From Vine to Wine: Non-Colored Flavonoids as Fingerprints

Fourteen non-colored flavonoids, including flavanols (catequine and epicatequine) and flavonols (myricetin, quercetin, and isorhamnetin and their glucoside/glucuronide derivatives) were investigated in over two hundred monovarietal red wines from the Canary Islands, as a continuation of a previous study available in this journal. This is the first comprehensive study on non-colored flavonoids in monovarietal Canary wines, highlighting their potential as chemical fingerprints for wine characterization. Flavanal and flavanol concentrations were similar to values reported in other regions. Concentrations of these flavonoids significantly varied by grape cultivar, denomination of origin (DO), island, and aging. International grape cultivars generally showed higher non-colored flavonoid concentrations than autochthonous cultivars. Strong correlations were observed among flavonols of the same chemical groups, as well as between flavonols and anthocyanins, indicating a shared biosynthesis pathway in grapes and equilibria in wine. Principal component analysis revealed relationships among the individual flavonoids. Lineal discriminant analysis (LDA) resulted in high percentages of correct classification by cultivar, DO, precedence island, and aging. The classification accuracy achieved through LDA, except for aging, notably improved compared to the previous study that examined only visible flavonoids, underscoring the importance and effectiveness of non-colored flavonoid profiling.