Abstract: Orthogonal design was carried out to optimize the ultrasonic extraction method of Lonicera japonica Thunb and spray drying method of Lonicera japonica Thunb. instant tea. Identification of the tea using caffeotannic acid and the reference herb of Lonicera japonica Thunb by thin layer chromatography (TLC) was performed. The contents of caffeotannic acid was determined by high performance liquid chromatography (HPLC). The optimized extraction method is as follows: using 10 times of water to extract for 3 times,1 h for each time. The optimized spray drying method is as follows: Outlet temperature 200 ℃,spraying pressure 180kPa. Can relative density of materials was 1.10mg/ml.The characteristic spots of Lonicera japonica Thunb could be detected in thin layer chromatogram. The linear range of caffeotannic acid content is from 0.984 to 5.24μg(r=0.9999),and the average recovery is 100.5% (RSD=1.84%).

Key words: Lonicera japonica Thunb instant tea, ultrasonic extraction, spray drying, orthogonal design, TLC, HPLC