Composition of Roasted Dendropanax morbiferus Leaf Tea after the Blanching Process

This study investigated the effects of blanching treatment and roasting temperatures (150, 200, 250, and 30 0℃) on the key components and antioxidant activity of Hwangchil (Dendropanax morbifera) leaf tea to establish the optimal manufacturing process. The total phenolic compounds, chlorogenic acid, and rutin contents were maximized when roasted at 200-250℃, and the contents of these components were enhanced further by the blanching treatment. The color of the tea water, and the L and b values did not show significant differences with blanching or change in the roasting temperatures. The G value increased in proportion to the roasting temperature and was lower in samples that underwent a blanching process. Taste profiling using an electronic tongue revealed that blanching reduced astringency and spiciness while enhancing umami, thereby improving sensory quality. Antioxidant activity, as measured by 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS+ ) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assays, was higher in samples which were subjected to roasting and the blanching process. The highest antioxidant activity was observed in samples that were blanched and then roasted at 200℃ and this aligned with the phenolic compounds content. This indicates that blanching significantly enhanced the antioxidant activity and active ingredients, such as phenolic compounds. In conclusion, we suggest that the optimal manufacturing conditions for improving the quality and sensual characteristics of Hwangchil leaf tea are blanching and then roasting at 200-250℃.