Natural Deep Eutectic Solvents for Solubility and Selective Fractionation of Bioactive Low Molecular Weight Carbohydrates

Imagine a sugar that could be selectively rescued from a mixture, like a lifeguard pulling a swimmer from a crowded sea—natural deep eutectic solvents might just be that lifeguard.

Natural deep eutectic solvents, or NADES, are emerging as the eco-friendly heroes of extraction chemistry. But until now, their ability to dissolve and separate small carbohydrates—the building blocks of many bioactive compounds—remained largely unexplored. This study changes that, offering fresh solubility data and a first-ever approach to using NADES for selective fractionation of these sugars.

The researchers tested three NADES formulations based on choline chloride, paired with different partners: ethylene glycol, glycerol, and oxalic acid dihydrate. They worked with several mono- and disaccharides, including key players like lactulose and tagatose. Interestingly, the acidic nature of the oxalic acid-based NADES caused some sugar degradation, especially for ketoses, so the team pivoted to the other two solvents.

Choline chloride with ethylene glycol or glycerol proved to be a winning duo. These solvents could selectively separate bioactive ketoses from their aldose counterparts in equimolar mixtures—think lactulose from lactose, or tagatose from galactose. Even more exciting, the ethylene glycol-based NADES boosted lactulose purity from 25% in a reaction mixture to 56% in a purified sample, showing real potential for food and nutraceutical applications.

This isn't just a lab curiosity. The ability to fractionate valuable carbohydrates from interfering sugars opens doors in food science, engineering, and pharmaceuticals. With NADES, we might soon have a greener, smarter way to isolate the sugars that matter most.

Key Points

• First solubility data for LMWCs in NADES
• ChCl:EtG and ChCl:Gly selectively separate ketoses from aldoses
• Lactulose purity boosted from 25% to 56% with ChCl:EtG