ABSTRACT
In the present study, the antioxidant activity of sweet potato leaf polyphenols was measured, and the effect of different pH values (3.0, 5.0, 7.0, and 8.0), temperatures (55, 65, 80, and 100°C), and light treatments on sweet potato leaf-polyphenols was investigated. Results showed that the O2− scavenging activity of sweet potato leaf polyphenols from cultivar Jishu No. 04150 was 5.84 and 6.20 times of that of tea polyphenols and grape seed polyphenols, respectively, at the concentration of 20 μg/mL. The oxygen radical absorbance capacity was 1.28 and 1.27 times of that of tea polyphenols and grape seed polyphenols, respectively. Sweet potato leaf polyphenols dissolved in pH 5–7 solutions showed higher retention rates of antioxidant activity. Heat treatment at 50 and 65°C and light treatment had little effects on sweet potato leaf polyphenols. In conclusion, sweet potato leaf polyphenols possessed high antioxidant activity and processing stability, having the potential to be a new type of natural antioxidant.
Acknowledgments
The authors are grateful to the Academy of Agricultural and Forestry Sciences in Hebei Province for providing the sweet potato leaves used in this study.
Funding
The authors gratefully acknowledge the earmarked fund for the China Agriculture Research System (CARS-11-B-19).