Antioxidant potential of white grape pomaces: Phenolic composition and antioxidant capacity measured by spectrophotometric and cyclic voltammetry methods

- Antioxidant potential of white grape pomaces from nine varieties has been evaluated.
- Cyclic voltammetry was used to measure the antioxidant activity.
- A RRLC method has been used to determine the phenolic composition of grape pomaces.
- Samples exhibited different phenolic profiles and antioxidant activities.
- Zalema variety was well differentiated from other varieties.

Antioxidant potential of white grape pomaces from nine different varieties has been evaluated and compared to Zalema variety. The detailed phenolic composition was measured by RRLC/MS, the total phenolic content (TPC) by Folin-Ciocalteu method, and the antioxidant activity by ABTS assay and cyclic voltammetry (CV). Grape pomaces exhibited different quantitative phenolic profiles and different antioxidant activities, with significant differences (p < 0.05). Parellada, Zalema, Sauvignon blanc and Moscatel showed the highest values of TPC and ABTS. The total flavanol, flavonol and phenolic acid contents were significantly correlated to the electrochemical parameter anodic peak current (Ip,a). Finally, a stepwise linear discriminant analysis (SLDA) was carried out, and Zalema variety was differentiated from other varieties based on the total flavonol content, mainly quercetin-3-O-glucoside.