Phenolic compounds and antioxidant capacities in grape berry skin, seed and stems of six winegrape varieties grown in Turkey

Abstract

In this study, seeds, skins and stems of the red wine grape varieties Boğazkere, Cabernet Sauvignon, Merlot, Nero d’Avola, Sangiovese and Syrah grown in Turkey were analysed for their phenolic compounds. The highest total phenolic compound and DPPH were found in the stem of Boğazkere respectively as 62550 mg GAE/kg dw and 614 µmol/g dw; the highest ABTS•+, (+)-catechin, (–)-epicatechin were detected in the seed of Nero d’Avola respectively as 617 µmol trolox/g dw, 8650 mg/kg and 1902 mg/kg dw; the highest total anthocyanin and rutin were measured in the skin of Boğazkere respectively as 143.52 mg/kg dw and 9692 mg/kg dw; the highest quercetin was found in the seed of Boğazkere as 49.21 mg/kg dw and the highest trans-resveratrol was measured in the stem of Syrah as 61.56 mg/kg dw.

Keywords

• grape seed
• grape skin
• grape stem
• trans-resveratrol
• ABTS•