Ćurko Natka, Tomašević Marina, Cvjetko Bubalo Marina, Gracin Leo, Radojčić Redovniković Ivana, Kovačević Ganić Karin
University of Zagreb, Faculty of Food Technology and Biotechnology, Pierottijeva 6, HR-10000 Zagreb, Croatia.
Food Technol Biotechnol. 2017 Sep;55(3):429-437. doi: 10.17113/ftb.55.03.17.5200.
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 [Cmim][Br] and 2.5 mol/L of 1-ethyl-3-methylimidazolium bromide [Cmim][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 [Cmim][Br] and 2.5 mol/L of 1-methylimidazolium hydrogen sulfate [mim][HSO] than with conventional solvent with the exception of anthocyanin-3-O-acetylmonoglucosides in the latter. On the other hand, 2.5 mol/L of [Cmim][Br] and 2.5 mol/L of 1-(4-sulfobutyl)-3-methylimidazolium hydrogen sulfate [sCmim][HSO] showed significantly higher selectivity towards anthocyanin-3-O-acetylmonoglucosides and anthocyanin-3-(6-O--coumaroyl)monoglucosides.
在本研究中，八种不同类型的咪唑基离子液体（ILs）被用作从葡萄皮中提取黄酮类化合物的新溶剂，并与之前未报道的传统有机溶剂萃取法进行比较。阴离子、阳离子的结构以及离子液体的浓度对萃取产率有显著影响。分别使用2.5 mol/L的1-丁基-3-甲基咪唑溴盐[Cmim][Br]和2.5 mol/L的1-乙基-3-甲基咪唑溴盐[Emim][Br]时，原花青素和花青素的质量分数最高。所研究的离子液体在花青素的萃取方面取得了优异的初步结果。与传统溶剂相比，使用2.5 mol/L的[Cmim][Br]和2.5 mol/L的1-甲基咪唑硫酸氢盐[mim][HSO₄]萃取得到的总花青素和所有游离花青素的质量分数显著更高，但后者中的花青素-3-O-乙酰基单葡萄糖苷除外。另一方面，2.5 mol/L的[Cmim][Br]和2.5 mol/L的1-(4-磺酸丁基)-3-甲基咪唑硫酸氢盐[sCmim][HSO₄]对花青素-3-O-乙酰基单葡萄糖苷和花青素-3-(6-O-香豆酰基)单葡萄糖苷表现出显著更高的选择性。
