Enhancing Quality and Processing Efficiency of Germinated Buckwheat Tea Through Hot Air-Assisted Radio Frequency Roasting

Buckwheat germination can increase bioactive compounds; however, it also increases moisture content, which then requires drying and roasting. This study focused on applying hot air-assisted radio frequency (HARF) roasting to germinated buckwheat (GB) tea to improve the tea quality and processing efficiency. Seeds were soaked in reverse osmosis water for 6 h, followed by germination at 25 °C for 24 h. HARF roasting (100 °C, 10 kW, 16 cm gap) rapidly heated one bucket (2 kg) and two buckets (2 + 2 kg) of GB to 140 °C in only 22 and 20 min, respectively, to reduce the moisture content from 40% to 5%. HARF roasting could save about 1/5 time and 1/11~1/18 energy compared with a cyclonic oven at 140 °C for 100 min roasting to 120 °C. GC-IMS and sensory evaluation indicated a superior aroma, taste, and higher overall acceptability for HARF-roasted GB tea. These results demonstrate that GB using HARF roasting enhances the functional, sensory, and industrial value of buckwheat tea.