Partitioning of Crocin in a Novel Aqueous Two-Phase System Composed of a Deep Eutectic Solvent and Acetonitrile

Saffron stigmas are considered as one of the mainsources for crocin extraction. Crocins have many therapeuticproperties and applications in different industries such as food andcosmetic in which their extraction and purification will be usefulcommercially and clinically. This work presents a study on thepartitioning of crocin in aqueous two-phase systems (ATPSs)composed of water, deep eutectic solvents (DESs), and acetonitrile(ACN). Two DESs based on choline chloride as the hydrogenbond acceptor (HBA) and urea and ethylene glycol as hydrogenbond donors (HBDs) were synthesized and considered as phase-forming components. Also, the effects of the hydrogen bonding,HBD species, weight percentages of DES, weight percentages ofACN, and temperature were investigated to evaluate the phase-forming ability of the ATPSs and the partitioning of crocin in these systems. It turned out that the choline chloride-urea/ACNsystem provides higher partition coefficients and a higher extraction efficiency of crocin under optimum conditions (40 wt % of DES,50 wt % of ACN, and 25 degrees C). Moreover, the conformation of crocin in the choline chloride-urea/ACN system was explored using aUV-visible spectrophotometer (UV-vis) and Fourier transform infrared spectrometer (FT-IR), and no change was observed duringthe process. In the end, the UNIFAC model was applied to estimate the equilibrium data of both systems, in which the experimentaldata of two studied ATPSs were well described

Automated summary

This study investigated the partitioning of crocin in aqueous two-phase systems and found that the choline chloride-urea/ACN system exhibited higher partition coefficients and extraction efficiency under optimal conditions.