Characterization of 20 Oenological Tannins from Different Botanical Origins for Formulation of Blends with Redox Potential Tuning Ability in Model Wine Solution

Twenty oenotannins from different botanical origins were studied in model wine solution (1 g/L, 12% ethanol, pH 3.5). An original device was created for measuring Oxidation–Reduction potential (ORp) of the solutions at 20 °C strict anoxic condition by electrochemical method platinum electrode zero-current potential. Reactivity against proteins and antioxidant properties related to chemical structure and, consequently, origin oenotannins. The highest turbidity after BSA addition (ΔNTU > 1000) values measured gallic hydrolysable tannins. ORp versus standard hydrogen ranged 420 260 mV. ellagitannins had power (AP%), followed condensed tannins gallotannins, highlighting a correlation with phenolic profile. Based on these findings, two formulations prepared as blend some tested oenotannins, ability increase (MIX1) decrease (MIX2) wine.