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 verasion 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. Keywords: grape berry, red grapevine varieties, polyphenolic compounds, liquid chromatography Polifenoli su sekundarni biljni metaboliti te vazni organski spojevi prisutni u grozdu, mostu i vinu. Vaznost polifenolnih spojeva prisutnih u grozdu uglavnom je vezana uz kakvocu vina obzirom da utjecu na boju, okus, astringenciju, gorcinu te potencijal starenja vina. Cilj ovog rada je utvrditi i usporediti kvantitativne i kvalitativne promjene sadrzaja polifenola male molekulske mase u kozici grozda 11 crnih sorata vinove loze tijekom dozrijevanja grozda. Uzorci su prikupljani periodicno od pocetka sare do tehnoloske zrelosti. Sadrzaj polifenola u kozici boba utvrden je tekucinskom kromatografijom visoke djelotvornosti (HPLC) uz prethodnu liofilizaciju i ekstrakciju. Temeljem dobivenih rezultata utvrdene su promjene sastava i sadrzaja pojedinih grupa polifenolnih spojeva tijekom dozrijevanja. Kljucne rijeci: boba grozda, crne sorte, polifenolni spojevi, tekucinska kromatografija Polyphenols are secondary plant metabolites and important organic compounds present in grapes, must and wine. The importance of polyphenolic compounds in grapes is mainly related to the quality of the wine. Those compounds affect the colour, taste, astringency, bitterness, and potential of wine aging. Recently, due to numerous research of the polyphenolic composition of grapes, their nutritional value as well as many positive effects on human health have been recognized. Their beneficial effect on the organism derives from antioxidant capabilities, chelating activity, and inactivation of certain enzymes that are attributed to antitumor, antimicrobial, antiallergic, neuroprotective, anti-inflammatory and many other properties. A large group of polyphenolic compounds such as phenolic acids (hydroxycinnamic and hydroxybenzoic acid), flavonoid stilbenes (anthocyanins, flavonols and flavan-3-ols) have been found in grape berry. The largest proportion of polyphenolic compounds in grape berries is contained in the seeds, then skin and pulp. Phenolic compounds are particularly important in red grape wine production technology, because they greatly affect the colour and the characteristic taste of wine. Therefore, the aim of this study is to determine the changes that occur in the polyphenol profile (hydroxycinnamic acids, anthocyanins, flavonols, flavan-3-ols) of 11 red grape varieties during ripening. The research was set up in a vineyard at the location of experimental station Jazbina, viticultural region Sredisnja bregovita Hrvatska, subregion Prigorje - Bilogora and vineyard area Zagreb. Samples were collected periodically, from the beginning of the verasion to technological maturity. They were adequately stored, lyophilized, and subjected to extraction. The obtained extracts were analysed with high performance liquid chromatography. Based on the obtained results, anthocyanins are the most common polyphenol compounds in the skin of the investigated varieties, followed by flavanol glycosides, flavanol-3-ols and hydroxymethyl acids. The mass fraction of anthocyanin and flavonol glycosides in berry skin increases from the beginning of the verasion to the technological maturity, while the mass fraction of flavan-3-ols, hydroxycinnamic acids and flavonol glycosides decreases by technological maturity.
Polifenoli su sekundarni biljni metaboliti te važni organski spojevi prisutni u grožđu, moštu i vinu. Važnost polifenolnih
spojeva prisutnih u grožđu uglavnom je vezana uz kakvoću vina obzirom da ...utječu na boju, okus, astringenciju, gorčinu te
potencijal starenja vina. Cilj ovog rada je utvrditi i usporediti kvantitativne i kvalitativne promjene sadržaja polifenola male
molekulske mase u kožici grožđa 11 crnih sorata vinove loze tijekom dozrijevanja grožđa. Uzorci su prikupljani periodično
od početka šare do tehnološke zrelosti. Sadržaj polifenola u kožici boba utvrđen je tekućinskom kromatografijom visoke
djelotvornosti (HPLC) uz prethodnu liofilizaciju i ekstrakciju. Temeljem dobivenih rezultata utvrđene su promjene sastava
i sadržaja pojedinih grupa polifenolnih spojeva tijekom dozrijevanja.
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 verasion 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.
