Optimization of anthocyanin extraction from mango peel wastes using ultrasound and microwave-assisted natural deep eutectic solvents

Mango peels are often thrown away, but they hide a treasure trove of colorful, health-boosting pigments—and scientists just found a greener way to unlock them.

Mango peels, the throwaway scraps of a beloved fruit, are packed with anthocyanins—natural pigments with anti-inflammatory and antioxidant powers. But extracting them efficiently has always been a challenge. This study turned to natural deep eutectic solvents (NADES), a new generation of green solvents, paired with ultrasound and microwave assistance to do the job better than ever before.

Among the solvent combinations tested, choline chloride combined with lactic acid (1:2 ratio) proved the star performer. Using a Box–Behnken design, the researchers optimized sonication time, microwave intensity, and microwave duration. The result? A dramatic boost in anthocyanin yield to 44.77 mg per gram of dry peel—more than ten times higher than the 4 mg obtained with conventional acidified ethanol.

But the benefits didn't stop there. The NADES extract also showed superior antioxidant activity and phenolic content. Its DPPH radical-scavenging activity reached 39 μmol AAE/g, and ferric reducing power hit 40 μmol AAE/g—both nearly double those of the traditional method. Even the color intensity was stronger, suggesting a more vibrant extract.

Spectrophotometric and stability tests confirmed that the extracted anthocyanins remained intact under various conditions. This research highlights a sustainable path to turn agro-industrial waste into valuable bioactive compounds, using non-toxic solvents and energy-efficient techniques.

Key Points

• ChCl:lactic acid NADES boosts anthocyanin yield to 44.77 mg/g.
• Ultrasound + microwave synergy outperforms acidified ethanol.
• Green extraction yields higher antioxidants and phenolics.