NLM-PubMed-Logo  doi: 10.17113/ftb. 

Extraction of Proanthocyanidins and Anthocyanins from Grape Skin by Using Ionic Liquids

Natka Ćurkosmall orcid_display_4pp, Marina Tomaševićsmall orcid_display_4pp, Marina Cvjetko Bubalosmall orcid_display_4pp, Leo Gracinsmall orcid_display_4pp, Ivana Radojčić Redovniković*small orcid_display_4pp
and Karin Kovačević Ganićsmall orcid_display_4pp

University of Zagreb, Faculty of Food Technology and Biotechnology, Pierottijeva 6, HR-10000 Zagreb, Croatia

Article history:
Received: February 6, 2017
Accepted: April 24, 2017

Key words:
anthocyanins, grape skin, HPLC, ionic liquids, proanthocyanidins

In this study, eight different types of imidazolium-based ionic liquids (ILs) were applied as new solvents in the extraction of flavonoids from grape skin, and compared to the conventional organic solvent extraction that was not reported earlier. The structure of anions, cations and concentration of ILs significantly affected extraction yields. The highest mass fractions of proanthocyanidins and anthocyanins were obtained with 2.5 mol/L of 1-butyl-3-methylimidazolium bromide [C4mim][Br] and 2.5 mol/L of 1-ethyl-3-methylimidazolium bromide [C2mim][Br], respectively. The studied ILs provided an excellent preliminary result in the extraction of anthocyanins. Significantly higher mass fractions of total and all free anthocyanins were extracted with 2.5 mol/L of [C2mim][Br] and 2.5 mol/L of 1-methylimidazolium hydrogen sulfate [mim][HSO4] than with conventional solvent with the exception of anthocyanin-3-O-acetylmonoglucosides in the latter. On the other hand, 2.5 mol/L of [C4mim][Br] and 2.5 mol/L of 1-(4-sulfobutyl)-3-methylimidazolium hydrogen sulfate [sC4mim][HSO4] showed significantly higher selectivity towards anthocyanin-3-O-acetylmonoglucosides and anthocyanin-3-(6-O-p-coumaroyl)monoglucosides.

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