Extraction time for soybean isoflavone determination

Studies were carried out on the optimization of the extraction procedures for isoflavones determination in soybean by HPLC Isoflavones were extracted from 100 mg samples of full fat soybean flour "Kinako" (milled toasted grains). Recovery of average total isoflavones was higher when extraction was performed with agitation(217.2 mg/100g), than without agitation(191.0 mg/100g). Isoflavone extraction without agitation for 1,4, 20 and 24 hours, were equally efficient for total and individual compounds. These results suggested that an efficient isoflavone recovery could be achieved with extraction for one hour with agitation.