Preparation and characterization of soy protein microspheres using amorphous calcium carbonate cores

Porous calcium carbonate (CaCO3) vaterite microparticles have been introduced a decade ago as sacrificial cores and becoming nowadays as one of the most popular templates to fabricate microcarriers. Herein we present a fabrication method of soy protein microspheres by templating on porous CaCO3 templates. The CaCO3 templates with a particle size (appx. 3–12 μm) were harvested with a yield of 47%. Soy proteins at varied concentrations from 0.05 to 0.25% (w/v) were applied to fabricate microspheres. Results showed that the highest coating efficiency of 87.9% was achieved at the protein concentration of 0.05%. And the highest protein loading ratio is 55.5 μg/mg. The protein coated CaCO3 microparticles has a spherical shape, however soy protein microspheres formed by dissolving the carbonate templates were wrinkled and partially collapsed. Results further indicated that the secondary structure of microspheres became more ordered with enhanced thermal stability. This study illustrates the feasibility to apply soy protein in the fabrication of microspheres based on calcium carbonate microparticles.