Effects of Brewing Temperature and Time on the Quality Attributes and Chemical Profiles of Cyclocarya paliurus Tea Infusions

Brewing temperature and duration jointly modulate the sensory perception, functional properties, and chemical composition of herbal tea infusions, yet their integrated effects on Cyclocarya paliurus tea remain poorly understood. Here, cold-brewed (4 °C) and hot-brewed (90 °C) C. paliurus infusions prepared over a 5 min–2 h time gradient were systematically characterized using a multi-platform analytical strategy. Brewing mode and time produced clearly differentiated quality profiles: hot brewing yielded darker infusions with stronger bitterness and astringency, higher phenolic and flavonoid contents, and greater 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical-scavenging capacities, whereas cold brewing produced lighter, milder infusions with more gradual time-dependent compositional changes. Volatile and non-volatile profiles were clearly separated between the two brewing modes, and their temporal patterns indicated compound-specific temperature- and time-dependent responses rather than a generalized increase in extraction efficiency at elevated temperature. In total, 61 volatile features and 3666 metabolite features were annotated, from which 50 core differential metabolites were screened; exploratory treatment-level correlation analysis linked tentatively annotated gossypetin 8-glucuronide to radical-scavenging capacity, kaempferol 3-O-arabinoside and sericoside to bitterness-related responses, and epoxypheophorbide a to color variation. These findings clarify how brewing temperature and time jointly shape the quality of C. paliurus tea infusions and provide candidate chemical markers to guide the selection of brewing conditions and the development of differentiated C. paliurus-based herbal beverages. As a single commercial batch of C. paliurus tea was examined, these findings should be interpreted within the context of the tested material and brewing conditions.