Changes in the composition and content of polyphenol compounds during the ripening of red grape varieties (Vitis vinifera L.)

Polyphenols are secondary plant metabolites and important organic compounds present in grapes, must and wine. The importance of polyphenolic compounds present in grapes is mainly related to the quality of the wine. Those compounds affect the colour, taste, astringency, bitterness, and potential of wine aging. Therefore, the aim of this research was to determine and compare quantitative and qualitative changes in low molecular weight polyphenol content of 11 red grapevine varieties during ripening. Samples were collected periodically from the beginning of vérasion to the technological maturity. The polyphenolic compounds were analysed with high performance liquid chromatography (HPLC) with prior lyophilization and extraction. Based on the obtained results, changes in the composition and content of researched groups of polyphenolic compounds during maturation were determined.