Phenolic compounds in the Crimean autochthonous grape cultivars

In the process of grape processing around 63% of phenolic compounds contained in the berries are transferred into wine, which, to a great extent, accounts for the antioxidant activity of grape wines. This fact determines the interest of researchers in the phenolic complex of grape and grape processing products. In the global viticulture of today the interest in autochthonous cultivars gains momentum both from the point of view of true regional resources and as base wine material that reflects their incomparable terroir. In Crimea there are more than 100 autochthonous grape cultivars. The polyphenolic composition of the autochthonous grape cultivars is virtually unexplored, and future research in the field will enable a more efficient use of the autochthonous grape cultivars for commercial purposes as well as in selection for the genetic improvement of cultivars. A detailed study of the polyphenolic complex of six autochthonous grape cultivars was conducted, which were selected from the ampelographic collection of Institute “Magarach”, Bakhchisaray region of Crimea. The conducted research has shown significant differences in concentrations of most components of a phenolic complex both of flavonoid and non-flavonoid nature in the autochthonous grape cultivars of Crimea. From among monomeric flavonoids (+)-D- catechin and (-)-epicatechin were found. D-catechin was identified in all the studied grape cultivars, and highest concentration (114.4 mg L^‑1) was detected in ‘Kefesiya’. Among the non-flavonoid grape polyphenols, hydroxycinnamic acids were identified. ‘Kefesiya’ showed the highest content – 64.2 mg L^‑1. Gallic acid was also identified. The sum of procyanidins (B₁-B₉) had the highest values in all the studied grape cultivars: ‘Kefesiya’ – 290.4 mg L^‑1, ‘Djevat Kara’ – 227 mg L^‑1, ‘Krona’ – 208 mg L^‑1, ‘KokurBelyi’ –229 mg L^‑1, ‘Shabash’ – 193 mg L^‑1, ‘Sary Pandas’ – 157 mg L^‑1.