Abstract:

Rape bee pollen was used as the raw material to identify its characteristic component-flavonoids. The optimal ultrasound-assisted extraction processing conditions for flavonoids from rape bee pollen were explored by quadratic regression orthogonal rotation experiments, response surface analysis and ridge analysis. The extracted sample with acid hydrolysis was analyzed using HPLC-DAD and HPLC/MS. Results showed that the optimal ultrasound-assisted extraction conditions were ethanol concentration of 76%, material-liquid ratio of 1:30, ultrasonic treatment time of 33 min, ultrasonic treatment temperature of 51 ℃. Under the optimal conditions, the yield of flavonoids was 1.89%, which was close to theoretical yield of 2.12%. HPLCDAD and HPLC/MS analyses exhibited that nine kinds of flavonoid aglycones were identified in rape bee pollen. The identified flavonoids included quercetin, kaempferol, isorhamnetin and naringenin. These investigations provide a research method and theoretical reference for the identification of plant sources and authenticity of bee pollen.

Key words: ultrasound wave, rape bee pollen, flavonoids, HPLC/MS