Microgels prepared from corn starch with an improved capacity for uptake and release of lysozyme

The combination of 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-oxidization and annealing was applied to modify structural properties of corn starch in order to obtain starch polymer microgels. Microgels were characterized by X-ray diffraction, ATR-FTIR and thermogravimetry analysis (TGA). The effects of microgels on the uptake and release of lysozyme were also analyzed. The formation of oxidized microgels through the crosslinking between starch molecules and sodium trimetaphosphate was confirmed by X-ray diffraction. The ATR-FTIR analysis suggested that TEMPO-oxidation results in the formation of carboxyl groups. TGA data indicated that oxidized-annealed microgels had less thermal stability than oxidized microgels. Furthermore, the oxidized-annealed microgels had an improved capacity for uptake and release of lysozyme. At this stage of the exploration, microgels prepared from corn starches by annealing and oxidation is simple and efficient.