Abstract
Previous studies have reported the optimum steeping time and temperature of roasted Jerusalem artichoke tuber tea for better color, taste, and inulin content. However, studies on functional components other than inulin present in this tea are inadequate. In this study, we investigated the effects of different steeping conditions on the total polyphenol content, antioxidant capacity, and α-glucosidase and angiotensin-converting enzyme (ACE) inhibitory activities of roasted Jerusalem artichoke tuber tea. Functional components responsible for ACE inhibitory activity were also investigated. The steeping conditions were selected based on the results of previously reported studies. Total polyphenol content, 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, and α-glucosidase and ACE inhibitory activities increased on steeping the tea for 2 minutes or more in hot water or 2 hours or more in cold water. The functional component responsible for ACE inhibitory activity may be nicotianamine in unroasted tubers and Maillard reaction products in roasted tubers.
https://ror.org/04f4wg107 
