Understanding Nebbiolo variability: assessment of wines produced under standardized winemaking conditions from 38 locations

This thesis focuses on the variability of the physicochemical, phenolic and color parameters of Nebbiolo wines produced under standardized winemaking conditions from 38 locations across six areas between Piedmont and Lombardy regions. This thesis analyzes a certain number of physicochemical parameters including pH, total acidity, ethanol content, glycerol, residual sugars and various acids (tartaric, malic, lactic, succinic and acetic). The study analyzes also phenolic compounds, among which are flavonoids, total and monomeric anthocyanins, as well as wine color parameters. The results have shown that while certain properties remained consistent across the areas, others showed significant differences, underlining the influence of environmental factors. Significant differences were observed for all the physicochemical parameters except for pH and lactic acid content. Significant differences were observed on phenolic compound such as flavonoids, flavonoids non anthocyanins and assays such as methyl cellulose precipitable tannins assay and vanillin reactive flavanols assay, particularly in Area 4, which exhibited the highest level of these compounds. Color parameters also displayed regional variation with wines from Area 2 having the highest color intensity. These findings demonstrated the importance of terroir in shaping the chemical and phenolic profiles of Nebbiolo wines. Limitation of the study is the small number of wine samples for certain areas, highlighting the need for further research with more sample to better understands the effects of terroir on Nebbiolo wines. This thesis provides valuable insights for Nebbiolo wine producers and researchers. Future studies could also explore the impact of climate change, soil composition and viticultural practices for Nebbiolo wines from different areas.