Phytochemical Profiles of Edible Kudzu (Pueraria thomsoniiBenth) Grown in China as Affected by Thermal Processing

Abstract

The objective of this research was to assess how home cooking methods affect the phytochemical profiles of edible kudzu (Pueraria thomsonii) grown in Zhuhai, China. Phenolic, flavonoids, condensed tannin and isoflavone content and antioxidant capacities of processed kudzu were compared with raw samples by employing colorimetric methods and high-performance liquid chromatography. DPPH free-radical scavenging assay, ferric-reducing antioxidant powder and ABTS radical-scavenging assay were used to analyze the antioxidant activities. Results showed that the frying process largely enhanced the phytochemical content and the antioxidant capacities. Boiling and steaming increased the isoflavone content of kudzu from 0.77 mg/g (in raw kudzu) to 2.12 mg/g (in the boiled kudzu) and 1.03 mg/g (in the steamed kudzu). These results indicated that most of the cooking methods were capable of enhancing phytochemical values of kudzu. It was suggested that frying and/or boiling the edible kudzu might help consumers in obtaining a higher antioxidation effect. Practical Applications Presented information will guide home-cooking practice and food industry to retain more health benefit components through selecting cooking methods. The results indicate that thermal processing remarkably affected phytochemical profiles of kudzu and significantly changed the antioxidant capacities of kudzu.