Comparison of Eleven Commercial Grape (Vitis vinifera L.) Cultivars in Terms of Phenolic Profile and Antioxidant Properties.

Grapes are a rich source of phenolic compounds with high antioxidant, antibacterial, and nutritional properties among fruits. The aim of this study was to investigate different classes of phenolic compounds in the berry skin of eleven Vitis vinifera cultivars. The phenolic compounds were flavonols, flavanols, flavone, anthocyanins, stilbenes, and phenolic acids. The highest amounts of catechin, epicatechin, ferulic acid, and chlorogenic acid were observed in 'Yaghooti' grape cultivar (P≤0.05). However, the amounts of catechin gallat, kaempferol, myricetin, and pcoumaric acid in 'Bidaneh Ghermez' berries were higher (P≤0.05) compared to other cultivars. Quercetin was the main flavonol and was highest (9.48 μg g^-1; P≤0.05) in 'Yaghooti' berries. Luteolin content, as a flavone, ranged from 0.49 μmol g^-1 in 'Rishbaba' berry skin to 0.88 μmol g^-1 in 'Bidaneh Ghermez'. Delphinidin-3-glucoside and malvidin-3-glucoside were highest in 'Yaghooti'. Cyanidin-3-glucoside and peonidin -3-glucoside were highest in 'Angoor Siah.' Petunidin 3-glucoside was highest in 'Bidaneh Ghermez' (P≤0.05). Berry skin resveratrol varied from 22.7 μg g^-1 in 'Monaqa and Fakhri' cultivars to 54.8 μg g^-1 FW in 'Bidaneh Ghermez,' with an overall average of 36.9 μg g^-1 FW. Among different cultivars, the antioxidant capacity of 'Angoor Siah' was highest (71.3%; P≤0.05) and 'Monaqa' was lowest. The 'Angoor Siah' cultivar had more antibacterial activity compared to other cultivars. In sum, the berry skin of 'Yaghooti,' 'Angoor Siah,' and 'Bidaneh Ghermez' showed the highest health-promoting bioactive compounds, potentially important for future studies. [ABSTRACT FROM AUTHOR]