Chemical composition of cool-climate Sauvignon blanc grape skins clones during ripening

AIM: Sauvignon blanc is the most important variety in cool valleys in central Chile accounting 15,522 ha which corresponds to 42.4% of the cultivated surface with white varieties in Chile (SAG, 2019). Casablanca Valley, one of the most important area for the production of white wines in Chile is located approximately to 35-40 km from the Pacific Ocean. Still, geographical area and the clone utilized could be decisive for the chemical and sensory characteristics of this type of wine (Duchene et al., 2009; Green et al., 2011), both during ripening and during ageing of wine. For this reason, the aim of this work is to study the concentration and composition of phenolic compounds and organic acids throughout ripening in grape skins of Sauvignon blanc clones grown in two zones of Casablanca Valley. METHODS: Sauvignon blanc clones 242, 1 Davis and 107 grown in two zones of the Casablanca Valley, central zone of Chile were chosen. The grape berries were sampled every 15 days from veraison until commercial harvest, using a completely randomized design with five replicates in each selected vineyard. The following chemical analyses were assessed: titratable acidity, total soluble solids, total phenols, CIELab coordinates, low molecular weight phenolic profile and organic acids using High Performance Liquid Chromatography (HPLC-DAD). RESULTS: As expected, titratable acidity diminished during ripening while total soluble solids and pH increased in all clones. Total phenols decreased in all clones during ripening, with significant differences in their concentration between the two geographical zones. Low molecular weight phenolic compounds showed differences in concentration between Sauvignon blanc clones and geographical origin showed that the grapes grown in the zone more closed to the Pacific Ocean had a higher concentration of flavonols, while organic acids differed in concentration but not in composition between clones and geographical origin. CONCLUSIONS: We observed differences in concentration on some chemical parameters between Sauvignon blanc clones that depends on the geographical origin, while its composition remains similar.

Authors: Alejandro Cáceres – Faculty of Agronomic and Food Sciences, Pontificia Universidad Católica de Valparaíso, Chile.,Pierina Peirano Faculty of Agronomic and Food Sciences, Pontificia Universidad Católica de Valparaíso, Chile.

Email: alejandro.caceres@pucv.cl

Keywords: Sauvignon blanc, flavonols, organic acids, cool-climate wines

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