Akademik Məlumat İdarəetmə Sistemi
Ukrainian Food Journal, vol.14, no.2, pp.273-289, 2025 (ESCI, Scopus)
Introduction. This study is aimed at investigating the changes in the activity of certain oxidoreductase-class enzymes and content of phenolic compounds depending on the level of grape maturity. Materials and methods. The white technical grape varieties Bayanshira and Rkatsiteli grown in Azerbaijan, as well as the introduced red technical variety Cabernet Sauvignon were used. The activities of ascorbate oxidase, odiphenol oxidase, peroxidase, and catalase in grapes were determined at different stages of grape maturation. Highperformance liquid chromatography was used for the analysis of phenolic compounds. Results and discussion. Depending on the degree of grape maturity, oxidoreductase-class enzymes remain continuously active. The enzyme activity in the grape varieties Bayanshira, Rkatsiteli, and Cabernet Sauvignon, grown in the Samukh and Goygol regions, varies throughout the ripening stages, with the most pronounced changes observed in unripe and overripe berries. In the Bayanshira variety, enzyme activity in unripe berries increased by 12.5-22.8% and 15.8-38.4%; in ripe berries - by 3.1-5.6% and 3.5-7.9%; and in overripe berries - by 20.4-42.5% and 19.0-33.3%, respectively, which is consistent with the data for the other studied varieties. The lowest enzyme activity was recorded in ripe grapes. Using chromatographic-mass spectrometric analysis, it was established that the studied grape varieties are rich in phenolic compounds such as flavonoids, phenolcarboxylic acids, and procyanidins. A total of 18 monomeric phenolic compounds were identified in the grape varieties, along with 21 anthocyanin compounds found in the Cabernet Sauvignon variety (a red technical grape). This indicates a higher content of phenolic compounds in the studied grape varieties. Conclusions. To obtain high-quality brandy wine material, it is recommended to use fully ripened grapes, as they exhibit the lowest enzymatic activity. To enrich the wine material with phenolic and extractive substances, the grape juice should be fermented in contact with the mash for several days.