Preparation and physicochemical characterization of soy isoflavone (SIF) nanoparticles by a liquid antisolvent precipitation method

Soy isoflavone (SIF) nanoparticles were prepared using dimethyl sulfoxide as a solvent and water as an antisolvent. Response surface methodology was used to analyse the influences of several process parameters on the mass median diameter (D50). The SIF concentration (20–40 mg/mL), volume ratio of antisolvent to solvent (5–7 mL/mL), stirring speed (800–1600 r/min), and reaction time (2–4 min) were optimized. The optimal conditions were determined to be a SIF concentration, volume ratio of antisolvent to solvent, stirring speed and reaction time of 29 mg/mL, 7 mL/mL, 1533 r/min and 3 min, respectively. Satisfactory D50 of SIF (101.24 ± 12.21 nm) were achieved. The processed and unprocessed SIFs were tested and characterized. By comparing the parameters, the chemical properties of the processed and unprocessed SIFs did not change, but the water dissolution rate of the prepared SIF nanoparticles was greatly enhanced.