Effect of Different Manufacturing Processes of Mugwort Tea on Its Polyphenol Content, Antioxidant Activity, and Sensory Characteristics

Mugwort (Artemisia princeps Pamp.) is a traditional herb widely used across East Asia; despite this, optimal processing methods to preserve its functional components and palatability have not been fully established. Thus, we aimed to, for the first time, systematically examine the effects of 16 processing methods that combine blanching (steaming or boiling), drying [freeze-drying (FD), mechanical drying, shade drying, or silica gel drying], and rolling on mugwort’s appearance, total polyphenol content (TPC), antioxidant activity, and sensory characteristics. Our results showed that steaming for ≥2 min followed by FD was the most effective method for maintaining a high TPC and a vibrant green color. In contrast, boiling with sodium bicarbonate preserved color but substantially reduced both TPC and chlorogenic acid (CGA) content compared with steaming. Sensory evaluation revealed that consumers consistently preferred steaming over other processing methods. Liquid chromatography–tandem mass spectrometry analysis revealed that prolonged drying induced CGA isomerization to neochlorogenic acid. Moreover, processing time substantially influenced CGA stability, while high TPC did not compromise mugwort flavor. Our findings imply that an optimized combination of steaming and FD maximizes both functional and sensory quality of mugwort, highlighting the potential of mugwort tea as a flavorful functional food.