Comparison of antioxidant capacity and phenolic compound contents in different tissues of sixteen red grape cultivars grown at Kalecik Viticultural Research and Experiment Station in Ankara, Turkey

Abstract

Many researches have been conducted on phenolic compounds because of their responsibilities for protecting grapevines against stress conditions besides adding color and flavour characteristics to the grapes. Another reason for intensive studies conducted on them is because they have antioxidative effects on human health. This research was carried out to determine and compare of antioxidant capacity and phenolic contents in different tissues of 16 red grape cultivars grown in Kalecik Viticultural Research and Experiment Station Cultivar Collection vineyard. Antioxidant capacity in the seed and skin; total phenolic compounds in the seed, skin, stem and leaves; total anthocyanin in the skin; catechin, epicatechin, quercetin, rutin, trans- resveratrol and cis-resveratrol in the seed, pulp, skin, stem and leaves were determined. The highest total phenolic compound contents were determined in skin, seed, stem and leaves, respectively; ‘Bogazkere’ (51.675 mg kg‑1 DW), ‘Trakya Ilkeren’ (107.625 mg kg‑1 DW), ‘Red Globe’ (123.250 mg kg‑1 DW) and ‘Red Globe’ (45.250 mg kg‑1 DW). ‘Syrah’ (493.8 μmol trolox g‑1 DW) had the highest antioxidant capacity value in the skin and ‘Okuzgozu’ (1.086 μmol trolox g‑1 DW) had it in the seed according to the results of analysis. The highest content of catechin was found in the seed of ‘Okuzgozu’ (30.069 mg kg‑1 DW), content of epicatechin in the seed of ‘Cardinal’ (8.151 mg kg‑1 DW), the content of rutin in ‘Trakya Ilkeren’ (733.0 mg kg‑1 DW), the content of quercetin (36.1 mg kg‑1 DW), trans-resveratrol content (45.7 mg kg‑1 DW) and cis- resveratrol amount (8.3 mg kg‑1 DW) were in ‘Kohnu’ cultivar.