Ultrasound-Assisted Extraction, Identification, and Quantification of Antioxidants from ‘Jinfeng’ Kiwifruit

What if the key to unlocking a fruit's hidden antioxidant power lies in sound waves? A new study on 'Jinfeng' kiwifruit shows that ultrasound-assisted extraction can boost antioxidant yield by nearly 20% compared to traditional methods.

Kiwifruit is a nutritional powerhouse, packed with vitamin C and phenolic compounds that fight oxidative stress. Yet, the specific antioxidants in the 'Jinfeng' variety have remained largely unexplored—until now. Researchers turned to ultrasound-assisted extraction (UAE), a technique that uses sound waves to disrupt cell walls and release bioactive compounds more efficiently than conventional solvent extraction.

Using response surface methodology (RSM), they optimized the extraction process to achieve maximum antioxidant yield. The winning formula: 68% ethanol, a liquid-to-solid ratio of 20 mL/g, 30 minutes of extraction, a temperature of 42°C, and ultrasonic power of 420 W. Under these conditions, the antioxidant capacity, measured by the ABTS assay, reached 70.38 ± 1.38 µM TE/g DW—an 18.5% improvement over conventional methods.

The study also quantified key phytochemicals: total phenolics at 15.50 ± 0.08 mg GAE/g DW, flavonoids at 5.10 ± 0.09 mg CE/g DW, and ascorbic acid. Through UPLC-MS/MS, 20 compounds were tentatively identified, with major ones like procyanidin B2, neochlorogenic acid, and epicatechin quantified by HPLC. This research reveals that 'Jinfeng' kiwifruit is a rich source of natural antioxidants, potentially offering health benefits as a dietary supplement.

Key Points

• Ultrasound boosts antioxidant yield by 18.5%.
• Optimal UAE: 68% ethanol, 420 W, 30 min.
• 20 antioxidant compounds identified in 'Jinfeng' kiwifruit.