Porous Starch-Based Material Prepared by Bioextrusion in the Presence of Zinc and Amylase-Magnesium Complex

摘要

A simple and sustainable preparation route for the creation of macropores in extruded starch was developed. Zinc ions were exogenously added into native corn starch, and then the Zn-modified starch was mixed with an enzyme (thermostable alpha-amylase)-magnesium complex as the biocatalyst prior to extrusion. The porous bioextrudates were characterized using SEM, XRD, FT-IR and water/oil absorption analyses. Results showed that the average pore numbers were increased (97 to 201 in the 160x SEM images), whereas the pore sizes (similar to 10-20 mu m) were almost unchanged with the amylase concentration increased from 0.04 to 0.12%. The crystallinities of the porous extrudates were decreased to 7.9-10.2% compared to that of the native counterpart (21.1%), but their structures all exhibited traces of rigidification. Furthermore, the water absorption capacities were greatly increased (similar to 450-500%) while the oil absorption capacities were slightly increased (similar to 40%). Overall, it extends the preparation and the potential application of porous starch in the field of materials.