Ultrafine comminution-assisted ultrasonic-microwave synergistic extraction of Pueraria mirifica (Kudzu flower and root) flavonoids

Extracts of the Pueraria mirifica (Kudzu) plant have several significant human health-promoting benefits. This study utilized orthogonal tests to evaluate the effects of differential ultrasonic power, microwave, and time on the rate of flavonoid extraction from Kudzu samples. Ultrafine processing resulted in finer powder microstructures (SEM) with high solubility. The smallest D50 measurements of ultrafine Kudzu flower and root particles were 11.7 +/- 0.004b and 14.3 +/- 0.013c mu m, respectively. Increasing ultrasonic power from 200 to 600 W yielded increased flavonoids. Increased microwave power from 200 to 800 W also yielded increased flavonoid extract. We found that the best combination factor was A3B2C3 (A-ultrasonic power, B-time, and C-microwave power), showing that flavonoid extraction rate was primarily influenced by micro-wave power, followed by ultrasonic time and ultrasonic power. Conclusively, ultrafine pulverization increased the flavonoid extraction rate from Kudzu powder particles. Also, scanning electron microscopy results showed that the finer particles had increased solubility.