Extraction of weak hydrophobic sulforaphane from broccoli by salting-out assisted hydrophobic deep eutectic solvent extraction

In order to extract sulforaphane (SFN) from broccoli via green and efficient ways, a novel method based on salting-out assisted deep eutectic solvent (DES) has been developed. Compared to known organic solvent-(such as dichloromethane, ethyl acetate, n-hexane, etc.) based liquid-liquid extraction, this new N8881Cl-based DES method exhibited excellent extraction efficiency for SFN, including a significant improvement due to the salting -out effect of KH2PO4. Under optimal conditions, 97.77 % of SFN was extracted by N8881Cl-EG DES and more than 82.5 % of SFN was recovered by activated carbon from DES. In addition, further studies with Kamlet-Taft pa-rameters and density functional theory showed that the H-bond accepting capacity of hydrophobic DES, the existing vdW interaction, and the electrostatic interaction between N8881Cl-EG DES all contributed to efficient extraction of SFN. This is the first time that the underlying mechanism for SFN extraction by DES was revealed.

Automated summary

A novel method based on salting-out assisted deep eutectic solvent (DES) has been developed for efficient extraction of sulforaphane (SFN) from broccoli. The method showed excellent extraction efficiency, with high recovery rates achieved using activated carbon. The underlying mechanism for SFN extraction by DES was also revealed.