Study on Extraction and Analysis of Flavonoids from Onion

Flavonoids were extracted by ethanol from onion,which was determined by UV-Vis spectrophotometry.The effect factors such as the concentration of ethanol,mass rate of onion to ethanol,extraction time,extraction temperature were investigated.The results showed that the optimum condition was that the determination wavelength was 504 nm.Good linear relationship with the absorption was achieved when the detection concentration of rutin was within a range of 0.080 mg/mL-0.400 mg/mL(R2=0.997 4).The concentration of ethanol was 60 %,solid-liquid ratio was 1∶18(g/mL),extraction n time was 2.5 hours,and extraction temperature was 77 ℃.Under the optimum extraction conditions,25.40 mg flavonoids were extracted from 6.00 g onion.