Biochemical Markers for Enological Potentiality in a Grapevine Aromatic Variety under Different Soil Types

Abstract

Pedoclimatic conditions affect grape and wine quality. In particular, the relationship between soil and grape quality is at the core of the terroir definition. The study focuses on cv. Aleatico, an aromatic and autochthonous grapevine cultivar grown in the northern part of the Latium region (central Italy) in a heterogeneous environment (Protected Denomination of Origin Aleatico di Gradoli). Five subareas were selected to represent the environmental variability. The grape-ripening parameters, along with volatile and phenolic compounds in wines derived from the grapes from these growing areas, were analyzed to assess the relationship between soil traits and biochemical grape and wine parameters. Pedoclimatic analysis was carried out following official protocols for determination of soil texture and calculation of bioclimatic Thermal Index of Winkler. Solid-phase microextraction with gas-chromatographic and standard methods were used to measure volatile and phenolic compounds, respectively. Data were evaluated using descriptive statistical methods (analysis of variance and Pearson’s coefficient) and multivariate statistical analyses (principal component analysis and hierarchical cluster analysis). The results showed a significant ‘soil effect’ on the biochemical composition of the grapes and wines. The soil had a significant effect on grape-ripening parameters, as the soil sand content (%) was highly correlated with concentration of total soluble solids and phenols. Soils with a sandy-loam texture and moderate skeleton content yielded the best wine performance in terms of aroma and phenolic content. The study highlighted the importance of microzonation, even in small winegrape growing areas, for more diverse and competitive wine production. The study enhances knowledge about the relationship between soil and grapevine aromatic varieties. Data indicated that identifying biochemical parameters may be indicators of enological potential according to geographic origin.