Comparison of Different Green Extraction Techniques Used for the Extraction of Targeted Flavonoids from Edible Feijoa (Acca sellowiana (O.Berg) Burret) Flowers

What if the key to unlocking nature's most valuable compounds lies not in harsh chemicals, but in green, eco-friendly methods? A new study on feijoa flowers reveals that the choice of extraction technique can dramatically alter which bioactive treasures you uncover.

Feijoa flowers, a delightful edible treat, hide a wealth of flavonoids—compounds with potential health benefits. But getting them out is no simple task. Researchers compared four green extraction techniques: ultrasound-assisted extraction (UAE), supercritical fluid extraction (SFE), subcritical water extraction (SWE), and deep eutectic solvents (DES). Each method acted like a different key, unlocking different compounds from the same floral treasure chest.

Using high-performance liquid chromatography, the team quantified specific flavonoids. UAE emerged as a star, yielding the highest amounts of isoquercitrin (18.36–25.33 µg/g) and quercetin (10.86–16.13 µg/g). Meanwhile, DES with choline chloride and lactic acid excelled at extracting chrysanthemin (90.81 µg/g), and supercritical CO2 at 300 bar won for flavone (12.69 mg/g).

The extracts also showed impressive antioxidant power. UAE gave the highest total polyphenol content (about 64 mg GAE/g) and strong antioxidant activity, particularly at 70°C for 30 minutes with 40% or 60% ethanol-water solutions. The study concludes that these green methods are not just eco-friendly—they are selective tools for targeting specific bioactive compounds, offering a sustainable path to functional ingredients.

Key Points

• UAE best for isoquercitrin and quercetin yields.
• DES excels for chrysanthemin; SFE for flavone.
• UAE tops total polyphenols and antioxidant activity.