Comparison of the Potential of “Green” Classical and Natural Deep Eutectic Solvents in the Production of Natural Food Colorant Extracts from the Roots of Alkanna tinctoria (L.)

A humble root could hold the secret to natural food coloring—and a new green solvent just stole the spotlight. But not all that glitters is gold, especially when it comes to safety.

The alkanet plant, a medicinal herb, has long been valued for its roots, which yield pigments for natural food coloring and boast antioxidant properties. But extracting these compounds efficiently and safely is no small feat. Researchers compared three classical solvents—ethanol and acidified ethanol/water mixtures—with four natural deep eutectic solvents (NADES), including choline chloride-based combinations and sodium acetate/formic acid. This study marks the first time choline chloride-based NADES have been tested on alkanet, offering a detailed look at bioactive compounds and their antioxidant activity via advanced spectrometry and chromatography methods.

Key Points

• First use of choline chloride NADES for alkanet extraction.
• Sodium acetate/formic acid NADES shows best antioxidant and safety profile.
• Alkannins only detected in NADES4 extract, not ethanol.