Valorization of artichoke outer petals by using ultrasound-assisted extraction and natural deep eutectic solvents (NADES) for the recovery of phenolic compounds

What if the outer petals of an artichoke, often discarded as waste, hold a treasure trove of health-boosting compounds? A new study shows how a green, solvent-free method can unlock them.

Artichoke outer petals are usually tossed aside, but they're packed with phenolic compounds—nature's antioxidants. Researchers have now found a smarter way to extract them: using natural deep eutectic solvents (NADES), a green alternative to harsh chemicals, paired with ultrasound assistance. This combo is like a gentle but powerful shake that pulls out the good stuff without leaving toxic residues.

The team tested different NADES mixtures, varying the hydrogen bond acceptors (choline chloride or betaine) and donors (sucrose, lactic acid, citric acid, oxalic acid, or glycerol). They compared results against a traditional methanol extract. The winner? A mix of choline chloride and lactic acid, which delivered the highest phenolic content (12.96 g GAE per kg dry weight) and antioxidant capacity (60.68 g TE per kg dry weight).

Chromatography revealed nine key compounds in all extracts, including gallic acid, chlorogenic acid, and quercetin. Notably, chlorogenic and ferulic acids reached their peak levels in the lactic acid-based NADES. This approach not only boosts recovery but also offers selectivity, making it a promising tool for transforming agricultural waste into valuable ingredients for food and pharmaceuticals.

Key Points

• NADES + ultrasound boosts phenolic recovery from artichoke waste.
• Choline chloride-lactic acid mix yields highest antioxidants.
• Nine phenolic compounds detected, including chlorogenic and ferulic acids.