Hot-Water Infusion as an Efficient and Sustainable Extraction Approach for Edible Flower Teas

This study evaluated hot-water infusion as a practical and sustainable extraction method for functional flower petal teas. Six edible flowers—Tagetes erecta, Lonicera japonica, Celosia argentea var. cristata, Centaurea cyanus, Hibiscus sabdariffa, and Malva sylvestris—were compared under hot-water and 80% ethanol extraction. Hot-water extraction was performed at 100 °C for 15 min. Hot-water extracts showed 1.3–4.0 times higher total phenolic content (TPC) and stronger antioxidant activities (ABTS, DPPH, and FRAP) than 80% ethanol extracts, reflecting efficient extraction of hydrophilic phenolic acids. UPLC-ESI-Q-TOF-MS and GC–MS analyses of hot-water extracts revealed chlorogenic acid, caffeic acid, coumaric acid derivatives, flavonoid glycosides, and aroma volatiles such as hexanal and α-pinene. These findings confirm that simple hot-water infusion effectively recovers both bioactive and aroma-active compounds, supporting its application in developing safe, natural, and functional flower teas.