Study on the total flavones extracted from red beans under ultrasound irradiation by orthogonal test

In order to obtain the optimal process condition of the total flavones extracted from red beans,the main factors such as extraction time,ultrasonic power,ethanol concentration,temperature and liquid–to–solid ratio which affected the extraction ratio of total flavones were researched by single factors experiment. Based on this,the optimal extracting condition of the flavones was studied by the orthogonal test. Studies showed that the optimum extraction conditions were as follows:extracting time was 30 min,power of radiation was 160 W,solid liquid ratio was 1∶40,extracting temperature was 60 ℃;ethanol concentration was 60%. Under the above conditions,the total amount of flavones was 15.07 mg/g. Recoveries of rutin were from 82.4% to 112.5%. RSDs were less than 1.11%. Effect of tannin acid on experimental result showed that phenols and acids in red beans had played no impact on extraction process of flavones. The extract of red beans was flavones compounds which were characterized by IR.