Germination may improve benefits of soybean seeds.
Brazilian scientists found that soybean germination can modify the total isoflavone content found in the legume and also some isoflavone components, especially daidzein and genistein, which may offer healthful benefits to humans.
The researchers evaluated the isoflavone content of whole and germinated soybeans of the low-protein cultivar BRS 133 and the high-protein cultivar BRS 258, which had been developed through the breeding program of Embrapa, the Brazilian Agricultural Research Corp. Soybeans seeds were cleaned with sodium hypochlorite for 10 minutes, and then rinsed three times with distilled water. The seeds were kept at room temperature for eight hours.
Germination was carried out in a germination chamber, and at the end of the experiment, the researchers froze the samples at -30 C. The investigators determined isoflavone levels by using high-performance liquid chromatography. They analyzed the impact of different germination times (12, 21, 42, 63 and 72 hours) and germination temperatures (18 C, 20 C, 25 C, 30 C and 32 C) using response surface methodology, a statistical technique.
The researchers observed the highest and lowest concentrations of total isoflavone content in cultivars BRS 133 and BRS 258, respectively. The optimal germination conditions--63 hours of germination time at 30 C for both cultivars--resulted in an increase of 26.76% in BRS 133 and 11.42% in BRS 258 of daidzein and genistein.
The hydrolysis of glucoside during the soaking and germination process (63 hours at 30 C) led to an increase of 212% and 312% in the amounts of genistein and daidzein, respectively, in BRS 133, and of 205% and 125% in genistein and daidzein levels, respectively, in BRS 258.
Further information. Yoon Kil Chang, Departamento de Tecnologia de Alimentos, Faculdade de Engenharia de Alimentos, Universidade Estadual de Campinas, Caixa Postal 6121, CEP 13083-970, Campinas, SP, Brazil; phone: 19 3521 4718; fax: -55 19 3521 4701; email: firstname.lastname@example.org.