A simple and green approach was developed to produce a novel nanogel via self-assembly of modified soy protein and dextran, to efficiently deliver riboflavin. First, modified soy protein was prepared by heating denaturation at 60 °C for 30 min or Alcalase hydrolysis for 40 min. Second, modified soy protein was mixed with dextran and ultrasonicated for 70 min so as to assemble nanogels. The modified soy protein-dextran nanogels were characterized by Fourier-transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) and ζ-potential studies to confirm the formation of NGs. Transmission electron microscopy (TEM) revealed the NGs to be spherical with core-shell structures, in the range of 32-40 nm size. The nanogels were stable against various environmental conditions. Furthermore, the particle size of the nanogels hardly changed with the incorporation of riboflavin. The encapsulation efficiency of nanogels was found to be up to 65.9% at a riboflavin concentration of 250 μg/mL. The nanogels exhibited a faster release in simulated intestine fluid (SIF) compared with simulated gastric fluid (SGF). From the results obtained it can be concluded that modified soy protein-dextran nanogels can be considered a promising carrier for drugs and other bioactive molecule delivery purposes.
Keywords: alcalase hydrolysis; dextran; heat denaturation; nanogels; self-assembly; soy protein; ultrasonication.