engleski

Study of phenolic phytochemicals of Croatian white wines

The phenolic composition of different white wines including hydroxybenzoic acids, hydroxycinnamic acids and flavan-3-ols was identified and quantified by using a reversed-phase high-performance liquid chromatography (HPLC) system coupled with diode array detection. Gallic and protocatechuic acids were determined from the group of hydroxybenzoic acids, whereas from the hydroxycinnamic acids caffeic, p-coumaric and ferulic acids were quantified. The most important group of phenolic compounds causing bitterness in wines is flavan-3-ols. Therefore, (+)-catechin, (-)-epicatechin and (-)-epicatechin gallate were identified from this group. The studied samples presented the most preferable white wines from continental part of Croatia (Rhine Riesling, Sauvignon, Chardonnay, Riesling, Traminer, Sylvaner) as well as from Istria (Malvasia istriana). The obtained results showed that caffeic and protocatechuic acids were the most abundant phenolic acids in tested white wines. In all samples were also determined total phenol content and total flavonoids content as well as antioxidant activity. For more reliable results, the antioxidant activity of wine was measured by β-carotene bleaching (BCB), 2, 2-diphenyl-1-picrylhydrazyl (DPPH) and 2, 2’-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid (ABTS) radical scavenging methods. The total antioxidant activities from BCB, DPPH and ABTS assays were good correlated with total phenol content as well as with total flavonoids content.

Antioxidant activity; flavan-3-ols; HPLC; polyphenols; white wine

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