Kinetics of daidzin and genistin transformations and water absorption during soybean soaking at different temperatures

The kinetics of the isoflavone transformations (diadzin, diadzein, genistin and genistein) and moisture content in soaked soybeans were studied in the temperature range 30–85 °C. The evolution of the moisture was described by Peleg’s model, and a modified first order kinetic equation was used to predict the transformation profiles of different isoflavones in the soaked soybeans. The dependency, on temperature, of the kinetic parameter was modelled by the Arrhenius equation and empirical equations. The measured β-glucosidase activity at different temperatures justifies the experimental profiles of isoflavone conversion.