Research On The Process Of Microwave-assisted Extraction And Separation And Purification Of Soy Isoflavones

It was studied systematically that the unit process of Microwave-assisted extraction process for the soy isoflavones from soybean firstly, then separation and purification of soy isoflavones with macroporous resin in this paper. And the content were determined by UV-spectrophotometry. The studies showed that:Aqueous ethanol was employed in microwave-assisted and pressurized solvent extraction method. The single factor experimental method was first used to investigate the effects of alcohol concentration (x), pressure intensity (R), ratio of liquid to solid (s), microwave power (P), radiation number(n) and soy pre-immersed time (τ) on extraction rate of soy isoflavones. Then the Design-Expert 6.0 software was used to carry out a response surface design and test with three factors (x, R and s) and three levels, and to establish the mathematical model with its optimum calculation. The results show that under the optimum technical conditions:x =61%, R=152.0kPa, s=21 ml/g, P=560W, n=1 and t=1.5h. The extraction rate of soy isoflavones reaches 3.56 mg·g-1Aqueous ethanol was employed in microwave-assisted and atmospheric pressure solvent extraction method. Similar to microwave-assisted and pressurized solvent extraction method, using the Design-Expert 6.0 software carry out a response surface design and test with three factors (x, P and s) and three levels on the basis of a single factor experimental method. The results show that under the optimum technical conditions:x=54%, P=420W, s=15 ml/g, n=1 and=1h, And the extraction rate of soy isoflavones reaches 3.20 mg·g-1.Quadratic polynomial regression equation of pressurized solvent extraction method and atmospheric pressure solvent extraction method are established respectively by Design-Expert 6.0 software. And the model is consistent with experimental results and can predict the extraction rate under different technical conditions.Macrophorous resin LX-38 was selected by comparing the properties ofadsorption and desorption of 3 types of macrophorous resins for soybean isoflavones.All process conditions influencing on the process of separation and purification the soy isoflavones with LX-38 resin were investigated in detail. The optimum absorption and separation process condition was confirmed when the feed concentration of the soy isoflavones was2.765mg.ml-1, the feed volume was 3BV(resin bed volume), the absorption velocity was 2BV.h-'; the desorption solvent was 70% ethanol of 5BV, the desorption velocity waslBV.h-1,the purity of the product was 41.8%.