Preparation Of Soybean Isoflavone

The isoflavone fraction in soybean belongs to the family of flavonoids, a large group of plant-derived compounds which have been associated with lots of biological activities. Moreover, the ability of isoflavone to prevent cancer and other chronic disease are much concerned. In this paper, we'll find the best technological operation to gain products of isoflavone.Isoflavones were first quantified by reversed-phase high-performance liquid chromatography. According to their MS characters, each isoflavone was identified. A Novapak C₁₈ column, 3.9×150 mm with 4μm packing, was used. Gradient elution was performed with solvent A - 0.1% (v/v) acetic acid in water and solvent B - 0.1% (v/v) acetic acid in acetonitrile. The flow-rate was 1.0 mL/min. Column temperature was maintained at 40℃. Detection was at 254 nm. Isoflavones were quantified by external standard method.The optimum condition of extraction of isoflavone from the soybean hypocotyl meal was as follows: solvent 60% ethanol, temperature 50℃, flow-rate 1.0 BV/h, solvent volume to meal's weight 4:1 mL/g. The content of isoflavones in the product was 6.43%.And then, we'll purify the product by column chromatography. Before that, in order to minimize the loss of malonyl-isoflavone, the process of high-temperature hydrolysis was conducted in this paper. After testing the stability, the hydrolytic temperature was set at 100℃, and for 5 h.Finally, the process of column chromatography was divided into two stages: adsorption and desorption. By studying the factors that effects the content of products and recovery of isoflavone, otherwise, concerning economic efficiency, the optimum condition was that: 40℃, flow-rate 1.0 BV/h, concentration 5.0 mg/mL in water, the total quantity 10 mg isoflavone/g resin, the eluting solvent sequence was:water 1.0 BV, 50% ethanol 1.0 BV and 95% ethanol 2.0 BV. At above conditions, the saturated adsorption capacity was 60.0 mg/g resin, the content of products was41.11% with the recovery of 76.4%.