To this work, 25 white grape varieties were selected [2], which were classified into 3 groups: Important varieties in Spain (Airén, Cayetana, Xarello, Palomino Fino, Parellada, Albariño, Merseguera, Moscatel de Grano Menudo, Treixadura, Loureiro Blanco, Malvasía de Sitges), Important varieties in D.O.Ca. Rioja (Viura, Verdejo, Chardonnay, Sauvignon Blanc, Alarije, Garnacha Blanca, Tempranillo Blanco, Maturana Blanca), and International varieties (Gewürztraminer, Riesling, Trebbiano Toscano, Chasselas, Semillon, Pinot Blanc). The experimental design was of 3 repetitions for variety, with 3 plants for repetition. The grapes were collected at their optimal technological maturity, approximately at 21.2 ºBrix. In each sample, general parameters were determined using official methods [3]: ºBrix, pH, total acidity, glucose+fructose, glucose, fructose, malic acid, tartaric acid, total phenols, amino nitrogen, ammonium nitrogen, and yeast assimilable nitrogen (YAN).

RESULTS: In general, Important varieties in D.O.Ca. Rioja and International varieties have short or medium growth cycle; however Important varieties in Spain have medium or long vine cycle. In the first group, Important varieties in Spain, Albariño and Loureiro Blanco varieties had more acidity; Cayetana presented higher concentration of total phenols; and Albariño, Treixadura, and Xarello had higher concentration of nitrogen compounds. Moreover, Chardonnay and Maturana Blanca grape varieties showed high concentration of acids and nitrogen. In the second group, Important varieties in D.O.Ca. Rioja, Chardonnay had the most concentration of total phenols. Finally, in the third group, International varieties, Chasselas had the most concentration of total phenols and nitrogen compounds, and Riesling grape variety showed a medium concentration of total phenols and a high concentration of acidity and nitrogen compounds.

CONCLUSIONS

The characterization of 25 white grape varieties has provided an image of the heterogeneity of grape varieties present in national and international cultivation, removing the terroir factor. We are working on the study of the phenolic, aromatic and nitrogen composition of all these grape varieties in order to know in detail their enological potential and possible adaptation to the new climatic scenario.