Isoflavone Accumulation Technology In Germinated Soybean And Its Nutrition Powder Development

In this study,we screened out isoflavone-rich soybean from four soybean cultivars for isoflavone accumulation.Besides,the optimized UV-B irradiation intensity and germination temperature were obtained.On the basis of these results,the impact of exogenous additives on soybean sprouts’ isoflavone content was further investigated.Additionally,using soybeans rich of isoflavone as raw materials,a nutritional powder was developed.The main findings were as follow:1.Under UV-B irradiation condition,isoflavone content,PAL(Phenylalanine ammonia lyase)and CHS(Chalcone synthase)activity of soybean cultivar Yunhe were significantly higher than the other three species.Germination rate of Soybean(Yunhe)was as high as 99.5%,which was higher than the other cultivars.Sprout length,respiratory rate,content of free amino acid and reducing sugar were also higher than the others.Thus,the cultivar Yunhe was selected for isoflavone accumulation in further experiments.During germination,isoflavone content,PAL and CHS vitality of soybean(Yunhe)increased and were significantly higher in the UV-B irradiation condition than in the dark environment.The macromolecular compounds soluble sugar and soluble protein trended to decrease while small molecules such as free amino acids increased gradually.2.The optimal temperature was 30.4℃ and the optimal intensity of UV-B irradiation was 37.23 μW·cm-2.Under these conditions,isoflavone content in soybean sprouts was 669.35 μg/sprout.Compared with the dark conditions,UV-B radiation significantly inhibited sprout length and respiratory rate.Free amino acids and soluble protein content of soybean germinating under UV-B radiation were higher than in the dark.In the later period of germination,soluble sugar and reducing sugar content were lower than that of soybean germinatinog in darkness.But in fact,UV-B radiation didn’t have great effect on nutrient substances content.UV-B radiation increased isoflavones content and the activities of PAL and CHS significantly.3.The optimal compositions of culture solution for isoflavone accumulation were KCl of 5.64 mmol/L,L-phe of 3.51mmol/L,6-BA of 8.65 mg/L.Under these conditions,isoflavone content in soybean sprouts was 839.42μg/strains.Components in the culture solution inhibited soybean germination but significantly increased isoflavones content and the activities of PAL and CHS compared with water.Sprout length was shorter and respiratory rate was increased.In the later period of germination,free amino acid,soluble sugar and reducing sugar content were higher than that of soybean germinated in water.4.The optimal formula of the isoflavone-rich powder was as follows:soy flour 12 g,brown rice flour 8 g,white sugar 4 g,maltodextrin 2 g.Powder of this recipe tastes better and retains unique flavor of soybeans.Moreover,per 100 g powder contains 158 mg of isoflavone,12.15 g of protein and 5.72 g of fat.