Studies On Screening,Characteristics And Utilization Of Soybean Mutant High In Isoflavones

Soybean isoflavone, one of the secondary metabolites in the plants, is mainly produced by the leguminosae plants, especially in soybean. Soybean isoflavone was proved to have multiple physiological functions such as lowering cholesterol levels, preventing prostate and breast cancers, osteoporosis, cardiovascular disease as well as relieving menopausal symptoms. Research and development of soybean isoflavones has an important significance on improving the health level of human and promoting the comprehensive utilization of soy isoflavones.Mutant high in isoflavones was successfully developed when the dry seeds of soybean line ZN01were irradiated by120Gy Cobalt-60gamma rays. Isoflavones contents and components, nutritional components and major agronomic traits of mutants SHIS-01high in isoflavones were comparatively studied with its wild type. The influences of different extraction methods and processing methods on the contents of soybean isoflavones were investigated. Results in details were as follows:1The contents of isoflavones in mutant SHIS-01were consistent higher than that of the wild type in the consecutive three generations, although the absolute contents of isoflavones varied in different times and locations. Except daidzein, the contents of isoflavones components i.e. Daidzin, Glycitin, Genistin, Genistein,6"-O-Malonyl daidzin,6"-O-Malonyl genistin,6"-O-Malonyl glycitin in mutant SHIS-01were all significantly higher than that of the wild type. The major agronomic traits of mutant SHIS-01were similar to the wild type, except significant bright yellow color of fresh new leaf and seed coat and the prolonged whole growth duration. Nutritional components in mutant were basically similar to that of the wild type, except the edible fiber. The large difference of pasting properties and texture properties between mutant and the wild type may be caused by the change of fiber content.2The contents of soybean isoflavones in mutant SHIS-01extracted by the microwave-assisted extraction and the ultrasonic extraction were4.74mg/g and7.01mg/g, respectively. The efficiency of isoflavones extraction by the ultrasonic method could be increased significantly, and there were1.48times increases compared to that by the microwave-assisted method. However, the optimal times required for the ultrasonic extraction need to be further determined.3Changes in the contents of isoflavones were observed in the processed soybean by three different processing methods i.e. fresh grinding, cooking, and baking. The contents of isoflavones were found to be decreased in turns of the soy milk, raw, baked and cooked soybean. The content of isoflavones in the soy milk was1.93times of that in the raw soybean, while16.67percentages of isoflavones were lost in the cooked soybean compared to that in the raw soybean. Therefore, the efficiency of the intake of isoflavones can be significantly improved when eating soybean in forms of soy milk or baked soybean in the daily life.Property of high soybean isoflavones content in mutant SHIS-01kept steadily, which is benefit for soybean biological breeding with high soybean isoflavone in the future, and provides excellent materials for the further researches of processing of soybean isoflavones.