Effect of different cooking methods on phytochemical content and antioxidant capacity of Platycodon grandiflorum root

Abstract

The root of Platycodon grandiflorum is conventionally used as either foodstuff or a traditional medicine in Korea. The effects of different cooking methods on the phytochemical content and antioxidant capacity of P. grandiflorum root were evaluated. Compared with the raw roots of P. grandiflorum, the vitamin C content was significantly reduced in the samples subjected to all cooking treatments (p<0.05). The total polyphenol, total flavonoid, 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging activity, and reducing power of the root extract were significantly decreased (p<0.05) after blanching and boiling treatments. On the other hand, steaming treatment preserved or increased the content of all phytochemicals and the antioxidant activities evaluated herein, with the exception of the vitamin C content and reducing power. The overall results of this study suggest that steaming was the method of choice for retaining the optimum benefits of the phytochemicals and antioxidant activity of P. grandiflorum root.