Discrimination of Romanian Wines Based on Phenolic Composition and Identification of Potential Phenolic Biomarkers for Wine Authenticity and Traceability

Demonstrating the authenticity and traceability of quality wines based on parameters that reflect their composition and provenance contributes to protecting wine authenticity and to increasing consumer confidence in moderate wine consumption, which is associated with numerous health-promoting properties. A wine’s phenolic fingerprint is increasingly used to assess its authenticity, even though wine phenolic composition is influenced by genetic and environmental factors, as well as vineyard management and enological practices, and storage conditions. This study presents a comprehensive analysis of the bioactive characteristics (total polyphenols—TPs, total flavonoids—TFs, antioxidant activity—AA, and total anthocyanins—TAs) by spectrophotometric analysis and phenolic compound profile (by UHPLC-HRMS analysis) of 19 white and 21 red wines with a Protected Designation of Origin (PDO) from four vineyards located in the wine-growing region of Oltenia, Romania. Multivariate statistical analysis, specifically principal component analysis and heat map analysis, applied to analytical data, enables the discrimination of wines based on grape variety and terroir, and across four consecutive vintages (2019–2022). The phenolic profiles of the wines obtained under standardized winemaking conditions depend on the climatic data specific to each harvest year (temperature, precipitation, duration of sun exposure during grape berry phenological stages, and ripening). The phenolic biomarkers of red wines, such as epicatechin, catechin, gallic, caffeic, <i>t</i>-ferulic acids, <i>t</i>-resveratrol and hesperidin, represent specific biomarkers of warmer and sunnier harvest years with lower precipitation, as observed in the 2021 harvest year. Additionally, our results contribute to the identification of specific phenolic biomarkers for geographical and varietal discrimination, as well as to the promotion of high-quality wines produced in a renowned wine-growing region of Romania.