Determination of optimal acid hydrolysis time of soybean isoflavones using drying oven and microwave assisted methods

► Microwave is easy, effective, and reliable hydrolysis method concerning isoflavones. ► The optimum condition of microwave was hydrolysed by 1 N HCl for 50 min at 100 °C. ► The highest isoflavone aglycone content after acid hydrolysis was achieved in 3 h.