Effect of grape seeds on the polyphenol bioactive content and elemental composition by ICP-MS of grape juices from Vitis labrusca L.

- Effect of grape seed on the polyphenol and mineral content of juices was evaluated.
- Grape seed increased the phenolic content and antioxidant capacity of juices.
- Grape seed addition showed positive correlations with minerals concentrations.
- Seed addition is an alternative to bioactive enrichment in grape juices.

The effect of grape seeds on the bioactive content and elemental composition of grape juices from Vitis labrusca L. varieties Concord, Isabel and Bordo, widely cultivated in Brazil, was examined. Grape seeds of each variety were macerated with berries at concentrations of 50, 100 and 200 g/kg of grape, followed by the extraction of varietal juices. The total phenolic content, monomeric anthocyanins and antioxidant capacity were determined in juices, and their correlations with seeds were assessed. The mineral content and metal contamination in juices was determined by ICP-MS. Grape seeds significantly increased the total phenolics and antioxidant capacity of juices, showing high correlations. In Isabel juices, seed addition at concentration of 200 g/kg increased about 8 times the polyphenols concentration. The addition of seeds was poorly correlated with anthocyanins content and positively correlated with minerals (Ca, Mg, Na, K, Mn, Zn). The trace elements Cu, Ni, Sr, As, Cr, Li, Ba and Al were detected. The inclusion of seeds in grape juice comprises a feasible approach to bioactive enrichment of this widely appreciated beverage and also an alternative to reduce vegetable waste in fruit industries.