The dynamics of the phenolic complex of grapes during ripening: comparison of Crimean autochthonous and classical cultivars

The autochthonous grape cultivars are a valuable bioresource for both generative and clonal selection and also for the development of authentic winemaking of the region. Phenolic components play an important role in the formation of wine quality. Studies of the change in the content of phenolic compounds in berries during ripening of autochthonous (‘Kefessia’, ‘Gevat kara’, ‘Ekim kara’) and classical (‘Cabernet Sauvignon’, ‘Shiraz’, ‘Malbec’) grape cultivars from the ampelographic collection of Institute “Magarach” were carried out using the HPLC. At the beginning of ripening (12.0-14.1 °Brix) in autochthonous cultivars the gallic acid content was 5.0-14.7 mg kg(‑1), and the hydroxycinnamic acid content was 83.3-155.9 mg kg(‑1); in classical cultivars it was 0-8.0 and 34.1-119.7 mg kg(‑1), respectively. At 18.0-22.5 °Brix phenolic acid content in autochthonous cultivars decreased 2.6 times, in classical 2.0 times. The starting summary content of quercetin, kaempferol and their derivatives in ‘Ekim kara’ and ‘Malbec’ averaged 34.8 and 24.4 mg kg‑1; in other cultivars - from 89.3 to 151.4 mg kg(‑1). During ripening these values in ‘Ekim kara’ and ‘Malbec’ increased 1.7 times, in ‘Shiraz’ - did not change, in others - decreased in 1.5-3.2 times. Initially the concentration of the anthocyanins in ‘Shiraz’, ‘Kefessia’, ‘Gevat kara’ was 87.6-100.2 mg kg(‑1), in others 223.2-389.9 mg kg‑1. During ripening it increased to 762.5-801.0 mg kg(‑1) in classical cultivars; to 501.1-1062.4 mg kg(‑1) in autochthonous. The initial concentration of flavan-3-ol in autochthonous cultivars varied from 529.6 to 847.4 mg kg(‑1); in classical on average 1.4 times less. During ripening it decreased 2.6 and 3.2 times in autochthonous and classical cultivars. The starting content of procyanidins (B1-B8) ranged from 510.9 to 889.6 mg kg‑1. Then it decreased 2.7 and 2.0 times in autochthonous and classical cultivars. Cluster analysis showed that the grape ‘Kefessia’ in the content of phenolic acids, anthocyanins, flavan-3-ol monomers and procyanidins is close to ‘Shiraz’; ‘Ekim kara’ - to ‘Malbec’.