The removal of pesticide residues from pakchoi (Brassica rape L. ssp. chinensis) by ultrasonic treatment

The removals of chlorothalonil, pyrazophos, and carbendazim residues form pakchoi by ultrasonic treatment were investigated in this study. The ultrasonic treatment has higher efficiency on the removal of pesticides compared to traditional water soaking. The removal rates of ultrasonic treatment for chlorothalonil, pyrazophos, and carbendazim residues were in the range of 13.87–74.86%, 21.74–45.68%, and 5.12–24.63%, respectively. The removal rates increased with the increase of ultrasonic power, while decreased with the increase of ultrasonic frequency. Besides, the physical damage and vitamin C loss for pakchoi leaves caused by ultrasonic treatment were also evaluated. Results showed that both the physical damage and vitamin C loss increased with the increase of ultrasonic power but decreased with the increase of ultrasonic frequency. A simple three-variable linear model was built up to estimate the loss of vitamin C according to the physical damage on leaves. In conclusion, ultrasonic treatment is an effective technique for the removal of pesticide residues from leafy vegetables. Ultrasonic condition should be considered to avoid the physical damage and the vitamin C loss for vegetables.